Windows & Doors into ICF openings....

[Gus Potter]

A structral requirement of the BC regs is that the windows and doors need to be positively fixed to the structure. Detailing this is difficult to meet the SE requirements. 

11 hours ago, Mulberry View said:

The Architect suggested

I'm not singling out anyone in particular as this problem is common across the board. We see loads of details but few that show the fixings and their capability to resist the wind loading on the glazing while accounting for head deflections and thermal bridging. 

 

In other words I think...  first thing to do is to make sure your glazing is fixed so it does not fall out and hurt someone. On large openings check the head deflection from the structure can be accommodated so it does not jamb the doors. Then think about the outside weathering detail and then last the thermal performance in terms of cold bridging. 

 

I know it's not not de rigueur but what do I know? Well I can tell you.. if your glazing is not properly fixed then no SE sign off. 

 

Here is a suggestion. Accept that you have to compromise, live with a bit more thermal briging and add a bit more insulation elsewhere. You will be not happy if water starts to leak in driving rain so that is why I put weathering as my second point. 

 

Threshold details can look great on a drawing.. but you need to make them idiot proof as few folk will keep out leaves, moss etc. You also need to make them buildable which many details are clearly not. 

12 hours ago, Mulberry View said:

This is the first-floor detail, it leads out onto a balcony.

Has your Architect put themselves in a builders shoes? How do you achieve this on site and how do you water proof the ends? If it's too complicate you'll likely end up paying more for something that probably won't get delivered on site. 

[Mulberry View]

16 hours ago, Susie said:

Norrsken measured my openings and we discussed our XPS ICF and it’s load bearing.  The ICF company were happy with its capabilities but it was Norrsken who were more concerned about the installation whilst in progress. I’m not sure of the compressive strength of your ICF but it was where the packers go and point load whilst in the installation process. It is possible to push your thumb in our ICF and make a small indentation and as it’s not memory foam that small indent will stay there under the frame.  Similarly the packers could push down in to ICF.  Norrsken provided stokbord to sit the frames on.  I EPDM before the stokbord and then taped the windows after. Were fairly coastal with high wind and rain and open to the countryside with no buildings buffering us. Windows have now been in a year I think and we’re not plastered so can still see the Icf and no water leaking in around windows. 
 

 

The packers digging into the ICF has been my concern, though I'm glad you haven't run into any post-installation problems.

 

My reveal detailing needs to be very precise due to the bespoke Aluminium flashings I'm having made. I can't really stand to add 6mm to the base of every window, unless I had prepared for it in advance by rasping the thresholds down.

 

I'm eager to see what other ICF'ers have done.

[Mulberry View]

On 11/11/2025 at 21:47, Gus Potter said:

A structral requirement of the BC regs is that the windows and doors need to be positively fixed to the structure. Detailing this is difficult to meet the SE requirements. 

I'm not singling out anyone in particular as this problem is common across the board. We see loads of details but few that show the fixings and their capability to resist the wind loading on the glazing while accounting for head deflections and thermal bridging. 

 

In other words I think...  first thing to do is to make sure your glazing is fixed so it does not fall out and hurt someone. On large openings check the head deflection from the structure can be accommodated so it does not jamb the doors. Then think about the outside weathering detail and then last the thermal performance in terms of cold bridging. 

 

I know it's not not de rigueur but what do I know? Well I can tell you.. if your glazing is not properly fixed then no SE sign off. 

 

Here is a suggestion. Accept that you have to compromise, live with a bit more thermal briging and add a bit more insulation elsewhere. You will be not happy if water starts to leak in driving rain so that is why I put weathering as my second point. 

 

Threshold details can look great on a drawing.. but you need to make them idiot proof as few folk will keep out leaves, moss etc. You also need to make them buildable which many details are clearly not. 

Has your Architect put themselves in a builders shoes? How do you achieve this on site and how do you water proof the ends? If it's too complicate you'll likely end up paying more for something that probably won't get delivered on site. 

 

Thanks for your detailed reply @Gus Potter. What is it about the detail that makes it harder to secure the door?

 

As a side-note, I've had loads of trouble with Architects and in fact we are now on our third. With our roofing disaster aside, professional services has definitely been by far the biggest stressor in the project so far.

 

This is all about structural support for the door above everything else. The concrete core simply is not wide enough to provide support for the whole depth of the profile, this is how to bring this in line with what ID Systems/Sunflex want.

 

I've got a large projecting Oriel Window and the detailing on that eclipses this by a long way, I'm struggling there too.