diynonstop

I need help! Possible leak coming between slab foundation and sill plate. I removed the baseboard and I can see the tiny bit of water seeping in. The area is above grade but the foundation does extend 4-5 inches beyond the house wall framing. (It looks like they were going to add brick to the outside and changed their mind.)
From the exterior you can see where the slab foundation meets the wall of ?concrete board?. If I press really hard the wall has a tiny little give to it. Making me believe the seam between the wall and slab is the source of water.
Removed the siding and the wood shows no sign of moisture damage. (yeah, no Tyvek) The concrete board goes up about 6-7 inches which is above where the vinyl siding starts. (of course the j channel is missing too) Just as a precaution, I sealed all seams with the waterproof adhesive tape that you use around doors and windows before putting the siding back on.
Previous owner was an idiot with repairs. Honestly, silicone was his best friend. When I see caulking I know there is another problem. He caulked the interior of this wall with about 2 cans of caulk as a barrier for the water to stay behind the wall. He also used thinset or something like that on the exterior to seal the wall to the slab to keep water out of the seam. Of course this is all flaking off.

This is an old picture The door is watertight now. I already replaced the door and removed the flaking concrete by the threshold.

Help!! I don't want to silicone everything from the inside, I want to keep the water out. What can I use to make a permanent waterproof seal on the exterior joint where the wall meets the slab?
Thanks, Paula

CallMeVilla

What were the thinking when they built this wall??? The problem is water landing on the concrete and seeping back into your house under the bottom plate. Good construction allows the water to sheet off the wall, past the slab and to the ground. Gravity is your best friend in that case.

Caulking inside just seals the water inside your framing, causing mold and wood rot. Caulking outside is a temporary fix which will always fail over time.

You have to stop the water outside and allow the inside to dry out (eventually). That will take a rework of your exterior wall. Here is a construction diagram (do not let it panic you) of a typical stucco exterior wall. Notice the bottom left side has a weep channel which sheds the water away from the concrete (which is shown on the bottom right). You need to build an add-on which sheds the water similarly. I do not like the aesthetics of a false wall with matching siding and a drip edge ... but that might be your only practical solution. Perhaps adding a sloped concrete border at the bottom of the wall with proper bottom flashing above it would be nicer.

I would ask a few local contractors to offer on-site solutions. You do not have to take their ideas or spend the money. But, this is probably not the only building in the area where this fool did something similarly.

nealtw

No house wrap behind the siding is likely the guilty party but the concrete should have been made to fit over the concrete and up behind the house wrap. If they uses a starter for the siding you don't need a bottom J trim

diynonstop

Could I use something like Drylock or roofing cement all along that area to waterproof?

nealtw

Dap makes a caulk for concrete, might seal it up.

bud16415

I would think about having some “Z” flashings formed up that would go behind the siding across the slab and then a downward drip edge of about an inch. The door openings need to be sealed as you have. And the garage door is best fixed with adding enough slope and a good seal on the bottom of the door.