Fitting a new plastic window

[David WE Roberts]

Despite attempts to find something cheaper B&Q seems to be the budget option of choice for both doors and plastic windows.

So - to fit a plastic window into a new wall, I assume that I have to build the aperture, place the cill across the bottom, place the window on the cill, and then screw in with frame fixings.

I then carry on building with a lintel over the window.

Is this too simplistic?

Presumably I will have to remove the double glazing to allow me to screw the frames into the sides of the aperture and then refit.

Also presumably I should put some kind of frame sealant all round to take up any small gaps.

TIA

Dave R

[Roger Mills]

Wouldn't it be better to construct the *whole* aperture - including lintel and another couple of courses of brickwork before fitting the window? That way, you'll be less likely to disturb the new brickwork when you drill for the frame fixings. [Make up a wooden frame - the same size as the window - as a guide when building the brickwork.

Very likely, unless all panes open. You should be able to unclip the beads after removing the rubber gasget strips on the inside.

After it's fixed firmly in position, yes. When fixing it, use packing pieces to keep everything square and to prevent the screws from distorting the frame.

[Dave Plowman (News)]

I'd make the complete opening first. Better - and less chance of damage to the window. Also if it opens, the frame needs to be not under strain.

Depends on type. Mine had fixings which fitted to the edge of the frame and were covered when filling the gap.

It's normal to use expanding foam. This on its own will hold the frame securely, provided the frame doesn't move while it sets. I then tend to rake it out by about 1/2" on the outside and do a neat mortar fillet.

I bought my windows and patio doors from Screwfix - but they only do (did) stock sizes. They came with full fitting instructions.

[David WE Roberts]

For some strange reason Screwfix (although linked to B&Q) doesn't seem to carry the cheaper doors and windows at the moment.

Quick glance suggests that they are about £80 more for a 1200 * 1200.

[John Rumm]

Sometimes easier to screw the plastic cill to the bottom of the frame first.

I would built the whole hole first....

Not really.

They usually come without the DG installed. Some have adhesive tape you apply to the frame before fitting the glass. If the frame is an opener, then the rigidity of the sash is partly derived from the sealed unit. So you need to add plastic packers such that you create a diagonal brace with the glass to stop the sash drooping over time. When fitting the beads, do the short ones first, otherwise they are a bastard to spring into place. With the long sides you can get both points in, and then work your way tot he middle.

Yup, I would tend to just use a couple of screws to tack it in place, then fix with expansing foam. When done you can rake back a bit and plaster inside (or dryline or whatever) and then use a framing silicone mastic on the outside.

[Stuart Noble]

All the pros I've seen wedge the frame in place, then use foam to set it. The fixings are applied a couple of hours later when the foam has more or less cured. Seems pretty foolproof and certainly the best method if you're working alone

[sm_jamieson]

The newer windows like I've just fitted tend to be internally glazed, and have bubble gaskets that are part of the beading. If you try and pull out the gasget on these you will wreck the beading. Best to check with the suppliers.

[sm_jamieson]

My local supplier was nearly as cheap as B&Q etc, and far better quality. Its work checking - but avoid the national chains like the plague !

Volume builders often use a PVCu subframe built into the wall, then the window just clips in. However, usual practice on self-build, DIY etc is to build the opening and then get windows make to measure. I built one opening aiming at a standard size (1200mm x 1050mm) but it actually ended up a bit taller after bedding in the lintel etc. In the end I had them made to measure from a local firm as I said above.

Build the opening first, then drill / fit when the mortar is set etc.

The glass on mine was supplied separately, not in the frames. If using B&Q etc, you don't take out the glass, they supply a fitting kit using brackets that slot into the PVCu profile and screw into the window reveal. I wouldn't like to take the glass out - who knows how they are packed. My B&Q window had a funny fibre- board type of gasket on the inside - I dread to think !

Fill around with *low* expansion foam - a proper gun is a lot easier than those cans, then cut back a bit and use frame sealant.

Simon.

[Dave Plowman (News)]

When I bought mine they seemed pretty competitive, price wise. And I'm very pleased with the quality. Seems better than some I've seen supplied and fitted by the well known names.

[Man at B&Q]

Download the Wickes "how to" leaflet for an idea of what is involved. The principles are much the same for any brand.

MBQ

[mogga]

Hmm, and the bricks and/or lintel you drop on your shiny new window will do it loads of good.

Finish the wall before you put a window in.

[Rick Hughes]

No ... absolutely no.

Build the opening, finish it ...... the best way is make a simple formwork up out of 3" x 2" with triangle of ply at corners to keep square.

Build up to it, fit lintol .... and if pre-stressed add appropriate number of course of bricks above it ... then fit window.

If you don't there is a chance you will load the frame, and possibly fail the sealed unit early... or bugga up any opening system. Remember when fixing you need at least 6-10mm gap underneath and 5mm or so on side and top ..... packed with appropriate spaces.

Fix with appropriate fixings .. tapcon, framefix etc. do up watching you don't bow frame. Remember if using uPVC cills fix them first.

Cowboy approach is then to inject foam around all 4 sides ........ I don't like that way, it is far too easy to bow a frame as it expands. Prefer to do a good silicone bead all round. (after fitting glass & squaring up)

I fitted 2 windows last week using this method.

If you do you Silicone make sure it's the right stuff .... neutral cure High Modulus .... not acetyl cure, and certainly not Low Modulus.

[Stuart Noble]

None of the frames I've seen are weak enough to be bowed by foam, and the use of a gun controls the amount accurately. AFAIK it's pretty much an industry standard method.

[Dave Plowman (News)]

Must be using cowboy frames too, then. Decent ones will be fine with foam

- it's the way most fix them.