How do I install a sink in a lightweight concrete wall?

[Dan M]

The work on the guest toilet continues and now I am at the sink. It will be mounted on a wall that consists of 8-9 cm lightweight concrete covered with a wet room board glued to the plastered lightweight concrete.

I am a bit concerned about the wall's stability. The old sink was mounted with three brackets, two of which were placed "sideways" from the wall to the left - a really ugly solution that I do not intend to apply. As I see it, I have three options:

1. Use brackets with screw fittings/"plugs" for lightweight concrete together with a lag screw. That's how I fastened the toilet fixture to the wall and it seems to hold fine.
   
   
2. Bracket - drill and attach threaded rod with the help of anchor compound. The holes in the bracket are quite close to each other, and I am a bit worried about making too many holes in the not so compact wall. However, there will be 3 rods per bracket, so it compensates.
   
3. Same as above but only one threaded rod and attach directly to the sink with the holes on the back. It would look the nicest and simplest, but I'm concerned about stability.
   

What are your thoughts?

 

[halj]

Lightweight concrete screw, for example: https://www.essve.com/sv/produkter/...tbetongskruv-hl/lattbetongskruv-hl-w-corrseal

 

[Alexn72]

What do the ones you're going to put up look like?
It might be an option to glue everything up.

 

[Dan M]

Thank you!

Lättbetongskruv, for example:
[link]

I don't really trust that it will hold, I've screwed some things in the lättbetong but I've never been really satisfied. Am I wrong?

What do the ones you want to put up look like?
It might be an option to glue everything up.

Quite standard Gustavsberg basin:

https://www.gustavsberg.com/fileadm..._Mounting/GB1921100248_Washbasin_Complete.pdf

The våtrumsskivan is quite stiff, but I'm not sure how well it is glued against the wall, so I'd rather not rely on just that.

 

[Farstatjej90]

I once attached a heavy thing to lightweight concrete and then I think I did some combination of 1 and 2. I drilled, blew it clean, filled the hole with anchoring compound, inserted a plug, and then screwed. It held for everything afterwards.

 

[Dan M]

I once attached a heavy item to aerated concrete and I think I did some combination of 1 and 2. I drilled, blew it clean, filled the hole with anchoring adhesive, inserted a plug, and then screwed. It held for everything afterward.

Great - that's how I imagine it, but with threaded rod. After all, it's a permanent installation, so I don't need to worry about "rearranging."

 

[Farstatjej90]

Top - that's how I envision it but with threaded rod. After all, it's a fixed installation so I don't need to worry about "rearranging."

But are you inserting the threaded rod into the plug? Does it expand correctly?

 

[pacman42]

I would have done like @Farstatjej90, screwed in a plug that sits in anchor mass.

 

[halj]

Thanks!

I don't really trust that it will hold, I've screwed some things into lightweight concrete but never been really satisfied. Am I wrong?

Pretty standard Gustavsberg basin:
[image]
[link]

The wet room board is quite stiff but I'm not sure how well it's glued to the wall so I would prefer not to rely on just that.

I live in a lightweight concrete house. Installed the fire escape ladder with those and it held like a rock! Additionally, all my kitchen cabinets, hat shelf, etc., are mounted with the same type of screw.

Each screw should support about 50kg. See page 176 https://www.itwconstruction.se/media/4251/2018-2019_fixing-design-guide_uk_bd.pdf

 

[Dan M]

Planning to follow ESSVE's instructions for anchoring compound:

The manufacturer of the sink recommends that the threaded rod should protrude 50 mm from the wall to fasten the sink, using a screw seems like a worse option then.

 

[Dan M]

It turned out like this, hope everything stays in place when I attach the sink!