Partitions: Timbers studs Vs Metal C studs

[MortarThePoint]

2 hours ago, nod said:

Most commercial bathrooms we do have a layer of ply for the first layer

 

Is that because there isn't a moisture resistant Habito?

[Adsibob]

On 16/06/2021 at 22:19, willbish said:

Ditto. That was my reason for going all metal. 70mm track, 50mm staggered I studs. 15mm soundbloc both sides. 

 

Ply lined for landing cupboards and walk in wardrobes. 

Sorry to ask a really stupid question, but how do you make a 70mm track work with a 50mm I-stud? Shouldn't the track be only slightly wider than the stud, as suggested here:

https://www.buildingmaterials.co.uk/50mm-i-stud-section-2700mm?mh_keyword=&utm_term=&utm_campaign=[LocationSet2]SmartShopping|PlasterboardAccessories&gclid=Cj0KCQjw5auGBhDEARIsAFyNm9EAKd--KgIIKas0jHqQ8TTmb7ouZ4-IfgiSRIyONWcfaih8m1Idz2oaAoy6EALw_wcB

You can tell I've never installed a stud wall (metal or wood) before can't you!

[nod]

9 hours ago, MortarThePoint said:

 

Is that because there isn't a moisture resistant Habito?

It’s mainly due to the amount of fixings Dryers handrails stalls etc 

Habito is  very resistant to moister 

[Dreadnaught]

7 hours ago, Adsibob said:

but how do you make a 70mm track work with a 50mm I-stud

This is 60/72 but you get the idea…

 

[nod]

You can get a 52 mil track or use clips and a 72 

[Adsibob]

11 minutes ago, nod said:

You can get a 52 mil track or use clips and a 72 

Presumably @Dreadnaught’s suggestion improves sound isolation by ensuring there is nothing joining either side of the wall?

[Russell griffiths]

Something I will add, make your stud walls as thick as you can 90mm minimum. 

I have a couple of 75mm stud walls and regret doing it, the thought was to save a bit of space in the en-suite bathrooms, in reality they are two thin to comfortably run pipes and cables in, it is always in my mind that 20mm from the surface of a wall I have a pipe/cable,even with drilling the studs exactly in the centre there is not a lot of meat left for the margin of error. 

[Russell griffiths]

31 minutes ago, Dreadnaught said:

This is 60/72 but you get the idea…

 

Try running a 40mm waste pipe through that, lots of planning needed if you go this route. 

[nod]

If you have the room Two freestanding 50 mil studs with a 20 mil cavity will give excellent acoustics 

[Adsibob]

16 minutes ago, Russell griffiths said:

Something I will add, make your stud walls as thick as you can 90mm minimum. 

I have a couple of 75mm stud walls and regret doing it, the thought was to save a bit of space in the en-suite bathrooms, in reality they are two thin to comfortably run pipes and cables in, it is always in my mind that 20mm from the surface of a wall I have a pipe/cable,even with drilling the studs exactly in the centre there is not a lot of meat left for the margin of error. 

Is that also the case if I have posi joists?

[markc]

6 minutes ago, Adsibob said:

Is that also the case if I have posi joists?

With pozi joists the top and bottom cord are deep enough to accommodate decent length screws so you shouldn't break through into the voids

[Adsibob]

5 minutes ago, markc said:

With pozi joists the top and bottom cord are deep enough to accommodate decent length screws so you shouldn't break through into the voids

Sorry, what I meant was that will I need to run many services through walls, when there are options to do so easily within the floor structure? Obviously, not all waste pipes can go exclusively through the floor, but I would have thought all water supply pipes and electric cables can? This would then mitigate, albeit not eliminate, most of the issue mentioned by @Russell griffiths.

[Russell griffiths]

10 minutes ago, Adsibob said:

Sorry, what I meant was that will I need to run many services through walls, when there are options to do so easily within the floor structure? Obviously, not all waste pipes can go exclusively through the floor, but I would have thought all water supply pipes and electric cables can? This would then mitigate, albeit not eliminate, most of the issue mentioned by @Russell griffiths.

Vertical pipes coming up to feed sinks, shower mixers, basins. 

Everything has to come up or down to its final destination, not a lot of things are actually fitted to the floor. 

[Adsibob]

42 minutes ago, Russell griffiths said:

Vertical pipes coming up to feed sinks, shower mixers, basins. 

