An improvement in an installation having a continuous water-impervious liner
forming
a barrier against the entry of water vapor and insects such as termites from the
sub-soil into a crawlspace. According to the present invention, the water-impervious
liner is provided with one or more access openings to the sub-soil, each covered
with a flap, patch or cover which is openable to provide access to the sub-soil,
and which is resealable to restore the water-barrier and/or water vapor-barrier
properties of the liner in simple fashion as often as necessary.
