Fitting uPVC Windows

[Onoff]

Got my small window made by a local company. Now I've only ever fitted two DG windows and from memory they were pre-glazed and I used tabs on the side. To long ago to remember tbh. Any tips?

 

Sill

How best to attach this? Options are mitre bond, Sika EBT, CT1 or some st/st wood screws up through the bottom. Or even a line of low expansion foam?Whatever, I think it needs a continuous "wet" seal to at least minimise draughts:

 

 

 

End Caps

Mitre bond?

 

 

Fixing

Got some generic M10x160 frame fixings. Good enough to save me buying any? 3 per side maybe? Window is nom 1000h x 600w.

 

 

Compriband

I've got some so seems rude not to use it. I've read you've got to be quick with it as it expands. My guess then is:

 

- Old window out and hoover all round.

- Assess where I can get a fixing (don't know what the wall construction is yet but think it's "solid").

-Trial fit window loose and gauge packs required

-Drill 10mm holes in uPVC frame 

-Window back in and drill thru holes in frame into wall reveals

-Window out, Compiband stuck on but cut where packs need to go?

-Window back in, fixings in but not tightened fully

-Packs in, tighten fixings

-Glass in with packs all 4 sides

-Leave Compriband to expand.

-Foam fill/mortar gun outside

 

Cheers

 

 

 

[Gone West]

@Onoff Are you going to foam fill the sill inner section? Compriband expands much more slowly this weather.

[ProDave]

TIP:

 

Pick a cold frosty day. Keep the compriband outside or even in the fridge (or freezer?). It expands much slower when it's really cold.  On a hot day when the compriband is also nice and warm, it will expand before you get the window in.
 

[Onoff]

7 minutes ago, PeterStarck said:

@Onoff Are you going to foam fill the sill inner section? Compriband expands much more slowly this weather.

 

You mean down this section:

 

 

I was thinking to do so. The sill is only 600mm long. I could get the foam gun nozzle in virtually half way from each end. I'd mask the sill ends before doing so of course.

[Onoff]

10 minutes ago, ProDave said:

TIP:

 

Pick a cold frosty day. Keep the compriband outside or even in the fridge (or freezer?). It expands much slower when it's really cold.  On a hot day when the compriband is also nice and warm, it will expand before you get the window in.
 

 

Good call. I've just taken the rolls and put them in the unheated conservatory. Mind you they were in the unheated kitchen and that's not much warmer!

 

Frost this morning but rain out there at the mo plus I need to scrounge a couple of pallets to stand on as it's a mudbath.

[PeterW]

The cills are designed to be hollow and are box section to be insulating - no point filling with anything as you could distort them. 

 

Fitting a cill is as simple as a quick bead of clear CT1 or silicone along the back up stand angle and then 3 decent woodscrews holding it on to the bottom of the frame. 

 

Mitre bond the end caps on, don't forget to make sure the cill is centered or that you take the horns off before you start. 

 

Is it glazed or have you got to glaze it too ..?

[Nickfromwales]

I always pack and level the cill first and concrete or tapcon it to the foot of the opening, sealing accordingly after with a combination of foam and frame sealant. Cut the horns first as said. 

Dont pre drill the frame ! Always drill with the frame in situ as you may pre drill on a hollow mortar bed or worse. . 

I line it all up, window in position ( unglazed ), shim it in tight with wooden shims and foam all around. DOUBLE CHECK AT THIS POINT THAT THE FRAME IS PLUMB, LEVEL AND SQUARE. 

Once set, only then do I drill for mechanical fix. 

 

[Gone West]

20 minutes ago, PeterW said:

The cills are designed to be hollow and are box section to be insulating - no point filling with anything as you could distort them. 

 

 

I have to disagree with that. It's a bog standard plastic sill and not designed to be insulating. The size of the inner section would allow movement of air. My Rehau frames have far smaller sections and they are also foam filled. If you use low expansion foam, fill in section by section and the ends of the sill are open there should be no distortion.

[PeterW]

9 minutes ago, PeterStarck said:

 

I have to disagree with that. It's a bog standard plastic sill and not designed to be insulating. The size of the inner section would allow movement of air. My Rehau frames have far smaller sections and they are also foam filled. If you use low expansion foam, fill in section by section and the ends of the sill are open there should be no distortion.

