First to preface this discussion, When I signed my life away and purchased a 110 yr old house, I had grandiose ideas about how I would put my college edumacation to work and totally rework, massage, renovate and make it over. Then the reality of 60 hr work weeks and thin finances set in.
I have a set of plans to demo the roof and add a second story, doubling the size of my small single story home in Milwaukee. Got the bids and started initial financing arrangements…. then my wife lost her job and we found out shortly thereafter that she is expecting our first child in November. So the major renovation is on hold indefinitely and over the last couple of months I’ve come to the conclusion that recent events are in fact a blessing in disguise (in more than one way!)
…So we’ve been talking about how we can possibly get by living in a cramped 2 bedroom with few closets and having a poorly designed layout.
Ima in the initial stages of planning a 3-400 sq foot first floor addition to my 1100 sq ft house and contemplating the foundation. DW and and I first agreed upon simple (traditional) foundation walls w/ no basement, no crawl space. After mulling it over for a few weeks, I am leaning more towards having a full height basement after all. The first floor height is roughly 3 ft above grade and footings are reqd to 4 ft below grade. The extra 3-4 feet of excavation and foundation wall would not add very much additional expense. I’ve been weighing the options of poured vs ICF vs precast panels and am leaning towards the two later options for different reasons.
Heres the rub: The current basement, 110 yr old cream city brick, has only 6.5-7 ft ceilings and we a re constantly battling water seepage (sometimes major pooling) from the bottom of the foundation walls. Proper grading has helped a lot but there are no drain tiles and no sump pump. If there ever were drain tiles they are surely clogged, collapsed. The proposed addition would be 12-18″ lower than the current, how do I keep water from becoming an issue? even if I still have some infiltration in the old part, it will never be living space as the ceiling height is soo low. I think further grading and increasing the roof overhangs (also part of the renovation) may actually solve the problem.
I’ll leave it at that… don’t want to throw too many issues into one post. Please comment/ discus
Edited 6/5/2007 2:56 pm ET by joemilw
Replies
Hi Joe,
Welcome to Breaktime, and congrats on the coming baby!
First, why will the new foundation be lower than the existing?
I may be missing something in your post (I usually am) - but if your new foundation is lower than your existing, seems like you would want to install drain tiles before you backfill, probably hooked up to a sump if your lot isn't suited to draining towards daylight.
As long as the backhoe is on site, you might consider trenching around the house and replacing the drain tiles elsewhere.
Justin Fink - FHB Editorial
Your Friendly Neighborhood Remodelerator
The foundation would be lower or at least the finish grade of the basment floor would be lower so that the 3-400 sq ft of new addition basment would be usable [living space] whereas the existing is not. (due to low ceiling height and water). I envision a couple of steps down into a nice cozy rec room/ den/ office.
I suppose digging out and waterproofing/ installing new drain tiles would be the ideal solution to water problems, however with the loss of the DW's job, our DINK status is also gone before the new addition to our family. Planning a smaller scale addition is a way to stay in our current neighborhood vs move to suburbia. With cost to dig up the old tile (if there ever was one) combined with the fact that I dont ever see the existing basment as anything more than a storage area, I would be more inclined to remedy the water issues with grading/ roof overhangs and or a french drain system.
Another bit of info for use in the discussion, residents are no longer able to connect outside drain tiles to the sewer. I am in an older section of the city with combined sewers and there is a huge push for residents to disconect drain existing drain spouts infavor of rain gardnens and storage barrels. Also, in the intrest of time money and effort in that order, Im not immeadiately ready to bust up the basment concrete for an interior perimeter drain system/ sump crock.
Is it feasible that the new section could be successfully kept dry give the construction (brick) and tendancy for moisture of the old?
Edited 6/5/2007 3:49 pm ET by joemilw
<< Is it feasible that the new section could be successfully kept dry give the construction (brick) and tendancy for moisture of the old? >>
I'm by no means an authority in basement waterproofing, but I can't see how a new foundation connected to, and lower than, an existing water-ridden foundation could be worked out successfully.
