ICF and window sizes

[Markuz]

We are just getting our plans drawn up for an icf extension and question came up around window sizes. 
 

Planning to have a 1.5mx1.5m window for a window seat and a 3 meter sliding door. The rest I would say normal window sizes, meeting any regs that required. 
 

Are there any restrictions in terms of size when you use icf? Or can you go crazy ?

Anything to look out for when designing and installing windows in to icf?

 

If you have large windows could you post dimensions please. 

 

 

 

Edited Sunday at 09:29 by Markuz

[ToughButterCup]

4 minutes ago, Markuz said:

...

Are there any restrictions in terms of size when you use icf? Or can you go crazy ?

...

 

Restrictions ? Yes

Crazy? Within reason - almost

 

 

The most difficult windows for us were those that are about 300mm wide : the issue was manufacture of the windows, not how to insert them in ICF.

(In our case Durisol).

[Markuz]

4 minutes ago, ToughButterCup said:

 

Restrictions ? Yes

Crazy? Within reason - almost

 

 

The most difficult windows for us were those that are about 300mm wide : the issue was manufacture of the windows, not how to insert them in ICF.

(In our case Durisol).

Thanks very much. 
 

is that a sliding door you have there? Looks great. 

[Russell griffiths]

 

how big do you want to go. 

[Markuz]

19 minutes ago, Russell griffiths said:

 

how big do you want to go. 

thanks very much.

 

In my view 3 meters sliding door is not too much Just have been asked the question why icf and a comment was made on window sizes.

 

 

[Nick Laslett]

@Russell griffiths, @ToughButterCup, great looking houses, gentleman. Well done. I might have seen pictures previously, but in any case, good to see them again. 
 

 

Edited Sunday at 18:47 by Nick Laslett

[ToughButterCup]

On 18/05/2025 at 10:41, Markuz said:

... Is that a sliding door you have there?

 

Yes. It's been open all day for the last month.

 

The other unexpected but massive advantage is that it stops teenage door-slams dead.

[Conor]

On 18/05/2025 at 10:28, Markuz said:

 

Are there any restrictions in terms of size when you use icf? Or can you go crazy ?

Anything to look out for when designing and installing windows in to icf?

 

 

This is a question for your structural engineer. We have several large openings, 2x2m corner window, and 4.5m wide bi-folds. The 2x2m was constructed with the ICF and extra rebar in that area, plus a corner post. The 4.5m opening needed a custom made steel box beam with welded plates and a thicker column to support.

[FM2015]

No restrictions really but at a certain stage and under specific conditions, an engineer might move towards steel lintels rather than cast in place.