Glossary of Retrofit Terms

Glossary of Retrofit Terms

Anchor Bolt

Anchor bolts are used to secure the mudsill to the foundation. An anchor bolt is a metal rod, usually with a threaded end, that is set in concrete and is embedded in the foundation or post-installed in existing concrete (see Titen HD).

(Metal) Connectors

Connectors are steel components that connect the frame of the house together. Connectors are used where two pieces of framing material meet. They are designed to strengthen a home and increase its ability to resist earthquakes, high winds and other forces.

Crawl Space

Crawl space refers to the space beneath a home, typically 18 to 48 inches high that is supported by short wood-framed walls known as cripple walls.

Cripple Walls

Cripple walls are short wood-framed walls between the first floor and foundation. They run underneath and around the perimeter of a house. These walls are constructed on top of a home’s foundation and are generally 12 to 30 inches high, but as high as 12 feet when located on a hillside. Cripple walls are vulnerable to earthquake damage and should be properly braced and bolted to the foundation.


Fasteners typically refer to nails, screws, bolts or anchors. Fasteners are used in conjunction with connectors to join framing materials together.


A foundation is the block wall, concrete wall or concrete slab a house sits on.

Joist (Rim Joists, Floor Joists)

Joist refers to the wood members that make up part of the floor system of a house. Rim joists run along the perimeter of the floor system.

Lateral Forces

Lateral forces are horizontal forces acting to move a home from side to side.


Load is an engineering term that refers to the weight of the material that is to be supported. The allowable load is the maximum design load that can be imposed on a connector or an anchor.

Mudsill (Wood Sill or Sill Plate)

A mudsill is the wood frame that attaches to the top of the foundation and to the floor system above. The mudsill should be properly bolted to the foundation.

OSB/Plywood Sheathing

OSB and plywood sheathing are panels made from wood or fiber materials that are applied to the outer studs, joists, and rafters of a home to strengthen the structure.

Post (Column)

A post is a load-bearing vertical wood member.


A retrofit adds additional bracing, anchoring or any improvement to a home.

Protected by Copyscape Originality Check