Stud wall insulation density

[cwr]

I've specified the following on my plans regarding stud walls, of which there only a few in our otherwise block build house plan:

• Where stud walls are provided between a bedroom and kitchen / utility / bathroom / en-suite or living room then provide a min 38x75mm timber studs at 400mm centres with minimum 25mm mineral wool quilt suspended in void. 
 

 

Building control have come back asking me to 'specify density of mineral wool used for stud walls'.

Any advice on density to specify? 

 

Thanks

[dpmiller]

I think ours are 10kg/m2?

[nod]

Most of the site work I do is 25 mil 

Which will stop the sound bouncing around Though we tend to use 65 mil for bathrooms 

In your case I would put 100 mil in all Like me you have very few studs As long as what you put in is acoustic 

[Oz07]

Just say to achieve x amount of db reduction. Make sure x is the building regs figure. 38?

[ADLIan]

Min. density is 10 kg/m³ - see Section 5.18 of Appr Doc E (same detail in Scotland too). Manufacturers will have suitable products with this spec, see 'acoustic roll' or 'acoustic slabs'.

[Moonshine]

If they ask for an indicative product, one is Isover APR1200, which is 12 kg/m³ 

[cwr]

10kg/m2 did the trick, BC happy with that added in. Thanks for the replies.