Browse Forums Bathrooms and Laundry 1 Feb 21, 2009 7:37 pm Hi
Recently started to have problems with cracked tile and water leakage around a shower recess in our early 70's, typical double brick and tile house. To our horror after removing a broken floor tile we found sand underneath. This doesn't seem to be overlying concrete (which we know is elsewhere in the house) as we could poke a stick down into the sand for more the 10-15cm. Was this normal practise then? It is a sunken shower recess so I assume the rest of the bathroom is ok, however we are keen to find out more before looking at our renovation options coz we assume this may make things expensive. Does anyone out there have any ideas what it might be and whether there is a solution or other problems we may not have anticipated? Re: Dirt floor underneat shower tiles 2Feb 22, 2009 11:53 am I've never heard of 150mm of sand in a shower.
Tiles are usually laid on a sand and cement bedding mix. (usually 25 to 60mm deep)Sometimes there is very little cement used. If this is the case the base will crack allowing the tiles to move or crack and then water penetrates through to whatever is underneath. To remedy this, the tiles and bedding mix need to be removed, area underneath needs to be waterproofed (three layers is good) and then the area retiled. Genrally this means the plumbing needs to be removed and then replaced. It sounds like youre talking about a slab construction. If there is no base in just the shower, you need to remove the tiles, bedding mix and sand as deep as you can to expose the drainage and reconcrete the shower base. I find it hard to believe that there is nothing underneath. You may have probed near where the drainage is and youve probed into an open space around where the drainage penetrates the concrete floor (although this should not exist as the concrete is usually poured around the drainage, but if the shower is near an outside wall, they may have left an open space for the drainage to be installed later and it was never properly filled in. If there is a blockout where the shower is, you need to fill it in and redo the drainage. Excavate the entire shower base to a depth to expose the drainage. If thats ok, (it can be tested by running water with flouroceine dye or vegetable dye down the line) then the area should be consolidated by filling with crushed bluemetal and then a concrete slab at least 100 (150 better) tying it into existing bathroom slab and then rewaterproofed and retiled. I hope thats been of some help to you. Re: Dirt floor underneat shower tiles 3Feb 22, 2009 2:23 pm Thanks for the advice.
It's no where near the external wall. Maybe we just gauged it incorrectly, but seemed impressively deep. A friend had told us that this used to be common practice (laying on dirt) but I couldn't see how tiling onto dirt would work. Surely it would just shift and crack. As the tiles had lasted the last 30 years I think it's very unlikely. So are you saying that they lay a sand/cement mix over the top of the slab, or a sand layer on top of the cement slab? And is the purpose to achieve the contoured slopes to optimise drainage? Because the area we checked was at the edge of the shower, so higher than elsewhere and therefore I guess would have a thicker layer of this stuff. Again thanks for the info. Re: Dirt floor underneat shower tiles 4Feb 22, 2009 5:28 pm You're welcome
Bathrooms/showers usually have a bedding mix over the original surface and yes thats partly to allow for fall. the bedding mix is either sand and cement or a commercial granular type product that does the same thing. Its when the tiler doesnt mix enough cement in the bedding mix that cracking problems occur. I've never heard of tiles laid on sand.....that would be paving and by definition wouldnt be water proof. In the forties they sometimes did use a type of ash mixed with cement as a base, but not the 70s. I'm guessing that when you probed with a stick you may have pushed nto an open void besides the drainage pipe. thats the only explaination I can think of. But it sounds like something that you should rectify. its not good to have water running or leaking under the slab and it sounds like that might be happening. You could do most of what needs to be done yourself. As you go post some pics and that might explain the situation a bit better. Re: Dirt floor underneat shower tiles 5Mar 28, 2009 11:39 pm Hi, I've recently encountered the same problem. I am getting rising damp in surrounding shower walls and crack in the floor tiles in shower. When I removed the floor tiles I found that the tiles had been laid directly onto compacted sand. I have removed the shower tiles and have dug down 20 cm in anticipation of laying a slab. I have several questions. - Do I need to reinforce the slab with mesh or rebar ? - What would be the correct concrete mix ? - Should there be a blue metal base and how deep ? All of the sealing membrane systems that I've looked at specify that the slab must have cured for at least 28 days. I'm hopeful, I won't need to wait that long for the shower to be restored to use. On that note are there any products out there that I can use for the slab that cure quickly so that the membrane system can be applied and the shower tiled in a short period ? (eg. quickset). many thanks 'L' Re: Dirt floor underneat shower tiles 6Apr 03, 2009 10:55 pm The reason for the cure time is that 'out gassing ' ocurs for 18+ days... It's the plus that'll get ya Out gassing can blow the coating off and do damage to the membrane. Where you are coming from is where you are going to... Thank you Splashers. Tomorrow I might check if I can get a few packs of 300x300 in the same tile finish. It may be good to use these could in the shower recesses. I'm not… 4 2857 They make the room much easier to clean for one, reflect more light (if light colour tiles are used), and you dont end up with dust on the top edge of tiles (cause most… 3 7695 CDC Housing Code 3 When to apply Floor Area external face of wall vs Gross Floor Area internal face of wall. Reading thru CDC Housing Code 3, lets take a lot 915sqm.… 0 11641 |