Welcome to the pleasure dome
Will Shields on the cusp of completing his first brick dome at The Serai. He offered a helping hand and I grabbed it and promptly inserted tools. But in truth, I knew he was a handy fellow and also that I would have him for only ten days, so I had prepared something unusual he could really get stuck into. Not many domes are built these days using fired earth bricks and lime but it’s all there on the web if you dig enough.
I toyed with various techniques until finding some ancient sketches from India showing a man using an L-shaped stick. Much easier than trying to get a sand ‘form’ to stay there in our strong winds and I modified the principle by welding a 10cm length of angle iron to the end of the stick in place of the ‘L’. This gives you the correct angle, both lengthways and sideways, at which to set each brick. A second, identical stick allows you to get on with the next brick while the last one placed remains supported until the mortar has made its ‘grab’. The height of the fulcrum and length of the stick determine the shape of the finished structure. A central fulcrum will create a spherical dome; if it’s offset a Mughal style results. Some care is needed in the calculations as only a centimetre’s difference in either stick length or fulcrum height will have a surprisingly large effect on the final form.
The wine and beer bottles ( 2 x bottom halves taped together) we thought might be a bit naff but actually they work beautifully (below) and the other main advantage of this stick technique is apparent here too: old bricks look fantastic on their own. You just have to brush the mortar as you go. If you were to build this on top of a sand form, once the sand was removed it’d look a right old mess on the inside and you’d have to plaster it. We finished off these ones with a steel reinforced white concrete render over the outside. Overkill I think, but I always have a tendency to over-engineer stuff. These domes are 2m diameter; Will built the first in 3 days and the 2nd in just two. And he’s looking rightly pleased with himself. Thanks Will.