Special Purpose - Webglas GC


Webglas GC is proving its worth in buildings where steel and other roofing or wall cladding materials deteriorate or corrode at an unacceptable rate. The sheet thickness is 2.2mm or 3660 grams per square metre and is reinforced with a heavy gauge woven glass mat which provides continuous strength and protection in every direction. The overall strength is such that wire safety mesh is not required. This is of particularly importance in chemically aggressive and corrosive environments where safety mesh can eroded and traditional steel cladding can quickly deteriorate.

Where corrosion resistance is vital, complete buildings can be clad and roofed with "Webglas GC" which can be either 100% opaque, or translucent to transmit natural light. For extreme environments, where high levels of acids or alkalines may occur, "Webglas GC+" which incorporates vinyl ester resins, will provide additional protection. What really sets Webglas GC apart is its combination of strength, high resistance to a wide range of chemicals and very low surface erosion. The warranty covers surface erosion for 20 years.

special resin technology used in the highly UV resistant surface coating and sheet is the same as that used for Ampelite's premium grade "Webglas GC", now very widely used in major projects around New Zealand and Australia. "Webglas GC" therefore provides a maintenance free roofing and cladding guaranteed for a specific lifetime.

Webglas GC now uses Ampelite’s Proprietary SL Group 3 “Bromine Free” Fire Retardant Resin System

Webglas GC manufactured in New Zealand after the 15 October 2020 will now use Ampelite’s proprietary Group 3 Bromine Free’ fire retardant resin system that is currently used to manufacture our SL sheeting products.

Surface Finish Properties have been tested to ISO 5660 and achieved a group number 3 performance in accordance with NZBC Verification Method C/VM2 Appendix

The physical properties highlight the benefits of "Webglas GC"
  • The additional reinforcing provided by the heavy woven mat construction eliminates the need to install wire mesh below the sheeting. This makes "Webglas GC" particularly suitable for use in public buildings and schools, or wherever there may be access to the roof.
  • Strong looking. Weave pattern has good visual appeal.
  • The standard thickness of 2.2mm has greater spanning capacity due to being heavy gauge combined with the additional strength of the woven mat.
  • The top (weather side) is gel coated with a specially formulated highly UV resistant resin. This part of the process is identical with Ampelite "webglas GC" premium grade sheeting and provides virtually undiminished performance for 20 years.
  • Loss of light transmission after 10 years is just 10% compared to a loss of 30% for standard fibreglass. Very high resistance to yellowing and discolouration. Over 10 years change is negligible and covered by Warranty, only minor changes occur in later years. In addition, inbuilt UV protection eliminates 99% of harmful rays.
  • Surface erosion is eliminated and covered by Warranty for 20 years. Low surface erosion also improves weathering properties. The gel coated surface provides an almost impenetrable barrier and is warranted against water penetration for 20 years.
  • Better resistance to a range of commonly used chemicals than standard fibreglass (which is good), details can be provided.
  • Fertilizer and Agricultural Chemical Plants
  • Corrosive Chemical processing
  • Petrochemical environments
  • Waste water Treatment
  • Marine Environments
  • Mining Industry
  • Paper and pulp manufacturing
  • Salt extraction and desalination plants
  • Power Stations
  • Sky lighting where safety mesh is not desirable

Webglas GC is fully trafficable and where corrosion resistance is vital, complete buildings can be clad and roofed with webglas which can be either or translucent to transmit natural light

Webglas GC is fully trafficable and where corrosion resistance is vital, complete buildings can be clad and roofed with webglas which can be either or translucent to transmit natural light

Webglas GC is fully trafficable and where corrosion resistance is vital, complete buildings can be clad and roofed with webglas which can be either or translucent to transmit natural light

Webglas GC features a 20 year warranty

For full warranty details, please download a copy of the Webglas GC brochure or  contact your nearest Ampelite office.

Available Colours

Webglas GC in available in clear, opal and grey or as a solid colour in 3 standard colours titania, gull grey and desert sand. Wonderclad and Webglas can be colour matched to any colour. For information on other colours, please contact your local Ampelite office.


Ampelite (NZ) limited is the only fiberglass roof sheeting manufacturer in NZ to be ISO accredited as well holding the internationally recognized 5 Tick standards certification mark.
Webglas GC industrial fiberglass is manufactured in strict accordance with AS/NZS 4256 parts 1 & 3: 1994. Standards License No.SMKB20116.
N.B.Type GC is surface coated with a S996 coating. The highest quality materials available and the very latest resin technology are used in the manufacturing process.


ISO Quality Endorsed Company    ISO Certified Product

Light and Heat Transmission
Clear 60 66
Opal 56 60
Solid Colour 0
Available Profiles & Spanning Capacity

All current profiles such as Corrugated, 5 rib, LT7, BB900, etc. plus most superseded profiles are available.
Please download our list of popular profiles

Profile Fastener Spacing

Fixing per SQMTR

1.5 KPA


Corrugated Every 2nd crest 6.5 1900 1500
5 Rib Every crest 5.2 2500 1700
Steelspan, Topspan Every crest 5 2900 2100
Metric,Windek,MC1000 Every crest 4 2400 1600
BB90 Every 3rd crest 3.8 2700 1700
Supersix Every 2nd crest 3.3 2900 2100
LT7 Every 2nd crest 3.9 2700 1700

Concentrated loads as per AS1170.2. For information regarding recommended spans in high wind and cyclonic regions please contact your local Ampelite office.

