Waterproofing Ensuite

[ptyltd]

Hi Folks,

Need some quick help regarding waterproofing the ensuite as part of an extension. I have AS3740, AS4858 and the Building Code however it isn’t as clear as I would have hoped.<O</O
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At this stage I have 16mm fibre cement sheeting on Joists for the floor and 6mm Villaboard for all the walls. The shower will be frameless so I will waterproof the whole floor and the whole area (walls and floors) will be tiled. I haven’t jointed the sheets etc. yet thus my questions are:<O</O
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Should I joint the sheet joins (wall/wall and wall/floor) with paper tape and 2 coats base coat? What about the nails?<O</O
What to use around the wall/floor joins prior to putting down the waterproof membrane? (flashing, silicone etc)<O</O
What to use for the waterproof membrane?<O</O
What to use for a waterstop at the door? (can you just use tile trim and then waterproof up to the top as part of the main membrane).<O</O
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I need to bed first before tiling to get the falls to the shower and floor waste so can a sealant be added to this and this form the main membrane? Should the membrane go under the bed or over it?<O</O
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I will go 150mm around the walls and 1800mm in the area that the shower is. <O</O<O</O

Anyone think of anything else I need to know?<O</O
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Thanks in advance<O</O

[markclad]

Hi,
When i did my bathroom, for the wall joints I put paper tape & 2 coats of base coat and did nail heads as thought was going to tile so far then paint. I waterproofer to to waterproofing, they put fiberglass matting down and coated with membrane and a bead was placed on floor around shower and coated with membrane to keep water in shower floor area and one bead was put in doorway. Shower walls were coated to height of shower screens. All the floor plumbing around floor wastes etc should be fitted and coated with membrane also. Then fitting can be fitted for tiling. My floor tiles were then fixed with a sand & cement mix and a tile adhesive for the walls. Hope this helps a little.

[mic-d]

Hi Folks,

Should I joint the sheet joins (wall/wall and wall/floor) with paper tape and 2 coats base coat? What about the nails?<O</O

No, use fibreglass tape and waterproof compound in the wet areas and flexible cement based tile adhesive for areas under tiling(outside of wet areas). Tile adhesive doesn't stick well to plaster.

What to use around the wall/floor joins prior to putting down the waterproof membrane? (flashing, silicone etc)<O</O

Use a bond breaker - Sikaflex Pro polyurethane is good - not silicone.

What to use for the waterproof membrane?<O</O

I would use a polyurethane.

What to use for a waterstop at the door? (can you just use tile trim and then waterproof up to the top as part of the main membrane).<O</O

Use a 40-50mm alum or brass angle. Bed it in sikaflex and then waterproof inside it.

<O</O

I need to bed first before tiling to get the falls to the shower and floor waste so can a sealant be added to this and this form the main membrane? Should the membrane go under the bed or over it?<O</O

Membrane first and then mortar bed.


<O</O

I will go 150mm around the walls and 1800mm in the area that the shower is. <O</O<O</O
OK, just do the nails and the joints in the shower with w/p too.

Anyone think of anything else I need to know?<O</O
<O</O

Thanks in advance<O</O

Having added all the info to your quote, I still strongly suggest you get a prof. waterproofer in to do the job. As I've said before, they are cheap in comparison to the damage a leaky shower can cause. A small ensuite might only cost $200-400.

Cheers
Michael

[ptyltd]

Looks like I have to go with a pro as my certifier tells me that I need a certificate from a Licensed waterproofer in order to pass final inspections (Brisbane based)

Thanks Mark and Mic for responding – appreciate your help<O</O

[ptyltd]

OK need some more help

Waterproofer is suggesting 40mm trims at door and shower area to allow for fall etc. however 40mm seems huge. I note mic-d that in a response back in 05 you comment about doing 3 hobless showers and also used 40mm trim and mortared the whole room etc. so what happens with the raised floor level? My concern was (refer pic) I have 19mm hardwood flooring in the bedroom and 16mm Fibre Cement Sheeting as flooring in the ensuite so if I have 40mm at the door (and mortar/tile to that level) the bathroom floor is significantly higher than the bedroom floor level. Anyone care to comment or share experiences (is that normal for example?). <O</O
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The ensuite is only 1.7 x 1.8 and the shower is 900x900 cornered so could I get away with say a 25mm angle which is allowing 15mm bed at it highest point (can I taper it down to nothing at wastes?) and 10mm for tile/adhesive?<O</O
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If I had thought about it prior to installing all the wall sheeting etc. I would have just checked the floor sheeting 20-25mm into the joists but if I did that now I would have a 20-25mm gap at the bottom. But saying that I assume in most instances the floor levels are normally level for joist type construction so what’s the norm with differing floor levels in rooms?<O</O
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TIA<O</O

[pawnhead]

Yes, It's quite common to have a step up to a bathroom. It's also quite common to set bathroom floor joists at a lower level (40mm or so) to compensate for the tile bed, fall, and tile thickness, which would then give a flush finish between finished floor levels. It's a bit of a pain in the bum, because you have to set down all the joists between two bearers, and pack up the parts of the floor outside the bathroom. If you wanted to rip down the parts inside the bathroom, you'd have to ensure they could span the distance with their finished depth.

With a small ensuite, you can just plane to joists with a slight fall to a corner floor waste, then just glue the tiles straight down to the membrane.

It's also quite common to install plastic angles glued down to the flooring around the perimeter and up the corners of a bathroom, before you install the wall sheets. This gives extra waterproofing protection, but obviously it's too late for this in your case.

I believe that you shouldn't go less than 20mm thick (at the thinnest point) with the cement bed under tiles. If you put a hob around your shower, then you could put a fall in your shower, and just glue the rest of the tiles straight to the membrane without any fall. Just put a slight fall (built up with glue) to the angle at the doorway. Of course it's not the best if you're in the habit of spilling a lot of water on your floor, or if you want to mop it by pouring water all over it, or if you get a leak in one of your fixtures, (eg cistern) but it will give you less difference between floor levels.

[mic-d]

20-25mm is the minimum you should be thickness you should be going for. 40mm is common and looks OK. You can hide the step behind a timber wedge or tiles if you like.

Cheers
Michael

[bricks]

To work out your levels you need to know the greatest distance from your floor traps to the furthest wall.

Eg measure from the floortrap to the wall furthest from it. You need to start prefferably 15-20 mm thick and add at the very least 15 mm per meter fall to the floor, preferably more eg 20-30.

Easiest way to do...
mark a 600 level at 500 mm put a wood chock 5-10mm thick at this point, tape it to your straight edge so that when the level is level the straight edge is at the correct fall for screeding.

[sco]

I agree with all on the 40mm step up - it's fine. I'm almost finished a bathroom where there is a 40mm step up from the existing timber floor. I was worried about tripping and have had no problems.

You'll need a significant fall in the shower if you're going frameless. Or you'll need a small strip that sits on the tiles to help keep the water in.

[bricks]

40mm step up from the existing timber floor. I was worried about tripping and have had no problems.

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I use a peice of hardwaood bout 150 wide infront of the doorway which tapers down to the outside floorlevel like a wedge falling away, you can carpet ontop of it or seal it to match floorboards.