[Greenbuilding] flooring underlayment

[Bruce Donelson]

>>My favorite underlayment is a 1/4" birch plywood with no voids in the
>> interior layers.

With glue that diffuses into the home environment?

It uses an exterior glue that outgasses something like 1% (the techies can
give you the best numbers, here) of the formaldehyde that an an
interior-rated glue will outgas. And the continuous sheet of flooring will
probably force much of that to the floor below, which may well be the
crawlspace. Moreover, it is resistant to water. If it gets wet, it dries
out, without exploding and ruining the floor. Considering that sheet goods
are frequently installed in wet locations, this makes for less floor
replacement. Around here, the vast majority of underlayment is 3/8" particle
board, with interior glue.

Moreover, unlike particle board, the plywood underlayment is accepted by all
of the sheet goods manufacturers, and they don't accept particle board,
because it can bleed beige colors through the surface of the sheet goods
sometimes. And because the plywood has no voids, it is resistant to dents
from concentrated loads (read "high heels.")

If somebody has something they like better, bring it on. I'm always ready to
look at new products.

Bruce donelson
A Better Builder