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Ladies and Gentlemen,
For the upteempth time today I came across the proverbrial leaky concrete porch, and would like to hear some suggestions for waterproofing them. For some background, these are older, brick or woodsided homes in Michigan, probably between 40 and 60 years old built in older neighborhoods (okay, that last part was obvious). You know, the typical older American neighborhoods (lots of Cape Cod style). Almost all of them have block foundations, without parging, tar, drain systems, etc. The porches themselves usually consist of an actual ‘bumpout’ in the basement, formed of the same blocks up to grade level, with either brick or block up to form short walls. Almost always, the steps and actual porch surface are a single, precast concrete unit that has been placed, and grouted, onto either the foundation blocks with the walls built above, or somehow attached to cover the “hole” in the basement. Almost invariably, they leak at the intersection of the house and the short walls to allow condensation into the basement. I cannot tell quite how they were originally waterproofed at the intersections between cast piece and foundation wall, but I’m guessing just mortar. All of them now, of course, have huge amounts of various caulks and compounds, sometimes concrete jammed into these intersections, which of course never seem to work. None were ever flashed, and a level shows them to either be flat or tilting back towards the home (why the hell don’t these things ever tilt out?). I’m looking for ways to permenantly solve these problems, and in doing so, I can easily pick up five jobs in the next two days. Here are some possible solutions I came up with:
1. Removing the first course of siding and bending flashing to insert into kerfs sawn into the concrete up near the house, then cauking them (or just flashing and caulking, but I’m a little leery of using caulk as a prime moisture barrier). I’d do this on the sides as well.
2. Parge coating the concrete with a thin layer to actually give the porches some slope, and of course adding the flashing.
3. Trying to use one of the newer rubberized, self-adhesive, walkable roofing sheets to cover the porch (up under the siding, in kerfs in the sides). Maybe even using a rubberized foundation coating? I’m afraid this would look REALLY bad, however.
4. Tearing the whole thing off, of course, would be what I’d like to do; not sure, however, what I’d cover the “hole” with (don’t believe I can still get that type of precase stoop, even if I wanted to). The customers would probably like this too, they just don’t want to spend that type of money on a porch.
Anyhow, any suggestions, comments, problems with my ideas, I’d love to hear. Thanks.
Replies
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how big a gap between the slab and the wall? and would you be able to strip all that old s%&t outta there? any caulk you do use, i would recommend good urethane caulk from one of your masonry supplies....Dymonic is a good one. Tremco offers several. If the gap is 3/4 or under you could neatly (with care and some masking) offer a lasting and decent looking repair at a reasonable price at least at that joint. egads on all the rest of the project. stopping the moisture from getting into that "basement under it" won't be easy. Don't screw up the roses. best of luck.
*Yes, as Calvin pointed out Dymonic would be a good choice. Make absolutely sure that you clean out the joint of all loose material. Use a chipper if you have to. Also, you should pack it first with a foam rope.Use any of the Mapei toppings to level them off.Gabe
*Gabe and Calvin, good ideas. Yes, the cracks or joints between the porch and wall are under 3/4", but rough--I could certainly grind them down better. What are Mapei coatings, if you please?
*Mapei has a whole mess of coatings for concrete, just do a search of the name Mapei and you'll be able to log on.Gabe
*jason... i'm not exactly sure if i have a good picture of your ((porches))but it sounds like an elevated slab... and it sonds like they probably poured tehm LEVEL or pitched away from the house... since the part away from the house was more or less on undisturbed soil.. the slab stayed put...and the slab against the house was on disturbed earth so ther was some sinking..OR.. the footings on the perimeter were not deep enough and the outside was heaved by frost year after year..since teh area against the house was protected by the heat of the house.. there was no heaving..one possible solution would be SLAB JACKING..if you honed your technique.. you could get to be pretty good at this... there were some postings here at the beginning of the year about SLAB JACKING devices that the contractors had made themselves..b but hey, whadda i no ?
*Thanks for the advice--we start next week and I'll try out the Mapei coatings. Mike, I appreciate your suggestions, however, the "concrete porch" is really just a cap; it's over the basement. Jacking, though, might make more sense (they really should just fill up the basement with concrete anyhow...). Thanks
*Jason,I see those from time to time in the Toledo area with exactly the problems you describe. Its not uncommon for there to be termites in the front entry framing as well; they really like those rotted sills and sill plates!Let us know how it goes; I'm at a loss in advising my home inspection clients what to do.Bob
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Ladies and Gentlemen,
For the upteempth time today I came across the proverbrial leaky concrete porch, and would like to hear some suggestions for waterproofing them. For some background, these are older, brick or woodsided homes in Michigan, probably between 40 and 60 years old built in older neighborhoods (okay, that last part was obvious). You know, the typical older American neighborhoods (lots of Cape Cod style). Almost all of them have block foundations, without parging, tar, drain systems, etc. The porches themselves usually consist of an actual 'bumpout' in the basement, formed of the same blocks up to grade level, with either brick or block up to form short walls. Almost always, the steps and actual porch surface are a single, precast concrete unit that has been placed, and grouted, onto either the foundation blocks with the walls built above, or somehow attached to cover the "hole" in the basement. Almost invariably, they leak at the intersection of the house and the short walls to allow condensation into the basement. I cannot tell quite how they were originally waterproofed at the intersections between cast piece and foundation wall, but I'm guessing just mortar. All of them now, of course, have huge amounts of various caulks and compounds, sometimes concrete jammed into these intersections, which of course never seem to work. None were ever flashed, and a level shows them to either be flat or tilting back towards the home (why the hell don't these things ever tilt out?). I'm looking for ways to permenantly solve these problems, and in doing so, I can easily pick up five jobs in the next two days. Here are some possible solutions I came up with:
1. Removing the first course of siding and bending flashing to insert into kerfs sawn into the concrete up near the house, then cauking them (or just flashing and caulking, but I'm a little leery of using caulk as a prime moisture barrier). I'd do this on the sides as well.
2. Parge coating the concrete with a thin layer to actually give the porches some slope, and of course adding the flashing.
3. Trying to use one of the newer rubberized, self-adhesive, walkable roofing sheets to cover the porch (up under the siding, in kerfs in the sides). Maybe even using a rubberized foundation coating? I'm afraid this would look REALLY bad, however.
4. Tearing the whole thing off, of course, would be what I'd like to do; not sure, however, what I'd cover the "hole" with (don't believe I can still get that type of precase stoop, even if I wanted to). The customers would probably like this too, they just don't want to spend that type of money on a porch.
Anyhow, any suggestions, comments, problems with my ideas, I'd love to hear. Thanks.