Southern Sheeting Supplies

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Southern Sheeting Supplies, Industrial, Agricultural, Domestic

G.R.P. Rooflights

GRP sheeting is manufactured using UV stabilised unsaturated polyester resin and glass fibre reinforcement material. The weathering surface is covered with a highly UV stabilised "gelcoat" layer. This new generation technology offers superior weathering characteristics to conventional methods of surface protection in the GRP sheeting industry.

GRP roof sheets are manufactured on an automated continuous line laminating machine using a thermosetting process. This process ensures consistently high product quality in successive consignments, and allows for any transportable length of sheet to be made.

A range of colours is manufactured, with the standards being clear, white (opal 50), green and blue.

All the generally used profile shapes, to match those of other non-translucent roofing and cladding sheets, are supplied by Southern Sheeting Supplies in any transportable length.

The internationally accepted unit of measurement (as used by us) for GRP sheeting is a nominal weight per area. The metric unit used is:

Kilograms per square metre of product (kg/m2).

Nominal thickness of profiled GRP roof sheeting should not be used, as this measurement will vary slightly from profile to profile when a uniform production weight is used. All continuous line laminating plants in the world manufacture to a mass or weight parameter, and not thickness.

The weights available are as follows:

1.8 kg/m2

2.4 kg/m2

3.0 kg/m2

3.6 kg/m2

Where a special or unusual application applies, or if any doubt exists, please contact us for advice.

2.4 kg / m2 is generally recommended


New generation UV stabilised unsaturated polyester resins are used in the manufacture of GRP sheets by means of a thermosetting process.

A "gelcoat" layer, consisting of extremely high grade isophthalic neopentyl glycol polyester resin, is chemically bonded to the weathering surface of all SABS 1150/1984 grade sheets.

Extensive weathering tests have been done, proving that, because of the "gelcoat" layer, no fibres become exposed during the normal lifespan of the sheet, and the layer of "gelcoat" cannot peel off.

The end result is a high-gloss surface providing a tried and tested method of protection against damage from exposure to the weather, UV, chemical attack, corrosion and surface abrasion.

GRP, as with almost all plastics, will be adversely affected by UV attack, over a period of time. This is called photodegradation.

What occurs during this process is the following:

The aggressive short wave length UV rays are absorbed into the polyester resin. They "excite" the chemical molecular bonds of the polymers, causing them to separate, resulting in a yellowing of the sheet.

This process is radically slowed down because of the presence of UV stabilisers and the excellent surface protection afforded by the "gelcoat" surface treatment which also incorporates UV absorbers.

The noticeable change in a GRP sheet, after a prolonged period of outdoor exposure, will be a slight yellowing

There will be virtually no change to the physical properties over this period, and, under normal conditions, a GRP "gelcoat" sheet will remain structurally sound for more than 20 years.