I got halfway through your response and was thinking to myself "perhaps he would consider an interior perimeter drain for the existing foundation?" - then you squashed that plan as well!
You will probably need to explain what you mean when you say you have considered a "french drain" - I've found that so much of the nomenclature for drainage techniques overlaps. The French Drain I know does the same basic thing as a drain tile system, only there is no pipe - you must be picturing somethign different. I could easily be the one who is wrong here (see my comment above - re: I'm no expert on this subject).
With the fixes you need for the drainage of the house, perhaps that second story addition is becoming cheaper and cheaper in comparison?Justin Fink - FHB Editorial
Your Friendly Neighborhood Remodelerator
also...if you're considering ICFs for the addition, read this article: http://www.taunton.com/finehomebuilding/how-to/articles/fast-foundation-for-an-addition.aspx?ac=fp
Justin Fink - FHB Editorial
Your Friendly Neighborhood Remodelerator
Jfink,
Ive always thought of a french drain as a similar set up to a traditional foundation drain tile system - utilizing pipe 12-24" below the soil surface running to low land or a "pit". The system I had in mind would include excavating a trench around the perimeter of the house. A cloth membrane (?) to stop soil migration would be layed down slopped away from the foundation, then stone then the drain tile at the bottom of the trench. The trench is then filled with more stone and its primary purpos is to control surface water and move it away from the house/ foundation.
Also, with the new addition I would have every intention of installing a proper foundation perimiter/ interior drain tile system and sump. being the lowest point, it would naturaly also collect water from under the existing basment slab. Probably would specifiy a sump and pump larger than normal in this situation...probably a back up.
The water problem I currently have is, I believe, 95-99% surface water or near surface water traveling down the foundation wall and exiting at the floor. (the pourous brick can never be a good seal with the mortar/ concrete bell footings). I could be wrong but controlling surface water is my biggest, and possibly ony issue.
I havent undertaken major grading landscaping yet to test this theory as we have been planning/ replanning something major for the last two year. I will attempt to address the grading issues while I have heavy eqiupment available to remove concrete patios/ walks/ stoops and move dirt around.
As you said, I dont seal basments for a living so Im just trying to the find major flaws in my logic. Would it help to see some floor plans/ drawings of what I am planning?
Edited 6/5/2007 4:20 pm ET by joemilw
It sounds like we're thinking of the same thing when saying French Drain... but I thought you said you were trying to avoid the expense of a Foundation Drain, which is basically a French Drain with a pipe. That's why I was asking what you were thinking of when you said French Drain...
I'm sure others will come along with opinions as well, but re-grading the soil, extending the downspouts, etc are always the best first options. You're probably right that most of your troubles are stemming from there anyhow. Justin Fink - FHB Editorial
Your Friendly Neighborhood Remodelerator
I understand how you misunderstood, I should clarify for anyone who is still confused... I mentioned that I was trying to avoid the expense and headache of a foundation drain around the [existing] house. The excavation itself would be problematic due to the proximity to my neighbors, one side would be impossible to get to with a full size excavator becasue Its a city lot (only 35 ft wide). My lot IS a bit deeper than most and the addition would be to the rear of the house.
I really should post up some pictures to make this all easier to follow.
