Browse Forums Bathrooms and Laundry 1 Nov 04, 2010 9:37 pm Hi, I've ripped my en-suite to bits and got someone to take the old asbestos sheeting away. Now I'm ready to starting building up. My question is, do I need to lay a pre-slope bed, plastic membrane, then tile bed, then waterproofing membrane before tiling? All the info I can find is American, and this seems to be the way they do it (pre-slope for weep holes etc.). I can't find one Australian example that doesn't look really *******. Do we even have weep holes in our shower drains here? The shower I just destroyed definitely wasn't done that way, but it was evidently no example to follow (water damage everywhere, ugh). What is the acceptable/best practice in Australia? I have a concrete slab house btw. Thanks! Re: Shower pre-slope or not? 2Nov 05, 2010 10:41 am Hi, Normally, a waterproofing membrane would be applied to the slab and wall linings, and turned down into the floor drain flange, with a bond breaker at all corners and joins. Then a mortar screed with a proper fall to the drain holes would be laid for tiling. The waterproofing membrane will be more reliable if it is applied over a reasonably smooth surface, so if the slab surface is very rough from demolition, you may want to apply a levelling compound first. Alternatively the membrane can be applied after the tiling screed, but then you must use a compatible tile adhesive. You can look here, although any details referring to suspended floors will need to be interpreted: http://www.jameshardie.com.au/home/asse ... on0906.pdf http://www.pacificislands.com.au/Produc ... gs-382.pdf http://www.crommelin.com.au/displayProduct.php?id= 43 Yes, drain fittings with weep holes are common here, called puddle flanges or leak control flanges. http://www.artplastics.com.au/assets/00 ... 030106.pdf Cheers Re: Shower pre-slope or not? 3Nov 05, 2010 4:23 pm Thanks so much Geoff for the quick reply. Those links are fantastic. So it seems our standards aren't so different to our US counterparts after all. - Seems as though pre-slope is not the norm but couldn't hurt, since I have (as you have rightly guessed) a fairly rough concrete substrate at the moment with about 65mm depth to play with for the shower pan. I'd rather go a little over the top, than have a chance of another leaking shower in the future. Anyone with more suggestions please chip in too. I'm all ears. Thanks. Re: Shower pre-slope or not? 5Nov 12, 2010 5:36 am I totally understand the extra waterproofing. I would hate to dig it all back up! I had a chat with a couple of tradies yesterday who knew their stuff pretty well (and were willing to share!) and it seems our Australian Standards have only recently (2004) been updated to reflect good waterproofing practices in wet areas. So.. I obtained a copy of AS3740 to have a look. There's no requirement to do a pre-slope pan, however given that my substrate is rough as guts, I'm putting the recommended 1:60 fall in the fist layer (which I will waterproof) and then mirror that for the screed tile-bed. I'll post some pictures of progress in the coming days. Just bought a heap of villaboard, cement, sand and tools yesterday... Job's on Re: Shower pre-slope or not? 6Nov 12, 2010 7:53 am There are a couple of very important things you need to pay attention to when waterproofing:
1 - Bond breakers All joins and corners must have bond breakers to allow the membrane to lift and stretch. The level of detail in these areas depends on the type of membrane you use. A class III Membrane (as per AS4858) requires only a 12mm wide bond breaker. Areas that need to be treated include: wall/wall junctions, wall/floor junctions, corners, junctions between different materials and joins between building sheets. Basically anywhere that may move. 2. Film thickness You need to apply the coats thick enough for the membrane to work propery. I strongly suggest using a brush (not a roller) and buy a film thickness guage (not expensive). 3. Apply correctly Remember that most modern membranes do not need bandages or reinforcing. In fact if you do use them it can reduce the performance of the membrane and increase your risk of failures. So read the application instruction carefully and call teh maufacturer if you are unsure. It makes more sense to apply it correctly than to just keep putting coats everywhere. Work "smarter not harder" and follow the manufacturer's instructions. A Class III membrane is a high performance option and are often the easiest to apply. There are some really good water -based ones on the market (Such as ASA's Dampfix Gold) that can have tiles directly bonded. Waterproofing can be tricky and it is worth getting right. If you are serious about it the Master Builders Association (MBA) in NSW has a waterproofing council and they have published a "best practices" book. It covers a lot of details the standard does not. So it is really worth getting if you want to get your job right. There are a couple in the series. You will need the "Internal Wet Areas" one. Re: Shower pre-slope or not? 7Nov 12, 2010 9:09 am Where you are coming from is where you are going to... Re: Shower pre-slope or not? 9Dec 15, 2010 11:21 pm Hi there, Forgive my ignorance - I'm new to renovating and attempting my first shower/bathroom. Completely re-tiling it, including pulling out mortar bed and relaying it. I'm still unsure as to whether the waterproofing should go on before or after my mortar bed. The James Hardie pdfs seem to advocate before (http://www.jameshardie.com.au/home/asset?file=file/WetAreaConstruction0906.pdf), whereas it seems to make more sense if it goes on after, so that the mortar bed has no chance of ever getting wet. I've found info on the net supporting both methods, but more commonly putting the mortar bed on top of the waterproofing. There must be a good reason for this? What do the professionals do? I'm still confused. Please help. Re: Shower pre-slope or not? 10Dec 16, 2010 2:14 pm oliwally Hi there, I'm still unsure as to whether the waterproofing should go on before or after my mortar bed. Hi There, After doing a fair bit of research and acquiring the current Australian Standards, it seems that (assuming you are using a class III membrane) either way is acceptable. As for what the professionals are doing, well, I've spoken to several now and they weren't even aware that there were any clear guidelines on how to waterproof a wet area - that made me feel less than comfortable! What I'm doing is laying a pre-slope screed (my concrete house slab was VERY uneven, so I thought I might as well slope it a bit), then I'm waterproofing up from that. Over that I am laying a tile bed screed, on which I will lay tile adhesive, tiles, grout and then grout sealant. If I didn't have to rip out the lower mortar bed originally (because of the ** work done prior), then I would have opted for the waterproofing membrane to be applied at the tile level and save myself a little time. - Side note: That stuff on the James Hardie information is almost a direct excerpt from the current relevant Australian Standards. Have fun! Re: Shower pre-slope or not? 11Dec 18, 2010 1:16 pm Thanks for your help mdelbridge. In my situation I think I'll but my mortar bed down on top of the existing concrete slab, and then waterproof at tile level as you suggested. Just seems to make more sense. Although, as far as I know, I'll have to use some special tile adhesive to stick to the waterproofing. But I'll need that for the walls anyway... Thanks again. Does anyone else have more wisdom on pre- or post-mortar bed waterproofing? A survey must’ve completed by a certified surveyor. This form part of every DA requirement 3 223610 Need advice on the backyard plan above. Should I excavate and cut all of the dirt to level with the house slab or semi-excavate as per photo above? Both left and right… 0 24865 Hi All, We have recently purchased a sloping block (3.5m fall building envelope, 6m overall). Just wondering if you know of any good builders that you would recommend for… 0 1774 |