Ceramic tile on concrete slab - floor protection needed?

[galega]

You guys have been great help as I plan to install a woodstove in a cottage in Portugal. Although I grew up in a house heated primarily with a coal stove, this will be the first stove of my own. I'm doing all the planning from here and communicating with people across the Atlantic, so I'm trying to get clear on all the details of how this will need to be installed so I can make sure things are done properly.

I've decided on a Jotul F3CB found a dealer that sells them, so off to a good start I suppose. I've also decided that it will be a top vent (double-wall stove pipe straight up to interior metal chimney).

As I posted before in one of my earlier threads, the cottage is simple concrete block on a cement slab. Above the slab is a ceramic tile floor. My questions are about floor protection and wall clearances.

(1) Floor protection

For the floor protection, I read in the Jotul F3CB manual:

FLOOR PROTECTION UNDER THE JøTUL F 3, MUST BE ONE OF THE FOLLOWING:
1. ANY NON COMBUSTIBLE MATERIAL WITH AN INSULATIVE r VALUE OF 1.1.
2. ANY UL, ULC OR WH HEARTH BOARD OR PREFRABRICATED NONCOMBUSTIBLE MATERIAL.
THE BOTTOM HEATSHIELD (STANDARD EQUIPMENT) IS REQUIRED IN ALL INSTALLATION

I guess the first question is whether the "r-value" requirement is based on an assumption that under the non-combustible floor is something combustible. That is, if I have non-combustible clay tiles on top of concrete slab, do I need to concern myself with whether the r-value is 1.1?

According to this one example table (https://www.hearth.com/econtent/index.php/articles/k_values_what_does_it_all_mean) the ceramic tile clearly does not have a high enough r-value, but if concrete is the only thing under it, do I even need to worry about that? Assuming no physical damage to the floor during installation of the stove (a separate issue that might warrant putting down some floor protection) should I be concerned that the ceramic tile under the stove will crack due to the heat?

If the floor heats up and the heat spreads out across the tile floor, I would see that as a good thing. That's one reason why I'm hesitating about putting down something like a brick floor where the stove will go. Of course, if the tiles around the stove just get painfully/dangerously hot, it would be no good!

From what I've read so far searching these boards, it seems I need to make sure that the ceramic tile was put down with "latex-modified thinset adhesive" so as not to be flammable?

Also, that bit in the manual about "THE BOTTOM HEATSHIELD (STANDARD EQUIPMENT) IS REQUIRED IN ALL INSTALLATION" ... I interpret that as just saying that whatever parts come with the stove (.e. the bottom heatshield) should not be removed. I don't interpret this as saying that anything separate needs to be installed as a bottom heatshield, am I right?


(2) Wall Protection

The walls are concrete block. They are wired for electricity near the floor, so that's the only thing in there besides concrete. Should I consider that a protected surface (6 inch clearance from wall) or an unprotected surface (10 in clearance from wall)? I understand I could install a wall shield and ensure that it's protected, but if it would be redundant I wouldn't want to do that since ideally I'd like to see if the stove would transfer some heat to the bedroom on the other side of the wall behind the stove (see diagram below). But of course, if it came down to a choice between a 10-inch clearance from the wall and using a 6-inch clearance from the wall, I'd build a heatshield if I needed to in order to get the 6-inch wall clearance.


Many thanks for any insight or advice!

 

[DAKSY]

Put your stove on your tiles on your slab & put the back of your stove AGAINST the cinder block wall if you want to.
ALL of the requirements cited in the Jotul install manual are in regards to combustible surfaces - you don't HAVE any.

 

[galega]

Thanks for the reply. That's what I was thinking, and it seemed like a stupid question to ask (but you know what they say, there are no stupid questions, only stupid people, er, something like that!) but I just wanted to make sure I wasn't missing something.

I'll probably still keep the stove about 6 inches from the wall, even though it's not a combustible wall, but good to know that it's not a strict requirement.

As for the floor, I haven't decided what (if anything) to put down on the ceramic tile. I'm thinking something that would distribute the weight across the tiles under the stove would be a good idea, just to prevent physical damage to the tiles.

 

[Highbeam]

If your tiles are properly set then they need nothing to distribute weight across them. I have seen many stoves set directly on tile, mine included.

 

[galega]

If your tiles are properly set then they need nothing to distribute weight across them. I have seen many stoves set directly on tile, mine included.

Good to know. Is it a tile hearth or just a tile floor like mine? If it's a tile floor, do you notice any heat transfer to the tile floor around the stove? I think that would be a great side benefit (thinking warm tiles on a winter morning are nicer than cold tiles on a winter morning!).

 

[Jags]

You are set. Assuming that the stove pipe adheres to all the rules (including proper clearance to combustibles and the proper ceiling/roof pass through, you have met the requirements.

 

[Highbeam]

If your tiles are properly set then they need nothing to distribute weight across them. I have seen many stoves set directly on tile, mine included.

Good to know. Is it a tile hearth or just a tile floor like mine? If it's a tile floor, do you notice any heat transfer to the tile floor around the stove? I think that would be a great side benefit (thinking warm tiles on a winter morning are nicer than cold tiles on a winter morning!).

I used a way oversized tiled hearth. Honestly, not much heat on the tile floor around the stove except right in front of the window. On a winter morning, most everything is cool. My stove isn't a cat stove so the fire is mostly out in the morning and the stove is under 200. The tile beneath the stove at this time is the same temp as any of the floor.