Stud Partions - Insulation?

Builderwoman!

Hi All,

What do you recommend for insulation in stud partions upstairs? Rockwool, Fibreglass or something rigid? All advice welcomed
Thanks

GreeBo

I'm guessing this is a new build?
What are you trying to achieve with this insulation?
Heat/sound/both something else?

Builderwoman!

Yes, thanks Greebo, it is a new build. We are trying to achieve good heat and sound qualities. Any suggestions welcomed.

rooferPete

Hi Builderwoman,

For stud partitions between rooms standard fibreglass should do the job as it takes the drum effect out of the partition.

If you have stud walls in a dormer bungalow then I would upgrade to Rockwool Rollbats or similar because the side walls will be exposed to the cold airflow in the roof space.

Between rooms noise transmission would be the main concern as each room will most likely have the temperatures to within a few degrees.

.

Corkey123

Whatever form of insulation you choose to use make sure it is in rigid format as loose insulation such as rolled fibre glass/rockwool etc. will settle over time in the partition and eventaully create a cavity at the top of the partition.

patrido

Hi Builderwoman!
rockwool flexi bats are great for this. they are rigid enough to not fall down over time, and they have a flexible edge, for a tight fit every time. Knauf and Moy Isover also make rigid or semi rigid slabs.

i assume that you are talking about the internal walls, because the "dwarf" walls in a dormer that rooferpete mentioned are a different story. The requirements here are quite high because they are backing onto an unheated space, and there is a high degree of thermal bridging due to the studs (about 15% of the total area).

in order to meet the building regulations, you are likely to need either
100mm of kingspan/xtratherm between the studs
OR 50mm between the studs with 30mm insulation backed plasterboard inside them (that's 30mm insulation plus 12.5mm plasterboard).

that's assuming 2 inch studs at 16 inch centres.

so filling the studs with fibreglass or rockwool will not meet the required standard on its own. you could add an insulated plasterboard inboard of the studs, but this is likely to cause a condensation risk due to having the higher conductivity product on the cold side..

Builderwoman!

Hi All, thanks a mill for coming back on my query. You know I always like to bounce questions off you guys as every insulation installer/supplier etc you speak do give you a different speil....depending of course on what they are endorsing.

The complete insulation story so far is....

Cavity walls with blown beads (should bring us to .27) might even opt for cellulose it "may" be better. Awaiting info on that.

Actis Tri Iso Super 9 on dormer slopes and coming down the short/dwarf walls. All properly sealed and then counter batoned.

12 inches fibreglass in the attic areas...maybe even bring this up to 16 inches as the attic space is small and pretty unusable for us tall people, (could rent it out to vertically challeneged I guess....!)

Studs: some guys say fibre glass others acoustic fibre glass and others say rockwool. We think the rigid stuff is the way to go as I think the softer formats will shrink/drop down over time. Insulation suppliers say "ah no" that won't happen. Another factor - husband is/was a sound engineer so sound is also an issue...don't want him to be moaning about sound transferance when we are living there!!!!

Our windows are 1.1 uvalue. For heat we are putting in a pellet boiler, also heat recovery system and solar panels.

So do you still think that the rigid rockwool is the way to go. Are we doing enough? All advice/opinions welcomed.

patrido

here are the sound absorbtion specs for moy acoustic (basically a roll of fibreglass) and rockwool flexi.
http://img115.imageshack.us/img115/5273/rockwool2st.jpg
http://img526.imageshack.us/img526/603/moy5mh.jpg

they give the coefficient of absorbtion for sounds of various frequencies. your hubby might know how significant the differences are.

Builderwoman!

Thanks Patridio. Do you think that we are doing enough insulation wise. I'd value your opinon. Cheers, BW!

patrido

yes, it's a pretty impressive spec and if it's all installed correctly with particular attention to air tightness, thermal bridging and condensation risks you should be nice and toasty on those cold winter nights.

you didn't mentioned the floor though - what's the story there?

Builderwoman!

Thanks Patridio. Hopefully all the outlay now will pay off over the forthcoming years! I think it was pretty much compliant the building regs that the guy doing the foundations put in (I was away when it was being done). I can't remember exactly what thickness but it was the standard kingspan/xtratherm.

Any tips on what to watch out for with the installers in order to ensure thermal briding, air tightness and condensation would be welcomed please?

joejoem

I put up a stud partition between a sitting room and bedroom about two weeks ago. I used Rockwool insulation. Its been fantastic for both sound and heat insulation.

Builderwoman!

That JJ. Did you use the rigid or rolls as a matter of interest?

Patridio, it might be belt and braces, but we are also putting insulated plaster board on all exterior walls. Forgot to mentiont that.