Replacement Windows on a rendered house - Rehau 60mm or 70mm - ease of fitting.

Hi

Firstly, apologies if i've picked the wrong forum.

The quick version: - should I pick 60mm or 70mm Windows to replace existing 65mm Windows on a 'rendered' house – i.e. no paint line to cover but render makes fitting difficult - advantages/disadvantages? (conflicting advice given)

Longer boring/detailed reason for the above question:

Our house is rendered - so the fitting of replacement windows is harder - and no paint line.

• Present wooden windows are 65mm in depth
• Modern house (20 years old)
• Keeping inside sills
• Builder suggested 60mm for ease of fitting – (this concerns me a little as I’m geared more towards the aesthetic finish rather than ease of fit.)
• Rehau have suggest 70mm as standard - hardly any cost difference between 60mm and 70mm – so their decision doesn't appear profit orientated.
• Not having plastic strips on the inside (apart from on the sill) – the builder will be filling.
• I'm not concerned about the difference in performance/protection rating between the two profiles.

So a bit confused but my main concern is the finish once the windows have been fitted:

As the house is rendered there’s isn’t a paint/filler line to cover, which would normally dictate the 70mm, but obviously, the render makes the fitting harder.

My concern is that fitting the 60mm 'may' leave a larger gap to fill once butted up to the render? And as I’m not changing the inside sills I’ll have larger beading and they’ll be more filling/future cracking etc?..

I’m also aware that I may be being incredibly naive and that even if the builder uses 60mm windows he’ll still have to hack away at render/plaster to get them to fit? (Anyone in the know I would be very grateful for advice on this…)

My main concern with the 70mm is that he’ll have to hack away at the render/plaster creating unnecessary work and even worse the windows may take up some of our sill/inside space. (Would he make the extra room for the windows from the inside or outside?)

I will obviously get clarification from my builder - but he's on holiday for the next 2 weeks. But I would like a clearer understanding so i can discuss the pros and cons with a little more knowledge when he gets back - as will then need to order almost immediately.

I hope the above makes sense – any hands-on advice or similar fitting experience appreciated.

Thanks

 

Thanks for the reply KIAB, appreciated.

Sure, I could upload some photos tomorrow, no problem.

Am I being unduly concerned about the 60mm and the possibility of large gaps - or would the builder probably have to cut away plaster/render anyway even with a 65mm gap for 60mm replacement window?

In my naivety I imagine if he was fitting 70mm he would cut the width to fit - but i'm wondering if that's even possible - i.e. he would need to cut a wider width to get the window in.

So it's a swings-and-roundabouts type thing for either profile (60mm or 70mm) due to the 65mm depth?

 

Here are a couple of pics - hope they are of some help:





Thanks.

 

Thanks for the responses guys - really appreciated.

With your above responses in mind would you advise me to go for the 60mm Windows as there's going to be 65mm+ gap to save the undue hassle?

What I mean is would they have to make a 75/80mm gap for 70mm windows to get them in? In which case the 60mm would suit me more, perhaps, as easier to fit and I wouldn't lose any internal sill space...

 

Thanks for all the responses, again really appreciate professionals taking the time to help (if you need any computer hardware/troubleshooting advice holler - happy to return the favour)

Thanks - there's little difference apparently - and I don't think the manufacturer realised the problems the render would cause. Admittedly, I'm not overly concerned with the performance factor as they'll be infinitely better than my present windows. And I'm more concerned about the ease of fit and aesthetics over performance (bad practice I know ).

Thanks I'll consider this (think I understand) - but looking at my sills I think they will take a lot of plaster with them - plus i'm guessing I would need to replace cills with new ones?

What I've pieced together from all your informed responses - the 60mm windows would need a bigger gap than 65mm anyway to fit in(?) due to the render and the plaster reveals - and the need for a bigger gap to angle the window in to fit?

This I think answers my original concerns - in that I was worried that they would be fitting 60mm windows into an unduly large space - when in actual fact they would need 65mm plus to fit the 60mm windows. And even if they used the 70mm Windows they would have to cut a larger width again to get them in any way - e.g. 80mm. They wouldn't be able to cut a 70mm gap and get them in neatly as I wrongly assumed? (keeping in mind the cills are/were being kept in place originally).

If I guessed right (?) - with all your really useful input - then I think I may go with the 60mm as it would seem that it will cause the less damage, less intrusion on inner cill space and would require just as much filling as the 70mm if they were fitted.

Please correct me if I've totally misunderstood.

 

I'll keep this in mind thanks.

So the 60mm would make more sense with this method? In that it would be a neater fit and less hacking - compared to getting a 70mm Windows to fit - if care was taken in removing original window and fitting external cill after as you suggest?

Or would the gap be too big - making the gap between window and old cill unnecessarily large compared to if i had used the 70mm? (i was told i would need a bead on the cill for either - is that correct? But he could plaster the reveals so no strips)

Lost me here i'm afraid - my knowledge void is huge with windows - but appreciate the advice none-the-less.

 

Thanks for taking the trouble to explain - appreciated.

So, they've essentially got to be wiggled into the gap left by the window - wide enough to slot against the render and wide enough to be covered by the inner plaster/board.

And looking at my pictures where the render meeting the window and yours/others comments it sounds like the render will be damaged no matter how careful the builder is - even with careful preparation.

Knowing all the above - would you recommend the 60mm Windows for ease of fit and neatness of resulting finish as I assume less hacking and less inner space loss? (As mentioned before i'm not concerned about the efficiency of the different units).

It's the neatness of the finish that is the most important thing for me - i don't want to cause undue work and perhaps an awkward finish due to the fitting of 70mm windows just because Rehau recommended them - not realising the awkwardness of the fitting.

 

Thanks for all your input Handyandy.

60mm is is then - neater finish and luckily the easier fit - that's the combo i ideally wanted.

I need to double check that they look the same as the 70mm - hoping that they do (they look the same from pics) - and my decision is made.

Thanks very much for yours and everybody's help - really appreciated.