Shop going in basement, trying to keep water out

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Forum topic by crank49 posted 01-19-2012 12:01 AM 2003 views 0 times favorited 12 replies Add to Favorites Watch
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4030 posts in 2969 days

01-19-2012 12:01 AM

Topic tags/keywords: question

My wood shop is going in my basement.
My basement is 50% ground level, with a drive in garage under one end of the house.
The shop is on the other end of the house, the part that is under ground level.

The moron who built the foundation put in a french drain; about 12” above the level of the slab.
When we get about a week of steady rain and the ground gets completely saturated there will be some weeping of water into the basement. I can open all the doors and it will flow out through the garage and out into the driveway. Then I have to run fans and a dehumidifier for a few days to dry everything out.

I have lived here for 33 years and have had about 10 times there was an inch or so of water in the basement.
I can’t afford to dig up the yard around the basement to lower the drain to where it should have been.

I think I can re-seal these block walls with a product like Thoroseal. Then drill holes in the blocks at floor level. That will keep the walls dry and let the water drain out. Then I want to install a curb wall, 2” away from the foundation wall to catch the water that drains out. I will make this curb out of solid 4” x 8” x 16” cap blocks. It will be 8” high an I will build a framed stud wall on top of the curb. This curb will have to be continuous around the perimeter walls and out to the garage doors wher any water that comes in will drain away.

Now for my question.
What is a good product to seal this curb wall to the concrete slab floor. And to seal the blocks to each other?

12 replies so far

View StumpyNubs's profile


7592 posts in 2799 days

#1 posted 01-19-2012 12:36 AM

This is a great question. I don’t have the answer, but I will be watching to see, and I think it will be a good one to have on here for future reference.

I suppose that, since I don’t have an answer, I shouldn’t be responding to this thread. But my wife isn’t home and I have little else to do.

Not that you needed to know that… am I still talking?...

-Jim; aka “Stumpy Nubs”
(The greatest woodworking show since the invention of wood is now online!)

-- Subscribe to "Stumpy Nubs Woodworking Journal"- One of the crafts' most unique publications:

View Don W's profile

Don W

18715 posts in 2566 days

#2 posted 01-19-2012 12:40 AM

If the french drain is working, is there a way to drain off one end (or better yet, both ends) of the drain? Get the water away before it gets in. No matter what you put up, eventually the water will win if it keeps trying.

-- - Collecting is an investment in the past, and the future.

View Sawkerf's profile


1730 posts in 3067 days

#3 posted 01-19-2012 01:27 AM

Does your surface grade fall away from the house like it should? If you have (or can get) adequate surface drainage away from the house, your French drain would probably handle the rest.

I don’t think that I would do your curb wall trick. If you frame another wall inside the basement walls, you’re creating a space that will probably become a moisture trap leading to mold, rot, etc.

-- Adversity doesn't build reveals it.

View TheDane's profile


5423 posts in 3661 days

#4 posted 01-19-2012 01:28 AM

crank49—I had a similar issue with a house I bought years ago in Des Moines. We didn’t get a lot of water, but any at all is not good.

When I sold it (1979), the guy who bought it financed through the VA, and the inspector raised hell about the drainage problem. We had a contractor dig down a few inches the level of the slab, water-proof the cement block from outside, and install a new french drain. Cost me what, at the time, was a small fortune. Never heard if it actually solved the problem.


-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

View sandhill's profile


2128 posts in 3922 days

#5 posted 01-19-2012 02:13 AM

If it were me I would dig down to below the slab and put in perforated 4 – 6 inch drain and Cover with 3/4” blue stone if you can grade it away form your house. It seems to me you are playing the little Dutch boy with his finger in the Dyke.

View casual1carpenter's profile


354 posts in 2474 days

#6 posted 01-19-2012 02:34 AM

crank49, my dad used that Thoroseal stuff some 20+ years ago, it worked pretty good. We still had a couple of leaks in the worst rains but nothing compared to previously. Those may have come from application error. I had heard a guy recommending opening holes into the basement walls at their lowest accessible points outside, say by the garage door. The Thoroseal, if it completely seals the wall will allow a lot of back pressure to develop, pressure that might need to be relieved.

Your answer is likely not a simple one. Landscaping to move the water along before it gets to the french drain.
Gutter drain improvements again to move the water away before it becomes a problem. The Thoroseal could be used more as a last line of defense. There was, or still is, an outfit B-Dry or some such that used a baseboard setup that channeled any water to a sump pump. In affect they caused the leaks to occur at points of their choosing, points where they collected it and moved it on it’s way.

just a couple of thoughts that came to mind. BTW, it’s not b-dry with the baseboard system, i googled them.

