I have purchased a hundred-liter water heater that is to be mounted on the wall. It weighs about 30 kilos, and when filled with water, the weight becomes over 130 kg. I plan to use the included bracket for mounting and screw it with a fully-threaded ten-millimeter screw.
Can I safely screw it directly into the wall, which consists of gypsum with OSB behind it? Will it hold?
Can I safely screw it directly into the wall, which consists of gypsum with OSB behind it? Will it hold?
OSB will not hold it up.
I would have screwed a 45x70 beam over two studs and then attached it to that.
That's what we did anyway, we have cc 600 between studs and 12mm plywood. Put a beam there and attached the fitting to it, then a beam lower down that it rests against.
I would have screwed a 45x70 beam over two studs and then attached it to that.
That's what we did anyway, we have cc 600 between studs and 12mm plywood. Put a beam there and attached the fitting to it, then a beam lower down that it rests against.
Thanks for the response, but different opinions don't make it any clearer. 
Personally, I think it should hold, but one wants to be 100 percent sure. Waking up one night with the water heater on the floor and water spraying everywhere is not something anyone wishes for.
Personally, I think it should hold, but one wants to be 100 percent sure. Waking up one night with the water heater on the floor and water spraying everywhere is not something anyone wishes for.
That's how I reasoned too.S Slas said:Thanks for the answer, but different opinions don't make things clearer.
I myself think it should hold, but I want to be 100 percent sure. Waking up one night with the heater on the floor and water spraying everywhere is not something you wish for.
Probably depends on the type of OSB that is used; many types have very sparse fibers, so I would probably screw up a piece of wood/beam anyway. There's also a breaking effect on the screw since the plasterboard sits between the mount and the OSB.
(my own theoretical idea!)
(my own theoretical idea!)
My 80L heater is mounted with 4 8mm French wood screws directly into the studs, on a chipboard wall. It's held up without any problems for 55 years now, so it's at least sufficient. Personally, I would never mount a water heater only on the board, except possibly a 30L. There are pipe joints that you don't want any movement in.
Best answer
You shouldn't listen to guessing. Especially with these records, there is a regular cycle where everyone seems to know that this or that won't hold. Here is the conclusion for the umpteenth time:
You can see for yourself that if you fasten with 4 screws, you are completely sure it won't fall down. And if you go up to 8mm screws, you have both suspenders, a belt, and tights on top.
Of course, the above assumes that your panels are secured to the studs, but that isn't likely to be an issue in practice.
You can see for yourself that if you fasten with 4 screws, you are completely sure it won't fall down. And if you go up to 8mm screws, you have both suspenders, a belt, and tights on top.
Of course, the above assumes that your panels are secured to the studs, but that isn't likely to be an issue in practice.
Thank you for that, exactly what I've been looking for! I have a tendency to "overdo" things when refurbishing (like if the instructions say at least four screws, I'll use eight) but I'm trying to train myself to stop doing that. In that case, data and numbers are very helpful. Now the heater goes up this weekend. Thanks again!MathiasS said:
Examples of good screws. There are other brands that are also nice (e.g., Essve and Jetting).
https://www.biltema.se/bygg/fastelement/traskruvar/traskruv-hex-2000038518
Just make sure you have threads where you need them on the screw.
I would probably use 8mm and pre-drill a little.
https://www.biltema.se/bygg/fastelement/traskruvar/traskruv-hex-2000038518
Just make sure you have threads where you need them on the screw.
I would probably use 8mm and pre-drill a little.