water leaking under the walls.

[fgl123]

I built my shop on an exsisting slap and during a heavy rain i have water running under the walls in some areas. I've ground down the edges of the concrete and put in drains to divert the water. This works in most cases but not always. My wall sheets are horizontal so there is a nice straight edge to seal. I've put down a few differnt sealants with no luck. Trim is an option but I don't really want a 6" piece to get abused. What's a good waterproof sealant or such that will adhere to concrete? Any sugestions appriciated.

 

[SALIV8]

Use a very good quality caulk like np1. Not the **** that hd sells... Biggest and best advice is- Don't forget the primer that's the key.

 

[7th Kahuna]

Sounds to me like you are trying to stop the water after it is already under the wall? Sealant on the inside? I would be looking for ways to keep it away from the building in the first place. One quick solution might be to dig around the slab, create a drain, add a piece of flashing from behind the bottom of the siding down over the concrete and backfill with gravel. Kind of mickey mouse but might work. Whatever your approach, I wouldn't want water sitting 'under' the wall. That has got to be bad news over the long term.

 

[ddawg16]

Let me guess....flat slab on grade?

Never could understand why people do it...except to save a few bucks. I tore down my old garage because of that issue (and others).

Built a larger garage....with stem walls. I no longer have water issues.

 

[collision1]

foundation coating on the outside waterlock on the inside...both are types of paint

 

[sands35]

Dig a trench around the garage, install french drains, fill with stone.

 

[theoldwizard1]

Dig a trench around the garage, install french drains, fill with stone.

This is the ONLY SOLUTION ! (Been there, done that !)

 

[laser3kw]

Dig a trench around the garage, install french drains, fill with stone

does the roof have gutters? if not you will have to dig the french drain a little wider and deeper to catch the drip line and the extra capacity of the full run off.

 

[finn]

Agreed: If the slab is sitting in a puddle, sealant will not fix your problem. Grading, gutters, drainage ditches, French drains, small stones, dry wells, and maybe even sump pumps are the tools at your disposal.

 

[BearsFan315]

Sounds like my issue... my garage was built in the 70's and is a slab on grade, to further compound my ordeal the driveway actually has a slight grade towards the garage. when I moved in whenever it rained my garage flooded !! the only way I could better the situation was to install a French drain of the sorts and run a drain towards the curb. I had to cut the drive across the front of the garage and install a grate drain. this helped immensely. now I only get water in the garage during a torrential downpour...

my ultimate solution is to tear it down and build a new one in its place, graded properly with a slab and blocked up. all in time... all in time...

 

[pattenp]

I think some respondents are not understanding your problem. If I understand correctly, you have a slab that's larger than the shop and the concrete ledge is catching rain which flows under the sill plate. Yes/No? How about some pictures?

 

[NUTTSGT]

My step-brother is having a similar issue because they built the garage on a larger slab. He needs to the french drain and lower the surrounding ground, which I believe will solve some of his issue till winter.

If those don't work, I'm going to suggest to him to cut his concrete. Making two cuts about 3/4" apart (1/2-3/4" deep)and chisel out the concrete, effectively, a small moat around the perimeter. While it may not look pretty, it should help.

I can't fathom why a builder (this was built by those awesome Amish) would build this way. I'm just a dumb fireman and I know that water will go under that wall, especially when the grade right next to the sidewalk is higher.

 

[sands35]

Pattenp raises a good point. Pictures?

Water flows downhill (duh) so you need to raise the garage or lower the ground.

"Slab on Grade" works just fine - if it is ~3-4" above grade and ground surface water is delt with properly.

 

[NUTTSGT]

Pattenp raises a good point. Pictures?

Water flows downhill (duh) so you need to raise the garage or lower the ground.

"Slab on Grade" works just fine - if it is ~3-4" above grade and ground surface water is delt with properly.

Yes, the water should be easy to deal with until you get a heavy or driving rain, it can wick under the walls if the surrounding slab is the same as the garage floor. The same goes for winter time and you heat the space, the snow outside the wall can melt since the concrete floor will be transferring heat to the outside.

 

[fgl123]

I think some respondents are not understanding your problem. If I understand correctly, you have a slab that's larger than the shop and the concrete ledge is catching rain which flows under the sill plate. Yes/No? How about some pictures?

Exactly! I put a drain in the front which helps keep it from coming under the roll up door

 

[K'ledgeBldr]

The easy explanation- as you explained it;

the exterior cladding does not extend past the sill plate and the grade is probably less than 6".

In the attached cross-sectional drawing you can see the foundation, sill plate, sill seal, and the exterior cladding well below where the sill and foundation meet.

Drains (french or otherwise) will do nothing to remedy this problem.

 

[theoldwizard1]

If I understand correctly, you have a slab that's larger than the shop and the concrete ledge is catching rain which flows under the sill plate.

Saw cut the concrete as close to the building as possible. Have a concrete "leveling" company lift the exterior slab so that it is pitched "properly" away from the building. I would probably "fill" the saw cut with something like Sikaflex.

 

[rweaver]

Is that a enclosed carport building on slab if so I'm following because I have the same problem. My building is 6 inches longer in back and front and that's where the problems are.

 

[fgl123]

yes its an enclosed carport. Versatube building. I got drains from a landscape supplier to remedy my problems at the front and back doors. You can see it in one of my pictures.

Cutting the concrete sounds like the best option but is there some kind of sealant that i can put down in the affected areas? I think that is my only option for hard rains.

 

[Kevin54]

By all rights, the slab should have been cut, and a piece of flashing, bent up, pit into the cut, then up against the wall before any siding was put on. Caulking is just a temporary fix. It may last a year, it may last five years, but it is still temporary. The proper and permanent way is either to have flashing put down into a saw cut, or the building should have been built to where the siding was over the slab.

I've built two garages on a slab, one was mine, and one was for a friend. In both cases, the siding was over the edge of the slab by about an inch, and never once was there any water that could penetrate underneath.

 

[theoldwizard1]

Cutting the concrete sounds like the best option but is there some kind of sealant that i can put down in the affected areas? I think that is my only option for hard rains.

Caulk/sealant even flashing are not "perfect" solutions. IMHO, saw cut and jacking the outside slab are your best bets.