Insulation for a 100mm Stud Wall

[heating12numpty12]

Hi

I am building a 100mm stud wall for a boot room which is in an un-insulated garage.

To comply with the latest requirements is 100mm of fiberglass acceptable?

 

[John D v2.0]

What's a boot room? If it's just a store then there are no requirements for insulation, if it's a habitable room you need more than that if it's only plasterboard, also ventilation etc.

 

[heating12numpty12]

What's a boot room? If it's just a store then there are no requirements for insulation, if it's a habitable room you need more than that if it's only plasterboard, also ventilation etc.

It's a small room that ajoins a kitchen, and is used for storing items, including boots.

 

[^woody^]

100mm celotex maybe for thermal, but not fibre

 

[chappers]

Are you planning to make it part of the house or will the original kitchen door to the garage remain

 

[heating12numpty12]

Are you planning to make it part of the house or will the original kitchen door to the garage remain

It will be part of the house/kitchen so will be heated via the kitchen radiators. The original garage door will be moved and changed to a fire door.

 

[jeds]

You need at least 100mm PIR foam between studs. I'd also fit 30mm across in a continuous layer as well before a finish layer of plasterboard.

 

[chappers]

60/25 should be sufficient for regs plasterboarded both sides.
You may also need 150mm liquid impervious layer at the bottom, depending on the layout of the original garage floor.
Assuming the rest of the garage will remain so.

 

[motorbiking]

150mm, but I'd go with celotex or similar as it will do it in under 100mm. i'd be tempted to go double plaster board though if there are combustibles in the garage.

There is a guide here on how to hit .28 U value..
http://stalbans.gov.uk/Images/Insulation Guide 2010 HTF_tcm15-14411.pdf

 

[John D v2.0]

Based on your update you'll need double layer of plasterboard and adequate ventilation as well as about 70mm celotex.

 

[heating12numpty12]

Based on your update you'll need double layer of plasterboard and adequate ventilation as well as about 70mm celotex.

Could you advise on the "adequate ventilation"?

Thank you

 

[John D v2.0]

Have a look at "approved document part f ventilation "
Basically the simple summary is you need 8000mm2 ventilation to another ventilated room or outside, or a constant extract.
The complicated rules you can find from the above approved document if you have a few hours to spare.

 

[John D v2.0]

Also remember that the insulation requirements apply to the ceiling and floor too!

 

[chappers]

150mm,

Not sure if you got what I meant the bottom 150mm of the wall need to be impervious to fluids seeping under the wall from the garage unless the garage floor slopes away at the required fall(sorry can't remember what that is but it is specified in the building regs)
Have a look on the celotex site, they have a u-value calculator, but for a garage divide, with plasterboard on both sides I'm pretty sure that 60mm between and 25mm over the studs will achieve the correct u-value.

 

[^woody^]

What you do to this boot room all depends on whether you are keeping the separation from the house where it is, or moving it. ie is the room part of the house or part of the garage.

Either way, by all accounts its a store room and does not need to be insulated or ventilated unless you want it to be.