Screed thickness +DPM

RVS6

New Member
#1
Hi
I have a 1 sq m area of concrete floor to damp proof and screed. I was planning to use synthaprufe, blinded with sharp sand and then lay a cement sand screed over. However, the thickness of the screed at a minimum would only be 30mm (it increases to about 50mm across the width). I have read that 50mm is the minimum for unbonded screeds (and Synthaprufe data sheet says it should be a min 50mm).

The area of floor was an old porch which is now internal and part of the hallway, so will get lots of foot traffic. It will be covered in resilient underlay and then 9mm laminate. If I went with the screed would min 30mm really be an issue, and would putting fibres in it help? If not I am into the territory of much more expensive DPM and screed products like Ardex or F Ball, probably about £200 for such a small area.

Any advice would be much appreciated!

Cheers
 

Ajax123

Active Member
#2
If it's only 1m2 you would probably do well to use a thick section levelling compound. Send cement at that depth is likely to fail in a high traffic area evenbwuth fibres. You could use an SBR additive but once you have faffed about with that you could have There are loads of thick section levelled out there. GYPSOL sureflo can be bonded in this fashion at 25mm minimum but will take a couple of weeks to dry for covering. Added have some deceb rapid drying compounds whichbyouncoild have in and covered in less than a day if time is an issue
 

Topspread16

Well-Known Member
#4
Flexy self level with fibres in. Chuck half a bag of granite dust in with 2bags of level. Use TPS doubled up for the damp, bit more flexible at getting into the corners. It’s only a m2 I wouldn’t worry about it to much. Granite will set like iron.
 

essexandy

The Lake Governor
#5
Personally I'd have no qualms about laying a sand and cement screed in the situation you describe. Going all modern I'd wack some SBR and fibres in though. The most important thing is to keep it hydrated, it's only rapid drying that would cause it to fail.
It doesn't feel that long ago that all screeds were straight onto concrete oversites at 50mm and there would often be areas where it ran tighter. Never had one fail.
 

zolco

Private Member
#6
Fibre reinforced self level deep base would sort that
 

malc

TPF Special Forces
#7
i would lay a sand and cement screed with sbr added to the mix. to cure the screed pour a bucket of water over it next day and cover with polythene for 1 week.
 

Mouldyoldspudgun

Well-Known Member
#8
Hi
I have a 1 sq m area of concrete floor to damp proof and screed. I was planning to use synthaprufe, blinded with sharp sand and then lay a cement sand screed over. However, the thickness of the screed at a minimum would only be 30mm (it increases to about 50mm across the width). I have read that 50mm is the minimum for unbonded screeds (and Synthaprufe data sheet says it should be a min 50mm).

The area of floor was an old porch which is now internal and part of the hallway, so will get lots of foot traffic. It will be covered in resilient underlay and then 9mm laminate. If I went with the screed would min 30mm really be an issue, and would putting fibres in it help? If not I am into the territory of much more expensive DPM and screed products like Ardex or F Ball, probably about £200 for such a small area.

Any advice would be much appreciated!

Cheers
Just throw some SBR in it and use fibres if you want
 

malc

TPF Special Forces
#10
Grout the floor first, throw SBR down then sweep a bit of cement into it, make sure your screed goes down before your grout goes off
we stopped using a cement grout over 30 years ago. the cement grout dries out before the screed giving a risk of a hallow screed.
 
#11
we stopped using a cement grout over 30 years ago. the cement grout dries out before the screed giving a risk of a hallow screed.
I get that but it’s one square metre even I could get that down before the grout went off