Drywall on existing wall, how to attach studs to ceiling etc?

[doglas2009]

I have read what was written in the other thread and understand what they wrote (I think...) and in that case, electrical outlets don't matter, just ensure there is insulation behind.
If it is to be attached to the wall, make sure it is an acoustic stud (with soft material against the wall and plasterboard; it's not the same with a "regular" steel stud).
There was also more info about disturbing frequency, so it won't be as important to decouple the wall, and sealing around won't make that much of a difference.
Good luck with the wall!

Thanks! Yes, exactly, definitely going to use acoustic studs!

 

[fiskbuggaren]

I might have misunderstood it, got this picture from the other forum, the left part is in my case the concrete wall. I thought you also attached the studs to the wall, but do you mean that you only attach the studs to the tracks in the floor/ceiling?

The important thing for the studs is that the two heavy surfaces are mechanically separated. The product in your image is a simple and compact way to achieve this when constructing an entirely new wall with drywall from both sides. It does not seem directly built to be easily screwed into an existing wall, but if you can manage, it will certainly work well. Not better than a freestanding stud wall, but perhaps close enough that it makes little difference.

 

[Mellanbarn]

I might have misunderstood, I got this image on the other forum, the left part is in my case the concrete wall. I thought you would attach the studs to the wall as well, but do you mean that you only attach the studs to the tracks on the floor/ceiling?

It's every other stud in each direction, you only need the ones that are in the new wall.

 

[fiskbuggaren]

It's every other stud in each direction, you only need those that are in the new wall.

I completely missed that there were staggered studs in the picture and interpreted it as if TS was thinking of a product like this: https://www.norgips.se/wp-content/uploads/2020/09/Produktdatablad-CW_akustikkstender_SE.pdf

 

[Testarn]

It's every other stud in each direction, you only need those that are in the new wall.

You're right... now that I look at the picture more closely, the studs are installed at half the distance than usual, and every other stud is offset to one side and the rest to the other...

That would mean that you should install a 95 mm top and bottom strip, then 70 mm vertical acoustic studs, with every other one attached to the existing wall and the rest to the drywall.

If you're working with 120 cm drywall, the vertical studs will be 300 mm c/c.

It might be just as well to extend the entire new wall from the existing wall and only attach the floor and ceiling tracks, then the vertical studs in these. That way, you can use 95 mm studs with 600 mm c/c and save a bit on the acoustic studs. They're not cheap...

 

[doglas2009]

Even I had missed that the studs were irregularly placed, lucky someone was on top of it...

Is there anything that says the studs must be attached with c/c 300 or can you go with c/c 450? Or will it become very unstable?

I still think I want to attach to the existing wall to avoid taking more space from the room than necessary, but finding 95mm acoustic tracks and 70mm acoustic studs in town seems easier said than done.

Is there anything to consider when choosing drywall or should I just grab the cheapest option?

 

[Testarn]

The board must be attached at the edges and in the middle, and if you stagger the studs, you double the number of studs because the boards on one side are attached to every other stud and the boards on the other side (in your case the existing wall) are attached to the remaining ones.

This means that if you use 120 boards, you should space your studs at 300 mm center-to-center, and if you use 90 boards, you should space them at 225 mm center-to-center.

The quality of the plasterboards is not so important; they should be heavy and not break when you screw into them.

 

[doglas2009]

The board must be attached at the edges and in the middle, and if you stagger the studs, you double the number of studs because one side's boards attach to every other stud, and the other side's boards (in your case the existing wall) attach to the remaining studs.

This means that if you use 120-boards, you can space the studs 300 mm c/c, and if you use 90-boards, you should space the studs 225 mm c/c.

The quality of the drywall is not so important, they should be heavy and not break when you screw into them.

Thanks for the answer! After sketching it out in Paint, I understand what you mean.

Another question. When attaching a fairly large number of studs to a concrete wall, is there anything you can say about whether it was "common practice" to install electrical/water pipes in concrete walls in the 50s/60s? Or is it only the building's plans that will provide answers to this?

 

[Testarn]

Thanks for the answer! After drawing it in paint, I understand what you mean.

Another question. How should one think when attaching a fairly large number of studs to a concrete wall? Is there anything to say about whether "they used to" place electrical/water lines in concrete walls in the 50s/60s? Or is it only with the building's plans that one would get an answer?

