Page 630 - 2018 National Home Improvement

2018 National Home Improvement Estimator, All Rights Reserved Page 503

* joining stepped or sloped side cripple wall top plates at each splice joint with strap connectors.
Heavy steel straps should connect securely on both sides of the splice. Make the top plate of a stepped
cripple wall act as though it were one piece along the entire length of the wall.
* structural panel sheathing applied over the stepped wall and on the downhill wall.

Split-Level Homes
The weak point in a split-level home is where vertical offsets join a common wall or other support at
different levels. See Figure 18-9. In an earthquake, floor and roof framing can pull away from the
common wall.

To reduce the risk of damage due to earth movement, add ties to the floor framing on either side of the
common wall. Where the offset in floor elevations is no more than the depth of floor joists, install steel
straps every 8 feet along the common wall. Where the offset is more than the depth of a floor joist, the
IRC doesn't offer a solution. You'll need help from a structural engineer.

Anchor Masonry Chimneys
Fireplace chimneys are heavy, rigid, brittle and very susceptible to earthquake damage. Chimneys in
older homes may not have reinforcing steel and usually aren't anchored securely to the house. In an
earthquake, large sections of the chimney can fall away from the house - even into the house. The IRC
now requires both horizontal and vertical reinforcing and chimney anchors that tie into the floor, ceiling
and roof.