I have rent free (whoo hoo!) access to a 60+ year old detached garage here in the rainy northwest. There is no heat or electricity to it. The floor is old asphalt, lots of cracks and bumps and old oil stains. Though the floor is flat, the garage is built on a slope and there is about a 2′ high retaining wall along half of one side, the sill plate is directly on the floor for the rest of it. The roof is water tight.
The problem is dampness. There is a horrible musty smell in it, an old car I stored in it for a while was covered with condensation inside and out, properly stacked and stickered green lumber I stored in it developed mould, etc. Air circulation is also poor.
The garage is not mine, so I am not keen to spend a lot of $$$ on the problem, but it needs to be solved otherwise the space is useless half the year for me. I was thinking of powerwashing the heck out of the floor in the spring and then slapping down a few coats of asphalt sealer. Will that stuff cut down on moisture coming up through the floor, or is there a better product I could use?
Thanks everyone!
Dan
Replies
I think the key words in your issue are “built on a slope”.
If there is a flow of water to, and under, the garage… you can seal it until-the-cows-come-home and not solve the problem.
The retaining wall slows the water coming down the slope (a good thing)… but does nothing (my guess) to redirect the water around the building.
I would start with abating the water flowing into, and under the garage. I would buy a roll of flex drain tile, rent a trencher, and have a load of stone delivered. Trench a semi circle around the garage on the high-slope-side of the building (bout 2ft.. maybe a bit more if you are in deep-tundra land). Remember… water runs best on the downhill J, so adjust the trench accordingly. Run the trench around the sides of the building and taper the trench off to drop the water back on the surface, well past the building (you may want to put some #2 stone at the surface openings to minimize erosion.
Drop the tile in, cover it with plenty of stone, and top off with soil (mix some sand with the soil if it is real heavy clay). The key is... surface water should percolate as fast as possible into the tile. The more sand and stone... the faster it will percolate.
If you think it will help abate water flow, trench upslope by the retaining wall and tie it into the previously described tile.
This will probably do much more to solve your problem than sealing the floor. But if you want to do it… use a good quality sealer after filling the cracks (sealer won’t do much to abate the seepage if you don’t fill the cracks first).
Biggest issue to remember, however… water that isn’t close to, or under the building… can’t seep into it.
aphalt and garages do not mix.The oil from th ecars eats up asphalt. Plus asphalt is a living creater. It exspand with heat and contract with the cold so it must be recompacted daily. Concrete is the only way. asphalt in the perfect life is only good for about five years.. 2+3=7
I was living with a similar garage for about 10 years. It's not a damp here in the northeast as where you are, but humidity was always a problem. I had some success controlling moisture wicking by lining the floor with asphalt felt (as a cushion layer), a 6-mil poly vapor barrier, then sleepers for a wood floor. I used foam board insulation between the sleepers. It cut the humidity some, but still required heat and a dehumidifier to keep things really dry.
The bottom line is, if you don't have heat and humidity control, all your doing is average out the highs and lows that are outside the building. You can control water, and slow down the wicking through the floor, but in your climate that might not be enought.
Edited 2/3/2006 7:55 am ET by FlashGordon