Expansion Data
Thermal Expansion 9.1mm 14.4mm 32.4mm 5.8mm 11.5mm
Thermal Co-efficient 1.9 x 10-5 cm/cm°C 3.0 x 10-5 cm/cm°C 6.75 x 10-5 cm/cm°C 6.75 x 10-5 cm/cm°C 2.4 x 10-5 cm/cm°C
Physical Properties
Tensile Strength 111 Mpa
Impact Strength 10 Joules
Shear Strength 90 Mpa
Modulus of Elasticity 5300 Mpa
Compressive Strength 151 Mpa
Flexural Strength 181 Mpa
Specific Gravity 1.6
Thermal Expansion 1.9 x 10-5 cm/°C
Thermal Conductivity 0.096 watt/m°C
Water Absorption .2% in 24hrs./26°C
Recommended Service Temperature Range -20° to +95°C
Technical Support

Projects involving corrosive environments often require supportive evidence regarding product suitability or manufacturers recommendations regarding the use of a particular material. Ampelite can provide extensive technical support to the extent of product development if necessary.
Contact your local Ampelite Office if you require this service.




Ampelite have a large range of accessories available to help make the installation of Webglas GC quick and professional. These accessories include a range of self-drilling that oversize the fastener holes as they pass through the sheet and self-adhesive tapes and profiled form filler strips for vermin protection.
Please download our Accessories and Fixings pdf.


Correct installation is important

Ampelite sheeting shall be installed in accordance with Ampelite fixing instructions and with AS/NZS 1562.3:1996, Design and installation of sheet roof and wall cladding, Part 3: Plastic. The requirements of the NZ building code and the NZ Metal Roofing Manufactures Association Code of Practice.

In corrosive environments we recommend that

  1. All fixings are Stainless Steel
  2. All fixings are metal profile washer and EDPM seal
Flashing and Capping

We recommend that all be Stainless Steel.
Please download a copy of the Webglas Installation Guide.

Please note these additional important requirements

  • Webglas sheeting matching positive fixed profiles shall be installed using the fastening length applicable to the main cladding and a. This combination gives a secure and weather tight finish. The fixing screws should not be over tightened to an extent that the sheet buckles, allowing water penetration at the seal or sheet overlap.
  • Fixing should be made at every crest at both ends of the sheet, and every second crest at intermediate purlins.
  • Normally safety mesh is not required under Webglas, but if sheeting is in CONTACT WITH SAFETY MESH a Protective Fibreglass Protective Strip should be installed over the safety mesh, to avoid fracturing of the underside of the sheet.
  • Where END LAPPING is required a minimum of 300 mm overlap is essential. On profiles such as corrugated, 5-rib or similar, we recommend the use of 25 mm Lap Seal Tape at the top and bottom edges of the purlin. This ensures the strips are concealed. For Decking profiles, two continuous beads of a clear non-hardening sealer (i.e. silicone), must be applied across the full width of the decking within the overlap. End lapping should only be applied to roofs with a minimum pitch of 5°.
  • IMPORTANT: Ampelite sheeting should be installed by pre-drilling oversize holes to allow for expansion and contraction. The basic calculation is 0.75 mm per lin. /m, plus shank diameter of screw. Do not over tighten screws.
    EXAMPLE: 10 m sheet - 10 (m) x 0.75 (mm) + 4 mm (fastener) =11.5 mm pre-drilled hole.
Clip Fixed Decking

Ampelite sheeting matching clip-fixed deck profiles shall be installed in conjunction with the main cladding and should be side lapped with overlaps on both sides (Ampelite sheets have 2 female laps). Fixing of sheets should be carried out in the same manner and practice as those stated for positive fixed profile roofing.

Wall Cladding

Pan fixing is required at each girt, and use of the correct Ampelite washer and seal ensures a weather tight seal. Over tightening must be avoided. Fixing shall occur in every pan at both ends of the sheeting, and every other pan at intermediate grits.

Cyclone Zone Installation

Installation in cyclone prone areas follows the recommendations and code for normal fixing, but further specific requirements must be met. Please contact your local Ampelite office for the latest information.


The sheeting should always be stored in a dry and fire safe area. Do not store heavy materials on top of sheets as they may fracture.

Recycling and disposal

Fibreglass sheeting is not recyclable and should be disposed of in a land fill. Do not incinerate fibreglass off-cuts as burning produces acrid smoke and noxious, toxic fumes.


Webglas sheeting is a trafficable material. Sheets should be handled with care to avoid damage. Guarantees will not apply to sheeting that has been damaged in handling, or mechanical damage.

Safety Data

There are no ill effects from handling 'Ampelite' Fibreglass sheets as a finished product.
Some exposure to air-borne particles occurs on drilling, cutting and trimming of the material. Although there are no known cases of harmful effect, even after long term exposure, it is recommended to take certain precautionary steps.

Effects of Exposure to Dust Particles
  • Eye (contact) Can cause irritation. Appropriate eye protection should be worn. If irritation occurs due to exposure to dust particles, wash eyes with running water using an eye bath or wash bottle. If irritation persists seek medical attention.
  • Skin (contact) Can cause irritation. Shower thoroughly using soap and a cloth or sponge.
  • Inhalation (breathing) Dust masks are recommended although particles are not respirable.
  • Ingestion (swallowing) Non toxic. Extensive studies have revealed no serious effects.
Fibreglass Teks. Fixing fibreglass sheeting to steel purlins

Clearfix Industrial - World Class Fasteners
Webglas GC Info (PDFs)