I have a problem that I hope someone can give a suggestion of how to fix. There is a detached garage (CMU construction), with an attached room that is about 10’x20′. This attached room is built on a slab, with standard 2x construction, t1-11 siding. Here is the problem: The slab was poured at the same level as the garage floor, but the ground slopes upwards towards the back of the structure so that by the time you get to the back the slab is 6″ below grade. The previous owner just piled dirt up against the siding, so every time it rains water comes pouring in between the bottom of the wall and the slab flooding the room. I have dug down to a few inches below the top of the slab, and so far the only thing that has rotted away is the siding.
I am trying to think of a way to add drainage along the slab, and at the same time keep the soil away from the siding. My initial idea was to build a small retaining wall, about 12″ away from the exterior wall, so that I could lower the soil level against the slab to just under the top of the slab. Without drainage, however, I may still have enough water build up in that area during heavy rains to flood the room. If I dig down far enough to add drainage pipe I’m afraid I will undermine the slab and have even worse problems to deal with.
So, short of some drastic reconstruction of this room, does anyone have any ideas of how to fix this? Thanks in advance.
Replies
Treat it like a shower stall.
Remove the sheathing and install cement board in its place. If possible, use thinset to seal the joint between the cement board and the slab. Then cover the whole thing with rubber membrane, down to the bottom edge of the slab. Use some thin cement board or some such on the outside, to protect the membrane.
(Just noticed the T1-11, so presumably no sheathing. Remove the bottom several inches of T1-11 and then do as suggested above, installing flashing at the top, and maybe some sort of trim detail to hide the joint.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
go back about 24" for your little retaining wall.
You can go down next tothe slab to put in perimeter drain to lead the water out and around
To fix the siding - if you go with Dan's suggestion, remember that cement board is not rated for constantly wet locations., nor is it water proof.
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That's why the rubber membrane's on the outside.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
Dig a trench along the back of the building (about 18" will do). Run a length a Delta Foundation Membrane (about 2' high) seeing that the membrane stands about 4-6" above grade and against the building. Drop in a 4" weeper making sure there is some slope before backfilling and that there is some place for the water to go. If there is no place for the water to go you may have to trench to a more appropriate drainage location. If there isn't a huge amount of water and you get decent drainage on the property, digging a dry well may be the answer. Dig a hole 3' in diameter and 3-4 feet deep and fill with 3/4" clear stone. Backfill your trench behind the building with a 3/4 clear stone. You may have to go down the side of the slab as well. You'll have to use your judgement on that.
Hope that helps.
Dave