I'm not sure you should attach so many studs to the concrete wall; they are attached to the ceiling and floor tracks that are screwed in, and then you can attach some of the vertical studs to the wall. They don't need to be attached so closely; maybe a couple of screws will suffice.

When it comes to electrical and water pipes in old houses, I'm no expert, but I guess they avoided installing too much. Heating pipes probably run in the outer wall or in shafts near radiators, tap water is gathered in walls/shafts near toilets/bathrooms/kitchens which were often adjacent to each other. Electrical conduits were cast into ceiling and wall elements, and I think they run along the tops of walls and then vertically down to outlets/switches. It's common to have junction boxes near the ceiling above outlets/switches, with straight conduits to these.

Junction boxes may be covered with wallpaper, so tap a little on the wall and listen. Then, a cable finder is good to use.

 

[doglas2009]

I'm not sure you should attach so many studs to the concrete wall; they're attached to the ceiling and floor tracks that are screwed in, and then you can attach some of the vertical ones to the wall. They also don't need to be attached so closely; maybe a couple of screws are enough.

When it comes to electricity and water pipes in old houses I'm not an expert, but I guess they avoided putting too much. Heating pipes probably run in the outer wall or in shafts near radiators, tap water is collected in walls/shafts near the bathroom/kitchen which often were wall-to-wall. Electrical conduits were cast into the ceiling and wall elements and I think they are run along the walls at the top and then vertically down to outlets/switches. It was common to have junction boxes up by the ceiling above outlets/switches and from there straight pipes to them.

Junction boxes can be wallpapered over, so tap a little on the wall and listen. Then a cable detector is good to use.

Thanks for the response!

No, you might be right, maybe I don't need to attach all the studs to the wall. I'll see what they think at Beijer tomorrow, one of the few places that seems to have all the materials I need.

There are junction boxes over both electrical outlets; otherwise, I think it should be fine on that front, it's just painted concrete so I think I would notice if there were any elsewhere.

Does a cable detector work in concrete too? If so, it might be worth renting one for a day to check the whole wall...

 

[Testarn]

Cable locators work by detecting magnetic fields, so they can get a bit confused by reinforcement or other iron, but if there is a load on the electric cable, it "should" cause a larger reading than otherwise. However, I'm no expert, so take it with a grain of salt. The locator I have is supposed to be able to find studs and electric cables, so I guess there are other ways to detect something, maybe ultrasound?

 

[doglas2009]

Now I have the materials at home, so it's getting close to the time when I will try this project.

One more thing I'm pondering when I look at Byggmax's guide on how to build an internal wall with steel studs is steps 16-17. You are supposed to attach the studs on both sides to the tracks, how would you do it in my case when the studs need to be attached directly to the wall? I can't reach to screw in the inner screw that is against the concrete wall, or would you screw right through the stud/track and attach it to the wall?

https://www.byggmax.se/bygga-innervägg-med-stålreglar

 

[Testarn]

Now I have the materials at home, so I'm getting closer to attempting this project.

One more thing I'm pondering when looking at Byggmax's guide on how to build an interior wall with steel studs is steps 16-17. You're supposed to attach the studs on both sides in the tracks, how would you do it in my case when the studs are to be attached directly to the wall? I won't be able to screw in the inner screw that's against the concrete wall, or would you have put the screw right through the stud/track and fastened it to the wall?

[link]

Since every other vertical stud needs to be attached on the side facing the existing wall, I would put a screw in the ceiling track and stud, as well as in the floor track and stud at the top and bottom and maybe one in the middle. The other studs are attached to the ceiling and wall track away from the existing wall before drywall is screwed into them. The ceiling and floor tracks are attached in an appropriate way with screws or construction adhesive.

 

[Mellanbarn]

Surely it should be possible to screw from the inside of the stud and attach it to the track.

The construction with crossed studs is used to stabilize both sides of the wall, but your wall will be one-sided.

 

[doglas2009]

Since every other upright stud needs to be attached to the side against the existing wall, I would place screws in the ceiling track and stud, as well as in the floor track and stud at the top and bottom, and maybe one in the middle.
The other studs are attached to the ceiling and wall tracks away from the existing wall before drywall is screwed into them.
The ceiling and floor tracks are attached in an appropriate manner with screws or construction adhesive.

Thanks! I forgot to mention that I researched a bit further on the other forum and realized that crisscrossed studs are not something I need to do, just something done if you're building a freestanding wall; therefore, I went with 95mm studs/tracks.