Roof Insulation For 2x4 Rafters

For light load roofs 24 o c.

Roof insulation for 2x4 rafters.

If you get premium kiln dried lumber then you could span 10 5 with the same size of lumber and. The original roof ceiling was framed with doubled up 2x4 joists for extra strength. There is no standard spacing it depends on what size of rafters you want to use and the span of your shed. For standard shed roof rafter spacing see rafter span chart.

Shaded or north facing roof pitches would be the most susceptible but with only 2x4 rafters and likely r13 or less the roof deck runs warmer drier than if it were insulated to current code min. The rebuild was done the same way. It s easy to say oh yeah just put 1 2 drywall on your ceiling forgetting that it weighs over 50 pounds. We just had rebuilt repaired the roof of a flat roofed addition to our house due to a roof leak and resulting breakdown and mold problems.

If your local building authority has a rafter spacing code you may not space rafters wider than required by code. Spacing your 2 4 shed rafters at 24 on center limits the width of your roof. It s already a low ceiling 78 ceiling on the low side and 87 ceiling on the high side. If your rafters are only 2x4 either you ve got about 400 sqft or you ve reinforcement load bearing partitions beams somewhere.

Install a timber stop batten across the rafters as shown in position c with the batten equalling the thickness of the quinn therm insulation. They are directly below the roof sheathing and are were insulated with fiberglass batts stapled between the 2x4 rafters. Visit the roof framing page for more information on cutting roof rafters and visit the roof pitch calculator for determining rafter lengths based on rise and run. So at 16 oc each joist is 2 2x4s together.

For instance 2 grade 2x4s at 16 on center will span just over 9. Moving to 16 on center you could span your spf 2x4s up to 6 for heavy loads and 9 for light loads which would still work with a 12 12 gable shed. A drywall sheet is 32 sqft. 2 4 rafters can span up to 7.

Let s say you ve 384 sqft of ceiling to cover. Whether there is a real hazard or not depends primarily on your local climate climate zone as well as your shingle color type and shading factors. Typical rafter spacing codes will specify a minimum spacing of 16 inches 19 2 inches or 24 inches. There are some unfinished crawl space areas in the corners on the upper floor.