11.06.2020 Cladding the dome.

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There is a tarpaulin projects making business not too far away. I have requested a colour chart after trying some handy options simply draped over the dome. The colours appear much lighter and brighter up there when seen from the ground. A light grey, trailer tarpaulin looked almost white.

Which my wife objected to. She wasn't too keen on the shine either. No doubt it will tone down with weathering and a daily UV bath. If it's sage green it will hopefully continue to go unnoticed.

I have ordered a new heat gun in anticipation of a cladding trial. My cheap one having expired years ago. YouTube has lots of videos on welding PVC tarpaulins. It doesn't look that difficult. I still need a roller. I'm not sure my nylon one will stand the heat. The cost of covering the dome in heavy duty, ~600gm/m^3 PVC is likely to be about £200 equivalent. A fraction of the cost of a replacement dome in any shape or form.

I can staple the top of each gore in turn to hang correctly. Then weld each overlapping seam to the next to keep the rain out. Though I could weld a strip over edge butted gores of PVC. Which would give a more traditional finish. I'll have to see what looks neatest. I could even replace the black rubber EPDM, with the coloured stuff, for a more uniform appearance. Or  cover the rubber with PVC for an even heavier skirt. One which won't flap quite so much in the wind. Though I do have a stiff upstand inside to stop rain blowing in.

Ordering a ready made tarpaulin would mean lots of creases from folding, edge seams and eyelets. This business may be able to supply 2.4m wide from the roll if they have an acceptable colour in stock. That means cutting gores from a long length with lots left to spare. We shall see.

At least it will give me a break from worrying about the rain pouring in. It was really depressing to discover how all that expensive marine sealer has cracked wide open on almost every joint. It is no wonder it is leaking like a sieve!

The use of tarpaulin, with its relatively long, useful lifetime, suggests a lighter dome design than mine. It would need a strong framework to resist crushing forces from the wind. Though there would be no need for the plywood panels because the tarpaulin becomes the stressed skin in its place.

Cross bracing between the ribs is probably still essential for adequate support. The shutters would certainly need plywood support. The framework ought to be smooth to resist abrasion wearing through the tarpaulin from the inside. Local puncture repairs can be dealt with by patches and a heat gun.

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