Sealing A Storm Room

monticellohomes

On a few homes I've built now we've put "storm rooms" under the front porches of a walkout. Its just the same walls as the rest of the basement with a concrete floor, some framing to support the concrete above. I am having a time keeping water from these things, usually only in driving rains does it happen...but homeowners usually aren't so understanding. When constructing these I took many precautions to prevent this. First, when framing the decking the concrete sits on we used sill sealer around the outside edges to hopefully create a good seal there, then we sealed any crack in Advantec actually used for the decking. Thirdly we applied roofers ice damming material actually creating a bowl the concrete would sit in and lastly the areas where siding sat on top of it, we flashed on top of the concrete (caulking it to the concrete).

I just got a call from one of the homeowners saying there was water, I tried to tell her what the likely culprit was but it didn't seem to matter or sink in. Any ideas/advice on sealing this up more? I think I am done with them for good, unless the homeowner insists and I am going to make them sign something that states they realize this is a possibility.

TimNJ

I think I would build the room in the basement rather than what sounds like outside attached to the basement. That way the room is weather tight in the house.
Otherwise look up some info on sod roofs and you should be able to see how to make a roof water tight that is "underground".

monticellohomes

Its not really outside the house, it is under the front porch. I think I found where some water might be able to make it through and recaulked there...so hopefully that does it.

andy builds

Look into some under decking companies. They will guarantee their product and it will serve as a roof under your porch deck. Problem should be solved.

cleveman

I only did one and we waterproofed the deck with some tar paper, etc., flashed the top against the house. As with you, this was a porch with a roof over it but with open sides. The concrete was sloped. It leaked a bit and the homeowner put some waterproofing on the concrete and it was good thereafter. I think he just thompsonized it.

I think I would slope the deck as well as the concrete on top and put 2" polystyrene on the top to prevent condensation.

If you have to guarantee it, build it like a shower pan and put a rubber membrane underneath, and again slope the bottom and top.

monticellohomes

I agree cleveman. I think if I do one again I am going to install a continuous rubber membrane, like for koy ponds, around the whole area flashing up the wall at least a foot and over the sides at least the same distance. Any seams that might be there use flashing tape. Then possibly even put a floor drain in that room with a sloped floor so if water did make it there is no worries because it has a way out.

I did slope the concrete on top at least a couple inches over 8ft. I think I found where it made it through, some flashing under the front door was caulked down but we had some really driving rain at the time so I think it found a way under. I recaulked under the flashing and at the edge of it...hopefully that does it. I told the homeowner they should only get that if there is driving rain, otherwise there is little that will even get wet given it is an 8ft deep porch.