Pitched Garage Roof Insulation

If the garage is open to the rafters the boards that support the roof use r 38 insulation between the rafters at the roof if they are 10 inches deep.

Pitched garage roof insulation.

Pitched roofs are a common sight in the uk owing to their versatility and typical low maintenance requirements when compared to other forms of roof construction. Pitched roof insulation between and under rafters arguably the most popular pitched roof solution installing insulation between and under the rafters uses the depth of the structural timbers to best effect. To get more insulation in the garage install a ceiling and provide access to the space between the ceiling and the roof. On new build or replacement pitched roofs the ideal build up would be insulation fitted over and then between the rafters giving a big boost for airtightness image credit.

Pitched roofs are fairly simple to insulate and involve the same process as insulating the loft in your main house. To ensure that i leave sufficient ventilation space i often nail timber stop battens to the side of the rafters. Most garages have flat roofs and despite the name none of them are perfectly flat. The space created above the garage would also have to be fully insulated in a similar fashion to the garage.

If it is a pitched roof or if you plan to build a room above the garage with a pitched roof in the future the requirements will be different than if you are dealing with a flat roof with less than 10 degrees of pitch. Like walls there is a minimum u value that must be met. For pitched roofs i always stick with my old faithful combination of kingsspan kooltherm k107 pitched roof board between the rafters and kooltherm k118 insulated plasterboard for the inside faces. This will allow you to add the needed insulation.

As this requires fitting insulation above the rafters the roof covering will have to be removed in order to fit the insulation. To create a warm pitched roof insulation such as kingspan kooltherm k7 pitched roof board should be fitted between and over the rafters. If the existing roof of the garage is pitched or if you are intending to build a space above the garage with a pitched roof then we suggest you look at our page on pitched roof insulation which covers this area in a bit more detail. Kingspan with a flat roof this issue does not arise but the u value constraint and the amount of insulation needed is just the same.

Another key advantage of specifying a pitched roof is the ability to provide a very high level of thermal performance in these roof types whether you re looking to insulate at joist ceiling level for a cold pitched roof or at rafter level if a living area within a warm roof construction is desired. A full guide on how to do this yourself can be found here. Before fitting any insulation to the sides of a pitched roof space any repairs to the roof should be completed once the insulation is in place it will be harder to spot any leaks inside the roof and any leaks will soak the insulation itself. They are in fact defined as any roof having less than 10 degrees of pitch and need some angle in order to funnel away rain water.