Partitions: Timbers studs Vs Metal C studs

[MortarThePoint]

5 minutes ago, PeterW said:

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

 

Internal. I have two kids and like the sound of mechanical clocks and a good read ? 

Edited September 3, 2021 by MortarThePoint

[MortarThePoint]

With a timber wall, you're looking at starting around STC32 and going into the 40s at best without using resilient bar (aka resilient channel) or doubling up on timbers.

 

Timber highlights from IR761:

Page 26: 406 c/c, 90mm timber studs, double layers of 13mm plasterboard, mid density insulation STC 38

Page 178: 610 c/c, 90mm timber studs, 16mm plasterboard, lower density insulation, resilient bar one side  406c/c STC 50

Page 218: 406c/c, 90mm timber studs, double layers of 13mm plasterboard, lower density insulation, resilient bar one side 610c/c  STC 57

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)

 

 

Some MF highlights (copied from previous post):

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, resilient bar one side 610c/c 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)

 

So looks like you get about the same result using 90mm timber studs with single sided Resilient Channel as you do using 65mm metal studs. Mapping to the UK that would be 95mm timber and 70mm MF. The timber option is about 40mm thicker and currently more expensive. 70mm MF is around £1/m of material whereas 4x2 is above £2/m of material and would need the resilient bar on top of that.

Edited September 3, 2021 by MortarThePoint

[MortarThePoint]

1 hour ago, MortarThePoint said:

70mm MF is around £1/m of material whereas 4x2 is above £2/m of material

 

That works out as £6.50/m of wall uplift to timber plus resilient channel at around £6/m of wall. 

[MortarThePoint]

Does anyone know if I should start a BG acoustic stud (Acoustud) partition on a blockwork abutment with a standard C-stud or on a vertically mounted section of floor/ceiling channel? The BG Acoustud doesn't have a flat back so won't work screwed t a blockowork wall. Tried getting an answer from BG but their swamped and haven't responded.

 

[saveasteading]

I have it on good authority that the stated acoustic performance never happens in real life, and to use the next spec up if you need to pass a test.

[MortarThePoint]

13 minutes ago, saveasteading said:

I have it on good authority that the stated acoustic performance never happens in real life, and to use the next spec up if you need to pass a test.

 

No test thankfully and likely overkill anyway ? 

[Adsibob]

How are people finding lead times for Metal studs (both C studs and I studs) at the  moment.

[MortarThePoint]

18 minutes ago, Adsibob said:

How are people finding lead times for Metal studs (both C studs and I studs) at the  moment.

 

OK for now. My local Minster and Travis Perkins have the standard stuff in stock. The BG Acoustic and deep track needs ordering in (e.g. from CCF), but that's only a couple of days (supposedly). Prices have been going up, but nowhere near timber.

[MikeGrahamT21]

1 hour ago, Adsibob said:

How are people finding lead times for Metal studs (both C studs and I studs) at the  moment.

 

I've just had a load delivered from Wickes, no problems at all. These are Knauf ones tho, not BG. I've got C studs and tracks

[PeterW]

41 minutes ago, MikeGrahamT21 said:

 

I've just had a load delivered from Wickes, no problems at all. These are Knauf ones tho, not BG. I've got C studs and tracks

Watch Wickes orders .. they are based on local stock not central stock. I ordered a load of timber for a date about 5 days ahead and when it came they had to deliver it in 3 different orders from 3 different stores. It being “in stock” when you order doesn’t guarantee it being in stock when they need to deliver it. 

[MortarThePoint]

I wanted to check the effect of varying Acoustic Roll thickness on sound and the headline is adding just 25mm is 5dB better than having none, but adding 50mm is a further 1.5dB better. It may be cheaper to upgrade the plasterboard than double the thickness of the Acoustic Roll (SoundBloc+25mm is better than WallBoard+50mm).

 

The Gory details:

 

Maddeningly, BG have changed their product selector website and it's near useless. Previously I remember you could select which studs and plasterboard you'd use but now its got all the detail codes instead of the stud type. It says "To see all Specifications that use a particular Product, please go to the Product page and look for the ‘Show me all specifications that use this product’ option." but if you select a specific stud type results include other types!

 

Sadly the madness doesn't end when you download the CSV. Although the table includes stud type etc, the columns are messed up so the data can be in the wrong columns 😞 How hard can it be! I added a column that concats all the columns after the abutment one (as many use C studs for abutments but other studs mainly) checked if the concat contains the stud name I want and then filter. {EDIT: easier to use find on column B}

 

Below is some extracts. The colours are Duraline orange, WallBoard white, Fireline pink, SoundBloc blue (red text if SoundBloc F), TileBacker grey, and Habito yellow. Multiple lines as different insulation options, the first of each group is no insulation.

 

The first 5 are the 15mm Duraline with the following insulation (APR 1200 unless says):

• none (42dB),
• 25mm Isover Acoustic Partition Roll (APR 1200) (47dB),
• 50mm Isover Acoustic Partition Roll (APR 1200) (48dB),
• 80mm Isover Modular Roll (49dB),
• 75mm Isover Acoustic Slab (50dB)

Other sheet types that have less options follow that order though (double check).

 

102mm Partitions with 70 S 50 C-studs:

 

97mm Partitions with 70 S 50 C-studs:

 

 

 

 

 

Edited March 28, 2022 by MortarThePoint

[MortarThePoint]

Amazing to think of the weight supported by studs. If doubling up on something like SoundBloc, Each stud is supporting about 80kg of weight (1.3kN/m).

