Stud wall

[John Brown]

Trying to work out how to determine if single or double with minimal damage, as my wife informs me that I don't need to move the light switch, since there's another one...
On the other hand, moving the light switch is a good way to investigate...

 

[Adam W.]

Break the end of the wall off if you're going to join on to it for certain or drill a hole, put in a cable tie square end, pull it till it catches the back of the plasterboard, mark it, pull it out and measure it.

Do the hole trick, she'll think you're awesome.

 

[Adam W.]

But don't drill by the light switch or any sockets, because you'll be not very awesome if you drill through a cable or pipe.

 

[John Brown]

Break the end of the wall off if you're going to join on to it for certain or drill a hole, put in a cable tie square end, pull it till it catches the back of the plasterboard, mark it, pull it out and measure it.

Do the hole trick, she'll think you're awesome.

She already knows I'm awesome, but thanks anyway.

 

[John Brown]

I think I can probably do it with two or three measurements, and drilling a hole through into the void from the non-important utility room side.
What thicknesses should I expect for single/double?

 

[Jake]

Just take the lightswitch plate off, you should be able to see from inside the box. It would be surprising if it was doubled up. Usual is just 12.5mm board plus skim.

 

[Lons]

Why does he need to know if it's single or double skinned Adam, unless there's a specific reason it makes no difference when matching up except possibly to use standard off the shelf studs which vary anyway unless they are PAR. You use suitable timber to make the stud frame allowing for the thickness of plasterboard and skim coat so if a single sheet of 12.5mm pb the timber would be set back around 15mm back from the existing finish, obviously there will be 2 sides to the wall so adjustment is usually needed.

Good point about removing the expanded metal corner trim but as the OP will be hiring in a plasterer he would do that as part of the job as well as scrim the joint and feather new into old. A different story if the OP was doing it himself.

A stud wall is one of the simplest construction jobs to do by any competent DIYer never mind a woodworker. I built many hundreds of metres of the damn things when in business and all you have to be able to do is measure accurately and cut straight.

 

[Adam W.]

He can lap a new board over an old board at the join, then it will never crack and he can just use regularised studwork throughout.

He's worried about it cracking, the plasterer won't, as he'll be long gone. If he wants a top job, then he'll need to fuss over it, and we all know that a plasterer will come in and want to skim it as quick as possible.

 

[John Brown]

Just take the lightswitch plate off, you should be able to see from inside the box. It would be surprising if it was doubled up. Usual is just 12.5mm board plus skim.

See post #12 there is no light switch on that wall.

 

[John Brown]

I am, indeed, very confident about building a stud wall and screwing plasterboard to it. It was the cracking I was concerned about, as I am not a plasterer, and suspected there could be problems. Adam's suggestion re cutting the existing board back to the centre of the last stud, or removing the top board back the the penultimate stud if double boarded, sounds like sense to me.

 

[John Brown]

I'll draw a rough sketch later, right now we have neighbours arriving for a socially distanced barbecue.
Thanks again to all for the help and advice.

 

[Adam W.]

Enjoy your BBQ, sorry about talking about you in the third person.

 

[Lons]

He can lap a new board over an old board at the join, then it will never crack and he can just use regularised studwork throughout.

He's worried about it cracking, the plasterer won't, as he'll be long gone. If he wants a top job, then he'll need to fuss over it, and we all know that a plasterer will come in and want to skim it as quick as possible.

Depends on the plasterer, like any trade there are good and bad, the ones I used had as much pride in their work as I did and I don't remember a single issue in 18 years or a complaint or call back from a customer because of poor plastering, as I said I'm not a plasterer and wouldn't want to be though I've done my share.
It's impossible to prevent hairline shrinkage cracks in new work, just look at any new build property but these are quickly sorted with usually just a scrape of fine filler or even just paint.

 

[John Brown]

Ok it's a very small project. I can't go straight across, as there's a giant picture window in the way.

 

[maitland.selwyn]

Heresy probably on a woodworking forum, but I try to never use 4 x 2 studs if it can be avoided. I find the difference in dimensions too frustrating. I use 50mm or 70mm C stud. It won't shrink or warp and is always the same dimension. Since I can't plaster, I then tape and skim (or sparkle as they say in the US). One way to avoid any cracking, whatever you use, might be to step the extension back 25mm and use a metal reinforced paper corner tape, if that would be acceptable aesthetically.

 

[John Brown]

Heresy probably on a woodworking forum, but I try to never use 4 x 2 studs if it can be avoided. I find the difference in dimensions too frustrating. I use 50mm or 70mm C stud. It won't shrink or warp and is always the same dimension. Since I can't plaster, I then tape and skim (or sparkle as they say in the US). One way to avoid any cracking, whatever you use, might be to step the extension back 25mm and use a metal reinforced paper corner tape, if that would be acceptable aesthetically.

Thanks for the suggestion. I think I'll stick to timber, as I have the tools, and some experience. As for stepping back 25mm, I had thought of that, but I reckon it'll look weird enough already, with the dog leg need to avoid hitting the window.

 

[Lons]

John
If you're hiring in a plasterer he won't even blink at that, it's a very simple job just tell him your concerns about that joint cracking. The fact you only need to match one side of the wall because of the return on the existing wall is a bonus and makes it even easier as the timber sizes aren't at all critical.
Just one point that would concern me is the existing utility room door, I would look at whether it might be better to hang that on the side next to the new wall, just my opinion and it depends if your drawing is to scale of course.

 

[Adam W.]

Any new timber you put in there will shrink as the MC is going to be higher than the existing, because it has been sitting in the builders merchants yard.

It will crack at the joint no matter how good the plasterer is, unless he's Dumbledore. Pressed steel stud and fussing over it, as I mentioned up thread is your answer for the joint area ( you only need one) if you are that worried about it.

The rest can be made of regularised.

 

[John Brown]

John
If you're hiring in a plasterer he won't even blink at that, it's a very simple job just tell him your concerns about that joint cracking. The fact you only need to match one side of the wall because of the return on the existing wall is a bonus and makes it even easier as the timber sizes aren't at all critical.
Just one point that would concern me is the existing utility room door, I would look at whether it might be better to hang that on the side next to the new wall, just my opinion and it depends if your drawing is to scale of course.

The drawing is roughly to scale. The new door will be closed 99% of the time, and we are used to utility room door opening that way, but thanks for the suggestion.

 

[John Brown]

Any new timber you put in there will shrink as the MC is going to be higher than the existing, because it has been sitting in the builders merchants yard.

It will crack at the joint no matter how good the plasterer is, unless he's Dumbledore. Pressed steel stud and fussing over it, as I mentioned up thread is your answer for the joint area ( you only need one) if you are that worried about it.

The rest can be made of regularised.

I'll look at pressed steel studs. Thanks.