What is Sand and Cement Screed?
I’m Andy Parkin Managing Director of the Multi-Award Winning Speed Screed. I am here today to talk about sand and cement screed.
Sand and Cement Screed Basics
Floor screed is commonly made by mixing cement with sharp sand. The most common ratio used for sand and cement screed is 1:3 or 1:4.5 which gives the most suitable consistency for adding to a concrete floor unit or slab.
The screed can be applied in three main ways:
• Bonded screed– where it is placed directly onto a concrete floor.
• Unbonded screed– where a damp proofing membrane is placed on the floor and the sand and cement screed is then poured into place.
• Floating screed– this is a similar process to unbonded where the screed is placed on the top of a floating insulation layer. This type of screed is often used where pipes are placed for underfloor heating systems.
Sand and cement screed can be reinforced if necessary by using fine polypropylene fibres or by inserting a fine mesh constructed from metal or glass.
Types of Sand and Cement Screed
Sand and cement screed is usually site batched, however it can arrive on site having been mixed in the factory. This type of ready-mixed product ensures that you can be certain of good quality and a consistent mix.
The screed comes into its own when applied as a top surface, known as wearing screed. Important factors to consider here include the type of traffic and amount of use the floor will receive. Some areas require more protection from abrasion or impact. How level the area is, how much slip resistance is required must be considered as well as any maintenance needs. In certain areas, aesthetics may also be a consideration. For wearing screeds different aggregates, and admixtures may be required to give it additional wearing properties.
To get the most out of screeds the base layer must be properly prepared bearing in mind the type of application you are looking for. Surface layers for all types of screed should be thoroughly cleaned – it is vital to ensure that the base is clean and free of any dirt or debris. If there are any joints in the floor these must be properly grouted and sealed before the screed is applied. It is only by proper preparation and the existence of a good, strong foundation that you can get the most out of your screed.
Whatever your reason for using screed the sand and cement screeds remain one of the most popular, adaptable and cost-effective floor screed preparations on the market.