When using polycarbonate glazing sheets the following should be considered:

1. Expansion and Contraction of Polycarbonate Glazing Sheets

With changes in temperature sheets can expand or contract approximately 3mm per metre in both directions so allowance must be made for this movement .

All Omega glazing bars allow for this movement; our bar caps can move with the glazing sheet. Each sheet should be screwed down at one end. (Remember to oversize the fixing hole by 3mm) This is normally done at the back wall plate or ridge so that the screws are covered by the flashing. This prevents the sheet creeping down the glazing bar as it contracts and expands.

To calculate the cut sheet width for a
given glazing bar centre to centre dimension simply deduct 12mm from
the
glazing bar centre to centre dimension.
Example:-
Glazing bar centre to centre dimension = 1.062 metre
Polycarbonate cut sheet width - 1.050 metre

Or

To calculate the glazing bar centre to centre dimension from a given
sheet
width simply add 12mm
Example: -
Polycarbonate cut sheet width 0.700 metre
Glazing Bar centre to centre 0.712 metre

2. Sealing the Sheet Flutes

The air inside the sheet flutes must be allowed to expand, i.e. the sheet must breathe. The top end of the sheet is sealed with self adhesive aluminium tape whilst the bottom (usually the gutter end) is taped with breather anti-dust tape. Taping is essential to prevent the ingress of dirt and insects. A sheet closure extrusion is usually fixed to the bottom of the sheet to protect the breather tape and provide a neat appearance.

You may purchase separate components to make up your conservatory roof or specify an Omega bespoke conservatory roof. In either case we recommend the use of 16mm or 25mm multi wall polycarbonate sheet which is available in clear, bronze, opal, combined bronze/opal or sheets that deflect solar radiation. 10mm twin wall polycarbonate is not recommended as condensation is likely to be a problem.

10mm twin wall polycarbonate sheet is normally used for these extensions. Multi wall polycarbonate sheet with its extra thermal insulation is not usually required. Car ports often have a low pitch roofs so where wide sheets are to be used it is important that these are fixed/buttoned to the purlins to withstand wind and snow loads. Advice is available from our sales office.

Indoor pool areas are usually heated so we recommend the specification of at least 16mm multi wall polycarbonate because of its high thermal insulation value which reduces condensation problems. This will cover any length pitch up to 7 metres although purlins will normally be required to support the rafters. For added strength buttons can also be used to fix to the purlins.

N.B. A swimming pool with a high chlorine content will have an extremely corrosive effect on stainless steel, galvanised steel or aluminium: therefore these parts should be inhibited with an etching agent or some other preventative action taken.

Please contact our sales office for advice.