Page 635 - 2018 National Home Improvement

2018 National Home Improvement Estimator, All Rights Reserved Page 508

One word of caution: A concrete wall or floor slab that doesn't have proper expansion joints can be put
at risk by too much crack repair. Generally, walls and slabs need an expansion joint every 8 to 10 feet.
Without joints, concrete walls and slabs will crack due to changes in temperature.

Epoxy injection can also be used to seal cracks that leak water into a basement. The application
procedure is the same except that full penetration of epoxy into the cracks isn't essential.

Floors Out of Level
Earth movement can cause uneven settling of a foundation even when the foundation remains intact and
structurally sound. No building is completely level. But if the floor above a conventional crawlspace
foundation is out of level by more than 1" in 20 feet, it may be possible to re-level the home.

Before making repairs, satisfy yourself that future soil movement is unlikely. A soils engineer may
recommend either pressure-injected grout or pipe piles. Both are expensive choices and may be
impractical for most homes. The National Construction Estimator includes cost estimates for both
pressure grouting and steel pipe piles.

Inspect the crawlspace under a home that's out of level. You'll probably find tilted support posts, floor
beams that lack adequate support and fractured or slipping mudsills. If you plan to re-level a home,
make repairs to posts, beams and sills part of the plan. Otherwise, the home isn't likely to remain level
for long.

To re-level a home with a conventional crawlspace foundation, jack the floors back to level using bottle
jacks and needle beams. Chapter 4 has details and cost estimates. Start by backing off the foundation
bolts. Then set needle beams under floor joists and begin raising the floor. This should be a gradual
process, no more than 1/4" per day. When the floor is back to level, inject grout under the mudsills and
shim other supports. Some cosmetic damage to interior finishes at wall corners and around wall
openings is almost inevitable. Exterior walls will show cracks at the sill line.

Framing Repairs
It's common for large beams to split and twist along the long axis as the wood dries. Frame walls tend
to creep at least slightly out of square and plumb as lumber dries. Normal splitting and twisting of
lumber is considered a natural event, not a structural problem. Earthquake damage to framing will be
more serious - such as walls racked so far out of alignment that windows or doors no longer operate
smoothly.