*
Hi,
I’ve been renovating my basement over an extended period of time. Wood studs are up on the exterior walls, Roxol insulation fits nicely. One year later, I removed some Roxol to run more wiring and noticed a super-fine white almost crystal formation. It’s so light that I can brush it off.
Does this pose a health hazard?
The basement appeared to be 100% dry prior to my work and the walls dry when i began, but I presume that there was just enough circulation in the air to evaporate any moisture on the walls. The foundation is made of concrete block and looks in very good shape (Built in 1956). I coated the walls with Xylex (sp) waterproofing to satisfy my paranoia. I’m tempted to re-install the Roxol and new drywall and think about improving the exterior landscaping.
David – Toronto
Replies
*
"I'm tempted to re-install the Roxol and new drywall and think about improving the exterior landscaping"
Give into that tempation to think about landscaping!
Efflorescence asuch as you describe is an indication that moisture is moving through the block wall outside to in: the moisture picks up salts from the masory units, reaches the inside wall and evaporates, leaving the salts behind as efflorescence.
Be sure to have positive grading around the house and good downspout extensions: 10' typical minimum.
*So Bob, are you saying that it's nothing to worry about. I'm moving into an older house, and a firend of mine may be having this problem.Gary
*No, that's not what I'm saying: effloresence is usually a sign of moisture movemenmt through a masonry wall / structure.You need to keep uncontrolled moisture out of a house, especially if you're going to cover over the areas that get wet because of the increased chances of mold growth. To control mold growth we have one effective avenue: control moisture - keep it out.
*Health wise i don't think the salts are a threat, but as Bob pointed out, it is a sure sign of a moisture encroachment problem. Covering it up without solving the problem may lead to a later problems with mold growth, which can become a health issue.