I am looking to have the floor in the shower fall in a single-direction towards to a linear drain, I'm planning to have a fall from 50mm (finished floor level) to 35mm (drain height) over 1400mm, there are underfloor heating pipes in the floor which are roughly 20mm high.

Firstly: Will a regular sand and cement mixture be strong enough to complete this job or will I need something stronger?

Secondly: The rest of the floor in the bathroom has already been poured, will I need something between the floors to allow for expansion/contraction or can I pour right up to the existing floor?

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    I like a pan under everything to prevent leaks, I have used both rubber and fiberglass. The rubber was easier to seal but the fiberglass held shape easier with an off set hole a linear drain in either style would work.
    – Ed Beal
    Jan 24, 2018 at 23:32

1 Answer 1


in a normal curbless install you want a 100% sealed system. it sounds like this over a concrete substrate, so once the drain is installed and secured, use a mud bed mix thats been fortified or add a latex into it, this will help with strength as the pitch gets shallow. in addition to latex in the mud bed, trowel mortar to the cement before the mud to help it bond to the cement.be sure to dampin the cement before combing mortar on it, so it doesnt suck the moisture out of it to fast and weakin its strength. after that its all about the water proofing, several options there from roll on to fabic membrains. choose the one you feel u can manage the best. showers are all about being water proof, if u cant take a shower before the tiles up without it leaking, then its not ready for tile.

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