Open Foundation Vents
A vented crawl space allows hot, humid air to flood into the crawl space during the warmer season and cold air during the winter months. This results in high humidity and moisture when it's warm and even humidity inside the home and cold floors and drafts in the home when it's cold.
As the humidity and moisture increase in the crawl space, it is soaked up by the fiberglass. As fiberglass gets wet it becomes heavier and begins to sag and fall, the moisture also deteriorates the insulation causing the fibers to pull apart from each other in a process called delamination, this is what makes fiberglass look like its "dripping."
Sealed Foundation Vents
Foundation vents are sealed off to prevent outside air carrying moisture and cold air from flooding into the crawl space.
Sealed Vapor Barrier
A heavy-duty, 10-mil vapor barrier is installed. All seams are overlapped and sealed and all piers are wrapped and sealed. This seals the crawl space off from the earth's moisture.
To help control the moisture seeping through the foundation walls, we install our vapor barriers about 6 inches above outside grade. This will direct any moisture down behind the liner and keep it out of the crawl space. Then, Closed Cell Spray Foam will be applied to the foundation walls at an R-10 to insulate and air seal.
Moisture & Efflorescence
Moisture seeps through the porous foundation walls and brings the minerals in the block to the surface with it. As the moisture evaporates into the air it leaves behind a white powdery substance, this is efflorescence. It's a clear indicator of where moisture is finding its way into the crawl space.
6-mil Vapor Barrier
6-mil vapor barriers are what are installed during construction. They are typically just laid out over the ground and in some cases held in place with "u" shaped stakes. These "barriers" do not seal the crawl space from the earth's moisture. In fact, all the gaps left behind around the edges and at the seams allow moisture to rise from the earth into the crawl space.