UK Micro-cracks in new Self Leveling Compound

[po-tay-toes]

Hi!

I'm looking for some advice, I have laid some SLC (Mapei 1210) in our conservatory in preparation for tiling. A couple of days after there's a lot of very fine cracks which have appeared, you can't even feel with a fingernail. Am I okay to proceed in laying my Ditra or should I rip the SLC up and go again?

Here's the process so far:

• Cleaned the existing concrete and previously (badly) leveled floor extensively
• Primed with an acrylic primer from CTD as recommended by them. I applied a 3:1 coat followed by a 1:1 coat as instructed.
• Mechanically mixed the 1210 with the correct amount of water using a measuring jug and poured from 1mm to 6mm thick in places.
• Left to dry for 36 hours
• Then noticed a very thin layer of fine white powder, after sweeping at it I then noticed these very fine cracks running throughout a good majority of the ~11m2 floor in seemingly random directions (i.e not from a particular corner of the room).

Here's what I've tested so far:

• Unable to feel the cracks, which so far do not appear to be expanding (although it's only been 3 days)
• Tapping with a hammer and dropping a golf ball on the floor does not sound hollow
• Walking on the SLC does not produce more cracks
• The SLC appears well bonded and does not chip

Any advice would be greatly appreciated!

 

[Dave]

Hi. 1: was it a warm day ? As in sunny.
2: is it levelled up tight to skirtings ?
3: you mentioned a dusty finish, you deffo didn’t add too much water.

 

[po-tay-toes]

Hi. 1: was it a warm day ? As in sunny.
2: is it levelled up tight to skirtings ?
3: you mentioned a dusty finish, you deffo didn’t add too much water.

Hi!
1: It wasn't particularly warm and we waited until the sun wasn't on the conservatory
2: In some places yes but the cracks are predominately in the middle
3: I'm confident I didn't, the bag said 3.8-4 liters and I used closer to 4

Cheers!

 

[Dave]

Hi!
1: It wasn't particularly warm and we waited until the sun wasn't on the conservatory
2: In some places yes but the cracks are predominately in the middle
3: I'm confident I didn't, the bag said 3.8-4 liters and I used closer to 4

Cheers!

What’s it maximum depth.

 

[po-tay-toes]

What’s it maximum depth.

6mm, I was using packers to check the depth as I poured

 

[Dave]

6mm, I was using packers to check the depth as I poured

I would say you’re fine but check quickly with mapei tech . I have seen some thin depth levellers crack but are still fully bonded.