The original doors were made by Westland Engineering (who now make helicopters!). They are made from an aluminium alloy, run on steel tracks and have concrete counterweights. The original doors have not been available for many years, and it is difficult to find acceptable substitutes: when we looked in 2019 the pattern we had previously recommended was only available to special order, with a setup cost of £3000 per batch.
Dimensions
We believe that all the original doors were the same size: 2250mm wide and 1965mm high.
The appearance of the door is critical, and should be as close as possible to the original: 28mm-wide horizontal grooves on a 175mm pitch, with the lowest ‘land’ being 200mm wide. The original doors had 11 lands (10 grooves), and the more recent replacements had 12 lands with slightly narrower grooves.
The doors are painted in ‘Cedar Chase green’ – British Standard 12 B 21.
Ideas
The existing doors are all of the ‘canopy’ type. It might be worth considering segmented doors if a suitable pattern can be found. These are usually in 4 pieces running on a track, and they never project forward from the line of the closed door. They work very well with powered openers.