Primer/ sealer for screed recommendations please

[crisscross]

I've got a 140 sq metre extension that has underfloor heating and a screed with fibre down at the moment.

I'm looking to tile it in the next couple of months ( when finances allow) but need some way of sealing the dust in for now.

I'd been told to use PVA but that seems lousy advice having read up on it on here.

Please can anyone recommend a decent alternative and what dilution I will need so it is walk-on-able for the next few weeks.

Thanks in advance.

 

[Qwerty]

PVA!!!! Noooooo!!!!
Use an SBR or acrylic primer 1:3 water. I recommend you use the primer from the same manufacturer as the adhesives you plan to use.
What screed is it though?

 

[Perfect Tiling]

Hi matey. As plan tec says above.....and never pva. The main issue though is the type of screed and how dry it is. If its anhydrite (devils tarmac) then this has issues. It there is a latience (skin) on the surface then it needs removed to allow floor to dry and tiles to stick. Whatever the floor though you need to ensure its dry as if you prime it you might trap the moisture within the screed. Anhydrite can take forever to dry...at least 1 day per 1mm thickness.

 

[Ajax123]

Hi matey. As plan tec says above.....and never pva. The main issue though is the type of screed and how dry it is. If its anhydrite (devils tarmac) then this has issues. It there is a latience (skin) on the surface then it needs removed to allow floor to dry and tiles to stick. Whatever the floor though you need to ensure its dry as if you prime it you might trap the moisture within the screed. Anhydrite can take forever to dry...at least 1 day per 1mm thickness.

Perfect tiling... sounds like you need some guidance and real info on anhydrite... Devils tarmac indeed.... In this instance as it has fibres it suggests sand cement anyway... It should not be dusty...if it is the likely hood is it has not been properly cured. This can affect tensile strength so you need to look out for shrinkage cracking and deal with it before tiling. By far the best anti dusting agents are Lithurin (a lithium based hardener) and penetrative epoxies eg spurs from Ardex...

 

[Perfect Tiling]

Hi Ajax....appologies if I got my info wrong. I though the floor was anhydrite. Its fairly new up here in NE Scotland and catching a lot of people out. I spent yesterday lifting a floor that had been tiled onto with an anhydrite floor. The whole lot was floating. Under the adhesive was a layer of grey powder. Spoke to BAL and they say it prob salts from reaction as no primer on floor. Customer looking at alternatives as not wanting same thing to happen.

 

[Ajax123]

Hi Ajax....appologies if I got my info wrong. I though the floor was anhydrite. Its fairly new up here in NE Scotland and catching a lot of people out. I spent yesterday lifting a floor that had been tiled onto with an anhydrite floor. The whole lot was floating. Under the adhesive was a layer of grey powder. Spoke to BAL and they say it prob salts from reaction as no primer on floor. Customer looking at alternatives as not wanting same thing to happen.

alternatives es to tiles?? If the want tiles there are loads of compatible addys available these days. The whole technology has moved forward since competition was introduced into the market. If you need some info feel free to ask.