Floor Screed

[garb]

Laid 6 sq metres of floor screed 10 days ago. 3:1 grit and cement. 70mm thick over kingspan. Fairly dry mixture. Tamped down and used polyurethane float. Finished with steel trowel but did have problem getting a smooth surface.
Laid polythene sheet over and went on holiday for a week. Came back and I can't stop sweeping up loose grit/cement from the surface. Should I leave it longer before puttiong a screed levelling compound down or try something to bind the surface first?

 

[PrenticeBoyofDerry]

It should be left for approx three weeks to cure, Ideally sprayed down and sheeted up.
If you intend to seal it to prevent dust, an acrylic primer will let the moisture through and allow it to breathe.

 

[garb]

It should be left for approx three weeks to cure, Ideally sprayed down and sheeted up.
If you intend to seal it to prevent dust, an acrylic primer will let the moisture through and allow it to breathe.

Thanks for that but I don't think I made it quite clear how dry it seems despite being covered with plastic for eight days. If I keep scrubbing hard with a brush, it seems it would go right through the screed to the insulation. Is this normal for the first couple of weeks? So far I've picked up a dustpan full from just 6 sq metres and if I kept going probably a lot more. The surface shows as deeply pitted which I suppose will fill with levelling compound.

Should I spray it and put the plastic back down for a couple of weeks?

 

[noseall]

The finished surface should be as tight as a drum and not friable or crumbly.

 

[willkelly]

Going back to your material 3 sharp sand to 1 cement, then the next day you should have sheeted it to retain the moisture then you would have been able to walk on it but NO heavy traffic.

it sounds as if its dryed very quickly, so you will need to use a two part leveling compound 1st lay the milk type fluid followed by the mixed compound , or use waterproof PVA neat with a roller.