Very big moisture problem -help! please!
Our house was built around 1910. It is balloon framed, limestone rubble foundation, masonry exterior. 15 or 20 years ago some idiot sprayed cellulose into the space between the lathe and plaster and the brick. The house is 3 stories including the “attic” space (which is mostly finished, although uninsulated in the roof space. The attic floor has had cellulose blown into it.
We just made some changes in the course of weatherproofing the house;
1. New high efficiency gas furnace which takes combustion air from outside and vents outside, but not through the chimney. (chimneys not being used at present and will be taken down next summer) Heating is forced air gas (not a change).
2. Sealed up lots of the cracks in the masonry from the outside (including holes in the foundation wall).
3. Had polyeurethane sprayed in the basement – just on the header joist and sealed to the stone foundation.
4. New vinyl windows everywhere.
5. Weatherstripped and insulated door from second floor to attic.
The house used to be too dry in the winter. Now we seem to be running 45 to 50% relative humidity in the living areas and stuff in the attic is getting sopping wet. Never mind the condensation on the insides of the windows on the first and second floors.
Our dehumidifier does not seem to be making much difference. Any suggestions to reducing the moisture content of the house significantly?
I was thinking… adding outside dry air to the cold air return system…
Replies
One more piece of information.
I live in Owen Sound, Ontario, Canada. Heating climate!
The humidity has been higher than usual all fall and just got really bad when the temperature hig -12 degrees Celcius (about 10 degrees Fahrenheit).
What Sphere said. Mostly likely source is in the basement.
What about exhaust fans in bathrooms and kitchens? do you have them, and where do they vent too? Many times HOs will add a vent fan durring a remodel, but don't take them through the roof, for fear of leaks. They can be a major problem with the temperatures you are experiencing. Get them vented outside the building envelope.
Dave
>>>What about exhaust fans in bathrooms and kitchens? do you have them, and where do they vent too? Many times HOs will add a vent fan durring a remodel, but don't take them through the roof, for fear of leaks. They can be a major problem with the temperatures you are experiencing. Get them vented outside the building envelope.There is no exhaust fan in the kitchen. Whenever we do alot of cooking I generally open up that window a bit.The bathroom vents into the soffit. I don't like this and will either fix this myself or have someone else do it. (I've got the stuff to fix it I just have to get my nerve up to go on the roof)Last year I didn't know what any of this stuff meant.
I am betting the basement is damp and wicking up into the house from below..try some "damp rid" and seee if it helps.
Also getting more airchanges would help.
Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations.
What is "damp rid"?Thank-you for replying.Last year I didn't know what any of this stuff meant.
Damp rid is an absorbant like silica gel in a container that is reuseable when it is redessicated.Ideally it would clue you in to how much moisture is present in your basement. It comes in a half gallon? size container and will reach saturation point over a period of time, might be a week, maybe a month.either way, it will show you where to focus your attn. I do not think it really is made to dehumidify the whole house (tho they market it as such) but certainly can spot treat say a room or such in a basement.
lemme see if I can find a link..
here ya go.. http://www.chemnet.com/show/damprid/ Spheramid Enterprises Architectural WoodworksRepairs, Remodeling, Restorations.
Edited 12/20/2004 3:37 pm ET by SPHERE
>>the attic has always been fairly cold I was not expecting a problem
It should be COLD,COLD!!
If it's not as cold as it used to be, why??
You need to move the warm moist air OUT of the attic. What is preventing it from doing so.
What is blocked or nor open?? Gable vents, windows, sophitt vents??
Windows, ya probably think I'm nuts. I lived in an old house that had to have the attic windows open in the winter. It was an attic though, not a living space. If you have converted your to any degree, then you most likely have a ventilation problem.
EricI Love A Hand That Meets My Own,
With A Hold That Causes Some Sensation.
>>> >>>it should be COLD,COLD!!a few nights ago I measured about -5 degrees Celcius (23 degrees Fahrenheit). The outside was probably 5 or 10 degrees colder.>>>If it's not as cold as it used to be, why??Actually I think it was as cold as it used to be. Perhaps a little colder. Two things I changed here were sealing up (insulate and weatherstrip) the interior door from the second floor to the attic and replacing the really leaky and half rotten windows with new vinyl windows. The heat vents to the attic were already blocked off.So, I guess reducing the heat to the attic (fixing the door) and reducing the ventilation (fixing the windows) cancelled out as far as temperature are concerned.>>>You need to move the warm moist air OUT of the attic. What is preventing it from doing so. >>>What is blocked or nor open?? Gable vents, windows, sophitt vents??I did open the windows for a while and put a fan in one of them. This seemed to help a fair bit.>>>Windows, ya probably think I'm nuts. I lived in an old house that had to have the attic windows open in the winter. It was an attic though, not a living space. If you have converted your to any degree, then you most likely have a ventilation problem.Maybe open windows are going to be part of the solution this winter. At least intermittently.I like your questions. Answering them is very persuasive.Last year I didn't know what any of this stuff meant.
Damp-rid is a chemical pellet that works pretty well for a closet or small area. The way you described it it would take a small dump truck load (:-), not the little quart containers they sell.
Your attic is improperly, un, or has blocked vent.
My guess.
Eric
I Love A Hand That Meets My Own,
With A Hold That Causes Some Sensation.
A few possibilities.
1. Is it a gas water heater? Where is it vented? Combustion produces a lot of moisture and an unvented/improperly vented water heater can cause interior moisture problems, (as well as kill you with carbon monoxide.)