View doncutlip's profile


2832 posts in 3554 days

#7 posted 01-19-2012 02:35 AM

I used Drylock, several coats. Not a drop of water has ever gotten through. I did the floor with poly porch/floor paint. Dry as can be.

-- Don, Royersford, PA

View ScottN's profile


261 posts in 2678 days

#8 posted 01-19-2012 02:42 AM

Rain gutters and impervious fill, with drainage away from the house. These are the 2 biggest causes of water in the basement. Unless your basement floor is close to the water table…that’s a whole different ball game.

-- New Auburn,WI

View Planeman40's profile


1176 posts in 2759 days

#9 posted 01-19-2012 05:51 PM

It sounds like your French drain is on the outside of the house. We had a French drain installed about two years ago and it was installed on the INSIDE of the house. They broke up and removed a part of the concrete floor to make a dirt ditch about 18 inches wide that runs around the perimeter of the basement floor next to the outside concrete block walls. Then they installed the French drain and re-poured the concrete floor section that was dug up. The concrete block walls were then lined on the inside of the wall with a 1/16” thick plastic. Any water that seeps through the wall runs down the wall between the inside concrete block wall face and the sheet of plastic into the drain. This water collects in the french drain and is routed outside. After the drain was completed we built a sheetrock wall in front of the concrete wall being careful to only connect it to the floor and ceiling joists. We didn’t want to penetrate the plastic covering of the French drain in any way. Now it looks just like any nice white-painted sheetrock wall. It has worked very well and now my basement is bone-dry! My shop has been saved! It was expensive, though.


-- Always remember: It is a mathematical certainty that half the people in this country are below average in intelligence!

View AlbertaJim's profile


47 posts in 2427 days

#10 posted 01-19-2012 06:06 PM

Many of the houses in our area have a hole cut in the floor with a sump pump that pumps the water out of the hole to the outside. When we did it in one house we never had water in the basement again.

-- My Boss was a carpenter

View crank49's profile


4030 posts in 2969 days

#11 posted 01-19-2012 06:50 PM

Thanks all for your comments.

Jim H. : chime in any time; fine by me.

Don : The french drain is not working because it’s above the floor. I do feel like the water wins sometimes.

Saw : I have, over the years, graded the yard away from the house, drained the gutter away, and all the other things you do to try to fix this. That’s why it only leaks in about once every 3 years. At first it was every time it rained.

Gerry : Yes, that expensive correction is what I’m trying to avoid.

Sandhill : I do feel like the Dutch boy sometimes.

Casual : Yes, what I’m trying is actually a homemade version of the baseboard gutter system. Along with the wall treatment and insulation and a strong vapor barrier.

Don : I’ll check out DryLock. Sounds like the Thoroseal which I have used. But, after 33 years the water pressure has caused the Thoroseal to spall off the wall in a few spots. I need to scrape it off and replace it.

Scott : House is sitting on a good layer of gravel fill and the floor is never wet; unless the walls leak onto the floor.

Plane : That inside drain was considered, but since my floor slab does not leak and is sitting on gravel which has drains going down the hill, and the water still comes through the walls sometimes, I suspect I have to fix the problem from the outside of the foundation. An expensive fix I am trying to avoid.

A. Jim : I have a sump, but the floor never leaks.

I think some of the problem is the hard clay soil in the bank I dug into to build my house. It was so hard the loader operator actually broke his bucket and an axle on his Deere 450. He said it was the hardest clay he had ever tried to dig. Took three days to dig the hole.

View helluvawreck's profile


31082 posts in 2865 days

#12 posted 01-19-2012 07:27 PM

We have a sump pump in our cellar. The cellar needs water proofing and the house is 50 years old so there is a little seepage that comes from the floor and walls but the sump pump takes care of it. Also a little water comes from condensation on the air conditioner and heating and air ducts. I’m not sure how to advise you on this but I have heard of very good results with some of the water proofing coatings and if you used a combination of those and one or two strategically placed sump pumps I believe that you could cut the problem down to where it’s just a small nuisance that you could live with. The small sump pumps are not very expensive. move a surprising amount of water, and are very reliable. I clean the sump out about once a year and sweep the cellar floor occasionally to keep any debri down that might clog the pump.


-- helluvawreck aka Charles,

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