Concrete too heavy?

[JohnRoss]

Prior to putting in a wood burning stove into a fireplace I want to build up a plinth for it to stand on. It will be 90x164cms and 8cms thick. The floor it will be going on is tiled and of concrete block construction suspended on concrete beams. I could do the job in concrete with tiling on top but I am a bit worried about all the extra weight on this suspended floor. The weight of the stove would be additional so what other materials could I use to make this plinth at a lower weight. I had though about some sort of hollow brick blocks or wood beams with chipboard and then tiled but I think that would flex under the weight of the stove and crack the tiles. I really don't know what materials are suitable/available for this, can anyone suggest something I could get at my local Brico.........................................................JR

[Pierre ZFP]

Well assuming the density of concrete to be 2400kg/M3 then your little bit is a smidge under 300 Kg or to put it another way, a loading of under 200kg per sq metre. This really isn't a lot, even with the stove on top.   I'd go for it.

If you're really concerned then have a look in your local brico for 'Parpaign'  (sp?) which are like hollow breeze blocks.

[JohnRoss]

Thanks for that. I will have a look at these blocks, maybe the smaller red brick ones that are used to build internal walls. They would have to be bedded in concrete with maybe a skim over the top as well to stop them moving independently of each other I guess. Having been down to the cellar I find that the main concrete support beam for the floor is 20x18cms in the middle of the floor. Other concrete beams are layed crosswise and the concrete blocks dropped into these. (Maybe called Hollow Pot in the UK though I am not sure about this.) The fireplace is just to the left of and above this main support beam. The easiest solution would be just to cast the plinth in one lump of concrete and from your figures one could only hope this would not be excessive in weight...........................................................JR

   

[BIG MAC]

any reason why you cant use concrete blocks laid on their side then rendered/tiled?

[JohnRoss]

Thanks for the suggestion but as the bloke wants to start tomorrow and as I have nadgered my back/neck and am in a surgical collar and cannot do much the bloke said he would do it for me and lay tiles on top for an extra 100 or so euros if I got the tiles so I will let him. He looked at the underside of the floor in the cellar and said he thought that it would take considerable extra weight..........problem solved..............................JR