Retrofit windows - draught proofing?

MacDanger

Hi

My parents are getting their ~40 year old single glazed teak windows replaced next week by one of the main Irish window companies based in the south of the country.

What's the best way to draught proof a retro fit job like this?

And how would you expect the fitters to accommodate the (presumably) extra depth of the new windows?

I haven't been involved in the process so far so I just want to get some advice here before they start ripping out windows and leave the place in ****

Thanks in advance

black & white

Have someone who knows what they are doing watch the fitters and make sure they do the job properly. Things like packing insulation into the gaps and sealing correctly

If it’s the company I think it might be, it often depends on which fitting crew you get. A family member got a big job done on an old house and the builder wouldn’t let the window company start work until he was there to supervise.

10-10-20

It does depend somewhat on the team that you get, but the standards and products are better than they were 20 years ago. Also most people are more aware of air leakage so the teams need to work smarter and raise their game.

My best advice would be to tell the installers on the morning of the install that your main objective is air-tightness around the frame, and to focus on that element as well as the finish. That and keep and eye on them in a good way, but also always find that they appreciate a cup of tea, or a place to have lunch (many will go to the van to eat anyway).

And how would you expect the fitters to accommodate the (presumably) extra depth of the new windows?

Any retrofit of windows where the internal reveals aren't being removed will result in a gap between the new frame and the blockwork. That's unavoidable but the gap can often (but not always) be backfilled with foam after the concrete anchor or frame fixing has been applied. Good teams should be using airtight expanding foam, but on a 40 year old house it's typically not all that critical as long as the frame has been sealed from both sides using silicon sealant. In my opinion the base of the window is the largest leakage point (as there is a drip piece which never gets sealed perfectly) and I either buy thermally expanding foam strips or just go for slight overkill on the expanding foam to make a good seal. Don't forget to address any leakage around the reveal via the cavity too, especially around the cill.