Thermal break lintel - VFM?

[Gabe]

We're about to extend our kitchen and install two sets of double lift-and-slide patio doors. One set will be 2000mm high x 2850mm wide, and the other set will be 2300mm high x 3450mm wide. One set will be installed in a newly formed opening in the existing structure of the house, and the other will be in the single storey extension. The overall u-value of each set will be 1.3.

 

I'm trying to decide whether it's worth paying the not insignificant premium for thermally broken lintels instead of the cheaper traditional type. The new extension will have a 150mm cavity, and I believe the existing structure is only 100mm. The house was built about 20 years ago.

 

Any thoughts on whether there would be an appreciable difference in comfort levels, or whether we would avoid condensation issues, by opting for the thermally broken lintels, or whether  it's a waste of money?

 

Thanks.

[MortarThePoint]

For shorter spans, there isn't much cost uplift and the removal of the cold bridge that the lintel represents is a similar upgrade to going from double o triple glazing. Those are some quote large spans so I'd imagine the lintels are sturdy. I used Keystone HT/XHD+ 100 WIL 2850mm lintels for 2485mm openings in 140mm blockwork and they cost around £200 each in 2020.

 

Condell used to be a sensible place to see how much lintels cost, but be careful as some of their prices (Catnic Thermally Broken) look a joke now.

 

When building an entirely new house it sometimes makes sense to remove a 'weak spot' that doesn't make sense removing in a renovation. I doubt you'd notice the difference in terms of condensation etc but it would make a difference to your heating bill.

[Gabe]

On 05/02/2024 at 18:38, MortarThePoint said:

For shorter spans, there isn't much cost uplift and the removal of the cold bridge that the lintel represents is a similar upgrade to going from double o triple glazing. Those are some quote large spans so I'd imagine the lintels are sturdy. I used Keystone HT/XHD+ 100 WIL 2850mm lintels for 2485mm openings in 140mm blockwork and they cost around £200 each in 2020.

 

Condell used to be a sensible place to see how much lintels cost, but be careful as some of their prices (Catnic Thermally Broken) look a joke now.

 

When building an entirely new house it sometimes makes sense to remove a 'weak spot' that doesn't make sense removing in a renovation. I doubt you'd notice the difference in terms of condensation etc but it would make a difference to your heating bill.

Thank you. If a thermally broken lintel is equivalent to triple glazing as opposed to double, is it an unnecessary expense if the sliding doors themselves are only double glazed?

[MortarThePoint]

You can just do one (tg or thermal lintels) you don't have to do both though both is better. I went with thermal lintels but no tg due to the cost benefit