Wall spec please...

[NickePicke]

Aloha,

I'm building a 2 storey extension and I'm not certain on what concrete block I can use.
The external walls will be block cavity walls with a rendered finish. 100 mm cavity with 50mm insulation so fairly standard. Without over designing the walls what block would you advise I use for the external walls.
By all means if you have any general comments about the spec you are more than welcome to suggest an alternative.
Many thanks!

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[jeds]

Structurally any block will do but it must meet the requirements of the u-value. With 50mm Celotex you will struggle to meet 0.28 with dense external blocks. My advice would be use 100mm full fill cavity batts instead with dense external block and Celcon Standard internally. That should get you a point or two better than the minimum u-value.

 

[NickePicke]

Structurally any block will do but it must meet the requirements of the u-value. With 50mm Celotex you will struggle to meet 0.28 with dense external blocks. My advice would be use 100mm full fill cavity batts instead with dense external block and Celcon Standard internally. That should get you a point or two better than the minimum u-value.

Great, thanks for your input.
So a standard celcon block will take the joists of the 1st floor?

 

[jeds]

Yes. Celcon 'Standard' are 3.6N which is plenty.

Note; in this case the word Standard is actually the name of a Celcon block rather than being used to describe a standard block. If you get what I mean.

 

[NickePicke]

Yes. Celcon 'Standard' are 3.6N which is plenty.

Note; in this case the word Standard is actually the name of a Celcon block rather than being used to describe a standard block. If you get what I mean.

I'm with you.. Thanks again!