Install squash blocks.
- Squash blocks are an alternative to rim boards or rim joists and blocking panels. Squash blocks are pieces of lumber usually 2 X 4 (38 X 89 mm) that are attached to the sides of the manufactured floor joists. The squash blocks are used to transfer the vertical loads through the floor system. Squash blocks are normally used on the main floor of a two-storey house and in combination with a single rim board. Squash blocks are to be cut approximately 1/16″ (2 mm) longer than the depth of the wood-I floor joists as shown in Figure 9.
Figure 9 - Flooring system squash blocks support installed with wood I joists
Problem: Wood I Joists Are Overstressed At Point Loads.
Cause: Wood-I hoists are not designed to carry large concentrated loads
The engineering system is based on the transfer of concentrated loads through the floor system on extra blocking. Wood-I joists can be made more economically when they do not have to be designed to carry concentrated loads.
Install solid blocking to transfer the loads through the floor system.
- Install solid blocking under all concentrated loads to carry the load to bearing walls, beams or the foundation. Jack studs supporting lintels, and columns supporting beams, are the most comm0on situations where concentrated loads are found as shown in Figure 10.
Figure 10 - Flooring System Blocking - Carrying Concentrated Loads
- Solid blocking under point loads is most often made from 2″ × 4″ (38 × 89 mm) or 2″ × 6″ (38 × 140 mm) lumber. The blocking must be lightly longer than the depth of the joists sot that the loads are transferred through the floor system to the foundation.
- Blocking should be installed when the floor is constructed, not added afterwards. When blocki8ng is installed at the correct time, it will take up the loads as they are applied. It is impossible for blocking added after the subfloor is in place to be of the required length.