2. Is the furnace actually vented outside (same issue - unlikely but you should check
Check those 2 things right away - tneither is likely as a cause of the problem but if they are the problem, they are also potrntial killers.
3. Note that sudden cold snaps (such we've had in OH) can cause "temporary" condensation problems
4. A very damp/wet basement will also result in condensation in attic areas. What shape is the basement/cellar in?
5. As someone noted, roof venting may well be an issue - older houses didn't need as much because of their draftiness - as you seal stuff up, the moisture heads up with the heated air and needs to be vented from the attic spaces.
But work first on reducing the amount of water/vapor getting into the house.
I don't know about yours, but my church isn't a hotel for the holy, it's a hospital for sinners
Sojourners: Christians for Justice and Peace
>>>1. Is it a gas water heater? Where is it vented? Combustion produces a lot of moisture and an unvented/improperly vented water heater can cause interior moisture problems, (as well as kill you with carbon monoxide.)>>>2. Is the furnace actually vented outside (same issue - unlikely but you should checkFurnace is new and vents outside. Combustion air comes from outside in another pipe. Hot water heater is electrical.>>>3. Note that sudden cold snaps (such we've had in OH) can cause "temporary" condensation problemsWe definately noticed this as a PROBLEM when the cold hit.>>>4. A very damp/wet basement will also result in condensation in attic areas. What shape is the basement/cellar in?The basement has a moderate water problem in the summer. That is why we have a dehumidifier. We never noticed any problem in the winter before.>>>5. As someone noted, roof venting may well be an issue - older houses didn't need as much because of their draftiness - as you seal stuff up, the moisture heads up with the heated air and needs to be vented from the attic spaces.The roof is not well vented, although, since the attic roof is not insulated and the attic has always been fairly cold I was not expecting a problem. However... I have one. I've got someone coming to look at that particular issue later on this week - or maybe it will end up being next week.Last year I didn't know what any of this stuff meant.
"The roof is not well vented, although, since the attic roof is not insulated and the attic has always been fairly cold I was not expecting a problem. However... I have one. I've got someone coming to look at that particular issue later on this week - or maybe it will end up being next week."
I'm going to bet that your attic plane is not well sealed. Even if the humidity in the living space is high, there should not be enough warm moist air escaping into the attic to make it wet up there. Bet you have air leaks into the attic space. Check the ductwork in particular. Venting is just a bandaid for poor air sealing.
Also, cellulose insulation should not be in contact with the masonry wall. You may be getting interior moisture stored up in the wall cavities.
>>>I'm going to bet that your attic plane is not well sealed. Even if the humidity in the living space is high, there should not be enough warm moist air escaping into the attic to make it wet up there. Bet you have air leaks into the attic space. Check the ductwork in particular. Venting is just a bandaid for poor air sealing.This makes sense to me considering all the drafts that I have been sealing up around baseboards. Of course, sealing everything at the envelope is much more efficient.Does anyone have any suggestions for what I would need to do to seal up the attic plane? The attic space has lathe and plaster walls and tongue and groove wood flooring (original to the house). In all the places I have seen there is cellulose blown in underneath the floorboards. This extends right out past the kneewall into the soffit area.>>>Also, cellulose insulation should not be in contact with the masonry wall. You may be getting interior moisture stored up in the wall cavities.This I know. It is very bad for the bricks as well. Annoys me and raises my blood pressure whenever I think about it too much. I certainly wasn't responsible for it. Around here people are telling me that it is too much trouble to get rid of.Last year I didn't know what any of this stuff meant.
"This makes sense to me considering all the drafts that I have been sealing up around baseboards. Of course, sealing everything at the envelope is much more efficient.
Does anyone have any suggestions for what I would need to do to seal up the attic plane? The attic space has lathe and plaster walls and tongue and groove wood flooring (original to the house). In all the places I have seen there is cellulose blown in underneath the floorboards. This extends right out past the kneewall into the soffit area."
Air sealing down low is not as effective as sealing the top of the envelope. The pressure at the top of the 'stack' is so great that incoming air to displace it will find a way to get in.
You will need to decide where you want your building envelope to end. The attic floor, or the attic ceiling.
The attic floor is easier in many ways, but your flooring complicates matters. Cellulose is better than fiberglass for blocking air, but is still not the best way to plug up big holes. Ideally you would rake the cellulose aside, and seal all the holes around pipes, wires, ducts. Block any open stud bays, chases, etc. Seal attic doors, hatches, etc.. Seal around chimney chases with sheet metal and silicone. Big holes like chimney chases and open stud bays are often the 'low hanging' fruit. Leaking ductwork is another. Added together, you may be talking about openings measuring many square feet. Like having an open window upstairs all winter.
Lots of good notions so far.
Question.....where are you running this dehumidfier?
Do you have an air exchanger?
Do you have and use kitchen and bath exhaust fans?
How many people live in the house?
Does everyone in the house take a shower every day?
Do you do a lot of cooking?
>>>Do you have an air exchanger?
>>>How many people live in the house?
>>>Does everyone in the house take a shower every day?
>>>Do you do a lot of cooking?No.
Usually 3, we have an extra 2 to 5 over the next week.
No.
Yes.Last year I didn't know what any of this stuff meant.
Check out an HRV ,or a ERV. for your situation. It can be incorporated into your forced air duct system, and provide 'make-up' air and also expel the moist air.
They are especially well put to use in the fluctuating Ontario climate , north or south parts, from Niagara Falls right up to Nipigon, and from the east to west (Ottawa to Windsor)
Vanee, venmar, Lifebreath are some good makes.
Check out Bardon for info, they are right in your area. (Springmount)
Does anyone have any idea how much an ERV or HRV system should cost me?Last year I didn't know what any of this stuff meant.
