Filling a void in the floor, ready for the installation of a log burner.

[Samc1987]

Hi

I've opened up my fireplace and installed a lintel ready for the installation of a 5KW, 85KG log burner.

As I got down to floor level I noticed it was very damp, so I removed the quarry tiles and found soil.

I am intending to hammer in some hardcore lay some DPM and fill the 3 inch void with concrete to make it level with the rest of the room before I tile over it.

The rest of the room has already had the quarry tiles removed and had a concrete floor laid with a DPM, but the fireplace was sealed off at the time.

I was also going to inject some damp zone cream into the mortar course to stop any further rising damp.

I was just wondering if my proposed method will work?
Is concrete it best product, if so with what additives etc..

I don't want it to sink under the weight or crack with the heat.

Regards
Sam

 

[Doggit]

Put some sand between the hardcore and the DPM, and you should be fine with what you intend to do. Having the DPM stops you needing any additives in the concrete, 3" of concrete (with ballast in it) will be more than sufficient for the stove. If the concrete doesn't level itself sufficiently, you may need to put some self leveling compound before the tiling, but that's down to experience. Have you worked out how far you need to tile into the room, and are you doing the stove under a building control notice.

 

[Samc1987]

Thanks.
I'm tiling the whole room so I'm planning to have a removable glass hearth once tiled.
I've got the form to notify local building control, I was going to send it off once the installation kit arrives.

 

[Doggit]

Are you going to tile under the glass hearth. If the tiles underneath aren't completely flat, then the glass hearth might break when the stove goes on. I tiled the hearth area, put the glass hearth on top, and then pressed everything down to level it all in one.