Roof Rafter Bridging

Structures such as sheds or barns can be frames with rafters every 24 again make sure to consult local codes.

Roof rafter bridging.

Failure to mitigate can account for overall heat loss of up to 30 so it s not a thermodynamics lesson to be taken lightly. With steel framing at about r 04 per inch it s thermal bridging on a whole different scale. The uninsulated roof framed with wood r value around 1 1 per inch means rafter lines covered with snow. Brush up on thermal bridging 101 here.

Place a long piece of framing lumber alongside the rafter so that the narrow edge is flush with the underside of the roof deck and the bottom reaches the ceiling joists. Steel framing typically reduces the in cavity r value by as much as 50 while wood framing reduces in cavity r value by a bit less than 10. Thermal bridging is the movement of heat through a material that s more conductive than the air around it. It can consist of lateral members spanning in between trusses t or i bracing on individual members sheathing or metal strapping.

Drive a nail into either end to hold the board in place. It is always better to have a large rafter rather than be concerned with a sagging roof. The weight of the piano is centered over a single joist but the bridging transfers some of the weight to the adjacent joists. If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center.

For example with bridging installed between joists a piano leg sitting over one 2 10 is actually supported by several. Most codes allow foil faced foam to be left exposed. The blocking or bridging between joists or rafters also contributes to this phenomenon. In either case seal the foam edges well to the rafters with spray foam.

Place a short piece of framing lumber against the rafter above it so that the two boards form a continuous line.