Can the use of timber wedges make the shower screed prone to cracking?

[charlie0123]

I was reading and watching Bunnings' "How to screed a shower base" and have a question here:Can the use of timber wedges make the shower screed prone to cracking along the wedge lines? It's because the wedges are removed and the gaps are filled after the screed is dry (12 hours later), and the new screed fill may not attach to the existing screed well.

https://www.bunnings.com.au/diy-advice/home-improvement/baths-showers-toilets/how-to-screed-a-shower...

[EricL]

Hello @charlie0123 

If you are worried about the screed not bonding together you can use the Lanko 5L 124 Ultraprime Primer to prime the surface of the first batch of screed. Once the primer cures you can then apply the remainder of the screed. If the drying process is well monitored and the screed is misted properly then it will cure with no visible cracks on the surface. The only reason you would get cracks in the screed is if the drying process was accelerated. Once the screed cures the waterproofing membrane will cover the surface and will prevent water from reaching the screed.

If you have any other questions we can help with, please let us know.

Eric

[charlie0123]

Thanks, Eric.

If cracks do occur, should anything be done? Waterproofing membrane may or may not cover the cracks (if the membrane is under the screed).

[EricL]

Hello @charlie0123 

If cracks do occur, they can be filled with Earl's 1kg Concremate Expanding Cement before the waterproofing membrane is applied. 

Eric