SHOULD MY FRAMES BE REINFORCED?
Years ago when PVCu windows first came onto
the market, some of the frames available just wouldn't have performed well
at all if they didn't have reinforcing in them. These early frames were only
50mm or 55mm deep with 2mm wall thickness and constructed with only two
chambers. Nowadays it's a different story. Virtually all of the top
extruders supply 70mm profiles with 3mm wall thickness and constructed with
five chambers and all of them have BS, CEN and BBA certification for their
There are a few 60mm to
65mm profiles available, mostly used for commercial or housing developments
where cost is a factor but so far as the general public is concerned, so
long as you buy a 70mm profile from a reputable supplier, you should have no
Reinforcing of uPVC frames is one of the
most misunderstood things about Windows and Doors. Most people, including
some builders and architects, think it is necessary to specify fully
reinforced frames when ordering PVCu products thinking that: -
- They will be stronger if they are
- The frames can be used as a structural
element to hold up other parts of the structure.
- uPVC isn't up to the job unless it's
However, this is not so. In most cases,
especially with small frames, reinforcing is not needed at all. In fact for
outer window frames, most fabricators don't consider reinforcing unless the
frame is over 1800mm in length, in which case it is usually reinforced as a
matter of cause. For window frames under this size it really doesn't need it
as uPVC profile frames are extremely strong.
The purpose of reinforcing PVCu window and
door frames is to control the rate of expansion and to provide rigidity to
frame sections over a certain size. It is also used to provide rigidity for
hardware, particularly where door locking mechanisms are fitted. Reinforcing
can be specified in exposed and coastal areas where wind loading on larger
frames is a consideration.
However, there is a case for fully
reinforcing PVCu frames. All foiled (wood grain) products are fully
reinforced as standard. The reason for this is to provide an enhanced
control of the rate of expansion for these products. The dark finish and the
coloured PVCu extrusions absorb heat far more than white extrusions and can
deform if not controlled by reinforcing. All of EasyFit foiled and wood
grain products are fully reinforced automatically as well as all uPVC door
uPVC WINDOW AND DOOR FRAMES REINFORCED WITH?
uPVC windows and uPVC door frames are
reinforced with either aluminium or galvanised steel. The choice is the
preference of the fabricator and there is a small cost differential too.
Aluminium is slightly more expensive but it is easier to work with and
doesn't add too much weight to the products whereas steel is heavier but
cheaper. The actual shape is no more than an "L" or "U" section of thin
steel or aluminium and does not go the full length of the profile; it stops
several centimetres short so as not to foul or interfere with the welding
process and where there are mullion or transom joints, the reinforcing is
fitted in pieces and is not normally inserted as a full length. Therefore
reinforcement is not suitable for structural support put purely for the
reasons outlined above.
For bay poles, bay posts and structural
mullions, a thicker section is used. This is to provide strength and
rigidity where frames are to be joined together and to provide a strong
fixing ground. Bay poles and posts can be used in a structural situation and
jacking plates are available if required.
Don't get hung up about reinforcing, leave
it to your supplier to provide a correctly fabricated product that will give
you trouble free service throughout it's life. Your can be assured that if
you buy your frames from EasyFit Window Warehouse the you will always be
supplied with the correct reinforcement suitable for your requirements.