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  1. #1
    Join Date
    Jun 2010
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    1

    Wink Stone foundation/leaky basement

    I bought a fixer upper house that has some wet basement issues. Stone foundation, leaks in walls and basement cement floor, no sump pump.

    We have a very high watertable in the area.

    Looks like previous owner cut a drainpipe in and started to cut a french drain but I don't know where it goes and it appears to be clogged. Should I unclog and reuse in some manner or seal it?

    This is my plan.

    1. Clear exterior bushes against house.

    2. Regrade exterior (I don't have much room to work with so no exterior trench drain). Should I try a "drain mat" under the regraded area? I wish I could dig a trench around the outside and mortar the stone on the exterior of the foundation, add waterproofing, etc..but many say that will compromise the integrity of the stone foundation.
    3. Then, what is my next step? The covering over the stone foundation is crumbling throughout the basement. I was thinking about brushing all that off and adding new layer of mortar to better seal the stones. Any advice on this?

    4. Once I do that cut a french drain and install sump.

    Should I put a vapor barrier up somewhere? What should I do to improve the cosmetic appearance of the visable stone after resealing stones? Throw a layer of cement over it? I don't mind bringing in a contractor for parts of this if it can get me a finishable basement, but I am not paying one of these sham "basement waterproofers" that want $10000-$30000 for work that is 95% labor.

    Please tell me anything that I can do to improve the situation myself without hiring a contractor. I'll take any exterior advice you can give too, but again, I do not have a lot of space to work with.

    I plan to keep this house a long time, so long term fixes only.

    DIYer in PA

  2. #2
    Join Date
    Jun 2010
    Posts
    1

    Default Re: Stone foundation/leaky basement

    ***! This could be a whole season of TOH.

    Water is not your friend when it comes to the foundation. I'm going through this same issue right now with a basement in a home that was built in 1995. So it is a myth that modern basements are better. Or should I say, cheap builders are the bane no matter the time period.

    Sump pumps are in your future, so you better find out what the rules are in your community. Some require that the sump pump discharge into the sanitary sewer system. Others allow discharge to the street or your yard. Also know if your area allows penetrations through the foundation. When I lived in California, you could not have a penetration through the foundation if you were in an earthquake zone. All penetrations had to be in the rim joists. Pretty ugly if you didn't think that through. But it was damn cheap and you didn't have water following the pipe back into your basement or crawl space.

    I started with a registered professional engineer that specializes in foundation issues. If you have a ruble stone foundation, I'd would want to know two things: is the foundation sound and does it sit on sound earth? If the foundation or the soil itself are compromised by water infiltration, a band aid approach isn't going to work. Not exposing the foundation has its risks as well. If all that is holding up the foundation is the outside earth, well, I would want a PE to tell me the up side and down side risks of doing nothing. I don't believe that the conventional wisdom you have received is correct. You don't have to take action, but at least the PE will give you the options.

    If the foundation is really compromised, then remortaring is a waste of time and money. You might be faced with the prospect of building a new interior cinder block wall in the basement to pick up the weight of the house. We did this in my grandfather's house that was an old farm house with rubble foundation. We didn't have to go all the way up. We only had to go about 5 feet up to stabilize the foundation wall and cement a cap. Small lolly columns then picked up the load on key beams and floor joists. The area between the cinder block and the old rubble foundation became the weeping tile space in the floor area, which was directed to a sump pit and pumped out of the basement.

    You can do some research on the uses of hydrolic cement and lime paste mortar. Portland cement is worthless as a water barrier material. There are several lime based parging recipes and it would be fun to use the basement walls to practice your finishing techniques. Lime based mortars get stronger over time and is what historical building used. As you know, many brick and stone buildings have their original lime mortar and it looks fantastic 200+ years later. Repointing stone is damn hard work if done right. Too many of the fly by night contractors come in, wire brush the stone and then top coat the stone with portland cement. The problem is that the joints only have about 1/8 inch of cement and after they brush off the walls, you might have even less. In a few months, when the cement fully cures, it shrinks and then it starts flaking off. Repointing stone should be hard work, digging out all the loose mortar and chiseling out to a good depth of at least an inch or more. The mortar really needs to be packed into the joints, to eliminate any voids or cavities.

    It is possible to redirect the water around your house by using what is called an underground flashing system. It is simply foam board angled from your foundation away from the house 12 or more inches underground. It is usually installed in two pieces, the part that touches your foundation is at a 30 to 45 degree slope and is about two feet wide. Its job is to catch water and shed it quickly away from the house. The second piece is as wide as you can afford in terms of space, but might be 2 to 4 feet wide and is at a much shallower angle. Its job is to keep water from seeping back under the ground towards your house by directing the underground runoff away from your house.

    A real belt and suspender method is to use a flexible flat roofing material and metal bar fasteners to attach the roofing material directly to the foundation under ground and it provides a secondary runoff catcher that the foam board might miss. Saw it in a book on foundations and it seemed like a good idea. The metal bars hold the material to the foundation and you would seal it at the contact point with your choice of sealant, just like flashing a roof.

    Both these methods are DIY and the materials can be found at most home centers.

    I wouldn't guess about underground pipes. Call a plumber to scope the lines and figure out where the the pipes go and what their purpose might be. No surprises should be your mantra.

    As for a vapor barrier, they belong on the outside of the foundation. I think you are asking for trouble with an interior vapor barrier. Avoid any interior finish that traps or retards water vapor. My limited experience is that you want water vapor to be able to move through the concrete and stone and exit the building, just like Elvis. So no plastic sheeting, no oil paints and no sheet roll flooring or carpet that can trap moisture or cause mold and mildew.

    I wish you the best of luck.

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