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1st April 2015

Insulation: Roofs

Insulating Flat Roofs

The simplest and most common way to insulate a pitched roof is to add insulation above the horizontal ceiling of the top floor. 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. Insulation can be placed above, between or just below the rafters. Upgrading a pitched roof at rafter level to a desirable standard can be complicated and is not without risks. Generally solutions will need to be individually designed and professional advice will often be needed.

 

Insulating Roofs at Rafter Level

The simplest and most common way to insulate a pitched roof is to add insulation above the horizontal ceiling of the top floor. 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. Insulation can be placed above, between or just below the rafters. Upgrading a pitched roof at rafter level to a desirable standard can be complicated and is not without risks. Generally solutions will need to be individually designed and professional advice will often be needed.

 

Insulating Thatched Roofs

Well-maintained thatch is a highly effective weatherproof coating; traditional deep thatched eaves will shed rainwater without the need for any down pipes or gutters. Locally grown thatch is a sustainable material, which has little impact on the environment throughout its life-cycle. It requires no chemicals to grow, can be harvested by hand or traditional farm machinery, requires no mechanical processing and therefore has low embodied energy and can be fixed using hand tools. At the end of its life it can be composted and returned to the land. Straw has a much greater insulating value than any other traditional roof covering. With the right choice of material and detailing, a well-maintained thatched roof will keep a building warm in winter and cool in summer and has the added advantage of being highly sound-proof. Changes to improve the energy performance of thatched roofs should only be attempted where necessary as many thatched buildings already provide adequate thermal performance and where the traditional ‘breathable’ performance of the building will not be compromised.