UPVC window frames & patio/french door queries

Discussion in 'Windows and Doors' started by Ruggers, 9 Mar 2021.

  1. Ruggers

    Ruggers

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    Few queries... I'm looking for info. on windows for a new build later in the year. Black anthracite outer with white inner, no trickle vents because of air tightness for MVHR.

    Is there such a thing as insulated frames in UPVC windows?
    I seen some of the high end windows at a home show having wooden core with aluminium exterior for sound and thermal insulation but wondered if all UPVC frames are hollow or can they contain foam?

    What sizes do the sills come in, I've currently got stubby cills sitting over concrete slip sills.

    Are modern patio sliding doors secure these days or best to go with french doors. I have an opening of 1575 wide and 2100 height to fill.
     
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  3. Swwils

    Swwils

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    Decent UPVC frames contain thermal breaks (chambers themselves) in the profiles that gives them a level of insulation where you need to generally worry about other things first.

    For instance the quality of the installation and potential thermal bridge between the edge of the frame and internal surface finish.

    Cavity closers with integral flexible PVC strip which sits inside the uPVC frame are a good example of the two systems working in conjunction to ensure good thermal performance as a whole.

    All decent systems will come with a u value for the frame and window to tell you this aswell as the rating.

    Yes frames can contain wood, more internal chambers or foam to get better performance. Even metal frames can achieve good thermal performance - aslong as the thermal breaks are executed properly.
     
    Last edited: 10 Mar 2021
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  4. Ruggers

    Ruggers

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    I was unaware of the thermal breaks in the frames, I'll try and keep a look out for frames with the foam in if available, tried one company but they don't offer it.

    I think personally for my budget it will have to be UPVC for all the windows, ground floor will be face bricks and the window sat directly to the brick or on a stooled concrete sill, so UPVC stubby sill might be best for this. First floor will have exterior cladding so i require a longer UPVC sill sat directly to the block work.

    My current windows sit on the outer cavity wall, but i'm not sure where the window frame fits with face bricks, is it still the outer wall or can they be set in a little bit? There will be a 150mm cavity with 100mm insulation and an insulated catnic type lintel above.

    Is the thermal bridging around the edges sealed with the cavity closers or using something different like foam?
     
  5. Swwils

    Swwils

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    I'm not an expert but have a look at a UPVC installation best practice guide, then also something like the BBA cert for a decent cavity closer.

    This should give you a good basis for what's going on - essentially there is a minimum distance the frame needs to be *over* the cavity closer for it to be useful and not introduce a cold bridge in a typical detail. (Can be different if the reveals are insulated etc)

    If you have a totally air tight design with MVHR there might be some more detailed design work already going on and you would need to stick to that, it's possible these specs have already been worked out and you would need to get at least xyz performance from the doors and windows, the basis of which would be a good site survey for the opening.

    Attaching image of alu profiles, it's pretty involved stuff![​IMG]
     
    Last edited: 9 Mar 2021
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  7. crank39

    crank39

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    To be honest I've never heard of or seen pvc profiles with a thermal break, in aluminum yes that's the norm now but what would you use as a thermal break in pvc when thermal breaks are a plastic type resin anyway.

    To the OP take a look at warmcore if you haven't already
     
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  8. Ruggers

    Ruggers

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    thanks swliss, i'll look up the info you suggested. I wasn't aware there were thermal breaks in the frames that do that, i thought they were basically hollow extrusions and done little to prevent heat loss, thats why i wanted to know if theres anything better on the market i should be looking at when pricing up windows.

    Crank39, I've dropped warmcore a message for some more info.

    I've got french doors now and they have been fine, patio sliding doors would give me more glazing to look out of but only half an opening size.
     
  9. Swwils

    Swwils

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    I was probably wrong calling them thermal breaks in UPVC only frames but they do have chambers in them to help.

    Take a look at the rating and U value info and it should be clear - the glazing also makes a difference as you would expect.
     
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  10. diy_fun_uk

    diy_fun_uk

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    I have to admit, I find looking at pics like that almost as satisfying as looking at emmm adult material :)
     
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