I'm no expert either, but I always thought a French drain was for surface water -- porous from surface to drain pipe some couple of feet down, draining by gravity to daylight on the downhill side of the house; whereas a perimeter foundation drain is for subsurface water -- at or below the level of the footers, porous in the immediate vicinity of the drain pipe but *not* porous all the way up to the surface (that would just direct surface water down to your foundation, where you *don't* want it), and draining either by gravity or with the assistance of a pump to somewhere away from the house.Rebeccah
Joe,What you are calling a French drain, I call a perimeter drain. Yes it is a kind of French drain, but I am used to using the application specific nomenclature.When you build the addition, if you have placed a drain plane next to the walls running down to a perimeter drain setting on top of the footing, and used a waterproofing on poured walls, youo should not need an interior drain system. You would merely have to plumb the drain inside to the sump pit.I would combine the landscaping/drainage of the existing with the landscaping of the addition. Excavate both to a depth of the root zone + 6" at the wall, but with a slope of 6" over 10', (5% slope,) outwards. Place the French drain trench at the outer edge of the sloped excavation around the existing house. Plumb the tile, (needs no slope,) to open air or a large enough gravel pit to handle the expected seepage. This 'carry away' line only needs a 1% slope, (1":100"). Cover the excavated slope with 6" of waterproofing soil, such as an approved clay or bentonite, then replace the foot or so of topsoil, maintaining as much as possible the 6":10' slope. If you decide to use a waterproof membrane instead of waterproofing soil, turn it up at the wall to just under finished grade and bond it to the wall with a good glue.This would be an ideal application of waterproof foam insulation under visqueen. It would really keep the cold away from the existing basement.Plan ahead. Before you pour the addition's walls punch two interior drain line holes into the existing footprint and connect them to the new perimeter drain system. Figure that you will have a 2' wide concrete bench around the floor space inside the existing basement/crawl space after you drop the floor.Finally, unless you, or your DW is in love with the Cream City Brick, give it's interior surface a parge coat with Zypex, a cementious waterproofing. Zypex can be dyed or stained.PS: The perimeter drain tile itself does not need any slope. It just needs to not have any dips. It is the drain pipe that needs slope.SamT
Praise the Corporation, for the Corporations' highest concern is the well being of the public.
I would make sure of the source of the water before choosing a strategy. I have a similar (in age) house with a wet basement with only 6 feet of headroom. In my case, the water is actually a high water table, and it has been pointed out to me that the basement is relatively shallow probably because they hit the water table when excavating. If you have the same situation, you may have difficulty excavating to the depth that you are wanting, and will never be able to keep it dry.
Good luck with your project,
John
I just put a smallish addition on my 80 yr old house and took advantage of having an excavator on site to clean up the downspout issues. My downspouts now all connect to drain lines that empty well away from the house. Added foundation drains as well surrounding the addition, which is at a low point in the grade. That went a LONG way to clearing up wet basement issues. Sump pumps connecting to interior french drains that used to run virtually continuously in wet weather now rarely kick on. Some judicious planning might get you tremendous improvement with little additional cost since you are digging anyway.
Mike Hennessy
Pittsburgh, PA
i did this exact same thing to my house so i can give you some ideas of what i did but first , you have to get some idea of where the water is coming from now,does it leak down the walls or does it rise from the floor? if it's rising from the floor,i would either forget the basement or maybe raise it 3 foot above the other one and do a split level type addition.[if your house is that old it might be hard to incorparate it into the orig. design of house. but if it's leaking from the walls you might be okay to go a little deeper.
i put a addtion on and dug a 1100 sf basement under it. the floor of the new basement is 14" lower than the orig basement floors. when the excavator was here, where i had decided to cut the concrete wall for a doorway i had him dig down a extra foot right there. when the concrete cutting guy cut the doorway we just gave it a push and let it fall into the deeper hole and filled around it with sand. worked slick. now when he was here with his saw he could only get within 2" of the floor so there is now a 2" high threshold. at first i wasn't crazy about that.but after thinking about it ,if the hot water tank or something breaks and floods it will all stay in the old part and let the sump pump take care of it.
now one problem i have that can be addressed easliy is when they poured the new wall up against the old wall ,it is a cold joint/crack i have fought and fought it leaking at both places where it ties in. ask your foundation guy how to elimante this problem or your new one will be wet. if i was doing it again i would run a saw cut down the old wall where the new foundation wall will be.down the center . i would then epxoy a spline into that made out of 1/4 aluminum or something similar to join the 2 walls.
back to the water issue when you do the addition you should at least have that one area of the old basement dry,you might think about going ahead and digging around the house and install drain tile to tie into your new basement sump pump. also i'm wondering if you dig that much lower maybe the water will seek out the drain tile that is lower and you might fix some of your problem.if you want some pics of my step down let me know and i'll try to get pics. larry
hand me the chainsaw, i need to trim the casing just a hair.