An ERV/HRV would start at roughly $1000 and could easily be twice that.
I think your answers are to:1) ensure proper attic ventilation. The attic temperature should be nearly the same as the outdoor temp.
2) Install a through the wall exhaust fan in the kitchen. The kitchen is called a moisture point load, and needs to be dealt with. Opening a window will have marginal effect, as the air is not really being forced out this opening and, to the contrary, more air is probably coming in, as controlled by the stack effect of air currents in your home as hot air rises.
3) I'm assuming that when you said the bath fans exhaust out the soffits you meant that the exhaust ducts did exit to the out of doors. If not fix this immediately. if they do vent to the exterior through the soffits, block any soffit vents that are within 2 feet of the bathroom exhaust fan outlets.
4) look for large points of leakage of heated air into the attic. It is difficult when loose fill insulation is installed. The attic entry hole would be the first place to look. Then around stack pipes, any chimneys or ducts that go up there from the living space. The list goes on and on.
You need to get this fixed soon, as there tends to be a "snowball effect": moisture condenses in the attic due to the cooling of warm air. Then insulation gets wet, allowing larger volumes of heat loss into the attic making the problem worse. Matt
>>>An ERV/HRV would start at roughly $1000 and could easily be twice that. >>>I think your answers are to:>>>1) ensure proper attic ventilation. The attic temperature should be nearly the same as the outdoor temp.I think you are right. I will be working on this. I hope that I can jury rig this one for the winter and make do with some of the other solutions. The plan is to totally rip out the plaster walls and ceilings in the summer. Move the house envelope right up to the ceiling of this space and spray with polyeurethane. Of course, the summer is when I have the money budgetted to do all this...>>>2) Install a through the wall exhaust fan in the kitchen. The kitchen is called a moisture point load, and needs to be dealt with. Opening a window will have marginal effect, as the air is not really being forced out this opening and, to the contrary, more air is probably coming in, as controlled by the stack effect of air currents in your home as hot air rises.This sounds like a good idea. I am sure that I can do that myself and that it will be fairly inexpensive.>>>3) I'm assuming that when you said the bath fans exhaust out the soffits you meant that the exhaust ducts did exit to the out of doors. If not fix this immediately. if they do vent to the exterior through the soffits, block any soffit vents that are within 2 feet of the bathroom exhaust fan outlets. r r - roof
r k - kneewall
r - - floorboards
r c - cellulose
k r
k V r
-----------ccccccc r w - stud wall framing for house
cccccccccccccccccccc b - masonry wall for house
w b V - bathroom vent exit
w bThe bathroom vents into the kneewall/soffit area as picured above. Notice how the only things sealing the gap at the top of the wall is loose fill cellulose insulation (there is some wood there too, but it does not seal). Also, notice that the loose fill insulation is also the only thing that stops cold air from getting underneath the floorboards in the attic space.I have a contractor coming to look things over. He asked me over the phone whether I had sprayed the top plate (i presume the gap with between the inner and outer walls with polyeurethane as well). Yes, there is no way that this is tight.At the least I can get the bathroom vent taken care of immediately. I have been working on this one for a while (figuring out how to do it).>>>4) look for large points of leakage of heated air into the attic. It is difficult when loose fill insulation is installed. The attic entry hole would be the first place to look. Then around stack pipes, any chimneys or ducts that go up there from the living space. The list goes on and on.I think your point about "large points of leakage" is amply demonstrated above. Thank-you.>>>You need to get this fixed soon, as there tends to be a "snowball effect": moisture condenses in the attic due to the cooling of warm air. Then insulation gets wet, allowing larger volumes of heat loss into the attic making the problem worse. Soon meaning a day or two? or a week or two?I can get the bathroom venting fixed up before christmas. The kitchen vent in the next week. I need to save some money to seal the attic.Last year I didn't know what any of this stuff meant.
Did you paint the entire interior of the house with latex paint recently? If you have lived there for several years, the source of the moisture or it's lack of getting out of the house is the likely problem. You've got a new furnace in a house that used to be too dry in the winter. Did they install a Humidifier onto that new unit? If so, adjust down the setting till you have comfort and minimal moisture problems.
A bit of moisture on the bottoms of insulated glass is common when the thermo drops way down. When air is limited from washing past the glass with blinds or new curtains, droplets of moisture will form. With old sash much of the moisture escaped the interior glass and formed on the storm windows as frost. Best of luck figuring this out.Remodeling Contractor just outside the Glass City.
Quittin' Time
Yeah, that's another question: What kind of windows do you have, and did you upgrade them recently?And, as Calvin says, it would be wise to double-check the new furnace to make sure it doesn't have a humidifier on it, or, if it does, that the unit is turned off for now. (You can turn it back on after the moisture problem is under control.)
The windows were just upgraded this fall. All vinyl windows.Last year I didn't know what any of this stuff meant.
It still seems to me like there must be some unusual source of moisture entering the house. Even with new windows and cellulose everywhere, a house that old shouldn't be that tight. If it is then, at very least, the window installers did an unusually good job.
My air sealing efforts included...
1. I went all over the outside walls and sealed cracks/holes and crumbling mortar all over. Particularly I did this on the above ground portion of the foundation wall.
2. Sprayed sill place with pollyeurethane, including filling any cavities from the inside into the foundation wall. the space around the basement windows was sealed as well.
