What are the various options for stud walls?

[Adsibob]

My understanding, though I'm often wrong about these things, is that a standard stud wall is 125mm thick, being made up of a 100mm timber stud plus 12.5mm of plasterboard on either side. I'm aware that one can go thinner by either using a narrower timber stud or a metal one. I have in mind using a 70mm stud plus 12mm of hardie backer on one side and 12.5mm plasterboard on the other side, so 94.5mm in total, but my builder has suggested he could use a 50mm stud - I presume he means a metal one.

 

What are the disadvantages of going thinner? I imagine predominantly it is a sound insulation issue in that the thinner the wall, the less mineral wool one can stuff it with, but would be interested in whether people have experience of building narrower studs, how you went about it and did you regret going narrower?

[TonyT]

My walls are made up with  100x47mm because my joiner and I don’t like thinner walls, happy to pay for the extra timber as the walls are more sturdy, and allow for services running in partition without taking too much meat out of the timber.

 

I think if you were to build something out of 50mm it would need sheeted with OSB or similar to give some stability

 

 

[Mr Punter]

With timber, 63mm x 38mm cls is really the minimum.  89mm x 38 standard on factory build timber frame internals.  100 x 47 is nice and strong esp doorways.

 

Timber good to fix to but shrinks, twists etc.

 

With metal, the 50mm (48?) I stud is good for a thin independent wall, or the 70mm C stud is what you get everywhere.

 

Metal needs more technique to fix to but is more stable.

[Moonshine]

2 minutes ago, Mr Punter said:

89mm x 38 standard on factory build timber frame internals

 

i am actually going for this on my build.

[Dudda]

First post in almost a year here. Going to try and get back to visiting and posting more.

 

You've two main types of stud walls. Timber and metal.

 

Timber walls are used generally where you've a timber frame house or the walls are used to support a roof or floor above and are load bearing. Also used where you've the trades onsite. eg if you've carpenters doing the roof they can do the internal walls.

 

Generally metal walls are used for non load bearing walls as they're better acoustically. You start with the metal stud usually 48, 70 or 92mm 'C' studs and then you've the plasterboard or layers either side. The type of stud, spacing, and layers you place either side will determine the strength and acoustic performance.

 

The options for metal stud walls are almost endless. Have a look at this page which has the standard stud walls https://www.british-gypsum.com/literature/white-book/partitions/gypwall-classic and click on the link to download in the 'Related Documents'. This allows you to see all the options and compare them in terms of the acoustic performance and duty rating.

 

For example it shows a 70mm C stud with one layer of 12.5mm plasterboard either side (Ref: A206013) will have a acoustic performance of 36db. Add 50mm of insulation and the wall (Ref: A206138) rating is 42db. The overall thickness for both is 97mm.

 

If you were happy enough with the walls around 125mm thick as per your original post then you could use the 70mm metal C stud and have two layers of plasterboard either side (Ref: A206142). This would give a wall thickness of 122mm. The main advantage now is the acoustic performance is 50db which is very good and the duty rating of the wall is now severe. This is a very good quality partition.

 

When you use timber the sound transfer through the wood and you don't get a good acoustic performance. Adding the insulation helps but if you want to reduce noise transfer you really need to look at metal studs. Timber is easier to build and what a carpentor is more used to but most builders will have experience with metal studs.

 

 

Edited March 29, 2021 by Dudda

[Mr Punter]

Just now, Moonshine said:

i am actually going for this on my build.

 

Check they are straight.  I have seen some batches really twisted and contorted.  Does not seem to matter if C16 or C24, you just sometimes get rubbish.

[Moonshine]

2 minutes ago, Dudda said:

When you use timber the sound transfer through the wood and you don't get a good acoustic performance. Adding the insulation helps but if you want to reduce noise transfer you really need to look at metal studs.

 

or stick some resi bars on the timber studs

[LSB]

what is the difference in cost between timber & metal, and how do they perform with wet rooms like bathrooms.

Also, what about attaching items like shelves etc. any preference there.

 

[Dudda]

5 minutes ago, Moonshine said:

or stick some resi bars on the timber studs

True, but you're increasing the thickness, labor and material cost even further particularly if adding to both sides.

 

The other advantage of using a metal stud wall is you can get a warranty for the whole wall. This isn't an issue on residential properties but I find it very useful on commercial or public sector projects. For example a classroom where you have to meet specific acoustic and durability ratings or a consultants office in a hospital where privacy is important.

[Dudda]

8 minutes ago, LSB said:

what is the difference in cost between timber & metal, and how do they perform with wet rooms like bathrooms.

Also, what about attaching items like shelves etc. any preference there.

If moisture gets behind plasterboard (timber or metal) you've already failed and have a serious problem. Wet rooms should have green moisture resistant plasterboard or cement board. In shower or wet areas this is then tanked. 

 

You can get plasterboard which can be used on timber or metal studs to support shelves such as 'Glasroc H tilebacker' but it's more expensive than regular plasterboard. The easiest thing to do is put in additional support where you want shelves. You'll be putting these in anyway for kitchen units, to support the WC cistern, TV's etc so no harm putting in extra wherever you think you may have shelves in the future.