Existing Walls – Slow Rise Foam
I have a 120 year old home with no insulation. Exterior wall construction is true 2 x 4 walls, with 3/4″ boards on exterior for sheathing covered by cedar shingles. Inside of studs are covered with 3/4″ T&G sheathing boards covered with plaster. Believe or not house is platform framed.
Initially I was leaning towards blowing in cellulose, however I have a son with asthma and I’m concerned about the cellulose dust. Manufacturers safety data sheets mention this may be an issue.
I was hesitant to consider pour in foam because I was afraid of blowing out the plaster walls. Since we opened up the walls and found hearty 3/4″ T&G lath I’m thinking that may not be an issue.
Does anybody have any experience with using SLOW RISE foam in an existing wall cavity. I would appreciate any information.
I would like to hire a contractor, but have been unable to find anyone willing to do existing walls with foam in the Chicago area. If you are in the area and would be willing to consider my project, email me directly at [email protected]
Thanks!
Replies
Go to the icynene website: http://www.icynene.com and use their dealer locator feature. I found 5 of their dealers within 50 miles of the 60601 ZIP.
The cellulose dust should only be a problem at the time of installation. Any places you find it along baseboards, etc. is a place to be airsealed as that's why the dust is there- a gap or hole that was costing you energy $$$$. I had a few customers (in the 1980's) with allergies/asthma to whom I brought a product sample into their house so they could live with it for a while. All were OK except one who had allergies to the older, smellier inks in newspapers.
The icynene foam has been given a clean bill of health after a few days of offgassing of initial chemicals. Since it will be enclosed in walls and not an open spray as in new construction, the offgassing may take a bit longer.
Yeah, I don't think that the cellulose dust is likely to be a problem for most asthmatics.
happy?
I talked to an icynene dealer and he said he wouldn't do the pour-fill stuff. He said the technology isn't there yet. He also said he had used it a bit before giving up on it. His claim: because the walls or sheetrock are generally not sealed to the floor, and the baseboards generally have slight gaps, the pour fill sometimes comes out the bottom of the wall and gets on the floor. You're not getting that off the floor easily.
I haven't used it myself but I figure if there own contractor won't do it, it can't be great. On the flip side, I'm optimistic about using this contractor since he sounds pretty unbiased.
As for a healthy alternative for foam - cotton is an insulation you could consider - essentially ground up denim jeans. Its pricey but R value is decent. Also Sheeps wool is an insulation - but very pricey.
If you pick up the november 2005 issue of "this old house" they've got a short piece on alternative "green" insulations. Far from technical, but an overview of what's out there.
Best of luck.
Bob,I was considering closed cell PU Foam, not open cell. Seems like closed cell with be better at keeping moisture out of the wall. Isn't open cell sponge-like?I guess I hadn't considered that the foam could come out gaps in the baseboard.I'm putting an addition on the house. They have pulled the original 1890's baseboards off the wall in a few spots. In these places the 3/4" T&G boards behind the plaster extend all the way down to the subfloor, and they look tight. The plaster also appears to extend all the way down to the subfloor. I sure though that there are some gaps along the base of the wall. I would hate to get foam squirting out onto my original stained woodwork.Another reason I'm concerned about using cellulose is that I have about a 2 foot high cavity between the bottom of my joists and the top of the stone foundation (see photo attached). If I blow in cellulose it will get down into this cavity and sit on top of the foundation wall. I'm afraid the cellulose will wick moisture out of the foundation wall and it will migrate up the wall. Now I'm thinking maybe the best solution would be a hybrid. Maybe I could drill holes from the basemeent through the brick between the joist and pour just enough foam into this cavity to cover the top of the foundation wall. Then I could dense pack cellulose into the cavity. What do you think about this approach??
I think I'm a little turned around. Sorry if I'm being obtuse, but which way is up in that photo?I don't know much about below/near grade stuff so I'm not going to try and give you any advice there other than to point to you the buildingscience.com site which may help out.THe cellulose will get everywhere. The previous owners of my house blew it into the walls and now whenever I do a renovation I find it in every gap - like when I pulled out the dishwasher!
