ᐅ Partition wall for a heavy washbasin

Created on: 17 Jul 2019 21:49
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BugsBunny
Hello everyone,

I have a question regarding the proper construction of a drywall partition with a stud frame to support a double washbasin and vanity cabinet weighing about 80kg (approx. 176 lbs) (undermount basin, 160cm (63 inches) wide, projection 55cm (22 inches)).

The plumbing company installed new piping in front of an existing 11.5cm (4.5 inches) thick perforated brick wall (approximately 4 x 2.5m (13 x 8 feet)). I now want to build a full-height drywall partition in front of that, to which the washbasin will later be mounted.

How should the wall be constructed to ensure that nothing falls off later? I have heard and found several suggestions online, but they vary widely:
1) A standard double-layer moisture-resistant gypsum board wall, 2 x 12.5mm (0.5 inch), fixed with hollow wall anchors
2) At least 22mm (0.87 inch) OSB board with a single 12.5mm (0.5 inch) gypsum board over it, then screws directly into the wood without anchors
3) A support beam only in the area where the cabinet will be hung (wood or metal)
4) A Geberit pre-wall installation frame (not entirely clear which one). The ones I have seen seem to be integrated into the drywall partition and additionally fixed to the brick wall with hooks or long connectors to transfer the load

There will also be a 160cm (63 inches) mirror cabinet above, but this seems less of an issue due to the smaller projection.

I would appreciate your tips or recommendations very much – thank you in advance!
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denz.
20 Jul 2019 09:46
We chose option 3. A piece of timber was placed between the drywall studs in the area where the cabinet is mounted.

Regarding insulation:
We do not have any insulation behind the drywall. In our case, this is a kind of shaft running from the utility room below up to the attic. All the cables go up through here into the upper floor ceiling, as well as the ventilation ducts for the upper floor. However, we currently have an issue with the acoustics in the bathroom.
There is a lot of echo. It might have been better to have insulation behind the drywall. I would recommend researching this further or consulting professionals on this topic.

For now, we are trying to improve the situation using bath mats and a pleated blind.
BugsBunny20 Jul 2019 14:08
denz. schrieb:

We chose option 3. A piece of timber between the drywall profiles in the area where the cabinet is fixed.

Thank you very much for your feedback. Was your vanity unit and basin similar in weight to ours (about 80 kg (176 lbs))?

Thanks also for the tip about insulation. In that case, I will make sure to install some—it doesn’t cost much.
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denz.
20 Jul 2019 20:44
I’m not sure about the weight, but it is a Villeroy & Boch Legato with a width of 1.6m (5 feet 3 inches) and on top are two Villeroy & Boch Subway 2.0 washbasins.
tomtom7921 Jul 2019 06:44
There are 80 kg (176 lbs) distributed across 6 screws, and these are shear forces, not tensile forces. Don’t worry, it will hold.

@denz if there’s a towel hanging and bath mats are on the floor, the situation changes immediately. It was the same for us at first.
BugsBunny22 Jul 2019 22:25
Thank you for your answers/help. Did I mention that I want to install a 50mm (2 inches) drywall partition – is that sufficient, or do I need a 75mm (3 inches) or 100mm (4 inches) one?