3. I have put 2 layers of heavy clear vapour barrier over each basement window.
4. I have been through the whole house looking at doors and windows. I caulked the seams between the old window sills and the walls. It is amazing how many gaps show up here. The new windows are actually installed into the old sills and framing. I made sure that they were well sealed around. The weatherstripping on all doors I replaced with up to date really good weatherstripping and I also adjusted the locking hardware on the front door so that it actually worked properly with the weatherstripping and the door frame. I also removed the door trim and sealed up the jams.
5. I have sealed around the baseboards on all outside walls. In some cases I just caulked between the baseboards and the floor, in other cases I removed the baseboards and foamed heavily in the gap between the floor and the wall. Amazing how big those gaps are.
6. I sealed up the bottom of all the "chimneys" that I found in the basement. That would be spaces that go straight up to the attic level. Places where wires and ducts go up. In some cases these places were also insulated.
The energy auditor I had in in the spring told me it would be almost impossible to seal a house this old too tight. I just read alot on the subject including an excellent article on the FineHomebuilding Site on air sealing a house.Last year I didn't know what any of this stuff meant.
No humidifier. The heating contractor suggested that we wait and seen how the house behaved with the new furnace before getting one of those. Good suggestion.Last year I didn't know what any of this stuff meant.
The answer to this problem is actually quite simple, cellulose sprayed against masonry notwithstanding (completely separate problem from indoor humidity issue).
The house is very tight. You need to ventilate this house. Your options are:
1. HRV or ERV (expensive to install, inexpensive to run)
2. Outside air duct to the return of your furnace and exhaust fans in bathroom and kitchen. One of the upper bath fans should have a dehumidistat. (cheap to install, expensive to run).
I routinely do blower door tests on houses this old in Canada where they are tight enough to require significant amounts of ventilation. Houses south of the border tend to be much, much much leakier than canadian houses, even old ones like this.
Changing the windows have tightened the thermal envelope.
Caulking, etc, has tightened the thermal envelope.
Changing to a condensing furnace and an electric hot water tank has eliminated all chimneys and consequently has dramatically tightened the thermal envelope (read this as a 5-7 inch hole in the house eliminated). This alone can push the air change per hour rate of a house over the edge. I often see houses with new condensing furnaces and elecric hot water tanks develop high humidity problems within a few days of install.
If you want to continue sealing the envelope (which is a good thing) you need to provide some sort of a ventilation sytem to ensure indoor air quality and humidity control. In a climate as cold as ours and houses as tight as we build them, we do not need moisture sources beyond normal living, breathing, cooking, and bathing to create the potential for condensation on surfaces. If you do not do this very soon you can expect more serious problems or damage.
There is no such thing as a house that is too tight.
There is such a thing as a house that is underventilated....
Gio
A good 150-200 cfm unit may run $1200, plus maybe another $300 to $500 for material. it depends where you live.
It also depends on what type duct system you have now.
I thought I would drop a line to everyone about how my big moisture problem turned out.I had a heating contractor in to replace my bathroom fan with a much higher output unit. Also, he vented it completely outside the house the way it is supposed to be.Now, with the fan running for a few hours every day plus whenever the shower or bath is being used... the problem seems to have gone away.Over the next few months I will likely install proper ventilation for my kitchen as well. When I go and completely insulate and seal my attic at the roof this summer the house will be even tighter than it is now.Thank-you for all your help and advice. I really appreciate it!Last year I didn't know what any of this stuff meant.
Its obvious, she plugged up the weep holes for the brick. insulation has become moist during the warmer months and now its being heated from inside and moisture is loading up near the colder areas (technically "dryer" air, relative humidity wise).
One shower a day is enough to produce this problem indoors without having ever been properly vented previously. The kitchen ventillation is something you should also do immediately.
You need to get those weep holes free again, and now you have a mush in the walls. I agree you must remove now before you cause a mold/mildew jungle to start eating your framing members.
Good Luck.
Edited 3/6/2005 6:33 pm ET by Ell
I don't think you can make a house that old that tight, at least not without ripping out the walls and installing poly everywhere. I suspect that you're getting moisture in from somewhere. (Plus, it sounds like the attic is insufficiently vented.)
The moisture could be coming from the ground, from a water leak somewhere in or near the house, or from improper venting of a combustion appliance. As has been said, if it's an improperly vented combustion appliance then it's a life safety issue, so you need to eliminate that possibility first.
Get up in the attic and lay a 4' x4'-8' piece of visqueen parallel to the joists completely covering at least one bay and lapping the bays on each side.
The next day, after cooking a big stew, or a couple of showers, trot back up there and see if there is any condensation on the bottom of the visqueen.
If there is, then you need to air seal the entire ceiling between the conditioned spaces and the attic.
If you have any fixtures penetrating the upper ceiling, you can count on moisture flowing thru them.
Because of the "stack effect", air and moisture will flow from bottom to top in a structure. It will flow thru every possible path. It will flow sideways in order to get someplace it can go upwards.
If you can find a way to string a thread from the source (bath/basement/kitchen) to the attic, you will have flow.
SamT
short note, if you do find that you need to add venting to fans, dont exhaust in the soffit, use a roof exhaust or if leaking scares you, vent out gable end. Try to find the shortest distance possible to gable, if you have a long run of hose, make sure the fans that are vented are capable of pushing the air. Reason: there isnt much point in pushing the moisture outside if it returns in other venting on the house. This has caused many people to have mold /mildew problems in the attic.
If you have a dirt basement, even a moisture barrier and a broom dragged rat slab would help immensely to hold back vapor and radon. If you are willing to do it yourself it can be pretty inexpensive.
