On 9 Mar, 09:23, "David WE Roberts"
wrote:
Life is always complicated.
So is this post.

I am planning to use B&Q windows because you can buy them off the shelf and
as this is a new build I can (more or less) plan the wall around the
windows.

We went to a B&Q Warehouse yesterday to make the final decisions and
generally sort out the fine detail.

[By the way, B&Q have this 'face board' at the door with pictures of the
staff and all their specialities - building, plumbing, electrical etc.
Excellent idea. We tracked down the two building experts. Turns out they
weren't really builders. One was a baker. They pointed us to the builder. He
wasn't happy that he was listed as a plumber because he didn't know about
plumbing. Go figure.]

The staff were very helpful (howver, see above).

We asked "Is there a set of instructions on how to fit the windows?".
[Reasonable question, as it is a good idea to know what is required before
you start, and any asssumptions made.]

The windows included on the label the size of the frame and the size of the
opening required.
The opening was 10mm wider than the frame and 80mm higher than the frame.
We asked "Why the extra height?".

Answers were "No" and "Don't know".
Further discussion - I can see that 30mm is for the cill but what is the
extra 50mm for - and we were told that the extra space was for the trickle
vent which was sold seperately and had to be fitted because of Building
Regulations.
40mm high strip that just clips on.
O.K. - the workshop is not a habitable room so this shouldn't apply.

It is nice to deal with mature people - a bonus in B&Q - because they
'borrowed' a set of instructions from a window so we could read them.
They then made a photocopy so we could take it away.
I did suggest that they might like to make a couple more for future
reference but I don't know if they did.
The other thing that they did was to show us the clip (another extra which
you wouldn't know about until you had read the instructions which were
sealed inside the window package) which clipped into the outside of the
frame and then protruded inwards (or optionally outwards) to be screwed to
the wall.

This was obviously a potential problem The window is expected to go into a
cavity wall opening so with a double skin wall there is plenty of depth.
We are building a single block wall so the opening is 100mm.
The frame is 60mm deep.
So if you sit the frame back into the opening (as is usual) you don't have
enough space at the back for the fixing.
Fortunately there is an alternative strategy - fit the brackets so they face
outwards, drill in at an angle of 70 degrees then cover the screw and
bracket with the silicone sealant bead you run round the outside.
Subject to further checking this may be a feasible option.

However there is another fly in the ointment.

We are looking at windows which are 905mm wide.
The dimensions on the package say that the opening should be 915mm wide.
The instructions say that there should be a 5mm gap all round - presumably
to allow for fine adjustment with packing to get the window exactly plumb,
also to provide some depth to fit the brackets.
Errrr.......
1 block is 440mm wide.
Mortar between blocks is 10mm.
A two block gap is therefore "Mortar-block-mortar-block-mortar" or
(10+440+10+440+10) which comes to 910mm.
The window requires a gap of 915mm.
......so why?

There seems to be no logic in that particular window sizing given the
accompanying instructions.
I am then left with the question "Can I build the opening to the tolerance
of 2.5mm each side, and if so will this be enough for any expansion and for
the brackets?".

Oh, and a supplementary.
Instructions suggest that the gap around the window is packed with foam
rubber to allow for expansion and contraction.
Foam rubber?
This is to be added after the window has been screwed into the opening and
all additional packing pieces (used to get the window true before fixing)
have been removed.
Do they mean squirty foam?
Or are there strips of foam rubber you push into the gaps before sealing
inside and out with frame sealant?

If anyone is interested I can scan the instructions in and post them on
photobucket - they provide useful information for anyone new to fitting
plastic windows.

Any information, as usual, gratefully received.

Cheers

Dave R

I ,too, used B&Q windows in a single skin garage/workshop.
You can make window 'openings' any size you like by varying mortar
gaps or cutting blocks. To suggest you could achieve an accuracy of
2.5 mm is fanciful.
The fixing clips can face fwd or back - I fitted mine with the windows
flush outside, clips to rear. They JUST fit in the 100mm (plus
external render).
Squirty foam, not foam rubber.
No need for trickle vents where the opening window can be locked
slightly open. No need at all in a non habitable building (presumeably
no airtightness).
Sill screws to window frame - I had to find some better screws....

Phil.