Foundations??

[JohnMo]

19 minutes ago, Nickfromwales said:

Did you install any below grade?

No, mainly because at time of design I didn't realise you could. Plus I didn't order enough to do it as a change.

 

A guy down the road did his with Durisol below dpc, full filled with concrete. He even did all the internal walls with Durisol.

[Nickfromwales]

2 minutes ago, JohnMo said:

No, mainly because at time of design I didn't realise you could. Plus I didn't order enough to do it as a change.

 

A guy down the road did his with Durisol below dpc, full filled with concrete. He even did all the internal walls with Durisol.

Ok, thanks.

 

Do they stipulate waterproof concrete below DPC like Nudura did with us?

[JohnMo]

8 hours ago, Nickfromwales said:

Do they stipulate waterproof concrete below DPC like Nudura did with us?

Didn't see anything, so presume nothing 

[lizzieuk1]

On 01/03/2025 at 19:33, Iceverge said:

Something like. 

 

Tiles

Tile battens

Counter battens

Breather membrane

11mm OSB

350 mm I joists with Cellulose.

Membrane 

20*70mm battened service cavity

Plasterboard 

Skim.

 

U value about 0.11. 

 

Would it be an option to use rockwool slabs between the I joists if we couldn't do the blown cellulose. Looking at thermal values they look very similar. 

No idea on cost comparison though so, any info on that would be helpful.

[Iceverge]

Cellulose is dearer than Rockwool but that includes fitting. About €150/m3 plus VAT near me. Not sure of UK prices. 

 

There's a notable difference between the cheap mineral wool "loft roll" and higher density batts like Rockwool so ensure you're comparing like for like. 

 

Cellulose has the advantage that it really helps the airtighess too when it's properly installed..

[lizzieuk1]

8 minutes ago, Iceverge said:

Cellulose is dearer than Rockwool but that includes fitting. About €150/m3 plus VAT near me. Not sure of UK prices. 

 

There's a notable difference between the cheap mineral wool "loft roll" and higher density batts like Rockwool so ensure you're comparing like for like. 

 

Cellulose has the advantage that it really helps the airtighess too when it's properly installed..

Thanks Iceverge, food for thought then. 

[Russell griffiths]

3 hours ago, lizzieuk1 said:

Would it be an option to use rockwool slabs between the I joists if we couldn't do the blown cellulose. Looking at thermal values they look very similar. 

No idea on cost comparison though so, any info on that would be helpful.

I used a product called knauf omni fit. 
far nicer to handle than rockwool if installed from underneath. 

Edited 20 hours ago by Russell griffiths