Foam Board Insulation In Attic Rafters

Better than spray foam thermal break and relatively consistent r 30.

Foam board insulation in attic rafters.

By adding the insulation under the rafters to maintain a ventilated roof at a cost of say1600 for a r28 airsealed radiant barrier product with the ability to add more if needed at a later date how is that a bad idea if an air sealed attic floor w blown in will cost roughly the same and i still won t have a good environment for hvac etc. Some types of thicker foam board insulation are available but they may need to be special ordered. For diy attic insulation you ve got two choices. It comes in standard size 4 8 sheets and smaller sizes in many different thicknesses from 1 4 inch to 2 inches.

Loose fill or batt the common term for blanket insulation. 2 snap a chalk line between the length measurements. Install them using panel adhesive or screws. Foam board insulation is easy to use and is a great diy way to add some insulation.

Once you ve decided which type is best for you examine the material options and prices to home in on the right product. Measure the length and width between two rafters in your attic and transfer the measurements to a 4 ft by 8 ft of rigid foam insulation board. Rigid foam board also known as foam board or insulation board can be an excellent option for insulation. The superattic system creates a continuous air and insulation barrier directly beneath the attic roof with no thermal bridging to compromise energy.

Smaller sizes are also available. They re much lighter and easier to work with than plywood sheets. It is lightweight and easy to work with. Unlike solid insulation products that require careful measurement cutting and fitting spray foam can cover even the most uneven surface instantly.

Typical thicknesses range from inch to 2 inches with estimated r values of r 3 for the inch to r 10 for the 2 inch board. A 4 by 8 board weighs next to nothing and can easily be cut to fit. The superattic system utilizes proprietary silverglo rigid foam insulation panels to fully seal and insulate the attic directly beneath the roof rafters and directly inside the gable ends. Both can be added to uninsulated attics or layered over existing material.

Here s how to use 3 layers of 2 inch polyiso foam board to meet code and keep your ne.