Everything has to come up or down to its final destination, not a lot of things are actually fitted to the floor. 

We are in agreement. That's what I was referring to when I said "mitigate, albeit not eliminate" the problem.

[Dreadnaught]

If anyone is interested in MF partition walls, flipping through the GypWall White Book may well open your eyes. I like that you can choose a wall build-up based, for example, on sound absorbency vs thickness.

 

https://www.british-gypsum.com/literature/white-book/partitions

 

Of course you don't need to buy the components from British Gypsum. They are standard and commoditised.

 

 

Edited June 18, 2021 by Dreadnaught

[Moonshine]

16 minutes ago, Dreadnaught said:

If anyone is interested in MF partition walls

 

I have one on my desk 

[MortarThePoint]

If you want to fully nerd out on all of this you can check out IR761: https://www.jhbrandt.net/wp-content/uploads/2014/11/ir761.pdf

 

A lot of the other sources of information for timber vs metal frame is subject to conflict of interest as the plasterboard manufacturers produce metal frames. I'm no saying they tell porkies, but there may be a configuration missing.

 

Page 21 (not sheet, page) of IR761 has "Wood studs – 1 layer gypsum board" - STC 34 (90mm studs)

Page 28 of IR761 has "Steel studs studs – 1 layer gypsum board" - STC 36 (these are 65mm studs though)

 

Looking through the document can turn in to an amazing game of spot the difference (e.g. page 28 vs page 29)

 

I don't readily see timber studs at 610mm c/c.

 

Basically it looks like if you start from 65mm steel studs at 406 c/c with 13mm plasterboard each side giving around STC 35:

• Changing 406 c/c to 610 c/c adds about 5
• Changing 65mm MF to 90mm MF adds about 5
• Changing 13mm to 16mm plasterboard adds about 5
• Doubling up plasterboard adds about 5
• Adding resilient channel one side adds about 7 (not shown with 610 c/c studs though??)

It definitely looks like you can have the insulation too dense (page 46 vs 40)!

 

Some highlights:

Page 89: 610 c/c, 90 steel studs, 16mm plasterboard lower density insulation STC 50.

Page 93: 610 c/c, 65 steel studs, 13mm plasterboard (double on one side) lower density insulation STC 51.

Page 120:  610 c/c, 90 steel studs, 16mm plasterboard (+13mm on one side) lower density insulation STC 55.

Page 124: 610 c/c, 65 steel studs. two layers of 13mm plasterboard each side, lower density insulation STC 55.

Page 245: 406 c/c, 90 steel studs, two layers of 13mm plasterboard each side, low/medium density insulation STC 60.

Page 350: Double timber wall, 610c/c, double layers of 16mm plasterboard, lower density insulation STC 69. Good below 125Hz (e.g. 26.7 @ 50Hz)

 

It's much harder to achieve good performance at lower frequencies (<125Hz). Of interest:

• Music: Spectrograms are a useful way of seeing the frequency distribution (and as an aside are good for AI like Alexa), Country music may be the worst in more ways than one as it turns out [link]. 'Subs' and 'Kick' are likely to be the most challenging [link] [another link]
• Snoring: "The fundamental snoring sound frequencies of the tonsil, tongue base, and larynx were approximately 330 Hz, 1000 Hz, and 652 Hz, respectively" [link]
• Farts: "The data show that most farts predominantly have power in sound frequencies between 200 and 400 Hz" [link ?]
• Films: Psycho (shrill music and women screaming) probably easier to cope with (if you're not watching it) than Jurassic Park, keep it down T-rex!

The insulation side of it is really interesting. Rockwool would have you believe in the acoustic benefits of their denser insulation which doesn't fit the data. Insulation G1 is good and has a density of around 12kg/m3 and air resistivity of ~4000 mks rayls/m (whatever they are).

 

[ADLIan]

The great Rockwool myth of 'denser = better' busted!! As a bit of background stone wool (Rockwool is a trade name) will always be about twice as dense as glass wool for the same thermal and acoustic performance. Any stone or glass wool in the normal density range, say 10 kg/m³ (glass) to 60 kg/m³ (stone) and at a given thickness will have a similar acoustic absorption value. There will be slight differences in these figures (only picked up in laboratory tests) but they are swamped, once installed in a wall, by the effect of the studs (metal or timber) and plasterboard facings. Look through Appr Doc E of the Regs, the Robust Details, the BG White Book and the above referenced document.

