Need to raise floor 40mm

[popupstands]

Hi I have laid 100mm insulation and around 60mm Screed but I need to raise it by another 40mm, do I need to seal screed? what is the cheapest and most sensible way to add 40mm

can I add another screed ?
would it be better to lay concrete with 10mm ballast for strength

Thanks in advance

 

[flynnyman]

Just wet it or even a cement slurry, I'm not sure what the minimum is for a screed on a solid floor but i think you will be safe

 

[beddy]

Latex with sharp sand added

Sent from my Nokia 3310 whilst having a poo

 

[Jgreenplastering]

Has it got to be spot on 40mm?
Could you not use another 25mm insulation then 18mm ply to create a floating floor?

If you want it solid then it's needs another coat of screed with fibres in and a good wet down/sbr between the coats To make sure they bond.
How did you manage to get 40mm short in the first place?

 

[A.plasterer]

Called arlita or similar here mixed with sand and cement lightweight i have built up floors by 8-10 inches but for sure anything below that too.
https://jontybarrett.wordpress.com/vernacular/hemp-lime-construction/

 

[kgreigh]

Floating floor could be the way, jgreens way gets you 43mm so not far off.

 

[carlos]

Or fix battens to the floor and chipboard over the top.

 

[A.plasterer]

Heres better link.
https://www.e-weber.com/our-solutions/expanded-clay

 

[Ajax123]

you can lay sand cement screed unbonded down to a minimum of 50mm or you can use an anhydrite screed down to 30mm minimum so 40mm is not really appropriate for sand cement unless you mechanically prepare the screed underneath. It is easily doable with anhydrite screed by simply laying a polythene membrane over the existing and pouring the anhydrite on top of it to the depth you need.

 

[carlos]

Never done it but I bet a well mixed sbr screed sweated onto a sbr scudd would be fine.

 

[cooptaza]

Throw it in. Be alright.

 

[flynnyman]

you can lay sand cement screed unbonded down to a minimum of 50mm or you can use an anhydrite screed down to 30mm minimum so 40mm is not really appropriate for sand cement unless you mechanically prepare the screed underneath. It is easily doable with anhydrite screed by simply laying a polythene membrane over the existing and pouring the anhydrite on top of it to the depth you need.

Is the 50mm not minimum for a floating floor?

 

[malc]

Just wet it or even a cement slurry, I'm not sure what the minimum is for a screed on a solid floor but i think you will be safe

cement slurry ! has been a no no for 20 years, slurry dries quicker then the screed leaving the screed hallow.

 

[malc]

lay a coat of sbr on the base, while the sbr is still wet apply the screed with sbr in the screed mix. you have then built up a key, screed the floor.

 

[Ajax123]

Is the 50mm not minimum for a floating floor?

No

 

[cooptaza]

No

What is the minimum

 

[Ajax123]

What is the minimum

floating i.e. on insulation minimum 65mm sand cement in domestic and 75mm in commercial or if pumpable self smoothing screed needs to be 35mm domestic and 40mm commercial.

 

[popupstands]

I have a guy who will screed floor this saturday, I am having screed delivered ready mixed with fibres would it be worth asking if I could add some SBR to mix ? or would this be a problem

 

[PFTwales]

500 membrane, then lay 40mm gyvlon directly over it. sand cement need help if its too thin

 

[Ajax123]

500 membrane, then lay 40mm gyvlon directly over it. sand cement need help if its too thin

or Gypsol screed (cemex supaflo, hopeflow gypscreed, Highflow S from Aggregate industries)