"Modern" construction methods - are any of them a good idea?

[AndrewT1275]

gfreeman said:

Working in the commercial world all non-block/brick wall use metal studs.
The manufacturers have a vast array of standard specifications for acoustic, fire, load bearing capacity, thermal performance etc. etc. so as long as the correct spec is selected you won’t have problems. If your home has them and they are flimsy or rattle it is because they have not been built in accordance with spec. Like a lot of builds!

If additional load bearing capacity is required incorporate additional studs if you know where specific loads are to be applied or a layer of ply for greater flexibility. We have seen problems with using osb that had a high moisture content warping when drying out, twisting the walls out of alignment, so have been a bit wary of this ever since.

Spray plastering? Okay for our colonial cousins - not so popular here in the UK. If you’re very good you get a very good finish. If you are not it will cost a fortune to make good.

What thickness of ply would you recommend as the minimum for hanging normal stuff i.e. pictures, mirrors and bookshelves rather than kitchen cabinets?

[dhutch]

My only real experience with steel studwork was in a commercial venture, the walls where taller than a domestic due to the false ceiling, but they seemed a lot more springy, less stiff, than timber.

Even double boarded boat sides, the walls where not as heavy or soundproof as the few lath and plaster walls we have in this place, ditto ceilings. Almost all walls even upstairs are brick, all walls downstairs are, lovely solid feel to the place and good sound isolation between the rooms.

Obviously I would swap the solid external walls for insulated cavity if I could, but they are dry due the large overhang of the roof, and otherwise it wears it's 120 years well. All the doors and round half the windows frames are original with original fittings, retrofitted with double glazing. They are in better condition than the tired 90s Rehau uPVC which needs a full rebuild, new seals, hinges, lock strips, and dg units.

Previous house was a 1938 council built house, and was also solid and in good condition throughout. Obviously thrown together, and cheaply rewired in the 80s, but straight and easy to work on and modernise. Cavity walls retrofilled with eps and it was a lovely warm home.

[gfreeman]

AndrewT1275 said:

What thickness of ply would you recommend as the minimum for hanging normal stuff i.e. pictures, mirrors and bookshelves rather than kitchen cabinets?

We normally install 18mm EN 636 - 2S which is probably over the top - structural and humid use/occasional wetting. In toilets the ply would be 2S or 3S.

If you are just sticking a telly on the wall you could just plan carefully and pop in some extra studs in the fixing locations.

[IJWS15]

Chainedtomato said:

Metal stud walls are just crap

Wish my house didn’t have them

What he said.

Easier for the builder but crap for the occupier. Thickness of the metal stud wall means you can’t fix anything substantial to them. In our house there is timber reinforcing at the door frames illustrating how bad it is if you want to fix anything substantial. Our house is 20 years old.

Daughter has a house built 4 years ago by a small local builder - timber studs.

Son is in a six year old Berkeley home - timber studs.

So steel is not universal

[ewanjp]

I just put up a metal stud wall - it's the same thickness that a wooden one would be if i'd used normal 63mm CLS to do it. You can get thicker stud if you want (I used 70mm as that seems fine). As for wood around the door frame, that's literally how the manufacturers recommend doing it isn't it? e.g. this how to: https://www.youtube.com/watch?v=H4tsQQvcQYo

[Equus]

smokey mow said:

Metal studs is almost universally used in the construction of domestic flats because it is more superior than timber for most of the above points you’ve listed.

Particularly with regard to fire resistance, acoustic and thermal performance.

I'm not sure I'd class metal studs as superior on any of those points:

• Fire resistance, as we all know, steel loses strength at a very low temperature. It's less combustible, sure, but in terms of retaining its structural integrity, it can be worse. Irrelevant for internal, non-loadbearing partitions, of course, but not if you're manufacturing the structural frame of the building from either material. Regardless, neither designers nor the Building Regulations take any account of the volume of combustible material in a building, so it's not a factor we apply in choosing which type of stud to use.
• Acoustic performance: more rigid materials transfer higher frequency sounds better.
• Thermal performance: The thermal conductivity of steel (K= 45 W/m.K) is roughly 400 times higher than that of timber (K= 0.11 W/m.K), so even allowing for the substantial difference in cross-sectional area, a timber stud with a cross sectional area of 38mm. performs about 3.7 times better than a 0.7mm. thick steel stud. Again, not really a factor we'd consider for internal partitions, but very much a problem to be overcome in terms of thermal bridging if you're making the loadbearing frame of the building from the stuff.

