Any issues with reducing Cavity wall size?

[Mr Sparkle]

We're building an extension and we want to maximise the space internally/ externally (gable wall)

One of the ways the bricklayer has suggested is by constructing the cavity wall a little smaller at 290mm as opposed to 300mm.

We are using thermalite blocks (100mm), plus 100mm cavity slab insulation.

Is there any issue/ potential issue with reducing the cavity wall size?

 

[cdbe]

I should imagine a slight compression of the insulation will have a slight affect on its performance but I doubt anyone will notice or care

I built my extension with a 75mm cavity filled with 75mm dritherm 32 insulation, brick outer skin and a slightly higher performance lightweight block finished internally with dabbed on plasterboard .

 

[stuart45]

10mm won't give you much extra space, but a cavity a bit too small is a lot more hassle with batts, especially with AAC blocks.
Normally it's easier to add a few mm to the cavity.
Can't you make the walls a bit bigger in the footings?

 

[^woody^]

Lol. 10mm. will the settee fit in now?

Perhaps his next lightbulb moment will be 9.5mm plasterboard, taped joints and no skim?

Or perhaps your designer could have specified a different, thinner wall?

 

[tony1851]

If this is a side extension and space is a bit tight, is it possible to remove the existing outer skin of brickwork (assuming the existing side wall is traditional cavity)?
That would entail some plastering work and a skip, but would give you another 150mm.

 

[Mr Sparkle]

Lol. 10mm. will the settee fit in now?

Perhaps his next lightbulb moment will be 9.5mm plasterboard, taped joints and no skim?

Or perhaps your designer could have specified a different, thinner wall?

Well aren't you sassy today?

Yes, it's 10mm.. but every little or should I say, millimeter, helps

Architect originally specified a solid wall but I wanted a cavity as I'm not a fan of solid walls.

If this is a side extension and space is a bit tight, is it possible to remove the existing outer skin of brickwork (assuming the existing side wall is traditional cavity)?
That would entail some plastering work and a skip, but would give you another 150mm.

It's a rear extension but thanks for the tip

150mm would be lovely

 

[tony1851]

deleted.

 

[^woody^]

Well aren't you sassy today?

I do my best