Glass gazebo canopy
It is true that sunrays still penetrate through glass, even the high quality types of glass that are used for these gazebo canopies. An easy possibility to overcome this, however, is to choose for a shade cloth over, or under, the glass roofing.
Most types of glass that are used for a glass gazebo canopy can resist all types of weather, with the exception of severe hail.
What we do often see in glass, are patio roofs! Which is in fact quite the same as a gazebo canopy, except that it is placed over a patio.
Possibilities with glass
A simple reason for this is, that it is seen as an extension of your house.
Some sort of orangery.
There are two types of glass often used.
Both have their own advantages and disadvantages.
The first is milk or opal glass. This is glass that still let's through a lot of light, but no of the sun rays. Ideal to choose for a gazebo canopy or pergola!
Another option you can choose from is high insulation glass.
This glass has three layers of glass, and reflects a lot of the heat that is sent out by the sun. However, there will still be a lot of sun and heat coming through this glass.
A good option would thus be to also choose for an extra shade cloth that you can roll out whenever it gets too hot under the gazebo canopy.
Advantages and disadvantages
The biggest advantage will, without a doubt, be the view that you have. With no other material -except perhaps PVC- you keep your full view.
Choosing for materials like wood will give you some maintenance work to do regularly. With glass, you will only need to clean it now and then. You don't need to use products to keep it 'in shape'.
As we said in the advantages of glass, you only need to maintain glass a few times a year. The problem with glass is that you can see everything that falls on it.
Whenever it starts to rain, or when leaves fall on the roofing, you'll probably have to clean the glass gazebo canopy.
Another disadvantage that we are all aware of, is that glass is fragile. If there is heavy hail, or wind, chances that the glass breaks are big.
The last disadvantage of glass, is that it's quite expensive...