Designing Your Conservatory

Roof - Glass or Polycarbonate?

When deciding on a glass or polycarbonate roof, it is important to consider the following:

	Glass	Polycarbonate
Light Transmission	Gives a clear view of sky, trees and stars.	Opaque. Transmits only 80% of the light transmitted by glass when new, deteriorating to 70% over ten years - a difference which will be noticeable in low light conditions such as evenings or winter days. Bronze tinted polycarbonate is available, but this will darken the conservatory and adjoining room considerably, and will not have any cooling effect - blinds will still be required in most south-facing conservatories.
Appearance	Does not deteriorate. Surface can be cleaned much more easily. Decorative patterns and solar reflective options available.	Surface is soft and easily scratched by birds, fine grit in strong winds, etc. Green algae and mould can form outside and within units. Stains easily, and cannot be cleaned using certain cleaning agents.
Insulation	Sealed double-glazed units. Pilkington 'K' coating can be offered.	Units cannot be sealed and therefore cannot provide the same heat and noise insulation as glass double glazing.
Noise	Double-glazed units reduce the amount of outside noise getting in and inside noise getting out.	Reduced noise insulation (see above). Very noisy when it rains. Can emit loud bangs or cracks with expansion or contraction during temperature changes.
Strength & Security	Withstands storms and heavy snowfall better because it is stronger. Could shatter if struck by a sharp object - NB. will shatter into many small pieces NOT long shards.	Easily cut or prised off by burglars. Can be torn out in high winds. Check insurance policies carefully - may not cover damage to polycarbonate roof sheets from fireworks, bonfire sparks, etc. Very dangerous to stand on.
Quality & Price	More expensive to install and replace. If fitted to a poorly-constructed conservatory, a glass roof will increase costs considerably, as the conservatory will not have the strength to support the additional weight. However, if fitted to an architectural aluminium conservatory, which will be some 25 times stronger than a uPVC equivalent, the additional cost will be low.	Cheaper. There are many different qualities of polycarbonate - it may not be easy to know the quality you are fitting without expert independent advice.
Weight	Very heavy to lift. Conservatory must be much more substantial to withstand weight.	Lighter - easier to fit. Can be fitted to cheaper, more lightweight conservatories.
Lifespan	Enduring quality appearance over many years. Sealed units can break down.	Limited lifespan - deteriorates under normal weather conditions. Ultra-violet degradation can occur, leading to possible penetration by hailstones. Some manufacturers offer only 5 years guarantee, or no guarantee against hailstones in some cases.