04/03/2010 - Just before the conservatory season starts.

When selling conservatories – remember:



Often the sides of conservatories have to be structural to hold the roof up.

There are NO structural Pvcu windows or doors produced by any UK fabricators.

Even windows of 600mm width need a lintel in masonry walls.

A 30mm Pvcu sill is 24mm of AIR unless you ask for reinforcement.

SNOW is an increase in dead load (& why calculations differ across the UK)

The conservatory roof industry calculates ring beam strengths with a built in deflection allowance of L/125 for polycarbonate & L/175 for glass.

The above means that it is ACCEPTABLE for a 3M ring beam to DIP (deflect) by 24mm for polycarbonate & 17mm for glass.

Try telling a consumer that a 24mm dip is acceptable. The normal human eye can see a 2mm difference in level.

This acceptable deflection is why Bi Fold doors will not work in a conservatory unless planned for in loading terms. It is possible to clear span openings with specific parts.

Best practice on all conservatories is to split the frames on every mullion & use a suitable joint. 6mm or 20mm aluminium joints, load bearing post kits, reinforced outer frames & sills are all available options. It is not advisable to use the 3mm Pvcu joint.

Door positions can hamper the best use of a conservatory (space & building); Edwardian doors are best on the projection facets & don’t forget Victorian doors on an angled facet require ‘squint’ brickwork.

Box gutters should be considered in the same light as ring beams because as well as carrying water they are a ring beam. They need support (not screwing to facia’s) just like the ring beam.

When supplied, tie bars are not optional items; they are necessary structural components & must be fitted correctly.

Remembering these points will allow you to successfully build conservatories, which will give you few if any problems.