Fixing the reciprocal roof on the Boiling Wells roundhouse

Work has been continuing on the repairs to the roundhouse roof originally built by Shift Bristol at Boiling Wells.

There have been big problems getting any covering to stay on the roof. The pitch was far too steep, approaching twenty degrees off vertical in places! Therefore, we decided to build terraces of timber which are not fixed down onto the roof below, but sit on it. 

Landscaping textile and old carpet were used to protect the pondliner from being damaged by the timber and also to hopefully soak up some water and prevent the roof drying out too quickly in summer. 

The compartments in the terracing were then filled with a layer of pea gravel. They will eventually have a layer of substrate (70% ground up brick, 30% compost) put on that and, finally, sedum mat put on top of that. Some areas are too steep for even the terracing to help, so may be partially enclosed to make 'window boxes' that can be filled with soil and then have herbs planted in them.

We have been lucky to have had extra help in the last two weeks, from people who are currently unemployed through an agency called 'Pinnacle People'. Their work has been a massive boost to the repairs and moved things forward a lot. Thanks to all of them.

Phil (who was part of the original Shift build crew) and Simon also volunteered and helped a lot. It's a great feeling to see the roof starting to look like it's nearing completion.

Some thoughts for anyone thinking about making a similar structure, as the repairs (hopefully) near conclusion...

I have to say that if I were to build a roundhouse in the future, I don't think that I'd put a reciprocal roof on it. The irregular angles and pitches have been a pain to deal with at times and, although pretty, the whole thing is really a bit impractical.

The reciprocal roof is made using a support called a 'charlie', which is removed to drop it into place. This makes it hard to control the angle that the roof finally sits at, which is made worse by the irregularities in the roundwood rafters causing bumps and lumps in the roof. I will admit that more experienced roundhouse builders may have solutions to these problems, but I'm not aware of them.

These bumps and lumps have made covering the roof a bit of a nightmare - things that need straight lines (such as shingles or tiles) don't fit properly and living cover can slide off. 

One solution may be to use old tyres to make roof terracing, which Shift Bristol has tried on another roundhouse build. This would look okay in summer, but when the vegetation dies back in winter it has an aesthetic that is perhaps not to everyone's taste.

I'd be far more inclined to put a flat roof with a slight gradient (between 10 and 30 degrees) on a roundhouse. It would be a much easier, quicker build and far easier to lay sedum mat on and to maintain. 

It was great to have the roundhouse built at Boiling Wells and Tony Wrench, the Shift Bristol students and the volunteers worked very hard in less than two weeks to do it. The structure is attractive and interesting and it's been fascinating to learn about such things as lime rendering etc. when finishing it. 

I would say to any organisations looking to have such a building built on that kind of time schedule and by a similar group of people, most of whom are inexperienced in this kind of construction, that they really have to have a decent pot of money in reserve to correct problems and to finish the build off (with doors, floor etc.).  Bear in mind that these things will cost you in time and money - possibly at least a couple of thousand pounds. These roundhouses are not necessarily cheap!