FAQ's
The following FAQ's are related to Modek products.
Feel free to contact us if you don't find your answer here.
- Fibreglass (Glass Reinforced Polyester – referred to as GRP) sheets are produced using a thermosetting process.
- Polycarbonate (referred to as PC) sheets are manufactured using thermoform plastic.
- Polycarbonate sheets have a very high impact resistance which makes them virtually unbreakable, and therefore makes them particularly suitable for use in high risk areas where damage from hail, high wind loads or vandalism is likely.
- The colour you choose depends on how much light transmission is required: but remember that plants do not like the colours green and blue.
- You need to remember the following when choosing a profile
- You need to match an existing profile
- There is a specific water run-off requirement
- Particular physical requirements (e.g. rigidity) are needed
- GRP: 2.4 and 1.8 kg / m2 sheets satisfy most industrial applications in South Africa.
- Modek's domestic range of products is manufactured between 1.0 kg/ m2 and 1.8kg / m2. These are designed to suit less aggressive conditions than those encountered in industrial applications.
- PC: 1.25 mm nominal thickness is deemed to be the Standard Weight Specification for all industrial installations. This specification will meet the rigorous conditions found in an industrial environment.
- 1.00 mm nominal thickness is manufactured as a lightweight PC sheet to be used mainly in those applications where exposure to wind is less (e.g. side wall applications).
- 0.8 mm nominal thickness is used in the domestic market only. We need to be aware of the shortcomings of this product and correct that during construction. i.e. purlin spacing to be 900 mm
- Ladder
- Cutting Tools:
- GRP Fibreglass : Fine Tooth Saw
- Polycarbonate: Circular saw
- Hand Drill and Drill Bits
- Fixing Nails, Hammer
- Tape Measure
- Straight Edge (Timber)
- Pencil
- Duck Boards
- Sealant (Non PVC for Polycarbonate)
- Safety Goggles
- For the domestic applications the rule of thrum is 900 mm.
- GRP: A fine-toothed hacksaw or angle grinder with standard masonry cutting disc or 40 / 60 grit diamond blade.
- PC: A tungsten-tipped circular saw blade. Must be firmly supported during cutting.
The following FAQ's are related to Modek products.
Feel free to contact us if you don't find your answer here.
- Use a high-speed steel bit and do not punch the holes,as it will split and damage the fibreglass and will not allow for expansion. Pre-drilling of the hole is recommended.
- The fixing nails should be between 50mm and 75mm
- The diameter of the washer should be a minimum of 20 mm up to 30 mm.
- Use a polyethylene (or similar) soft washer backed with a steel cup washer.
- Always place the sheeting weather side up because the UV protection is on one side only.
- The weather side is marked with a sticker.
- Fasten every crown at both ends of the sheet and alternative crowns on intermediate purlins. If there are end laps, these will be fixed at every crown.
- NB: Do not fasten through the valley of the profile.
- Do not locate a primary fixing closer than 50mm to the end of the sheet.
- Beware of areas which may be in the immediate wake of obstructions such as a tower or surface which may be swept by high winds. Beware also of potential high wind speeds In narrow gaps between buildings.
- On large projects which take some time to complete, consideration must be given to the risk of wind damage which may occur to partially clad buildings during adverse weather conditions.
- If there is a normal direction of weather in your area (e.g. Rain from the north-west in the Cape), ensure that the side laps of the sheets are installed away from the prevailing conditions.
- Seal end laps on roof sheets, which have a pitch of less than 10 degrees. Use a PVC or Mastic sealant for Fibreglass. It is advisable to apply a bead of silicone under the washer to prevent possible leaks at fixing points.
- The profile should match the end and side laps of the adjacent metal or FC roof sheets. These laps should be sealed with A sealing mastic or a closed cell white self-adhesive tape by applying the sealant to the bottom sheet before laying the top sheet over.
- Where sheets are installed in a continuous run, the side and end laps should be double sealed with a sealing mastic or a closed cell white self-adhesive tape to avoid dirt and moisture getting into the laps.
- Fastening must be square to the sheeting so that the cup and soft washer seals firmly on the sheet.
- PVC sealants must NOT be used with Polycarbonate.
- Protective gloves and eye protection should be worn when handling, cutting or drilling the sheets. Dust protective masks should be worn when cutting sheets.
- Avoid working on a roof in excessively windy conditions, and take precautions to avoid the sheets being damaged by wind when handling.
- This process is radically slowed down in a MODEK GRP sheet because of the presence of UV stabilisers and the excellent surface protection afforded by the gelcoat surface treatment, which also incorporates UV absorbers.
- PC: The sheets are similarly affected by UV attack over a period of time.6
- GRP: As with almost all plastics, will be adversely affected by UV attack, over a period of time. The noticeable change, after a prolonged period of outdoor exposure, will be a slight yellowing.
- Because of the gelcoat layer, no fibres become exposed during the normal lifespan of the sheet, and the layer of gelcoat cannot peel off GRP.
- The layer of UV protection on PC sheets will not peel off.
- GRP: The weathering surface is covered with a highly UV stabilised gelcoat layer. For the Industrial range and a resin rich service protection for the Superdek and Econospan range The sheets do not transmit harmful UV rays.
- PC: Has a UV surface layer co-extruded on the weather side
- Standard GRP sheets will resist chemical attack in most usual industrial and marine environments. PC can be more affected – please consult the chemical resistant charts.
- Both GRP and PC are combustible when in contact with flames.
- Whilst PC sheets do burn, they are self-extinguishing when the source of the flame is removed and will not promote fire or assist spread of flame.
- GRP sheets are highly scratch resistant.
- PC sheets should have extra care taken when handling, as their resistance to scratching is low.
- No, if fastened correctly, and the supporting structure is even and stable.
- Regular maintenance should be carried out in order to maintain designed light transmission.
- Periodically clean the sheets using warm water and detergent, and wash down with fresh water.
- Periodically inspect fastenings and flashings and re-tighten or renew as necessary.
- It is not recommended that you paint the sheets.
- Providing it is watered and has light it will grow.
- Plants will not grow under GREEN & BLUE sheets