That's the good thing about cellulose, it leads you to the worst airleaks and quite a few of the small ones also. I once blew quite a bit of it under the kitchen sink in one older house through a mouse hole
Bob,The photo I previously posted is the corner of my existing 1890s home with the sheathing removed from one side. The top is up.At the bottom you can see the triple sill plate of the wall framing resting on top of the stone foundation wall. The top of the foundation wall is only about 3" above grade.At the top of the photo you can the floor joists resting on a horizontal board nailed to the inside of the wall studs. Basically the walls of the house extend 2 feet below the floor joists. I'm not sure why they built it this way. I attached another photo showing how the existing walls extend almost all the way down to the ground.Back to the previous photo: On the left side you can see the brick wall. This brick wall was built directly on the inside of the stone foundation wall and it extends up higher than the stone foundation wall all the way to the bottom of the subfloor. The way this was built creates a horizontal cavity that is inaccessable from the basement, or from the outside without removing the original cedar shingle siding. This cavity is open to the stud bays. If I were to pump insulation into a stud bay it would fall to the bottom and start to fill this cavity. From what I understand cellulose should not be placed directly against a brick or stone wall.If anyone has any ideas how to insulate this space, fire away.
Nice looking house , Mike. That's the age of building I used to like to do! Little or no insulation in it , a few little oddities such as the overhanging corner at left, the upper bay, maybe some open floor cavities into the veranda porch entry ceiling. With airsealing, could usually get people 30-45% savings in a whole house retrofit. And usually get some nice "complaints"also- "It's too hot upstairs now". Got one of those last winter! (After running an insulation co. for 10 years, I still do 5-8 houses a year for some extra spare change. I'm in the home inspection/consulting field now. Got to finish a house this AM with a young realtor- his first rental investment property)
Is the brick wall supporting anything? I'm thinking about being able to break into it or even more radical- take it down to do the work I'd be doing if it were my place. That wall may have been built only to give a flush inner wall from the inner stone surface upward. It would also provide a bit of "insulation" from the infinished wood wall that we see.
With stone/rubblestone foundations and only a few inches clearance from grade, it is recommended to not enclose the sills fully with insulation and airsealing. Water may be wicking up very slowly through mortar/stone but drying with no damage since the wood is open to air. By enclosing the sills, rot might become a long term concern.
If the sills were made accessible, I would install 2 inches of high R foam in the walls between the studs up to the floor boards. Airseal any major cracks found at the sills but don't try to get everything at first as this may be the air that provides drying if wicking moisture is a potential problem.
Stuff the bottom of the upper walls above the installed foam with fiberglass or cut/fit foam to close off bottom of cavity. Blow upper walls with cellulose or fiberglass. (cellulose is my preferred product.)
Experienced,Thanks for your comments.You make some good points. As far as I know the brick between the joists does not support anything. I think however it does act as blocking to keep the joists vertical. I suppose I could remove the brick, insulate, then add some wood blocking.Now you got me thinking. If I remove the brick between the joists I would have access to the stub bays of the wall. Could I dense pack cellulose by pushing the tub up from the basement?We have a large open staircase in our house. The heat goes upstairs and the 2nd level is usually much warmer than the lower level. The front of the house faces North. The downstairs front rooms are very cold and drafty in the winter. My plan was to insulate the front first level walls only.Sounds like you know insulation. What is the best way to find a quality insulation contractor in my area? What questions should I ask to screen out the bad ones?
Mike:
I looked at the inner wall picture again. I think you could get 3" of foam board in between the studs and still have enough "breathing room" at the tripled mud sill/sill plate.
your quote: If I remove the brick between the joists I would have access to the stub bays of the wall. Could I dense pack cellulose by pushing the tube up from the basement?
Yes, you could do it like that. (I did some cathedral ceilings by shoving the hose to their tops from the kneewalls yesterday AM) With that much space/height at the bottom of the cavities, it would be one of the easier blows for a wall.
With the blowing pressure and air/material mix you should use for walls to prevent settling, a hose should be inserted to about 2 -3 feet from the top of the cavity. If the house is balloon framed or varies from platform framing, some of the material may get into the second floor joist cavities from the walls. This is not too bad as long as its not blowing 5-6 feet in from the walls but only 1-2 feet. This actually blocks a large air/heat loss area that you can't reasonably do (Price wise) with platform frames. The cellulose will stop quite a bit of the air leakage.
A problem may arise in the corners (or maybe other areas also)depending on how they braced the walls- you won't be able to blow above the bracing if its full 2x4 across the cavity. Another area you won't get is small cavities over the tops of windows.