After a couple of days to think about your responses, I think the best thing to do is water proof the entire basement walls as long as the excavator is on site.
Couple other notes/ questions. Three foundation walls are brick, with one CMU wall which was presumably replaced sometime in the 70's...probably due to the water issues. If I water proof the basment walls/ add an exterior foundation drain will the water proofing product seal up the conection between the footer and brick/ CMU ?
Also since their is very little slope to the lot and no way to "drain to daylight", will this application also require an internal perimeter drain and sump pump? There is no storm sewer to connect into.
My head is spinning right now...
another quick thought. what is your guess for the cost of foundation versus basement and all the drainage problems. i'm going to throw out a number of 15k difference.
if i had a water problem i would look at a foundation and take what i save and expand the addition by 100 -200sf and stay dry. my 2 cents and it's overpriced at that. larryhand me the chainsaw, i need to trim the casing just a hair.
Hi Joe, I know foundation specialists and they all agree, no product will waterproof, they will direct water down the foundation wall to tiles. IF in fact you to have a high water table, then you have a whole new ballgame to deal with.
Rick
Hi Joe, I used to be a home inspector and know a thing or three about homes. It is highly possible altho probably very expensive to dig down the floor in the existing basement. The big question is the existing foundation depth, if it is possible to go deep enough, you can remedy the water problem by installing tile and pump before the new floor is poured, this would make it the same depth as the new addition. Are the existing walls in good condition to begin with? I know quite a few people in different trades in the surrounding Milwaukee area. Big thing is do all the math on paper, and when satisfied DO NOT change anything, that gets really expensive once work begins.
Rick
Joe,
I'm in the Chicago area. I put a 2 Story addition on my 1890s house. We had the same situation with a 7' deep original basement and a 8' deep basement under the new addition. We put a sump pump in the new addition (required by City). We have found that since the new basement is lower all the water from the original basement ends up under the new basement and get pumped out by the sump pump. It is nice since it keeps water out of the old basement. We have the sump attached to buried 4' black plastic pipe which goes to the back of the lot and drains through a pop up bubbler pot. It works well to keep the water away from the house.
Another issue you might want to consider is structurally shoring up the old foundation where it meets the lower new foundation. The city required us to put in a large reinforced concrete 2' x 2' footer to shore up the bottom of the existing stone foundation, see attached photo. Not only does the footer take away from the usable floor area of the basement, but it was a cost increase. It might be a good idea to talk to an engineer prior to constructing the basement.
MikeK-
Could you expand on your pre addition conditions? did you have a Wet/ Moist basement? were there exisiting footer drains? if not did you dig the entire exisiting to install footer drains? Also, you say that you pump water to the back of the lot to a bubbler, how far is the run and is there any slope? How often doe the new sump run?
Thanks,
J
<< did you have a Wet/ Moist basement? were there exisiting footer drains?>>
Typical old stone foundation - we had some dampness on the foundation walls and concrete slab floor, and a little water come in during heavy rains. No sump, footer drain or french drain of any kind in the original basement.
<< if not did you dig the entire exisiting to install footer drains? >>
No, we left the original basement alone. Typical footer drain tiles were put on the two sides of the addition that did not abut the original house.
<< Also, you say that you pump water to the back of the lot to a bubbler, how far is the run and is there any slope? How often doe the new sump run? >>
Originally the GC had only a 2' PVC pipe coming out the side of the house to drain the sump. The sump was running very often because the water was being dumped so close to the house. I installed a 4" underground landscape pipe that goes downhill about 50' towards the back of the lot. Now that the water is being moved away from the house the sump does not run very often. Interesting thing is that the old stone basement appears to be much less damp then before we built the addition. My theory is that the new basement is acting as a giant sump pit and draining the water away from the old basement. I attached a better photo showing the large footer we had to put in to shore up the old foundation.