Under Rafter Roof Insulation

An efficient room in a roof in a new build property where over rafter insulation is not desirable.

Under rafter roof insulation.

Radiant barriers work best on sloped roofs that are perpendicular to the direction of the sun. From retrofit applications to new builds superfoil is the perfect insulation for your pitched roof project. The 4 of rigid foam under the rafters at least give you r26. It will help you to eliminate problems that may come when the house becomes extremely cold in the winter and terribly hot in the summer.

Arguably the most popular pitched roof solution installing insulation between and under the rafters uses the depth of the structural timbers to best effect. Look for water stains on the roof sheathing or damp or moldy spots on attic joists and existing insulation as a clue to where leaks might be. Superfoil manufacture a wide range of products suitable for both under rafter and over rafter installation. When specifying the insulation for the pitched roof it is important that the thickness of insulation used achieves the required u value.

Roof attic insulation options costs and pros cons. Also radiant barriers are best utilized in warmer climates than in cooler. Superfoil makes pitched roof insulation a breeze with its easy and quick installation methods with no excessive measuring or cutting required. But a 2x6 rafter with a 1 5 vent space would give you the ability to put 4 of rigid insulation r 26 in that space which was not filled.

In order to add moisture barrier under metal roof you can spray the undersides of the roof by using a thick layer of polyurethane spray foam. The quest for greater energy efficiency in buildings has led to increasing interest and need for insulation improvements in hvac equipment more airtight construction new materials and assemblies. Water is insulation s enemy. Senior engineer manager at icynene john broniek makes the case for the unvented attic assembly and why insulating the underside of the roof makes sense.

There is a requirement when refurbishing a roof to have a minimum u value of 0 18 w m k in england and wales but for a complete re roof in wales the minimum u value required is 0 15 w m k. It creates a breeding ground for mold and mildew and ruins the air trapping pockets that block heat flow. 2 would be to create the baffle in the 1st place. Think of the same example of a wall and attaching drywall with the tons of screws.

Radiant barriers use large aluminum foil sheets under the roof s interior to reflect the sun s heat. Set the boards onto a wide 30mm bead of vapour resistant sealant applied to the under surface of all the joints and cross noggins. The general advice we give is that you should always insulate between and above the rafters or between and under the rafters on our u value calculator we don t give an option for putting insulation between the rafters. Box out light fixtures.

Polyurethane spray foam metal roof insulation.