What is the mix ratio for floor screed?

Screed is usually a cementitious material made from a 1:3 to 1:4.5 ratio of cement to sand. A simple cement and sand mix will be fine for a simple application but more sophisticated mixes are suitable for a wider range of applications. Some of these new compounds can be laid on substrates other than concrete.

How deep should underfloor heating pipes be?

The minimum screed thickness you should use for warm water underfloor heating systems is: Minimum depth of 65mm for hand-mixed screed. Minimum depth of 50mm for liquid screed.

Can you use central heating pipes for underfloor heating?

The answer to this question is yes, you can have both systems on one boiler. It is possible to create zones in your home, where one part gets heated via the radiators and others warm up with underfloor heating. You can even have both in the same room if you wish.

Does screed need expansion joints?

Heated screed or concrete floors will expand and contract slightly during use; the edge insulation is normally sufficient to take up this movement. However, in certain situations and especially with floor finishes such as tile, marble or stone, screed expansion joints will be required.

What thickness should floor screed be?

A minimum thickness of 25 mm is required for a fully bonded screed, 50 mm for an unbonded screed and 65 mm for a floating screed (i.e. on top of insulation). 75 mm is the minimum in a commercial environment for a floating screed.

What is the best mix for floor screed?

Mix your floor screed at 4 sand to 1 cement. The mix should be fairly dry. The way to tell if you have it right is to grab a handful of mixed screed (put your marigolds on first) and squeeze. The mix should stay in one firm lump in your hand but very little liquid, if any, should come out.

What temperature should I set my boiler for underfloor heating?

Underfloor heating requires a flow temperature of 50°C flow and 40°C return, so using UFH with a condensing boiler is ideal for taking advantage of this.

Is underfloor heating bad for your circulation?

Economical, eco-friendly and comfortable, underfloor heating has long been accused of being bad for the legs, especially for blood circulation. But thanks to new low-temperature techniques, this disadvantage has been completely eliminated.

Why does screed crack?

Cracks typically form in new screeds because the excess water evaporates from the surface at a faster pace than it is replaced by the residual water, trapped in the concrete slab. This can be caused by not enough or too much water added during the mixing process or simply poor mixing.

How thick can you screed a floor?

The optimum thickness of a sand and cement bonded screed is 25–40mm, an unbonded screed should have a minimum thickness of 50mm, whilst a floating screed should have a thickness greater than 65mm for lightly loaded floors and 75mm for more heavily loaded floors.

What is the minimum screed thickness?

The minimum thickness of an unbonded traditional screed will usually be around 50mm. An unbonded Cemfloor Screed would usually require a minimum of 30mm thickness. Floating screed: This is where the screed is overlaid on something that is compressible and not rigid.

What to do about central heating pipes in concrete floor?

No doubt this is a 1970s build. Basically, you need to extract as much of the piping as possible and replace it OR feed the radiators from upstairs, which might be easier. The pipes should be sleeved in insulation suitable for direct burial, like Armaflex class-O with the joints glued and taped over.

Is there a leak in the central heating pipe?

Hi, we found a long standing leak in the copper central heating pipe which was buried in the concrete floor. Plumber came out & removed the bit of pipe with the leak & adding a replacement bit in using copper pipe & joints.

What kind of screed do you use for UFH pipes?

This traditional screed mix is made up from sand and cement at a 1:3-5 ratio and is then spread onto the floor and allowed to solidify around the UFH pipes or cables. Nowadays, most installers will use fibres to add strength and reinforcement to the flooring and will aim for a thickness around 75mm.

When to install underfloor heating and floor screeds?

Underfloor heating loops should not be installed until all external doors and windows have been installed and the property is water tight, ensuring that the installation is protected from damage due to frost in the pipework loops during cold weather. BS EN 1264 provides guidance on the design and sizing of the system.