Insulating Roofs At Rafter Level

When insulating a pitched roof at rafter level there are a number of key design considerations which will affect the build up of the roof and the choice of insulation.

Insulating roofs at rafter level.

You can also add rigid foam insulation under the rafters which adds r value and eliminates thermal bridging through wood rafters. The simplest and most common way to insulate a pitched roof is to add insulation above the horizontal ceiling of the top floor. 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. How is roof insulation installed at rafter level.

Recommended home insulation r values. It creates a breeding ground for mold and mildew and ruins the air trapping pockets that block heat flow. The higher the r value the better the thermal performance of the insulation. Insulation is friction fitted between rafters with the option to underline the rafters with a layer of thermal laminate to further enhance thermal performance.

Insulation level are specified by r value. In this blog post we explore some of the options available. Consider using high density r 30 batts which are as thick as r 25 batts but fit into 2x10 framing. It can be advantageous to combine more than one of these approaches for example by insulating between and below rafters.

Firstly just to make it clear when we are talking about rafter level we mean the timbers that support the pitched roof. The table below shows what levels of insulation are cost effective for different climates and. Pitched roofs can be insulated between below or above the rafters. A vent baffle should be installed between the insulation and the roof decking to maintain the ventilation channel.

Insulation can be placed above between or just below the rafters. From part l of the building regulations england and wales or section 6 scotland we recommend that the u value of a pitched roof insulated at rafter level should be 0 18 w m 2 k for a domestic refurbishment. However the design of the building may restrict some of these options. The current trend is for a warm roof where insulation is installed between the rafters thereby keeping the roof timbers warm.

Water is insulation s enemy. Insulating roofs at rafter level for buildings with rooms in the roof space insulation can be added above between or beneath the rafters or as some combination. R value is a measure of insulation s ability to resist heat traveling through it. However if the top floor is open to the rafters and is used as habitable accommodation then insulation will need to be provided at rafter level.

The first decision is whether to insulate a pitched roof at ceiling or rafter level.