>>>If you have a dirt basement, even a moisture barrier and a broom dragged rat slab would help immensely to hold back vapor and radon. If you are willing to do it yourself it can be pretty inexpensive.The basement walls are parging over limestone rubble. The parging is not in excellent condition most places.The floor is concrete slab.Last year I didn't know what any of this stuff meant.
I was hoping not to have to completely redo the attic until this summer. At that point we are going to completely seal it at the roof. Install all of the proper roof vents. Polyeurethane mostly.The attic floor is actually a usable floor. This space is mostly finished. In the old days I suspect that it was actually used as living space.Last year I didn't know what any of this stuff meant.
"... some idiot sprayed cellulose into the space between the lathe and plaster and the brick."
That sounds like a good thing to me.
"The house used to be too dry in the winter."
There used to be a frequent poster here who would often say "A dry house is a leaky house".
You fixed lots of leaks. Now you are not dry.
"I was thinking... adding outside dry air to the cold air return system..."
You could do that, but you just spent a bunch of money to keep outside dry air out. Now you are going to spend more money to bring it in??
Good points above about exhaust fans and checking that combustion appliances are venting to the outdoors.
Sealing the attic floor is a good idea, but it doesn't solve the humidity problem in the living space.
Where are you running the dehumifier???
What does the basement look like??
The solution is in the basement. You need to take steps to stop water vapor from entering in the basement.
Rich Beckman
Another day, another tool.
I have been running the dehumidifier on the first floor. It is not picking up much water. Less than two litres in 24 hours.Right now I tried moving it to another spot with more air circulation (it was in the kitchen).Last year I didn't know what any of this stuff meant.
Put the dehumidifier in the basement and see how much water you get out of it there. If you had a crawlspace instead of a basement, then I have a good understanding of how to seal that up to cut down on the humidity in the living area. But I am not sure how you would go about "sealing" up a basement.I don't recall much discussion here about sealing (filling opennings to prevent the flow of air) the basement ceiling to prevent the humidity in the basement from entering the living area. But maybe that would help. Definitely examine any HVAC duct that runs in the basement for leaks. The seams should be sealed with mastic, not with tape.What people are saying about sealing the attic floor is also a good thing to do. It will do a lot to alleviate the water in the attic, not to mention lower you heating bills.After you've successfully dried out the living areas and sealed the attic floor, if you are still getting condensation in the attic, you should then address the attic venting.Edit: Matt's points in message #20 are good. Also, I forgot to mention that if the basement humidity is high it might help to check the exterior of the house and make sure the ground is sloped away from the house and that the downspouts are removing the water further away than just the elbow at the bottom of the spout.Rich BeckmanAnother day, another tool.
Edited 12/20/2004 9:35 pm ET by Rich Beckman
The problem is too much moisture in your house.
You didn't have the problem last year.
Where is the moisture coming from ?
My bet is from something inside.
Is it new and different moisture than last year ?
Doubtful.
What is different now compared to last year ?
New furnace.
Nice, but by itself, not necessarily a source of moisture, unless.....
it has a new humidifier we don't know about, or
it is running incorrectly and water vapor from combustion is staying in the house rather than exiting the tailpipe.
You have a masonry structure that was previously drafty at cracks and windows.
Thanks to you, it is now nice and tight. (good thing)
As you go from summer to winter, do you notice the basement dehumidifier needing to be emptied less ?
Where does your clothes dryer vent ? This is often an issue.
When you say your bathroom fan vents into the soffit, what exactly does that mean ?
Is it a vinyl flex hose pointed at perforated soffit ?
I'm with Rich on this that HRV's are nice but not for what you need. You need to either stop the creation of the moisture or better vent it. Once you have the moisture problem resolved, then you can consider bringing fresh air into the house but not for moisture control.
carpenter in transition
>>>The problem is too much moisture in your house.
>>>You didn't have the problem last year.
>>>Where is the moisture coming from ?
>>>My bet is from something inside.
>>>Is it new and different moisture than last year ?
>>>Doubtful.
>>>What is different now compared to last year ?
>>>New furnace.
>>>Nice, but by itself, not necessarily a source of moisture, unless.....
>>> it has a new humidifier we don't know about, or
>>> it is running incorrectly and water vapor from combustion is staying in the house rather than exiting the tailpipe.The only difference with the furnace (i can see) is that it is no longer using interior air for combustion. That comes directly from outside now. Of course this means that the furnace is no longer helping to suck air into the house through cracks in the walls... (see next point below)>>>You have a masonry structure that was previously drafty at cracks and windows.
>>>Thanks to you, it is now nice and tight. (good thing)There were many cracks in the brickwork, most of which are now sealed up. Also, there were "cracks" in the above ground portion of the limestone rubble foundation wall. I use crack fairly loosely here since some of them my cat could have gotten through. In addition, the sill plate area of the house is now completely sealed up with 3" of polyeurethane. Any cavities into the outer wall from inside have been filled completely with polyeurethane(with regard for expansion of the foam in a cavity). This is very tight now.>>>As you go from summer to winter, do you notice the basement dehumidifier needing to be emptied less ?The humidifier was turned off in late August as soon as the weather stopped being to humid and rainy.>>>Where does your clothes dryer vent ? This is often an issue.I already fixed this one. Vented outside.>>>When you say your bathroom fan vents into the soffit, what exactly does that mean ?I exlained this in a previous post with a diagram that did not work very well. Basically it vents into an area underneath the roof plane. The "floor" of this area looks like a typical unfinished attic with uninsulated plaster walls on the inside, and loose cellulose between the floor joists. Of course there is no blocking between the joists where the plaster wall is located and there is no sealing between the masonry wall and the balloon framed stud wall.>>>Is it a vinyl flex hose pointed at perforated soffit ?Yes. It is a vinyl flex hose. Currently it is pointed at a small gap in the structure. This is an improvement that I just made a few nights ago. Previously it made no effort to get the moisture out of the space. This is a priority.>>>I'm with Rich on this that HRV's are nice but not for what you need. You need to either stop the creation of the moisture or better vent it. Once you have the moisture problem resolved, then you can consider bringing fresh air into the house but not for moisture control.The picture is fairly clear to me right now. I stopped outside air form getting into the house both by tightening it up and by replacing the furnace with one that takes its combustion air from the outside (less negative pressure). Now I need to provide some more effective ways for moisture to get out of the house at the appropriate places, stop it from getting to inappropriate places (the attic), provide adequate venting in the attic, and possibly if all else fails add some ventilation to the whole house.Last year I didn't know what any of this stuff meant.
