Fiberglass window frame connections
I attended a local fall home show this past weekend. I spoke to several local window companies, and when i asked if they supplied fibreglass windows, they all turned up their noses, and essentially denounced fibreglass.
So I pressed them a little, “why do you hate fibreglass”. The common response was, “oh, you can’t weld/fuse fibreglass, like you can with vinyl!” “The mechanical joints used in fibreglass windows are junk, they leak, nothing beats a welded joint!” to which i responded, “Houses are full of ‘mechanical joints’, such as the wall to window connections, or wall to floor/roof connections, which rely on quality detailing and installation of said connections”. To which they respond “welded pvc connections are stronger and can handle more load”. I had to walk away, i simply wasn’t armed to respond accordingly.
I was under the impression that fiberglass windows were stronger, allowed for thinner frame profiles, were the least susceptible to expansion and contraction.
While a welded joint surely is an attractive feature, i don’t know why a mechanical joint can’t be just as good? Fibertec, for example, claims to use nylon keys and high quality sealant for their frame joints.
Fibreglass windows score just as good, if not better on the NRCan product listing for all categories, air leakage, water resistance testing, etc etc. Is there any valid reason, or testing which shows problems, or lack thereof?
I had been fairly set on fibreglass windows, mostly in large part from the recommendations found on this site.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part