Neighbor asked me to fix a section of his wall in the basement where the brick had been plastered over. All the plaster crumbled off the wall and I can see a lot of salts coming out of the brick. On the other side of this 2 course brick wall is a 2′ tall deck set on top of a concrete patio. The deck boards are tight up against each other (but not cupping) Two sides of the deck are up against the inside corner of the L shaped house. One side is all stairs and the 4th side is car siding set tight up against each other, so the underside of the deck is sealed up tight. I took one deck board off and all the wood and the bricks are very damp. Wood is starting to rot and I think the moisture went through the bricks and caused the plaster to fall off on the inside.
So my plan is to take the siding off the one side and put in lattice. Then take up all the deck boards and shave 1/8″ off one side of each one to make a gap. Then add a bunch of 2″ round vents to the stairs. Will this create enough ventilation to dry everything out well? Any other insight on this problem is appreciated.
Replies
My question for this is where is all the water coming from? Where is the roof draining? Is it rain or just a high water table? Are there foundation drainage/soil issues too?
The deck boards are tight to each other and aren't cupping because they are full of moisture. They will shrink when they dry
Using latice or round vents doesn't address the actual problem. Open up the sides to get the existing moisture out, then correct the source of the water. Once the deck drys you will have the desired spacing.
Ok, thanks for the advice, I'll open up the deck and get it dryed out.
The gutters are clogged and dumping water on the deck right up against the house. I didn't mention that the first thing I am doing is getting the gutters in shape.
Thanks
Rich
I agree that the damp below is keeping the decking from it's usual shrinking. Spacing wider might help, but I wouldn't shave off anything-I'd eliminate as many boards as it takes to gap it bigger. You'll never hit the same holes in the joists with your screws. Probably be a good idea to lay some flexible peel and stick membrane along the tops of the joists to seal all the exisiting and new holes.
The natural convection of air usually needs the same opening sq ft (inches) as the exit area. 2" vent caps sound small.
The way the deck is configured, the furthest inside corner will not get much air movement. And that appears to be the problem area with the dumping gutters.
Just some more thoughts to think about b/4 you act.