 

Whilst I agree it's a bog standard cill they are chambered for both strength and insulation purposes. The issue is that second web is already bent slightly and tbh it's not going to take much to distort that cill completely. 

 

Rehau and Profile 22 cills are 5 chamber minimum and are designed to be either filled with a packer or come from the factory pre insulated - Rehau use flow foaming to fill chambers as it is extruded and the cill profile material is much thicker to ensure rigidity. They also do the same on some of their higher spec frames and use recycled plastic "E" section as frame reinforcing where other fabricators use galvanized steel which is seen as a cold bridge. 

 

UPVC profile isn't that strong and I've seen it distorted by badly fitted packers and fixings and also by foam expansion - like @Nickfromwales I prefer Tapcon or other screws as fixings but you have to ensure that you don't distort the edges if you do over tighten them - they are there to stop the window falling out, not to jam it tight to the opening ..! Pack either side of your fixing and you can minimize any bending. 

[Onoff]

What have I started? 

 

I personally like the idea of foam filling the sill. Plus I'll be doing something.....albeit without really getting anywhere! Saying that I guess the actual window frame isn't foam filled? Though I understand some are to achieve better U values. Don't forget I'm at the bottom end of all this, no 0.8 values for me.

 

I don't think the low expansion stuff would distort the profile personally. If it does then hey ho I go and buy another bit. I was a bit worried than the resulting foam fill could be hygroscopic? Did even think I could neatly saw a length of ESP and slide that in.

 

I like the idea if fitting the sill first so I'm only dealing with one piece. I might take from everyone; CT1 the sill and st/stwoodscrew it in then foam fill. I'll tell you the bit that bugs me most is the gap between sill and frame between those two anchor shaped tabs (first photo). I know that's where things drain but to me it seems to defeat the whole object and be a weak point in terms of insulation/design. 

 

Cheers for the advice. Not sure what I'm doing today tbh. Wife is sick and bad (both ends ). Went to my elderly parents last night used the land line (caked) the light switch (sticky) and must have picked something up!

 

EDIT: How about screw the sill on packing with st/st penny washers to hold that cavity together more?

 

I know 90% would have it in and fitted by now!

Edited January 29, 2017 by Onoff

[PeterW]

12 minutes ago, Onoff said:

I'll tell you the bit that bugs me most is the gap between sill and frame between those two anchor shaped tabs (first photo). I know that's where things drain but to me it seems to defeat the whole object and be a weak point in terms of insulation/design. 

 

Do Not seal that gap ..!!! You will end up with a window frame full of water...!! 

 

We went back to a house where someone had done that - water running into the house as he had blocked that and the drain holes "to stop draughts".... 

[PeterW]

16 minutes ago, Onoff said:

How about screw the sill on packing with st/st penny washers to hold that cavity together more?

 

UPVC section has very poor pull strength for screws - try and do it up tight and you will find the screw spinning and just creating a hole. 

 

A frame that size may not have any reinforcing in it either - way to check is look inside and out around the frame for a series of small screw heads that mean either steel or ally has been added for strength.  Not needed for plastic strengthening as it's weldable so doesn't matter if it moves slightly. 

 

CT1 on that back joint will be fine - the rest is all pretty standard. 

 

 

[Onoff]

52 minutes ago, PeterW said:

 

Do Not seal that gap ..!!! You will end up with a window frame full of water...!! 

 

We went back to a house where someone had done that - water running into the house as he had blocked that and the drain holes "to stop draughts".... 

 

Oh no I wasn't going to just seems a silly design "feature" or is that oversight?

 

The more I look the sillier the idea is of screwing the sill on. As I see it I would be penetrating the window frame for a start. Any hole would let water run down the screw thread and into the sill cavity. I don't really hold with the "mastic the screw threads" idea. At the moment water in the frame should exit via the front hole and down the slope of the sill.

 

 

As I say I'm in the "cheaper" seats here. It's funny but I was brought up at a time when having "double glazing" was seen as a proper sign of affluence. My parents had aluminium at first which failed and now have replaced them with generic uPVC. It's only because of this site I realise all double glazing is NOT created equal!

