Annoyingly after final floors went down (microcement) we noticed shower drain rocking and subsequent cracking of microcement.

 

turns out linear drain wasn’t seated correctly into mortar by plumber - 5mm gap under ‘wing’ of drain.

 

Gap fixed now with epoxy.

 

 

You can see I removed a lot of screed cement during my investigation:

 

 

should I repair this with concrete or sand+cement? 

in any case I’m thinking of using some steel dowels to connect all the elements.

 

its about 100mm deep

but only 15mm deep over pipe!

Edited January 23, 20242 yr by westcoast

Christ what a mess!

 

I can't see how that could be patched in, but I have zero experience with laying microcement.

Is this the finished shower surface? How are you going to waterproof the patch? You'll have to use something that won't shrink. 

Microcement people are coming back to sand down whole tray and re apply microcement so waterproofing is not an issue

 

im just wondering if I should pour concrete in the hole for strength or match the screed material (sand and cement)

Edited January 23, 20242 yr by westcoast

I'd use concrete with small stones, just because it's cheaper and faster. I'm sure you've some insualtion to slot in first then foam in to place.