Bathroom vent fan
I would recommend running 4" pipe (not flex) through the roof or a side wall. Venting throught the soffit is not recommended because the moist air will come back up through the soffit.
carpenter in transition
Not true.
The velocity of the fan's force will expel the air far enough away from the soffit to ever come directly back into the soffit.
sorry Hube, but the black mold growth which I see on a regular basis on the bottom of the roof sheathing directly surrounding the vent location is evidence enough for me that this is not a good practice.
the 60 cfm fans which these builders so commonly use aren't pushing much harder than a fart by the time they get through 15 feet of flex.
carpenter in transition
I know you don't want to hear this but if "stuff in the attic is getting sopping wet" you have a serious problem. Look in the yellow pages and find someone who is listed under 'energy consultants and management'. Also sometimes government housing corporations have a team of professionals, call them and get them to have a look, do it soon.
Hi,
Joe Lstiburek http://www.buildingscience.com/about/who/default.htm is an expert on this sort of thing. He’s got an entire website dedicated to building science.
As a member in good standing on the BSA Building Envelope Committee and speaker at “Build Boston”, “Rainscreen Applications and developments” with Dick Kelleher, I can tell you straight away, it’s the cellulose in the cavity between the masonry and plaster.
“Idiot” doesn’t quite make up for the costs you’ll incur to remove it. Sorry.
Rex,
What is the difference between the cellulose insulation installation in this guy's house compared to how we are doing today ?
A layer of plywood ?
If the house is truly balloon framed as stated then it is sheathed with 1x12 boards.
Now what is the difference ?
A layer of 100 year old felt on the walls ?
I doubt the home is balloon framed. From its age, I think more likely it is double wythe brick with furring on the inside.
Either way, the problem is definitely not the cells in the walls. They weren't causing any problems last year before he made the noted changes.
The problem is the creation of the water vapor and the improper means of venting it at the 3rd floor and roof area.
carpenter in transition
Hi Tim,
“What is the difference between the cellulose insulation installation in this guy's house compared to how we are doing today ?”
The author describes a condition where cellulose insulation has been introduced in the cavity between a brick veneer and the back-up wall. One of the latest issues of FB has an article on this very thing actually, and I direct you to it in order to avoid reiteration.
In summary, the cavity between a veneer and the backup wall must remain unobstructed to allow airflow and gravity to counteract the pressure drop between the warm interior surfaces and the cold exterior surfaces. i.e., ideally, moisture will condensate/collect on the cold plane/barrier and drain out via weeps in the veneer.
If the path between the veneer and the back-up plane is interrupted by something like absorptive cellulose, it’s like living in house surrounded by a sponge.
Rex is getting to the issue I was about ready to address. I spent around 30 years in Chicago, and that means, if one lived in pre WW II buildings like we preferred, they were mostly brick. typically, solid brick walls, with floor/ceiling/roof joists set in sockets in the walls. Then 1 X 2 furring, then wood lath, then the 3 coats of plaster. The furring left enough air space that 100-year-old wood lath and plaster walls are still in good shape.
However, there were exceptions. A 14-story condo building we lived in (built in 1927) had reinforced concrete frame, and several layers of common Chicago brick for exterior walls, then some moron troweled plaster directly on the inside of (in our 5th floor apartment) 3 layers of brick. Tuckpointing (i.e., mortar joints between the bricks) was in bad shape there, so a LOT of rain/snow came through the wall, and then caused the plaster to come off inside. Mold, too. It's been 30 years now, but I think I remeber I finally cured it with cement-based plaster on the inside, and getting the mortar joints outside tuck-pointed.
Since then, I've come to know a number of masonry experts, especially brick. You should definitely get rid of the cellulose in the walls, even if it means ripping lath and plaster off the inside, if you can possibly afford it. Solid brick walls, brick veneer walls, they all will absorb moisture unless you have (rare) glazed brick, and waterproof mortar in excellent condition. I hope when you sealed all those cracks in the brick, you left the weep holes unobstructed. Should be over all doors, all windows, and at the bottom of the brick wall. Those are crucial to draining moisture out of the wall cavaties. If they are plugged, the moisture will soak up the cellulose, and possibly go up to the attic.
There MUST be an air space between the brick, and whatever your interior wall is. If you want to insulate, fine, but leave that air space next to the brick.
I hope your vinyl windows are small. I installed a 5' tall one about 4' wide, excellent Canadian design, but the thing was simply too large. Vinyl expands and contracts FAR more than other window sash material, and consequently, virtually impossible to have them weather-tight at all temperatures. Replaced with vinyl-clad, solid wood sash, Andersens for all 44 windows in our Chicago 4-flat, and much better than the few vinyl only windows we had used to replace drafty original wood sashes.
