Not all of them require a fabric. Laticrete Hydroban is the only one I know of that does not require it. There may be others.

The fabric makes the liquid into a more monolithic piece so that shifts in the structure won't cause separations and therefore leaks. Without the fabric it's easy to peel the dried liquid off, especially if it's applied to sheetrock.

When I use liquid in a shower, I use a CBU because the liquid seems to bond better. You have to tape and mud the CBU seams just like normal, and with some liquids you have to use fabric on the seams as well.

The plastic under the mud bed does keep the subfloor from drawing moisture out of the mud. The mud bed will dry through the top, and you will be able to walk on it the next day, but leave it alone for several days before you start waterproofing it.

CBU?

should I continue with my plan of laying the plastic first - or is it not really necessary?

There's a big difference in drying times for a drypac mud bed and regular concrete. You won't be able to apply any liquid membranes to a concrete poured curb for 14 days or more depending on temperature and humidity. Even at that, unless you do a moisture test it's going to be risky.

I would seriously look at another method of curb construction if your in a hurry.

Jools, I also noticed in previous posts you mentioning pouring the shower base in concrete. That's just asking for trouble.
Bases are always done with drypac mud. I hope its just a terminology mistake.

thanks RC - it wasn't a 'terminology' mistake - so I appreciate your pointing out that out. I'd actually done some more reading last night and realized that any and all instructions on how to build a base start with drypac mud to form the slope 'layer', and had decided to take everyone's advice and do it that way. I'll need to source products for waterproofing to see if there's a huge savings in costs associated with one or the other before settling on a method (that assumes that they both ultimately do the job). All things being equal, I think the liquid method seems a little more foolproof, but again, I could be mistaken.

We're not in a hurry - but 14 days might be a little longer than we'd want to wait between steps - other than constructing it out of wood (as discussed earlier), is there any other methods you can think of?

Did I mention that I'm (at best) a novice, having only ever done wall tile installations - constructing the shower base and curb is a bit of a daunting proposition, but certainly nothing that I don't feel I can handle, with the right advice and guidance, that is!

My first choice would be to fabricate it out of 2 bys as already suggested and cover it with cement board. The one I use is 1/2" PermaBase Flex Cement Board and it is bendable. Minimum radius is 6" and it does not require kerf cuts or wetting.
It's not a stock item and is usually a special order.

You may be able to use 1/4" cement board,seeing as the strips will only be about 4-1/2" wide. It would take two layers.
You should be able to pick that up at Home Depot.

Hi,

After a few weeks of planning, purchasing fixtures and flooring, we have finally started our guest bathroom project! Last weekend we ripped out the tub and the old drywall/plaster walls where the shower is going to be installed and have had the rough in plumbing installed. (This house was built in the 50's, when I believe they were just beginning the transition from lath and plaster to drywall - so, what we have is a hybrid of sorts -drywall panels covered with a 1/4" or so of the old type of plaster (does it contain horsehair?) Anyways - today I'm hoping to get the curb built (depends on how much work I can squeeze out of my husband between his old-timer's hockey game this morning and when guests start arriving for the Superbowl get together this afternoon). I have an aversion to skill and jig saws, ever since my dad cut off his thumb when he was building cabinets in our basement (in the '60's) - so I rely on my husband to do anything requiring electricity and blades.

What we've decided to do to build the curb - is to cut two pieces out of 3/4" plywood using a jig saw (we have a full sized template of the curb) - the width of a 2X4. We'll screw one piece to the floor and then lay 2X4's along the top of it for the straight sides and then cut the corner curve out of a 2X10 (probably in two pieces) and screw in place. On top of the 2X4 we'll put the second 3/4" ply curb and screw to secure. This will give us a very solid curb that will equal the thickness of 2 2X4's, with solid sides for securing the mesh. I'll post photos of our work in progress.

(If anyone sees any major flaws in our thinking, hopefully you'll see this and respond before we get started.)

If (that's a big 'if') we can get this much done today, then I plan to start on the shower pan tomorrow, while my husband is at work - following the step by step instructions posted on this site.

You need more than 2pcs of 2by in thickness.
Your rough frame curb needs to be a minimum 4-1/2" in height, unless you are skilled enough to do a mud bed /lath build-up over the 3" of your rough framing.

Thanks RC for confirming what I was wondering about this morning while lying in bed 'planning my next move'. Thankfully, things didn't progress very quickly yesterday and the top plywood layer hasn't been attached - we'll be adding another layer of 2X's to give it a height of 4 1/2", which should be adequate.

Does anyone have any suggestions on how to apply the mesh (over the membrane) on the curved part of the curb? Would cutting and bending it to fit be the best method or should I overlap smaller pieces around the curve (I was thinking it might get too bulky)?

What was the final decision on the shower base construction?
Are you using a Kerdi drain with Kerdi waterproofing or standard drain with a liner?

I was planning to use a standard drain with liner - per the instructions on the 'how to build a shower pan' thread. My plumber dropped by a plastic drain that has threaded sides and is apparently foolproof, as you simply screw the fitting into place prior to building your mortar bed (if I understood his instructions correctly), but because there are no apparent weep holes, I'm a little concerned. I'll have him explain how this 'system' works again (and again, until I understand) - but in the meantime, I think I'll go looking for a standard drain - is there one that you recommend?

I think the kerdi drain/liner system is overpriced ($100 for the drain alone!) - and if I can find another method that works as well, I'd rather spend a little extra time than extra money.

thanks for your help