Installation of a turf roof on a log cabin using Oldroyd Xv cavity drainage membrane
The log cabin was built in the garden of an existing house to provide an additional, cost-effective dwelling.
The clients were inspired by the timber buildings with turf roofs that they had seen whilst husky racing in Scandinavia. They were also attracted by the environmental benefits of a turf roof, in particular the high degree of insulation that these types of roofs provide. Turf roofs are known for their ability to provide an extremely constant temperature throughout the year. During the winter they keep the heat in, and in the summer they provide a relatively cool environment. It was also felt that a turf roof would blend in with the surrounding environment better than other roof-types.
Building the Log Cabin
A hand-built, “true” log cabin was constructed using traditional techniques by Log Cabin UK of Aberystwyth. The cabin was built from specially selected trees from a renewable source that were felled, and then milled to a diameter of six inches. The logs were shaped and jointed on-site. As each layer of the cabin went up it was held to the layer below by means of large wooden pegs.
Constructing the Turf Roof
The wooden roof structure was constructed with a narrow spacing between the rafters to support the added weight of the turf. 20 mm marine ply was fixed to the rafters and roofing felt was fixed on top. Special “turf hooks” were then nailed into place around the perimeter of the roof. The Oldroyd Xv Black membrane was then laid on-to the roof with the studs facing downwards. Where joins were necessary, the membrane was allowed to overlap and a seal was created using Oldroyd sealing rope.
Timber battens were then fixed to the turf hooks, creating a “lip” around the whole roof area, creating a space for the turf to sit in. 100 mm of soil was then applied to the roof, follwed by 50 mm of turf.
The contractor was particularly impressed with the grip that the “x-pattern” on the Oldroyd Xv membrane gave him while working on the roof.