- Q.How soon can concrete forms
be stripped from a foundation wall? Can we build on
them as soon as they’re stripped?
A.The forms should
remain in place for at least 8 to 12 hours after
the wall is poured, if the temperature is above
50° F. You can begin laying your sills and
joists, and building light frame walls, immediately
thereafter. But avoid backfilling or other work
that places a lot of stress on the foundation
walls, for at least seven days after the pour. By
this time, the concrete should reach 80% of its
ultimate strength. If the concrete is placed in
cold weather, you should wait longer before
building and backfilling to compensate for the
delay in the setting reaction.