Insulation you never see
If your San Jose home sits on a raised foundation, its floor insulation is out of sight: batts fitted between the floor joists, above the soil of the crawl space. You may only notice a problem when a floor feels cold or a home inspection report flags it.
Many San Jose homeowners book crawl space cleanup with us, and new floor insulation can go in during the same visit, on one written quote.
Signs the floor insulation has failed
Look from the crawl space access with a flashlight. Any one of these is worth a free inspection:
- Batts hanging down from the joists or lying on the soil.
- Bare spots where you can see the wood subfloor.
- Batts that are damp, stained or smell musty.
- Droppings on or inside the batts, or batts torn apart by rodents.
- A home inspection report that flagged the crawl space insulation.
Batts lying on the ground do nothing for the floor above them.
Why batts end up on the ground
Under the house, batts usually come down for one of three reasons: they were never held up properly, they got damp, or rodents pulled them down. The University of California (UC IPM) notes that Norway rats burrow along building foundations and, indoors, keep to the ground level, which puts a crawl space right in their path.
New batts only last if the cause is dealt with first: the crawl space cleaned out, the foundation vents and pipe gaps sealed with galvanized steel mesh, putty and concrete, and the new batts properly supported. See crawl space cleaning in San Jose and rats in the crawl space.
How we fit batts under a San Jose floor
First the old, fallen or soiled batts come out. We haul them away, and the removal is its own line on your written quote.
Then new batts are cut to size and pressed snug between the floor joists, worked around pipes, wires and framing. Metal wire supports hold them up against the floor, so they do not sag back onto the soil. Details on the batt insulation page.
Which R-value under the floor?
Batts come in set thicknesses for each R-value. Under the floor, R-19 is the most common. For every job we install the R-value that fits your home, based on what you ask for and what we recommend at the inspection. The attic gets a thicker layer than the crawl space; see attic insulation in San Jose.
Kraft-faced or unfaced batts?
We install both. Part of the choice is yours: some homeowners pick one over the other partly because of cost. When the old insulation is taken out first, kraft-faced batts are usually the better choice. We go over the options at the free inspection, and your quote names the batt type and the R-value, so you can compare it line by line with any other quote.
Vapor barrier and ducts in the same visit
With the old batts out, it is the easiest time to cover the soil. A white vapor barrier goes over the ground; we install 10, 15 and 20 mil, and thicker holds up better where people crawl or store things. If the ducts under the floor are torn or chewed, they can be replaced with a new duct system in the same visit. Two or more services get 10% off (one discount per job).
Job day
Most jobs take one day. Please be home, and clear the path to the crawl space access of breakable items, like pictures and vases. The crew covers the path from your front door to the access with drop cloths or plastic sheeting, and our crew sends you before and after photos.