Top 5 Crawl Space Repair Mistakes


Several homeowners search the internet for crawlspace repair information and end up in home repair forums. While there is a few quality information in forums, there are many examples of bad and outdated advice related to fixing your crawlspace. May possibly witnessed firsthand the results of bad crawlspace repair and would like to describe the worst 5 crawlspace maintenance I've seen:

1 . Adding more vents to the crawlspace - Old building codes and bad recommendations have resulted in homeowners adding more vents to their crawlspace in order to dry the high moisture content on their crawlspaces. The thinking behind ventilation was that air circulation would force the moisture in the investigate space air to end up outside. Through testing, it has been proven that warm, humid outdoor air brought in the crawl space through foundation vents in the summer can lead to increased moisture levels in the crawlspace.

Also, air movement in a home does not move side to side through the vents, but instead upwards (Stack Effect). This Stack Influence draws air inward from every crawl space vent and up into the living space of the home. A properly encapsulated crawlspace is the only solution to reduce high moisture levels in a crawlspace.

2 . Spray Foam a damp crawlspace foundation wall - While spraying open or closed cell foam in your home is one of the most efficient forms of efficiency, it is rarely applicable in a crawlspace. Spray foam insulation traps water and moisture in the block walls or between the wall and the foam. This moisture has nowhere to go but UP, especially since some sort of building's air movement is upwards (Stack Effect).

Up above the foundation are wood components (sill eating plan, floor joist, bandboard, and subfloor) that are susceptible to wood rot and mold growth. See my article on spray foam insulation in a crawlspace for more information.

3. Attach a vapor barrier to the floor joists - I have not seen a single crawlspace repair mistake more responsible for wood rot and mold as compared to when plastic is attached to the floor joist system. The thinking behind this is to stop moisture intrusion in the crawlspace air from entering the wood components. There are many problems with this; but the most important to know is that a lot of crawlspaces are vented and the cooler surfaces such as duct work, pipes, and the floor will condensate inside summer. The plastic will trap the condensation up against the floor structure causing mold and wood decompose to occur.

4. Insulating a damp crawlspace with fiberglass insulation - This is another example of aged advice resulting in mold growth. Paper faced insulation is "mold candy". Do not insulate your floors using fiberglass insulation.

5. Improperly installed drainage system - Many crawlspaces have water standing on the ground floors after heavy rains. There are many reasons why water enters, and several solutions to prevent or remove the standing water. That worst solution is to ignore this recurring problem, or repair the problem with a stand alone pit and send (especially a pump in a five gallon bucket). A sump pump alone cannot pump all the mineral water that pools around the perimeter or in the middle of the crawlspace. A perimeter drain is necessary to intercept the pool and facilitate it to the pump.