Anhydrite screed: underfloor heating, drying, sanding

What the price depends on

Screed is priced per square metre, and the total depends on layer thickness, whether there’s underfloor heating, and how much preparation is needed: membrane, edge strip, setting levels. A small area costs more per metre, because the mix is pumped and setting up the pump takes the same time whatever the size. Labour rates are in the table.

What’s in the rate and what’s extra (the mix itself, delivery, sanding, waste removal) is set out in the handyman’s offer. Materials are usually paid for separately.

Rather hand the job over? More here: apartment fit-out in Warsaw.

Anhydrite or cement

Anhydrite screed is based on calcium sulphate. It’s fluid, spreads by itself and fills the space around the pipes completely, so underfloor heating warms the room faster. It can be laid thinner than cement screed and needs fewer movement joints.

Its one weak point is moisture. It isn’t poured outdoors, in garages or anywhere the floor stays wet. In a bathroom it’s fine, but only under waterproofing. One more thing: cement-based adhesives and mortars don’t go straight onto anhydrite; a suitable primer goes first.

Cement screed copes better with moisture and works almost anywhere, but it’s laid thicker, dries more slowly and takes more effort to level. The room decides, not fashion.

How pouring works

1. The base, insulation and membrane are checked, and an edge strip goes along every wall.
2. Underfloor heating pipes are fixed down and kept under pressure, so any leak shows at once.
3. Levels are set with a laser, and the pour follows them.
4. The mix is pumped in, then immediately worked with a special dappling bar to let the air out.
5. For the first few days the room stays closed to draughts and direct sun, then it’s aired so the screed can dry.
6. The surface laitance is sanded off, and moisture is measured with the CM method before flooring. Underfloor heating is started following a heat-up schedule.

Common mistakes

• Windows flung open right after the pour, and the screed cracked.
• The top layer was never sanded, so tiles and parquet come away together with the laitance.
• Laminate or parquet laid without a moisture test, and the floor warped a few months later.
• A membrane full of holes: the mix leaked into the insulation and floated it up.
• No edge strip along the walls, so the screed has no room to move and cracks.
• Underfloor heating switched to full without a heat-up schedule.

What to prepare

• A floor plan with room sizes, and details of the underfloor heating.
• Fitted windows and closed openings, since the screed needs warmth and no draughts.
• Access for the vehicle with the pump and mix, plus water and power.
• Empty rooms with the building rubble cleared out.
• A decision on the final flooring, because sanding and the allowed moisture level depend on it.

Frequently asked questions

How to order

Describe the job in the app: the area, which floor, whether there’s underfloor heating and what flooring you plan, and add photos. Tradespeople near you will send offers with their own price and timing. Pick one by reviews; only that person sees your address.

You pay the handyman directly and they issue the invoice. They stand behind their own pour and will put right what they got wrong, such as a wrong level or a missing edge strip. Cracks from draughts after they’ve left, a base laid by someone else and pipes installed before them are not on them.

Pour anhydrite screed and have your own pump? Join as a tradesperson and take jobs near you. The business form and the paperwork are your choice.