Fireproof partition wall behind the fireplace?!

Hope this is bes

The chimney sweep was here and inspected the shell construction and the chimney. It was already clear where the air supply is, and the inspection passed without any objections. I'll be going to the stove builder tomorrow anyway to ask. After that, the chimney sweep will probably hear from us as well. It's really annoying because you could have planned and built such a wall in the last few months (if it was really necessary).

We spoke with two different chimney builders. It was about two things. First, the cladding of the back wall of the fireplace and primarily about stability. The fireplace does have a so-called cantilever, but it cannot hold the weight of the upper fireplace structure 100%. The cantilever is attached to the back of the fireplace in the base plate and pulls it downwards. The now additionally required and also commissioned 10 cm thick wall (as wide and high as the fireplace) will be connected to the room wall. Additionally, the fireplace will be anchored in the new wall. This is an empirical value from the last installations of the fireplace. A size smaller cantilever would have sufficed, but due to the structure of our fireplace, the additional reinforcement is necessary. If the cantilever had been sufficient, we could have alternatively taken a 4 cm thick fireproof Promat cladding. Ultimately, still acceptable in terms of price but a pity that this was only noticed so late. I just wanted to at least provide the answer since you all are always helpful with tips and advice.

Regards
Paule

Hello Paule,

thanks for the contribution. It helps us a lot with the planning! Do you have no problems regarding room air independent / ventilation system / extractor hood? I am still interested in that. Here, you hear something different from everyone. Sometimes a pipe for outside air is needed from the floor, sometimes room air is sufficient.
Thank you very much

sometimes the room air is enough.

I dare to doubt that.

Behind the fireplace, there must be a Promat board at least 5cm thick, which is glued to the wall, whether drywall or stone, with special adhesive. This is usually how the chimney sweep wants to see it.