Glazing seems to have a bit of “better hire a professional” mystique to it. Having fitted the windows and doors, I don’t think it’s deserved and is perhaps testament to the FENSA scheme for gatekeeping the industry. To compound the issue of regulatory compliance, there seems to be a conspiracy to prevent buyers from getting quick and easy quotes online.

For window and doors, I aimed to get a very air-tight seal around the edges of the frame, since this is clearly somewhere that a lot of air could escape given the relatively long perimeter and the dissimilar materials (aluminium to wood). Looking online, I found that a lot of the best Passivhaus installers, and CharlieDIY, were using expanding foam tape rather than low-expansion spray foam. Therefore, I used foam tape around the sealed units and around the frame, only relying on expanding foam in a few hard-to-reach places. Door and window were fixed in place with Timco C2 Clamp-Fix 8 mm x 120 mm screws. These worked well but required careful thought about where to position them as the heads are tall and wide and risk bending the frame or interfering with the locking mechanisms if used incorrectly. Definitely a case of measure twice, drill once. Frankly, I think these were far stronger than they needed to be and life might have been easier with slightly smaller fixings.

Window

Applying expanding foam tape Planning fixings to avoid window hardware The window in situ Fixing with Timco screws

I bought the window from an architect friend whose client had rejected it because it opened inwards. It’s an aïr MOD Tilt & Turn in a custom brown/bronze colour. It’s a lovely window, though a bit pricey at over £2,000 RRP.

To fit:

  1. I taped the blue external membrane to the window opening.
  2. I fixed the cill with small screws to check alignment. I wanted to make sure that the weep holes in the cill didn’t empty behind the cladding. This would have been easier without battens and the cill was only just long enough.
  3. After checking that the cill was in the right place by offering up the window (without glazing), I laid a bead of low modulus black silicone and fixed the cill with the Timco screws.
  4. I then applied the expanding foam tape to the sides and top of the window frame, quickly put it into position and fixed it in place with the Timco screws, being careful not to rack the window out of square. The laser level was useful here to check alignment. I also measured the diagonals with a tape measure, though that’s more fiddly than you might expect.
  5. After a day or so, once the foam tape had fully expanded, I filled in any remaining gaps with foam and then taped around the window frame from the inside and outside.

Door

Door frame as delivered Fitting the door frame (outside view) Fitting the door frame (inside view) Applying Tyvek tape to the door frame

Door Specs

I used the same supplier that Ali Dymock used, modernupvcwindows.co.uk but, instead of using their own-brand PVC doors, I ordered Korniche aluminium patio doors. I think that these doors are great value at around £1600, the service I got from ModernuPVCWindows was excellent and their website was easy to use.

In case you need similar, the door was a custom 1580 mm wide by 1995 mm high, which I settled on by measuring the opening carefully and subtracting about 10 mm from the smallest dimensions (e.g. the height of the opening is 2005 mm at its lowest and the width is 1590 mm at its narrowest). To get to the right price calculator, you’ll want to go to the home page and click “Aluminium bi-folds” → “2m” → “2 sections” at which point you can choose between bifold and french doors. Choose “French door, Master door left” → input width and height of the desired door (not the opening) and click “Size is correct”. For the options, I chose:

  • Black matt frame
  • Black handle
  • No internal blind
  • No external cill
  • Opening outwards
  • No trickle vents (as I have MVHR)
  • Integrated cill as the “threshold”
  • Double glazing
  • No frame extenders

Since acoustic glazing is considerably more expensive and offers no thermal benefit (claimed U-value is the same), I opted for standard glazing.

Customer support confirmed to me that you either choose an “external cill” size or an “integrated cill” threshold, but not both.

Fitting

Door fitting was much the same as the window, except that it was larger and had an integrated cill. The shape of the door extrusions meant that it made more sense to fix through the thermal break than the frame. Lots of googling couldn’t determine whether there was any real difference and the instructions from the manufacturer were vague. In fact, the only real downside to Korniche doors, as of 2023/24, is that the website and installation guide are both aimed more towards skylights and bifold doors than patio doors. I’m guessing that they started with bifolds and are extending their offerings but the docs haven’t caught up yet, leaving the customer to make it up as they go.

Thoughts

As mentioned above, fitting the glazing isn’t that difficult as long as you take your time. I’m sure that I did a more thorough job than the majority of commercial outfits would have when it comes to air-tightness. The foam tape is a nice invention, and I’m sure that it does the job, though it’s not as clear to me whether the performance justifies the extra cost over low-expansion foam.

Rant

On principle, I don’t think I’d buy from a glazing supplier who doesn’t can’t give an instant online quote. Many claim to give instant quotes but actually expect you to give your contact details so that they can get in touch with the hard sell. The glazing industry is clearly far behind many others when it comes to web presence and price competitiveness and could use some reform.

Tools Used

  • Tape measure
  • Drill and Impact Driver
  • Laser level
  • Expanding foam gun
  • Sealant gun

Player of the Match

Expanding foam tape is less messy than expanding foam. I think it’s the future of glazing insulation, and I’m looking forward to the price coming down in time.

What I’d do Differently

I’d either skip the battens or get longer cills. As it is, the 150 mm cills barely extend beyond the cladding, even with the frames almost flush with the outer walls. I’d have preferred to have the frames sunk a little deeper into the openings to give a bit more protection from the elements.