Insulating Roofs At Rafter Level

The higher the r value the better the thermal performance of the insulation.

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

Our insulation solutions for warm roofs maximise both space and thermal efficiency whilst also contributing to acoustic performance. Firstly just to make it clear when we are talking about rafter level we mean the timbers that support the pitched roof. Insulation is friction fitted between rafters with the option to underline the rafters with a layer of thermal laminate to further enhance thermal performance. R value is a measure of insulation s ability to resist heat traveling through it.

How is roof insulation installed at rafter level. Consider using high density r 30 batts which are as thick as r 25 batts but fit into 2x10 framing. In this blog post we explore some of the options available. 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.

The first decision is whether to insulate a pitched roof at ceiling or rafter level. Box out light fixtures. Water is insulation s enemy. 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.

Insulation can be placed above between or just below the rafters. A vent baffle should be installed between the insulation and the roof decking to maintain the ventilation channel. 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. It can be advantageous to combine more than one of these approaches for example by insulating between and below rafters.

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. However the design of the building may restrict some of these options. It creates a breeding ground for mold and mildew and ruins the air trapping pockets that block heat flow.

The techniques explained in this guidance are compatible with most pitched roof coverings notably tiles slates stone slates and shingles.