# Leak at sill Plate of 8-foot basement - Help!



## deepstuff (Aug 3, 2008)

Hi,

My house has vinyl siding, tyvek building wrap and an 8-foot basement. I have a leak between the concteate basement and outside 2x10 floor joist. This happened during the spring thaw while there was still snow. I want to stop it so I can develope my basement. Where the leak occured the top of the concreate wall is about 8 inches up from ground level. Snow was about 2-feet and melting at the time.

It was suggested on another forum that I insert a rubberized membrane (water and ice shield used in roofing) along the whole bottom course inside the Tyvek house wrap. 

Does anyone here agree or disagree with this solution? Will it cause other problems?


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## inspectorD (Aug 3, 2008)

I would try to seal the sill plate to the concrete. The house has an air leak at the sill and you need to fix it.
From the inside use the expanding foam insulation. From the outside use 50 year rubberized silicone all the way around. Installing this will keep the moisture on the outside from thawing to fast and melting into your house.

The human fly paper(grace ice and water sheild) will help, but with all 3, you should not have an issue.


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## deepstuff (Aug 3, 2008)

My leak is more between the sill plate and outside floor joist (rim Joist?).  I get the leak during the spring thaw and mild periods while we have snow.  Expanding foam will seal and won't soak water?

Thanks!


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## mudmixer (Aug 3, 2008)

Your leak is not at the plate and sill area. That is where it shows up.

You have a leak above at at the roof or at the windows and doors above. Since vinyl siding is not a waterproof barrier, the leak could be almost anywhere above. A leak can saturate your wood structure and only show up when there is another source of moisture to cause it to  flow down and/or horizontally until it hits a barier and is forced inward.

you may want to contact a moisture instrusion soecialist to look at the walls of your home. An experienced person with the right equipment (deep probes) could spot any wet/moldy wall areas quickly.

As a temporary fix, expanding foam will stop leakage into the basement at that point, but it may show up elsewhere if it is not forced outward.

Dick


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## deepstuff (Aug 3, 2008)

At the time I noticed the leak, wind was blowing on the side of the house and bubbles could be seen from inside the basement.   This was during the spring thaw with snow about 2-feet up the side of the house.


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## deepstuff (Aug 3, 2008)

I removed the siding and noticed that nothing was holding the bottom edge of the tyvek down. Shouldn't it be under the starter strip? 

Why rubberized silicone?  

Should I look for anything special if I use spray foam?

Thanks!


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## deepstuff (Aug 4, 2008)

Since wind is getting under the tyvek and blowing water bubbles through the Sill plate - rim joist seem I assume water must also be wicking or blowing up to the joint during the spring thaw? Is it reasonable to believe that this is the source of my leak and that it doesn't come from above.


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## deepstuff (Aug 4, 2008)

The ice shield I purchased says to prime the concrete. What should I use for this?


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## inspectorD (Aug 5, 2008)

To stop chasing leaks around and wondering about advice, my suggestion is to run the hose around that side of the house and see if you get water in the sill area. Then start to remove siding and see where it is coming from. Remember, to find a leak you need to be the water...it goes anywhere downhill always.
Basically do not tuck your raincoat into your pants or you get wet shoes. 

Then you will know exactly what you need to do to stop the water.
If no water comes in, then you have a sill issue when it freezes, I have seen it before when there is no sill seal.


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## deepstuff (Aug 5, 2008)

Something I should add.  I've been in the attic while the water was coming in and didn't see anything.  No staining in the attic either.  

I can also see the sill plate gasket.  It's the pink sponge type.


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## inspectorD (Aug 6, 2008)

Mabey you have some tyvek going the wrong way as Mudmixer suggested. I would check around all your windows with the hose first and spray everything. You need to check from the top on down, then you will be sure. If it happens again this winter, it will be to late to fix it in the cold again.

Sorry, just telling you what I would do if a customer had this issue, it is a lot of investigation and work.


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