But my main objection to steel is on the grounds of carbon footprint: it takes a hell of a lot of energy (hence carbon emissions) to manufacture steel, whereas timber actually locks up some carbon, at least for the life of the building.

[IJWS15]

ewanjp said:

I just put up a metal stud wall - it's the same thickness that a wooden one would be if i'd used normal 63mm CLS to do it. You can get thicker stud if you want (I used 70mm as that seems fine). As for wood around the door frame, that's literally how the manufacturers recommend doing it isn't it? e.g. this how to: https://www.youtube.com/watch?v=H4tsQQvcQYo

Good example of why the product is crap, you need some of the older product to stiffen it.

If I lean on the internal walls at home they bow!

[Sycamore]

I used to design steel studs, for external and internal walls, and complete structures made out of light gauge steel.
Also took part in lots of the fire and acoustic testing for them.

I'd not want to buy a house made from it.

[Mr Whippy]

Equus said:

smokey mow said:

Metal studs is almost universally used in the construction of domestic flats because it is more superior than timber for most of the above points you’ve listed.

Particularly with regard to fire resistance, acoustic and thermal performance.

I'm not sure I'd class metal studs as superior on any of those points:

• Fire resistance, as we all know, steel loses strength at a very low temperature. It's less combustible, sure, but in terms of retaining its structural integrity, it can be worse. Irrelevant for internal, non-loadbearing partitions, of course, but not if you're manufacturing the structural frame of the building from either material. Regardless, neither designers nor the Building Regulations take any account of the volume of combustible material in a building, so it's not a factor we apply in choosing which type of stud to use.
• Acoustic performance: more rigid materials transfer higher frequency sounds better.
• Thermal performance: The thermal conductivity of steel (K= 45 W/m.K) is roughly 400 times higher than that of timber (K= 0.11 W/m.K), so even allowing for the substantial difference in cross-sectional area, a timber stud with a cross sectional area of 38mm. performs about 3.7 times better than a 0.7mm. thick steel stud. Again, not really a factor we'd consider for internal partitions, but very much a problem to be overcome in terms of thermal bridging if you're making the loadbearing frame of the building from the stuff.

But my main objection to steel is on the grounds of carbon footprint: it takes a hell of a lot of energy (hence carbon emissions) to manufacture steel, whereas timber actually locks up some carbon, at least for the life of the building.

Thanks for the supportive clarification.

I’d been reading recently about metals vs timber for heat conductivity, metal being much worse.
I was specifically thinking how these popular huge bifold type doors may have triple glazing etc, but the frames despite being diminutive in area, have literally hundreds of times the conductivity.
This was while discussing the merits of large wooden framed panels with just an opening door, which ultimately would be sufficient for many.

I have about 5m of opening onto my patio but it’s opened as a novelty. For ‘normal’ houses these must add a whole lot of heat loss for a fashionable novelty.


And as you note, that effectively covers sound wave transmission too. Hence hearing a train coming on the rails from many miles away.

[Equus]

Mr Whippy said:

I was specifically thinking how these popular huge bifold type doors may have triple glazing etc, but the frames despite being diminutive in area, have literally hundreds of times the conductivity.

The frames are now usually 'thermally broken': there is an 'insert' of rigid plastic separating inner and outer aluminium profiles.

[Mr Whippy]

Equus said:

Mr Whippy said:

I was specifically thinking how these popular huge bifold type doors may have triple glazing etc, but the frames despite being diminutive in area, have literally hundreds of times the conductivity.

The frames are now usually 'thermally broken': there is an 'insert' of rigid plastic separating inner and outer aluminium profiles.

I assumed they must have something to stop the transfer of heat.

I have 'reflective' blinds on the inside to stop the kitchen turning into an oven, and even at this time of the year the glass is almost too hot to touch on the inside.

The aluminium outside is scorching hot, the inside not so much.

But now it's the glass letting all the energy in, and heating the frames now it's trapped by my blinds.

It seems you can't win once you have all this metal around outside/inside interfaces... or even as a bridging oppotunity it seems risky.