Recently we were asked to take a look at a crawl space that smelled a little musty. During our review of the crawl space we determined a few problems:
1. Some of the joist batt insulation had fallen down
2. Some of the joist batt insulation was installed backwards
3. A few pieces of the rim insulation had fallen out
4. The min. of 6-mil (or higher) polyethylene sheathing to cover the ground was missing
5. Fungus was growing on the floor joists
Here are some steps to take to rectify the problem:
Step 1
It is important that the fungus/mold gets treated. Most folks think that straight Clorox is the solution. This is indeed not the case since it may actually harm the wood fibers. A 5:1 water to bleach mixture would be suggested to kill what mold that is there. Exterminators recommend coating the wood with a solution of Boric Acid (BORON) and water. It will kill the fungus and keep it from coming back (and in addition any other wood boring insects that ever try to eat the wood). Boron dehydrates the fungus and mold but it will also kill carpenter ant, termites, boring bees, powder post beetles who try to eat the wood. If you can find Boric Acid, you can also use a product called Roach Away ( approx. 95% Boric Acid) which is an insecticide that can be found in many local stores and mix it with hot water. Apply the solution with a pump sprayer to the affected areas.
Step 2
Install the batt insulation. Insulation with a vapor retarder should be used. Pay attention so that the vapor retarder faces up towards the heated area of the home. The insulation should be installed tight up against the subfloor. The insulation should stay temporarily in place. Once the insulation is in place, hold it in position with insulation support wires. Make sure the ends of the batts fit snug up against the band joists.
Step 3
Infill the missing rim insulation where need. You can use the same vapor retardant faced insulation as in Step 2.
Step 4
Cover the ground with black min. 6-mil polyethylene sheeting,overlapping joints by 12" or more. Then use duct tape to join the overlaps and or use rocks to hold the material in place. This will prevent ground moisture from entering the space, rising to the flooring above and causing fungus, mold or wood rot. The polyethylene sheet makes a great moisture barrier.
You trusted handyman Handy Andy
Visit us at www.HandyPro.comSeptember 2013