When you replaced the windows, were there sash-weights for the old wood windows? If so, it's crucial to fill those enormous cavaties with some sort of insulation.
There have been many excellent suggestions, so I probably haven't added much.
Did price a heat exchanger which would bring in fresh air from outside, transfer most of the heat from the exhausting air to the fresh air, and also a HEPA filter. $2,000 to add to my forced air furnace. We took a pass. Others are right; check that combustion gases are well out of the house, vent the bath and kitchen.
Our Chicago 4-flat has solid brick foundation, 100 years old, but a LOT of effluorescence in the basement for the portion of the walls below ground level, even tho built on pure sand. (Close to Lake Michigan, and that area was part of the lake 150 years ago.) Had a good masonry/brick contractor spend a winter installing metal lath as needed, and parging with a heavy layer of mortar with acrylic binder and fiberglass fibers to reinforce. After 5 years, there are several places where the parging has popped off. Obviously, should have sealed the outside, but not too practical with extensive foundation plantings, sidewalks, etc. next to walls.
My Chicago church also had a limestone foundation, and in the 1980's, excavated the crawl space, and created usable basement space. Took a lot of mortar to seal the joints in the limestone foundation, and of course, even though built on sand in 1912, the building still seeped some water to the interior, so I would guess your limestone foundation is still bringing some moisture in, in spite of all your sealing. Probably coming through the stone itself to some extent.
Good luck. Goose
>>>Since then, I've come to know a number of masonry experts, especially brick. You should definitely get rid of the cellulose in the walls, even if it means ripping lath and plaster off the inside, if you can possibly afford it. Solid brick walls, brick veneer walls, they all will absorb moisture unless you have (rare) glazed brick, and waterproof mortar in excellent condition. I hope when you sealed all those cracks in the brick, you left the weep holes unobstructed. Should be over all doors, all windows, and at the bottom of the brick wall. Those are crucial to draining moisture out of the wall cavaties. If they are plugged, the moisture will soak up the cellulose, and possibly go up to the attic.>>>There MUST be an air space between the brick, and whatever your interior wall is. If you want to insulate, fine, but leave that air space next to the brick.I dug through the middle of a wall and did find somewood sheathing betwee the plaster and the brick. I guess the only place I have ever looked before was around a doorway or a window. Nothing there.>>>I hope your vinyl windows are small. I installed a 5' tall one about 4' wide, excellent Canadian design, but the thing was simply too large. Vinyl expands and contracts FAR more than other window sash material, and consequently, virtually impossible to have them weather-tight at all temperatures. Replaced with vinyl-clad, solid wood sash, Andersens for all 44 windows in our Chicago 4-flat, and much better than the few vinyl only windows we had used to replace drafty original wood sashes.The windows we chose were all to fill the old spaces. Most of them are about 2' by 4' to 5'. One of them is about 5' x 5'. The idea was to change the look of the house as little as possible. However the windows do have a lifetime warranty and the gentleman who installed them has been around for years and tells me he has only had to go back to one customer for warranty work. So, we will see.>>>When you replaced the windows, were there sash-weights for the old wood windows? If so, it's crucial to fill those enormous cavaties with some sort of insulation.Since the window were installed into the existing sill structure I do not know. That looks like a good project for the next year. Rip off the trim and look behind it.>>>Obviously, should have sealed the outside, but not too practical with extensive foundation plantings, sidewalks, etc. next to walls.I here you with this one. In my case the space between the houses is less than two feet on one side and about 4 feet on the other. My plan for this summer is to dig down about 6" on both sides of the house and from our house right to the neighbours. I will then put down a layer of some kind of water proofing membrane which will take groundwater right to the back of the houses. At that point I can channel the water into a proper drainage pipe and disperse it through out our back yard with a french drain (the back yards all have hills in the middle of them which go down steeply about 4'. I have some similar plans for the front of the house as well.I don't see a way that I can practically trench right down to the footings and put in proper drainage membranes etc... Not with just a few feet of clearance. I can stop surface water though!>>>My Chicago church also had a limestone foundation, and in the 1980's, excavated the crawl space, and created usable basement space. Took a lot of mortar to seal the joints in the limestone foundation, and of course, even though built on sand in 1912, the building still seeped some water to the interior, so I would guess your limestone foundation is still bringing some moisture in, in spite of all your sealing. Probably coming through the stone itself to some extent.This is very typical of rubble foundations. There are some things to block that off completely, but they apply more specifically to concrete or block foundations. The involve insulating the basement wall and the floor with rigid foam and allowing space between the foam and the floor/wall for the system to drain. Unfortunately, my understanding is that insulating a rubble foundation and so allowing it to freeze is an invitation to have a crumbling foundation.You can find the insulation system I describe at http://www.buildingscience.com, although it never mentions a rubble foundation.Last year I didn't know what any of this stuff meant.
Tim Kline is right about the soffit exhaust, I mentioned this on #12 of this thread. There is a ton of information showing the mold and mildew damage of soffit venting, a lot of times the HO has to rip the sheathing, roof, and some rafters out to control the damage of the damp air regenerating the house and going up the roof on the inside.
Creates a cone pattern across the sheathing like a shotgun blast.
Edited 12/22/2004 12:46 pm ET by zendo
My plan for this summer is to dig down about 6" on both sides of the house and from our house right to the neighbours. I will then put down a layer of some kind of water proofing membrane which will take groundwater right to the back of the houses. At that point I can channel the water into a proper drainage pipe and disperse it through out our back yard with a french drain (the back yards all have hills in the middle of them which go down steeply about 4'. I have some similar plans for the front of the house as well.
