Make life easy, search the forum.

Discuss Poured concrete screed preparation in the Tiling Advice | Tile Forum area at TilersForums. USA and UK Tiling Forum

Reaction score
118
Please checkout the following advertisement.
Hi everyone. I have a floor tile job coming up that is a poured concrete screed over piped underfloor heating. The screed has been down for many months (completely cured and underfloor heating has been ticking over on low). My issue is that the surface is quite smooth with a light sheen. Would this need to be mechanically abraded prior to laying a decoupling membrane? Can't find anything on surface preparation for poured concrete screeds. Will this be the same as surface laitance on a anhydrate screed? Or is this just the surface finish (similar to levelling compound)? Any help or input would be greatly appreciated đź‘Ť
 
Reaction score
21
Sometimes its the curing agent that gives it that shine. I always get them sanded to be 100% sure of a good bond.
It’s called laitance: a weak surface layer that results from a poorly mixed (weak and watery) cementituous or calcium sulphate subfloors.
It’ll be flaky and easily lifted/scraped into by a sharp blade or strong tape. This should not under any circumstances be tiled onto without mechanical abrasion to remove such a layer prior to priming and tile.
 
Reaction score
21
Sometimes its the curing agent that gives it that shine. I always get them sanded to be 100% sure of a good bond.
Hi Dave,
I’m fairly sure that laitance (fines found on the surface) is a deposit that forms when too much water is added to a screed mix. The screed companies want to save costs and make it as weak as possible. Water is cheaper than bags of product after all.
I’ve seen some total sh*T screeds in my time.
 

Dave

TF
Staff member
Arms
Esteemed
Reaction score
389,871
Hi Dave,
I’m fairly sure that laitance (fines found on the surface) is a deposit that forms when too much water is added to a screed mix. The screed companies want to save costs and make it as weak as possible. Water is cheaper than bags of product after all.
I’ve seen some total sh*T screeds in my time.
On the Agila screeds ( cement based ) a curing agent is sprayed on. The newer ones have it inbuilt now. The buggers keeps changing bloody things each yr.
 
M

MultiHire Power Tools

Reply to Poured concrete screed preparation in the Tiling Advice | Tile Forum area at TilersForums.com

Or checkout our tile training advice or the Tile Standards

This website is hosted and managed by www.untoldmedia.co.uk. Creating content since 2001.
Please visit our sponsor websites, they keep the forum free to use!

New Tiling Questions

UK Tiling Forum Stats

Threads
66,600
Messages
866,701
Members
9,509
Latest member
flooringdemand
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock