Last year, I glued a fire protection board according to the seller's instructions. It felt stable and was approved by the chimney sweep. Now, a year later, the boards are neatly standing to the side, and the glue is in the trash bin.
See image:
I got some time off from another project, so I thought I'd complete a few smaller projects like this and spackle the transitions and apply some paint when I discovered that the boards suddenly flexed. So, I tapped a bit on one of them, which then came completely off the wall.
The glue only remained on the edges of the wood closest to the wall in the picture. Not a trace was left on the OSB board, so I assume that's a reason? But at the same time, there wasn't much glue left on the fire protection boards either, rather it sat like a shell with a few attachment points, so it came off pretty quickly when I took the boards down and tapped a bit on the glue.
So my thought was to remove the OSB board and replace it with a drywall to avoid anything organic, but what more can I do to ensure that this won't have to be redone again after a while?
I'm fairly sure the board comes from Jötul (I bought offcuts so there wasn't an original packaging), and I assume the glue matches (a white plastic tube with orange stuff), but the installation instructions on their site just lead back to the "Accessories page" where it states that the board is the best in the world and very easy to install.
I don't have much more to go on than the seller's description, which was "spread the glue like you do with tile adhesive and press the board against the wall and look happy."
Any more insightful words of wisdom about this installation so I can succeed better?
You have two options, right?
1, Do as they suggest, meaning mess around and be happy.
2, Whatever.... (summon Shiva)
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3, Await expertise that will be conveyed here.
If it wasn't clear enough, I have already tried option 1 (stick it on and smile) and that's when it ended up like in the picture after just over 1 year
I can answer the question myself now after getting in touch with a guy at Jötul who had a bit more knowledge than the Swedish dealer. According to him, the glue that comes with it is not particularly good, and he recommended Tec 7 instead. The problem for me, however, is that the chimney sweep insisted that the included glue should be used to maintain proper heat protection, and since the chimney sweep has a monopoly on everything related to the chimney, I can't do anything but try again with gypsum as a base instead of OSB (even though it would work regardless of the substrate). The Jötul guy also suggested a couple of screws, but that was a definite NO from the chimney sweep. You could also try using tile adhesive as glue, and the chimney sweep didn't have any strong opinions on that, at least.
But how does the chimney sweep know which glue you've used then? The primary concern is that the boards are in place. How they are attached is presumably not their department.
A wild guess is because the glue is falukorv-colored and the tiles are light gray. It can be seen from 18 miles how it was glued since the original glue should be applied with a notched trowel, so in my case it gets pressed out along the entire long side of the tile. The chimney sweep who approves this is nice and all but very thorough, and my construction is so far only verbally approved since the roof safety will be approved next year (re-roofing) and only then will I get in writing that everything is approved. So I dare not gamble on a solution that the chimney sweep will complain about.
Is it a calcium silicate board? It might be mentioned somewhere in the thread. I fastened one behind our stove. I positioned the screws so they wouldn't receive too much radiation. The chimney sweep approved this without any issues.
Is it a calcium silicate board? It might say so somewhere in the thread. I screwed one behind our stove. I placed the screws so that they didn't receive too much radiation. The chimney sweep approved this without any issues.
Judging by the appearance, it is a calcium silicate board, yes.
Yes, I have to hide everything behind paint and putty and make it look nice later, and I don't think the chimney sweep would notice if I used something else now that a new attempt is being made. But when it was relevant for the inspection of the fireplace installation, many of my thoughts and suggestions were criticized. Among others, screws, construction adhesive, and even other types of boards (minerit/similar). But as I said, I already have the adhesive now, so for the sake of peace at home, I'll just make a new attempt with it.
