Sash windows airtightness

[NickK]

Hi and all the best in 2021 (although I said the same last year and look how it turned out).

 

Does anyone have any experience with performance of sash windows at all? I was doing some reading about Georgian style house, which tick quite a lot of boxes for me. Easy shapes to build, symmetricity, simple roof, etc. However, I do wonder about sash windows. You can get some with very good U values but if they are not airtight, isn't it a false economy? Any real live experience or solutions? I have seen Mock Sash Windows but not really sold on them.

 

I am not building anything right now, just gathering knowledge :-).

 

Thanks,   

[willbish]

33 minutes ago, NickK said:

Hi and all the best in 2021 (although I said the same last year and look how it turned out).

 

Does anyone have any experience with performance of sash windows at all? I was doing some reading about Georgian style house, which tick quite a lot of boxes for me. Easy shapes to build, symmetricity, simple roof, etc. However, I do wonder about sash windows. You can get some with very good U values but if they are not airtight, isn't it a false economy? Any real live experience or solutions? I have seen Mock Sash Windows but not really sold on them.

 

I am not building anything right now, just gathering knowledge :-).

 

Thanks,   

 

Hi Nick,

This year i've installed Green Building Store timber sash windows on my new build, which I think look loads better than a lot of the 'mock' sash windows on the market. They score a class 3 on air tightness (out of max 4), this is with both top and bottom sash openers. I specified many of my windows as fixed, non opening and some with only one sash sliding. I am hoping that, having installed them correctly, I will still be able to achieve a very good air tightness score. 

 

[Gav_P]

I’ve got unbranded upvc sash windows.

 

Positives:

look ok. Great variety of opening options. Nice and secure. Zero maintenance. RAL colour options. Easy to clean. Light weight to slide and tilt.

 

Negatives:

Crap for air tightness.

I wouldn’t have them again. But I guess you get what you pay for, they were cheap. In fact I am wondering if I should swap them out for more normal casement windows. 

[NickK]

@willbish I have to admit that the Green Building Store mock sash windows just look odd but that is based only on pictures. It may be different in the real world. I hope airtightness will spot on for you.

 

@Gav_P You get what you pay for as with anything in life. I agree normal window is lot better but if we are talking Georgian Style, sash is almost non-negotiable.

[Gav_P]

1 hour ago, NickK said:

@willbish I have to admit that the Green Building Store mock sash windows just look odd but that is based only on pictures. It may be different in the real world. I hope airtightness will spot on for you.

 

@Gav_P You get what you pay for as with anything in life. I agree normal window is lot better but if we are talking Georgian Style, sash is almost non-negotiable.

Based on my experience, although they had a fairly decent u value (afaicr), any consideration to sash windows needs to focus on the draft proofing and tolerance between frame and unit. 

[willbish]

@NickK Apologies if I want clear. I haven't installed the mock sash but the sliding sash.

 

 

 

[tonyshouse]

You can buy retrofit brush seal staff and parting beads and manufacture or  router in seals to top, bottom and meeting rail 

[NickK]

6 hours ago, willbish said:

@NickK Apologies if I want clear. I haven't installed the mock sash but the sliding sash.

 

 

 

I love the colour. Really stands out. What are walls going to be?

[willbish]

@NickK Walls will be rendered, in a TS06 from the Fassa range 

https://www.fassabortolo.it/it/365-a-year-of-colors?line=Tuscany

[NickK]

@willbish just out of interest, how much did your windows set you back? If you don’t mind me asking.

[willbish]

7 hours ago, NickK said:

@willbish just out of interest, how much did your windows set you back? If you don’t mind me asking.

 

The porch window pictured above, as an example, was £785

[TonyT]

My sash windows are from Bereco.

fitted them 14 years ago on the original house and 2 years ago on the extension

timber, prefinished decent spec

fitted With metal brackets and then foam around the gap, then tescon tape over onto the timbers- tape hidden by plasterboard and internal cill 

[jayc89]

On 12/01/2021 at 19:08, TonyT said:

My sash windows are from Bereco.

fitted them 14 years ago on the original house and 2 years ago on the extension

timber, prefinished decent spec

fitted With metal brackets and then foam around the gap, then tescon tape over onto the timbers- tape hidden by plasterboard and internal cill 

 

Sorry to resurrect this thread, would you still recommend these @TonyT? If you don't mind me asking, how much did they cost you when you last ordered some?