What is the best rafter insulation?
Normally, people use mineral wool or insulation boards to insulate the rafter space. We prefer recycled insulation for obvious reasons. If you are planning to use wool then it is imperative you wear protective clothing, goggles and a face mask, since the wool is an irritant.
Should there be insulation on roof rafters?
Insulating between rafters will do no good, because the attic should be ventilated, and the rafter insulation would be between two unheated spaces. You can add insulation to the floor; the more the merrier. Just don’t put it in the eaves. Also, make sure the attic is well ventilated.
How do you super insulate a roof?
One of the best ways to insulate a roof (whether sloped or flat) is to install rigid foam on top of the roof sheathing. Exterior foam can reduce air leaks, limit condensation at the sheathing layer, interrupt thermal bridging through the rafters, and make ice dams unlikely.
What roof is the most energy-efficient?
Metal roofing
Metal roofing is by far one of the best choices you can make for your roof in general. They’re the most energy-efficient roof for residential installations, can last more than 50 years, and require very little maintenance. Metal roofs are very reflective, which is why they get so hot to the touch.
What is the highest R-Value insulation?
Insulation R-Value Chart
- Closed Cell Spray Foam: R-6 to R-7.
- Foam Board: R-4.5 to R-5.
- RetroFoam Injection Foam: R-4.6 to R-5.
- Open Cell Spray Foam: R-3.6 to R-3.9.
- Cellulose (Loose-Fill): R-3.1 to R-3.8.
- Fiberglass (Batts): R-2.9 to R3.8.
- Fiberglass (Loose-Fill): R-2.2 to R-2.9.
Can insulation be thicker than joists?
For the most effective results, insulation that is thicker than the depth of the ceiling joists should consist of two or more layers. The thickness of strips making up the first layer should equal or exceed the width of the ceiling joists.
Is a black roof less energy-efficient?
While the exact numbers are tough to run, in general, lighter-colored metal roofs are more energy-efficient than darker-colored metal roofs.
How do you insulate between the rafters of a roof?
Additional insulation can be placed between the rafters using batts, dense-pack or low-density spray foam to reach the desired overall R-value. An additional benefit of a properly insulated roof is protection from ice dams. Dense-pack blown-in insulation has two advantages over the more common batt insulation.
What kind of rafters do you use for a 16 inch floor?
To achieve the 16-inch depth we wanted for insulation and an air space under the sheathing, we used open-web, parallel-chord trusses as the rafters. These trusses, typically used as joists, have diagonal bracing or “struts” and are made in Quebec by Open Joist Triforce.
How many layers of insulation do I need for my roof?
With three layers of 11⁄2-in. polyisocyanurate insulation above the sheathing and approximately 91⁄4 in. of cellulose insulation in the rafter cavities, the roof shown here has an R-value of approximately 63. The three layers of foam help to seal air leaks, but to make this assembly perform well, you need to incorporate some unconventional details.
What are the benefits of insulation on a roof?
An additional benefit of a properly insulated roof is protection from ice dams. Dense-pack blown-in insulation has two advantages over the more common batt insulation. First, dense-pack naturally fills all gaps and cracks, while hand-cutting batts inevitably leaves voids and compression that lead to unnecessary heat loss.