I don't see a way that I can practically trench right down to the footings and put in proper drainage membranes etc... Not with just a few feet of clearance. I can stop surface water though!
The main thing is to make sure that the ground slopes away from the foundation and into a swale of sorts, where it can run away. If the swale is really narrow, you can dig up the area and place a piece of perforated plastic tile under, drained to "daylight".
Sounds like there are some more good ideas for helping solve the moisture problem.
The perforated drain pipe idea you mention, reminds me of another problem I had on the 50' X 107' lot our 4-flat sits on. To give readers an idea of how buildings cover it, front lot line is at the back edge of the public sidewalk. Front steps take up at least 15' of the width for the first 10' of lot depth. Then, the tall 2-story building is the same 50' width as the lot for the next 30', angling to about 25' wide for 20', and then bumping out to 30' wide for the back porches -- all centered on the width of the lot.
On the remaining 47' of lot, there is a 22' X 25' double garage, and an irregularly shaped patio built with compacted stone, then precast concrete pavers, probably 200 square feet. Also, a back concrete walk, slab to park garbage carts on, back stairs, and concrete basement stairs, which leaves very little permeable soil, but fortunately, pure sand subsoil.
A low spot in the back yard near the back stairs always left a big puddle when it thawed on the surface on warm winter days, and of course, froze into a large patch of ice when it got cold at night, often endangering the many users of the popular back stairs.
A few summers ago, I excavated the path around to the east side of the apartment building, to the side yard there (garage is on the west side of the back end of the lot, as is the sidewalk leading to the back stairs) down a few feet, and sloped the trench away from the low spot. I filled in several inches of pea gravel, water permeable membrane to keep dirt out, and wrapped it around a 10' length of perforated PVC, 4" in diameter, then covered with pea gravel to ground level. I added another solid 10' length, draining away further into the east side yard, and then left the end open, but wrapped so dirt couldn't get into the pipe, but water could exit. Crude version of the suggested french drain.
In the few years since, the pea gravel seems to drain without freezing, and seldom any puddling in the low place.
Does sound like your building is tight to the lot lines similar to my 4-flat's situation. Might discuss with your neighbor(s) about either widening the excavation onto his(their) lot(s) so you can reach the foundation, or see if it might be possible to shore the excavation so you can dig deep enough on your own property to reach the footings.
City of Chicago is supposed to do new curb and sidewalk along one of the 30' long sidewalls of our building, and when they do, I hope to arrange with them to excavate 4' down to our footings, and fully waterproof at least that brick basement wall on the outside. I could have done a 10' wide section of the front while installing new copper water service a few years ago, and we had that front yard dug up anyway, but it was December, and unfortunately, did not think of it.
You might discuss with some concrete contractors who do basements and foundations in your area, and see what they think of pouring concrete for several inches of additional wall thickness outside your limestone rubble, and sloping the top of it into the limestone (so rain doesn't splatter on the siding, or seep into the limestone). Should help seal the foundation, especially if the outside of the concrete is waterproofed. Probably would not be cheap, however.
If your window trim boards are 4" or more wide, quite likely they cover sash pockets. If there were pulleys in the top of the jambs on each side, you definitely had sash weights at some time, and there would be space for the weights behind the trim boards. Some reader experienced with old Canadian houses might have more specific knowledge and thoughts on the subject. I'm speaking strictly from Chicago old building experience.
Good luck! Goose
>>>What is the difference between the cellulose insulation installation in this guy's house compared to how we are doing today ?
>>>A layer of plywood ?
>>>If the house is truly balloon framed as stated then it is sheathed with 1x12 boards.Based on this last comment I did some digging in the middle of an outside wall. I seem to have detected some kind of wood sheathing; and the cellulose is between the plaster and the sheathing. In the past the only place I had looked right through the wall was at a doorway or window opening. The sheathing obviously was not built right up to those openings. This makes me feel a lot better about the future of my walls.>>>Now what is the difference ?
>>>A layer of 100 year old felt on the walls ?
>>>I doubt the home is balloon framed. From its age, I think more likely it is double wythe brick with furring on the inside.Only one layer of brick.>>>Either way, the problem is definitely not the cells in the walls. They weren't causing any problems last year before he made the noted changes.
>>>The problem is the creation of the water vapor and the improper means of venting it at the 3rd floor and roof area.And this is how I am approaching the problemLast year I didn't know what any of this stuff meant.
I have actually read alot of what is posted at http://www.buildingscience.org and http://www.brickinfo.org and a whole bunch of research sites both in canada and the united states. That is why I was annoyed about the cellulose against brick.Based on some other people's comments I just went for a dig into the middle of a wall to see how it was constructed. Apparently I do have some kind of sheathing on the outside of the studs. In the past the only place I had ever dug right through the wall was around a door or a window, where there wasn't anything. Now I feel a lot better about the walls.I measured the relative humidity of the basement at 55% yesterday and last night I moved the dehumidifier down there. I bet that will help alot.The bathroom vent will be done today or tomorrow and the kitchen vent will be started and finished by the mid part of January.I also just pried off a floor board in the attic and got a good feel of the cellulose underneath. It has a very slight damp feel but is not soaking wet or even moderately wet(this was at one of the worst spots in the attic). I seem to have lucked out on this.The last couple of days I have left the windows in the attic open with a fan blowing out one of them to promote air circulation.I have an energy auditor coming in tomorrow to look things over and a contractor early next week who specializes in dealing with old houses.This should be fun!?!Thank-you for your help so far, I really appreciate it.Doug HopkinsLast year I didn't know what any of this stuff meant.