 

Check you Structural Engineer's allowance for partition weight as sometimes it's only 1kN/m.

[Blynchy]

I'm looking into designing my internal studs. I've decided to go metal based on all the comments. Living in rented accommodation at the moment in a standard developers semi-d. Even though the inter stud walls don't crack, they do have a feeling of movement especially if a door is closed with any small bit of force. What would be the best way to overcome this? Is it doubling on the plasterboard? or larger steel sections or more fixings? Has anyone advice of the build up that they used for the bedrooms and toilets?

[MikeGrahamT21]

11 hours ago, Blynchy said:

I'm looking into designing my internal studs. I've decided to go metal based on all the comments. Living in rented accommodation at the moment in a standard developers semi-d. Even though the inter stud walls don't crack, they do have a feeling of movement especially if a door is closed with any small bit of force. What would be the best way to overcome this? Is it doubling on the plasterboard? or larger steel sections or more fixings? Has anyone advice of the build up that they used for the bedrooms and toilets?

larger steel sections from memory, they are more profiled to absorb shock. Double boarding on these will also likely help

[MortarThePoint]

I was finding it hard to find the British Gypsum Site Book and Good Practice Guide so thought I would upload it here for anyone else who wants it.

British-Gypsum-Good-Practice-Guide.pdf

[MortarThePoint]

Here's a potential gotcha. For bathrooms, C-studs should be at 400mm c/c if using any 15mm Gyproc moisture resistant grade plasterboard. It doesn't actually say what stud c/c to use if using 12.5mm moisture resistant plasterboard.

 

A Siniat video about metal stud partitions says they should be at 400mm c/c due to the extra weight of tiles.

Edited April 23, 2022 by MortarThePoint

[Conor]

We ply-lined walls to be tiled.

[Pocster]

7 hours ago, Conor said:

We ply-lined walls to be tiled.

I marine ply in bathrooms on the stud . Whether that’s worth the extra cost compared to osb is debatable. But I sleep better at night not thinking about it 

[MortarThePoint]

A point worth knowing is that British Gypsum 70mm C-studs accommodate 32mm waste pipe through their cut-outs but Tradeline don't. Neither accommodate 40mm waste pipe. The cut-outs in 70mm Acoustic studs are way to small.

Edited May 2, 2022 by MortarThePoint

[Nickfromwales]

51 minutes ago, MortarThePoint said:

A point worth knowing is that British Gypsum 70mm C-studs accommodate 32mm waste pipe through their cut-outs but Tradeline don't. Neither accommodate 40mm waste pipe. The cut-outs in 70mm Acoustic studs are way to small.

If adhering to Bregs, I'm pretty sure the BCO will not want waste pipes buried in a wall dividing a bedroom from a room with such services in it. The 'preference' is to surface mount the waste pipes inside the 'offending' room. You could mitigate with deeper studs and a double layer of acoustic plasterboard to the bedroom side, but best to ask your BCO first in case they turn out to be a jobsworth.

Edited May 2, 2022 by Nickfromwales

[Nickfromwales]

On 23/04/2022 at 21:55, MortarThePoint said:

Here's a potential gotcha. For bathrooms, C-studs should be at 400mm c/c if using any 15mm Gyproc moisture resistant grade plasterboard. It doesn't actually say what stud c/c to use if using 12.5mm moisture resistant plasterboard.

 

A Siniat video about metal stud partitions says they should be at 400mm c/c due to the extra weight of tiles.

Remember that kg/m2 rtings must include tiles and adhesive / other wall covering. Hence the normal Bregs requirement for 400mm OC's in bathrooms. 

On 24/04/2022 at 03:28, Conor said:

We ply-lined walls to be tiled.

Ply / OSB3 whatever, but boarding out a bathroom is a complete no brainer for strength / solidity, and to allow the occupier the means to screw anything anywhere with excellent purchase for the fixings.

Nothing pisses you off more than a loo roll holder that wont stay straight, or a glass shelf that is drooping. 

[MortarThePoint]

Top tip for Acoustic studs, use a different brand of screw. When inspecting a wall after the fact, if you've used a different branded screw with a logo on its head (e.g. Dewalt has DF on) or a BZP screw like the Screwfix ones it is then easy to inspect. The screws mustn't be too long (e.g. you want 25mm with a 15mm plasterboard) so if you only have 25mm screws of that type it's easy to check the correct screw has been used.

 

https://www.screwfix.com/p/easydrive-bzp-bugle-head-fine-thread-uncollated-drywall-screws-3-5-x-25mm-1000-pack/25899

[MortarThePoint]

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

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

This link is now dead, but it can't be found by Googling ir761.pdf. I am attaching here anyway.

 

Gypsum board walls: transmission loss data
Halliwell, R. E.; Nightingale, T. R. T.; Warnock, A. C. C.; Birta, J. A.

20331556.pdf

[LiamJones]

Has anyone fitted resilient bar to a stud wall, with only one sheet of plasterboard either side? All the British gypsum details for resilient bar, specify double boarding to both sides? Anyone know why? 

[Mike]

5 minutes ago, LiamJones said:

All the British gypsum details for resilient bar, specify double boarding to both sides? Anyone know why?

Resilient bars help reduce impact sound. Double boards help reduce airborne sound. It would be unusual to construct a partition that's enhanced to resist impact sound only.