Hi,
My name is Andre.
I am new here, though was reading your site for about year. Found a lot of interesting info and always recommend it to my friends (very active DIY team).
After interviewing 4 contractors (none did not want to install pre-slop in tiled shower) I decided to build it myself.
I used instructions posted by Harry Dunbar.
I used black plastic drain assembly purchased in HD (it looked the same as was used by Harry).
After building pre-slop (1/4" per ft slop as recommended) and installing membrane, I proceeded with leak test. After I drained the water, there is still small pool of water around drain assembly (just as high as 3/8" high lower portion of top flange as shown on attached photo, about 1 ft in diameter).
How bad is it?
What solutions can you recommend (if it is really ba problem)?
What about carving small channels on downward surface of top flange of drain assembly?
Or, better to change a slop?
I drew a picture here (drain assembly cut-out).
I hope it will help to clarify my question.

I am also going to install Durock cement boards on walls.
Installation instructions call for 1/8" gap between the boards. Could be a problem if it is less than 1/8"?
In my case, 2 standard size boards can fit tightly with no gap between them. Shall I still cut the boards to have a 1/8" gap?
http://profile.imageshack.us/user/andruxa/images/detail/#222/drainyk5.jpg
http://profile.imageshack.us/user/andruxa/images/detail/#217/draincutoutqf5.jpg

I am confused, please help.
Regards, Andre

Hi Andre

Unfortunatley, your pictures didn't show up for us to see. Are there any bumps in your membrane that are holding the flow of water?

Did you make your preslope come up flush with the top of the lower drain assembly?

Hi,
I hope this time pictures will work. I changed links in original post.
The slop starts flat with the top of lower flange.
Oakley lining is sandwiched between top and lower flanges (I also used silicon between lining and lower flange).
There are no bumps.
The water stays about 3/8" high (just reaching lower portion of top flange). There are no holes for water to escape.
Seems to me that this particular drain assembly is designed that way.
Regards, Andre

Andre

There should be some where for water to escape around the screws. Any chance you plugged them up with silicone? Also, in the picture, you can see a little square dark spot on the back end of the lower flange. Any chance that is a weep hole?

Oh I think I know what you mean now. That's normal to have a little bit of water which can't make it up over the top section of the drain to the weep holes. Don't worry about it, the slab will be dry enough throughout it's use that the water will sponge into it around that small area and evaporate between uses.