When it comes to greenhouse construction, ensuring that your glazing is secure and weather-resistant is crucial for creating an ideal growing environment.
Twinwall polycarbonate sheets are a popular choice for greenhouse glazing due to their lightweight nature, excellent insulation properties, and UV resistance.
However, the challenge lies in correctly fixing these sheets to an aluminium greenhouse frame to ensure they stay in place through all kinds of weather conditions.
In this guide, we'll walk you through the step-by-step process of securely attaching twinwall polycarbonate sheets to your aluminium greenhouse, ensuring a sturdy and long-lasting installation that will keep your plants protected and thriving.
Materials Needed:
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4mm twinwall polycarbonate sheets
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Aluminium glazing bars or profiles (if your greenhouse has existing ones)
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Polycarbonate fixing buttons or screws with rubber washers
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H-profile or U-profile aluminium edge strips (optional, for edges and joints)
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Drill with a bit suitable for aluminium and polycarbonate
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Measuring tape
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Protective gloves and eyewear
Guidance:
- Preparation:
- Measure the area where you will install the polycarbonate sheet to ensure it fits correctly.
- Clean the aluminium frame and the polycarbonate sheets to remove any dust or debris.
- Positioning:
- Place the polycarbonate sheet onto the aluminium frame where it will be fixed. Make sure the UV-protected side (if labelled) is facing outward.
- Align the sheet properly, ensuring that the flutes (internal channels of the twinwall) run vertically to allow for proper water drainage.
- Drilling:
- Drill holes through the polycarbonate sheet and into the aluminium frame. The holes really should be about 2-3mm larger than the screws to allow for thermal expansion of the polycarbonate.
- Space the holes about 300mm apart along the edges and at the centre of the sheet for secure fixing.
- Be careful not to overtighten the drill bit to avoid cracking the polycarbonate.
- Fixing:
- Use fixing buttons that we supply (or screws with rubber washers) to secure the polycarbonate sheet to the aluminium frame. The rubber washers will help to seal the holes and prevent water ingress.
- Ensure that the screws are tightened just enough to hold the sheet in place without deforming it.
- Edge Protection (optional but recommended):
- If needed, fit H-profile or U-profile aluminium edge strips along the edges of the polycarbonate sheet. This helps to protect the edges from damage and improves the appearance.
- For joining two sheets together, use H-profiles, which will hold the sheets securely while allowing for expansion and contraction.
- Final Check:
- Once all the sheets are installed, check that all the fixings are secure and that the sheets are properly aligned and undamaged.
General Tips:
- Thermal Expansion: Polycarbonate expands and contracts with temperature changes, so always account for this by not overtightening screws and allowing a little space around the fixing points.
- Sealing: If your greenhouse is in a particularly wet area, consider applying a UV-resistant sealant around the edges to ensure water tightness.