I would appreciate your advice before I tackle the builder who has installed a new triple carb roof on my conservatory.

The original roof, some 7m wide and 4m deep, was laid on wood rafters. The polycarb (triple glassed) sheets had a series of aluminium capping bars holding them down onto the rafters. The bars were screwed down into the rafters between each pair of sheets. The width of the new poly carb sheets is metric and hence different from that of the original roof (1985). The builder laid the new sheets on the rafters without cutting them to fit; as a result, the joins do not coincide with the rafters. The sheets are joined where needed, using a lightweight aluminium strip under the joins, with a simple "plug-in" plastic seal over the top, (which seems to be waterproof). This arrangement obviously means that the weight of the roof is taken by the rafters. However, because the sheets cannot be screwed down to the rafters, each one is held in place by two screws at the top and two at the bottom through plastic cups (approximately 4cm in diameter) with rubber seals etc .

Because the sheets are some 4m in length and are only secured at the top and bottom, the whole roof lifts and flexes if the doors are opened and the wind is blowing!! Not very satisfactory.

How should the sheets have been secured and what needs to be done to solve the problem? An expert's view would be very welcome.

Regards,

Peter Lacy

peter Lacy, July 2009

peccavi has said it all really,your builder has done a poor job,polycarbonate sheets can be sourced very easily cut to size so no need to join them where he has.get him back to sort or threaten trading standards
mark
kingfisher replacement conservatories

mark cairns, July 2009

You paint a scary picture - snow on the roof may well be supported by the rafters underneath but the way you describe the fixings on the long edges with no hold down fixings other than at the outside edges makes me think you need a visit from a qualified person to give you a formal report that you can use as evidence in court.

The area of the roof you describe is 300² ft. A Spitfire is a mere 242, weighs 6000lbs and can fly at 80mph. When the wind blows strongly your roof will just take off and fly about - like the opening scenes in the Wizard of Oz.

Your builder appears to have been negligent with respect to the potential effects of the wind. If the panels don't bend and break with the aerodynamic forces, the simple screw fixings will be continually stressed until they eventually lose their hold - once the weakest one goes the rest will soon follow.

Peccavi, July 2009