Our Step By Step Guide On How To Screed A Floor

The correct preparation is the key to a successful flow screed flooring. Here at Flow Screeding Services, we strive to ensure that all of our installations follow a proper procedure, so please find below our guide on how to lay screed over underfloor heating!

Step 1: Make Sure The Building Is Watertight

We must ensure that the building is weather tight. The roof and all of the external doors and window openings must be fitted with their final fixtures or a weather proof fixing, in order to ensure the building is completely sealed.

Step 2: Exposed Edges

We have to install a temporary formwork to door opens or any other changes in level.

Step 3: Installing A Membrane

Floor Screed Preparation

Well taped joins in DPM. Isolation strip and well pinned heating pipes.

We then install a polythene or similar separating membrane to the floor insulation or to the concrete substrate (depending on the build type). Any joints are overlapped by a minimum of 100mm and joined with 50mm tape for the entire length of the joint.
The joins are well taped in DPM. Isolation strip and well pinned heating pipes.
All of the creases are stretched, being careful not to puncture the membrane. The floor screed should never be allowed to come into direct contact with foil covered insulation.
An 8 – 10mm isolation strip is also fitted at the wall-floor junctions and around any stairs, columns, pipe work etc.

Step 4: Underfloor Heating

Heating pipes or cables are then securely fixed down with good quality clips pinned through the membrane. All warm water pipes are filled prior to application of the floor screed to minimise the risk of the pipes floating when the screed is being poured.
Flowing screeds have a high flexural strength, which means they can be laid much thinner than a traditional floor screed, with an increase in overall strength. Piped underfloor heating systems are usually laid to 50mm thickness.Diagram of floor screeding

Cross-section diagram of
floor screeding
Under floor heating preperation

A Floor with underfloor heating
ready for flow screeding

We hope our guide on how to lay screed over underfloor heating has helped you, if you require anything else please don’t hesitate to get in touch today!

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