Is your lower siding a narrow 3 inch exposure wood clapboard? It can be removed and re-installed where necessary to get above the bracing/windows. A bit of paint touch up and no one will know the difference. Also, I have done houses from the inside through the plaster using 1 inch holes. So there are options to get the whole wall.
You say there's no insulation in the house at all and you're only considering doing the lower walls now. Seriously consider doing the whole house!!! There'll be quick returns that makes your mutual funds investments look like they're standing still (unless you've been in oil & gas recently)
How to find a good insulator?
-Length of time in business (times like this can spawn a lot of newbies)
-Educate yourself, let them talk, ask a few good questions like: how many bags they might need to do the wall areas (have this calculated yourself; it'll take a minute or so for them to do); what density will they be blowing to to prevent settling? (About 2.5 -3 lbs/cu ft with new style cellulose); they should be mentioning or trying to sell you some airsealing if you talk to them about doing the whole house;
A book with lots of info called Keeping the Heat In is available from our "Natural Resources Canada". The site has a lot of other good info but I find it's a bit hard to navigate
http://oee.nrcan.gc.ca/keep_heat_in/index.cfm
-Ask for recent and past references
-Insurance, workman's compensation?
-Condition of trucks, equipment
-can you go and watch them at another site?
-how long have key personel been with them?
Nice looking home!I am a Corbond fanI am also an asthmatic.Therre are different things for diffeerent people as to what triggers their asthma. Both dust and some chemicals will trigger mine. You need to know what the trigger is in your family.I have only recently learned of the pour in fioam choices so I don't have experience with them yet.
But there is definitely a diff between the poly and the icy. The closed cell will repel water from each cell. If it is low density, there might be a small amt of moisture that can get trapped between cells. With the icy, the water can actualy enbter the cells themselves and totally destroy the insulative value if it becomes water logged. Corbond is a closed cell poly with borates added for protection against molds and insects.Cellulose dust does bother me. My impression is that if there is any openning that will let poured in foam leak out, the dust would also leak out. Another thing on the blown-in, it needs a path for air already in the stud cavity to escape or you will not get a dense bklown quality. too much air in there will cause a fluffed effect that will letthe cellulose settle later.An idea you could look into is chopped fibreglass, marketed as BIBBs ( blown-in blanket systems) there is a tiny amt of dust vs. cellulose, it is less effected by moisture, and r-value is equialent.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Your quote: "Another thing on the blown-in, it needs a path for air already in the stud cavity to escape or you will not get a dense bklown quality. too much air in there will cause a fluffed effect that will let the cellulose settle later."
You are obviously thinking in a theoretical manner as to what happens in a wall cavity. Theory in this case is not close to fact. These older wall cavities are sieves with no problems with air escape routes. Anyone else on these threads that has blown retrofit insulation can attest to that fact. That's why these houses test from 8-9 to 20+ ACH @ 50 pa pressure difference-lots and lots of holes. Not knowing your equipment, product and having inexperienced installers is why blown anything settles!!
Your quote: "Corbond is a closed cell poly with borates added for protection against molds and insects."
Cellulose has borax and boric acid added to stop mould growth/rot and also fight against insects.
Your quote: "My impression is that if there is any openning that will let poured in foam leak out, the dust would also leak out."
The dust may leak out at the installation. Those areas should be airsealed afterwords. I have used cellulose since 1977 and continuing dust problems have not been mentioned to me ever.
Your quote: "An idea you could look into is chopped fibreglass, marketed as BIBBs ( blown-in blanket systems) there is a tiny amt of dust vs. cellulose, it is less effected by moisture, and r-value is equialent."
BIBB's is an open wall system.
There area couple of papers (from the 1980's) I have somewhere in my files from the State of NY and federal DOE about moisture and cellulose where they state that cellulose handles condensation water better than fiberglass and , in fact, may have stopped damage in some cases. It can absorb the water and release it later when conditions change. The borax does not allow mould/rot. Fiberglass strands cannot absorb the water so in condenses on the strands and runs to the bottom of the cavity or to the ceiling where staining/mould/rot may occur as it does not have the borax.
