Windows fitted flush to blockwork?

Discussion in 'Builders' Talk' started by Bodgett & Leggett, Aug 11, 2019.

  1. Bodgett & Leggett

    Bodgett & Leggett New Member

    Hi, I reckon I'll get a torrent of no-no's to this one but hear me out...

    I'm building a nearly new house (for myself.. mix of DIY and going direct to trades). Due to keeping existing narrow footings I've had to do solid 215mm block walls (fibolite, not thermalite don't worry) which will be insulated internally.

    I'm having patio doors fitted. These are triple sliders (quality ALUK system via Sliders UK) so the base track is 150mm wide. The normal ali cill that goes with this is really wide, about an extra 150mm beyond the door track (other cills aren't flat enough to bear the 150 track). I don't want this massive width of track/cill to step over, so am going for a stub cill. This only overhangs the wall by 30mm so my total step width is only 180mm.
    (Yes if i have a minimal threshold I could do without a cill, except I'm leaving my options open in case I want to leave the patio low with a step down, in which case I need the cill to cover the bricks under).
    To get this cill overhang will require the patio doors to be fitted flush with the outside face of the block walls.

    My plasterer (a perfectionist) says he can overlap the render stop bead just past the edge of the patio door frame on the sides, to hide the edges, packers etc. The walls are new and very true (top brickie) also I've got a good window fitter so no reason why the frame shouldn't be pretty flush with the blockwork. Any minimal gap between the back of the stop bead and the door frame, could have a neat silicone bead. (also doors are white ali so won't move as much as grey in the sun). Same idea at the top, I guess with a drip bead over.
    Doors won't be entirely flush as will have render thickness beyond it (sand cement, say 10-20mm?).
    Also having a PVC back door fitted, wondering about also having this fitted flush with a stub cill again.
    My other windows have a small reveal say 25mm (before render) so hopefully the mix won't look weird.

    NB I've got another 2 courses of face brickwork above the cill height so a) rainsplash onto render won't be an issue and b) render bell / drip bead will be easily above the cill and won't clash with it.

    Oh and
    The back elevation with patio doors & back doors in is south west facing so shouldn't get worst weather.
    I'm in south east England and nowhere near the sea if that makes any odds.

    I realise this fitting flush isn't normal practice but don't see why it shouldn't work? And as above it's not entirely flush. I did ask my (private) building inspector before about window reveals generally, he said normally about 40mm but seemed a bit vague about it. I can tackle him later.. just want to know if the plan stacks up first.

    Any wisdom appreciated....
  2. gas monkey

    gas monkey Well-Known Member

  3. Bodgett & Leggett

    Bodgett & Leggett New Member

    Thanks gas monkey, is flush window fitting done a bit then, and can you add any comments to back up saying its ok?
  4. gas monkey

    gas monkey Well-Known Member

    dont fret been about 40 odd refurbed built you name
  5. Bodgett & Leggett

    Bodgett & Leggett New Member

    Trying to decipher your cryptic reply! Sounds like 40 refurbs had this??
  6. gas monkey

    gas monkey Well-Known Member

    be ok
    been in the game 40 yrs fret not it will be fine
  7. andyscotland

    andyscotland Active Member

    One thing to watch is if you're insulating internally then there'll be a big cold bridge along the inside of the opening. You will potentially get damp/peeling paint/mould from condensation in this area. That's one reason windows/doors are usually set back roughly in line with the insulation. You'll want to make sure you put insulation between the blockwork and the plasterboard/whatever to control that.

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