About Screed

Applying Underfloor Heating Screed

Screed, when used in reference to underfloor heating, is the floor substrate that surrounds the pipes that carry the heated water or electric cable (depending upon the heating system being used) and helps to efficiently transfer the heat throughout the floor of a home.

Using the proper screed can help to spread the heat more evenly throughout the floor and thus the home. Typically, when installed in structures with a slab floor, the base slab is poured first and then the heating system is placed above that and the screed is poured over the heat source and the slab. The finished floor is applied over the screed.

Screed can also act as a leveling compound to help level out imperfect slabs. Concrete and sand can be used as screed for under floor heating. Many other proprietary types of screed are available in the market today. The ideal floor screed will not have any air voids that hamper the transmittal of thermal energy from the heating system.


When installing underfloor heating, the effect of heat on timber framing or subfloors should be carefully considered. A rigid cement board may need to be used as a screed. The effect of heat on some forms of vinyl and laminate flooring should also be considered. Definitely consult the manufacturer if in doubt. Using a heavy carpet and/or a heavy carpet pad may restrict heat output of the heating system. Be sure to consider the advantages and disadvantages of all types of flooring when using underfloor heating.

Underfloor heating provides a superior level of warmth over a forced air heating unit.

The proper screed helps to transmit heat throughout the floor and warms the home from the floor up. No air registers are mounted at the base of the walls so the placement of furniture in the home is not restricted. Floors in areas that can become damp, such as kitchens or bathrooms, dry much quicker because the heat is directly under the flooring.

Superior Heat

Underfloor Heating Screed Works

Underfloor heating does have some disadvantages. It warms up the room rather slowly, especially when compared to its forced air counterpart.

underfloor heating screed

Cabinets or dressers should not be placed over underfloor heated areas. In a kitchen or bathroom this isn’t so much of an issue because the base cabinets are typically fixed.

In other rooms it becomes an issue because furnishings such as dressers and bureaus can be moved around. When heat is directly under dressers or cabinetry, it can cause condensation issues leading to mold and mildew problems.


Even with the proper floor screed, keeping pipes from freezing in an underfloor heating system is a high priority. Frozen pipes can burst causing untold amounts of water damage. 

Many homeowners have an alternative source of energy to keep the pump running in the event of a power outage such as a generator. Other homeowners use alternate forms of heat such as wood stoves, wood burners, coal burners or kerosene heaters in case of power loss. 

Some water based heating systems can use antifreeze in the system to keep the water from freezing.

Learn more about underfloor heating screed.

Read The Facts


There are numerous suppliers of water underfloor heating systems and we are not here to recommend one supplier over another. Instead we want to give you the independant facts to help you make up your own mind based on your own individual needs. Read more...