Edited 11/19/2005 3:05 pm ET by experienced
I agree with much of what you say, the diferences coming in that I was refering to installation and you pointed to after the fact. The child should not be in the house while any of these are installed.I do disagree with you last point based on my own experiences here. The very fact that the FG will not absorb the mositure means that it drains through and out faster, while the cellulose holdsit long ebough to cause rot in the surronding lumber.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Your quote: "I do disagree with you last point based on my own experiences here. The very fact that the FG will not absorb the mositure means that it drains through and out faster, while the cellulose holdsit long ebough to cause rot in the surronding lumber."
Sounds like you don't like cellulose, an insulator through the centuries-straw, seaweed, sawdust, shavings, leaves, sphagnum moss, etc
The amount of water I (and the researchers) was talking about here was minor condensation with dripping, etc. If you've got more than that in any part of the house then you've got other serious internal moisture issues or rain/snow leakage. Don't look at the insulations, work on the serious moisture problems.
OR since you live on an island in a martime climate, the moisture that comes in through your attic venting may be part of the problem. One study on this phenomenon says that this constant moisture keeps the sheathing at close to saturation during the cooler seasons so that any condensed surface moisture must drip as the wood can/will not absorb even a little condensation. They suggest that it may be better to have less venting in maritime locations. This is an extension of Joe Lstiburek's teachings/books- that we have a number of climatic zones that each require a bit of tweaking for our more complicated house conditioning/insulation systems to work well. I'm in Nova Scotia and we've required rain screens for wood siding in our building codes for about 5 years
The dampish cellulose (its not all wet like a newspaper in a mudpuddle-the image most peole get) will impart some of its rot resistance to the surrounding wood since the borax is soluble.
You've gone beyond the scope of this thread and specific situation and gone to giving me advice about my jobs. I was not arguing either way, but offering several different options for the OP to consider, without pushing any one of them, just counting the pros and cons so he could decide. Personally, I don't care aas much for cellulose, but that is neither here nor there. I make the decision on each individual job what is best for that job based on the budget, design, access, etc. There is no one material that is best for all situations.The man had questions and I added to his knowledge base. I don't intend to argue the fine points all week. There is no gain in that.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Piffin,My 2 year old has bad asthma. We just had him tested for allergies this week. As luck would have it the only thing he tested positive to was cat and dog. As much as it breaks my heart I'm going to have to find a new home for my 10 year old lab, Lucky.Since my son is only 2 his ability to communicate is limited (mostly kicking, screaming tantrums). Is there a way to test him to see if he has a problem with the cellulose dust? I guess if there is any chance it could trigger his asthma we should not consider cellulose. Once it's in the wall there's no way to get it out. At that point we would have to move.I put to much time into renovating this house to move now!
Cellulose is not likely to be a reactive allergen to him. If he reacts to any dust, he would react to cellulose and vice verse. There is a diff between allergies and asthma to some degree. Asthma can be triggered by an allergen though. But if he is primarily allergic and not asthmatic, then the dog is the primary problem. But he can develope allergies to other sources over time as all of us can.both cellulose and FG are inert and unlikely to cause an allergic reaxtion and once they are in and stabilized, they will be done moving about to expose him. Foams could off-gas for a limited time. I have no trouble being around sprayed faom the next day in an open environ.Doubtless, as I said in an ealier post, he should not be in the house the day the insulation is installed, regardless which kind is chosen.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Get hold of some cellulose and the doc can test him for sensitivity to it. This can be as simple as using a bandage to hold some cellulose against his skin (generally the back) for about 24 hours.
If ignorance is bliss why aren't more people
happy?
Mike,Both the open-celled and the closed-cell varieties of polyurethane will abosorb water when exposed to it. The only foam I know of to absorb little to no water is XPS, and that cannot be foamed in the field, as far as I know of. What distinguishes open-celled from closed cell foam is the R-value, expansion factor, stiffness,expansion pressure, and the perm-rating, among other things. Open-celled foam is more permeable, more forgiving in closed-cavity installs, and it has a lower R-factor.I'm not a building science guy, so I cannot comment on whether your install is safe for any kind of foam product, though I will say that we used Corbond and Icynene throughout our house in failry similar environments. In general, I now like Corbond better (at least in our application) though Icynene is much easier to work with after the fact.As for pouring the stuff into Wall cavities, I could see where the hesitation comes in to play... polyurethane is a pain in the rear to remove, and it'll find any hole to squirt out of. That said, a throrough inspection by the installer should clear that mine-field.