[Nickfromwales]

For a window that size, if it were me, I'd be fitting 6 screws. 2 top, 2 where the window slams shut and two at the bottom. With the foam and getting tiled in it's not going anywhere. I've fitted plenty of smaller ones with just the head fixed and the rest shimmed and foamed + frame sealant. 

Dont over think / do this one or you'll end up distorting the left and right legs. 

Damp the brickwork prior to applying LE ( pink ) foam and go have a brew. Hour or two later see just how good that is without screws and report back  

[Onoff]

2 hours ago, Nickfromwales said:

I always pack and level the cill first and concrete or tapcon it to the foot of the opening, sealing accordingly after with a combination of foam and frame sealant. Cut the horns first as said. 

Dont pre drill the frame ! Always drill with the frame in situ as you may pre drill on a hollow mortar bed or worse. . 

I line it all up, window in position ( unglazed ), shim it in tight with wooden shims and foam all around. DOUBLE CHECK AT THIS POINT THAT THE FRAME IS PLUMB, LEVEL AND SQUARE. 

Once set, only then do I drill for mechanical fix. 

 

 

So do you screw the sill on, guessing not?

[Nickfromwales]

1 minute ago, Onoff said:

 

Oh no I wasn't going to just seems a silly design "feature" or is that oversight?

 

The more I look the sillier the idea is of screwing the sill on. As I see it I would be penetrating the window frame for a start. Any hole would let water run down the screw thread and into the sill cavity. I don't really hold with the "mastic the screw threads" idea. At the moment water in the frame should exit via the front hole and down the slope of the sill.

 

 

As I say I'm in the "cheaper" seats here. It's funny but I was brought up at a time when having "double glazing" was seen as a proper sign of affluence. My parents had aluminium at first which failed and now have replaced them with generic uPVC. It's only because of this site I realise all double glazing is NOT created equal!

Water is ok to enter between the window and the cill, been done that way for many years by many fitters. You need to fix the frame to the cill, end of, and stainless screws coated in silicone will not let anything through to the cill cavity. 

[Nickfromwales]

4 minutes ago, Onoff said:

 

So do you screw the sill on, guessing not?

Foam and frame sealant. This advice is for your small window. For eg I'd use concrete screws through the frame AND cill if this were French doors / similar or a large window. 

 

Edited to add. Don't forget to keep checking the cill for level whilst the foam cures. Best to weigh it down imo. 

[Onoff]

3 minutes ago, Nickfromwales said:

Foam and frame sealant. This advice is for your small window. For eg I'd use concrete screws through the frame AND cill if this were French doors / similar or a large window. 

 

Ta, presumably that recess in the base of the sill is meant to go on a mortar bed?

 

EDIT: I could easily use all my likes up on you today!  

Edited January 29, 2017 by Onoff

[Nickfromwales]

Fill your boots, your catching me up 

 

[Nickfromwales]

You can sit it on mortar but remember to check your head height or the window won't fit  

[Declan52]

Putty is easy to work with as well.

[Onoff]

So I thought, do I really need haunches on the sill?

 

 

 

Maybe the Evolution chopsaw wasn't the best idea!

 

 

[bassanclan]

I think you are overthinking this!

3/4 s/s screws to fit the cill (they were probably supplied, used for fixing the packing to the frame)

2/3 concrete screws/zebras, low expansion foam, frame sealant.

All done in less time than you've spent writing on this thread!

[Onoff]

14 minutes ago, bassanclan said:

I think you are overthinking this!

3/4 s/s screws to fit the fill (there were probably supplied fixing the packing to the frame)

2/3 concrete screws/zebras, low expansion foam, frame sealant.

All done in less time than you've spent writing on this thread!

 

Me, overthink things? 

 

Might come from having an older, more successful brother and my always seeking approval.... as my parents say "We've Adam the eldest, a barrister don't you know! Then the other one who likes playing with bits of wood!"

Edited January 29, 2017 by Onoff

[bassanclan]

That was your parents way of saying "stop overthinking things, leave the thinking to Adam!"