 

Very dense stone wool compressed into a partition wall will have an negative affect on the acoustic performance. Low density products and/or an airspace acts a 'spring' between the 2 (or more) layers of plasterboard. A high density product, compressed, effectively couples the 2 layers of plasterboard so sound energy can be transferred much more efficiently.

[MikeGrahamT21]

15 minutes ago, ADLIan said:

The great Rockwool myth of 'denser = better' busted!! As a bit of background stone wool (Rockwool is a trade name) will always be about twice as dense as glass wool for the same thermal and acoustic performance. Any stone or glass wool in the normal density range, say 10 kg/m³ (glass) to 60 kg/m³ (stone) and at a given thickness will have a similar acoustic absorption value. There will be slight differences in these figures (only picked up in laboratory tests) but they are swamped, once installed in a wall, by the effect of the studs (metal or timber) and plasterboard facings. Look through Appr Doc E of the Regs, the Robust Details, the BG White Book and the above referenced document.

 

Very dense stone wool compressed into a partition wall will have an negative affect on the acoustic performance. Low density products and/or an airspace acts a 'spring' between the 2 (or more) layers of plasterboard. A high density product, compressed, effectively couples the 2 layers of plasterboard so sound energy can be transferred much more efficiently.

From memory isn't it always preferable to have an airgap inside the partition, i.e. the insulation shouldn't full fill, so that any sound can reverberate and be absorbed.

[MortarThePoint]

On 12/07/2021 at 19:20, MortarThePoint said:

Page 245: 406 c/c, 90 steel studs, two layers of 13mm plasterboard each side, low/medium density insulation STC 60.

 

This one includes Resilient Channel

[MortarThePoint]

I'm tempted to go for MF I-studs rather than C-studs but they are about 3x the price without supported pricing. In terms of feeling solid, Does anyone know how 70mm I-stud compare to 92mm C-stud? Having a 6y.o. who already likes slamming doors doesn't bode well for the years to come if I don't have solid feeling partitions.

Edited September 1, 2021 by MortarThePoint

[MortarThePoint]

I've been getting my head around Partition duty and I think I'll be happy as long as it is Severe duty in certain places.

 

BG Habito is expensive (£20) and only available to me in Pallet quantities (38 @ 2.7m). It's good stuff though and the BG System Selector says a sheet of Habito either side of a 70 S 50 C-Stud is Severe duty rating with Sound Insulation of 38dB. That's with no insulation and they don't give a value with insulation. However, I can deduce from page C04.S02.P04 of the White Book that adding 25mm of acoustic insulation adds 6dB, so would make that combination 44dB.

 

Given the incremental cost, I think I'll go with the Acoustud and SoundBloc upgrades which give Severe duty and 58dB sound insulation, the same as insulation +  2x SoundBloc each side. That gives me some combinations that all have 58dB:

• Habito + Soundbloc both sides £65/lm
• Habito + SoundBloc one side, 2x SoundBloc the other side £57/lm
• 2x SoundBloc both sides £49/lm

In less sound and duty sensitive locations, I can go single skin with 50dB:

• Habito both sides £47/lm
• Habito one side, SoundBloc the other side £39/lm
• SoundBloc both sides £31/lm

Future proofing with Habito is going to cost me a fair bit, but not as much as if I was to put Plywood or OSB in at their current prices. I may end up with some Habito sheets left over though. I can do this as I don't have many metres of partition to address.

 

For reference, a 40dB 70 S 50 wall (with insulation) would be around about £18/lm I think. On this, SoundBloc each side adds about £8/lm and the Acoustud adds about £5/lm.

 

I don't have any fire requirements above 30 minutes.

 

[MortarThePoint]

Important to remember that any wall with a door in is pointless to soundproof ?

link

Edited September 2, 2021 by MortarThePoint

[MortarThePoint]

11 hours ago, MortarThePoint said:

Important to remember that any wall with a door in is pointless to soundproof ?

 

My comment was made a bit quickly. Pointless to go nuts with the soundproofing if the door isn't specifically sound proof. Even then, the door is likely to be the weak spot in any wall above 44dB which is a single skin each side (denser board type) insulated wall of C-studs.

Edited September 3, 2021 by MortarThePoint

[PeterW]

Still not sure why you want all the soundproofing ..? Are you looking to block environmental sounds (ie external to the building) or internal sound..?