We're often asked this question and we always recommend toughened safety glass because it is strong and safe. 

Traditionally, greenhouses are supplied with 3mm-thick horticultural glass because it's cheap. Unfortunately, however, it isn’t safe, because it breaks easily.

Here's our guide to getting the right glazing for your greenhouse.


This is the traditional standard in greenhouse manufacture.

However, the safety concerns outlined above are the reason behind the current trend towards safer and stronger glazing alternatives. 

The individual panes supplied measure 2ftx2ft and overlap mid-way on each section of the greenhouse. The panes are then held together with "S" clips.

The major disadvantage of 3mm horticultural glass is that when it breaks it does so into large, dangerous shards. Cleaning also proves difficult, because dirt and algae gather in the joins where the two panes meet.


Toughened safety glass is the best option. It offers a good degree of safety, and if it breaks, it breaks safely.

The large panes have no overlaps, which means fewer draughts and they are easy to keep clean.




Twin-wall polycarbonate has the advantage that it offers increased insulation, which may be useful in the winter months. 

It does, however, suffer from two major disadvantages. Polycarbonate is so light that it makes the greenhouse vulnerable to wind damage. It also reduces light levels, which can be a problem for your plants.

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