Fiberglass Greenhouse Glazing

Fiberglass greenhouse glazing, which is still an option on todays market when selecting a glazing material for your greenhouse is not as common as it used to be. While it has been a very affordable option in the past, it has largely been replaced by other materials; mainly polycarbonate greenhouse glazing.

The reason that we’ve seen a trend away from using fiberglass to cover greenhouses is due to the short falls of the plastic resin that covers fiberglass panels used for this purposes. As time passes this outer coating can begin to breakdown and erode which causes the fiberglass to darken. This, as discussed in our article about how greenhouse glazing works, leads to less light being transmitted through the glazing and reaching your plants.

Although other materials have surpassed fiberglass for most people when they are designing their greenhouse as a whole; it can still be very useful for specific applications. Fiberglass sheets lend themselves very easily to being used for end wall applications.

Fiberglass comes in rolls, much like Christmas wrapping paper. The size of these rolls varies, but in general the cost per sq. foot will be less when you buy in bulk. Likewise it would be a shame to near the end of a project and run out of glazing material and have to reorder. For these reasons make sure you sit down with a pencil and a calculator and figure out how much material you will need. As with any material that is flexible and comes in sheets, you need to remember that a greenhouse “breaths”, by this we mean that the greenhouse needs to expand and contract. For this reason, when installing fiberglass sheeting make sure to use rubber gasketed screws to allow for this type of movement.

Advantages of Fiberglass Greenhouse Glazing

  • New fiberglass glazing is manufactured in a way to add additional UV resistance to resist yellowing.
  • Fiberglass is lightweight when compared to traditional glass glazing.
  • Fiberglass diffuses light – which means it is less likely to “burn” plants.
  • Although more lightweight than glass it offers light transmission at the same level of glass.
  • Fiberglass offers better heat retention characteristics that glass.

Disadvantages of Fiberglass Greenhouse Glazing

  • Like most plastic or synthetic glazing materials fiberglass can have condensation problems.
  • As mentioned above, the outside resin layer can breakdown leading to a darkening of the glazing.
  • Inexpensive fiberglass can have a short lifespan – 5 years or less.
  • Cheap fiberglass can yellow quickly

Fiberglass, though once the glazing of choice, has been replaced by several newer types of greenhouses glazing. But it does have its advantages in certain situations, so you shouldn’t dismiss it outright. Greenhouse glazing is one of the most important choices you will make when designing your greenhouse. Make sure your choice is well informed.

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