Helping my brother renovate his basement on the weekend.
We debated on whether to rip out the old stucco drywall or just put new drywall overtop.
Happily our younger help was up for more demolition.
Glad we did ....
We discovered black mold on the concrete behind the drywall. This can be a big health hazard especially for underground dwellers living everyday in basement apartments.
The cause:
The previous basement finishing job left an incomplete area behind the furnace that had only insulation on the outside wall covered with an old curtain. --- No vapor barrier plastic -- no drywall !
This left a large area exposed to outside air movement around the Air conditioner pipes and tiny gaps between the concrete walls and the wooden base of the upper house.
This air movement allowed the cold winter outside air to mix with the warm humid inside air causing moisture to form on the walls.
Over time this encouraged mold growth blackening the concrete wall behind the drywall.
The Fix:
We cleaned it with a spray bottle of bleach and water mixed. Within minutes we saw the wall change from black to the old gray concrete.
After some searching of the internet I realized how dangerous cleaning mold can be. Had I read it first I would have taken more precautions (wearing air masks, hanging plastic sheets creating negative pressure etc.)
Of course the bleach smell was strong and we opened all the windows. we could have done other things. I read that Hydrogen Peroxide is great for killing bacteria.
Hydrogen Peroxide is apparently much safer than bleach because it does not give off gas a bleach does that can burn your lungs.
Hopefully none of us get sick later from our cleanup.
Repairs:
We used spray foam to seal the gaps around the AC pipes and gaps in the wall.
Fresh insulation , vapor barrier and drywall is being installed.
This time it will be completely closed and sealed.
Next we will need to rip out the old wall in the laundry room because we see black peeking out from that side.
The moral of the story:
If you are renovating a basement and are considering leaving the old walls, DONT.
Its the opportunity see whats going on behind. It may not be pretty!
