Cementitious Flowing Screed
What is a cementitious flowing screed?
Cementitious flowing screeds are a specially formulated mix of limestone-based binder, cement, sand and water. When the components are mixed the result is a free-flowing and pump-applied liquid screed, which is suitable for all types of flooring applications. The screed is quick drying, which allows for faster installations of floor coverings and has exceptional performance with underfloor heating.
What are the advantages of a cementitious flowing screed?
The performance of the screed:
- Due to its fluid nature, it is nearly completely self-levelling, easily achieving an SR2 standard for flatness (plus or minus 5mm over a 2m straight edge).
- It has low shrinkage compared with traditional screed, which means that the screed is much less prone to cracking and fewer control joints are required.
- The screed can be laid at thinner depths – 25mm bonded, 30mm unbonded, 35mm floating over insulation and 25mm cover to underfloor heating pipework.
- Drying times are reduced even further than anhydrite screeds. In the right conditions, some floor coverings can be laid in as little as 7 days.
- Cementitious flowing screeds are compatible with all standard types of floor coverings, cementitious adhesives, damp proof membranes and levelling compounds.
- There is no laitance formed on the surface screed after drying unlike anhydrite screeds, meaning there is no need for the screed to be sanded after installation.
- Quality control is improved as tests are carried out on the screed both at the plant after it is batched and on site by the installation team. The suppliers will also only supply to approved installers who have undertaken proper training and invested in the necessary equipment to carry out the works.
Productivity can be dramatically improved:
- Liquid screeds can be laid up to ten times faster than traditional screeds with areas exceeding 1000m2 achievable per day. Not only will this help reduce the overall build time of your project, but it will also result in extra savings on labour costs.
- After installation the screed will have gained enough strength after just 24-48 hours to allow for foot traffic, so trades can get back to work sooner.
It is far less labour-intensive:
- The screed is delivered ready-mixed at a local concrete plant and delivered to site on a concrete mixer where it is pumped into place, removing the need for labour-intensive mixing and manual handling on site.
- Once the screed is poured it is self-levelling and self-compacting, so there is no requirement for tradesmen to level and compact the screed on their hands and knees as is the case with traditional screed.
It has superior performance with underfloor heating:
- As well as having a greater density than sand and cement screed, due to its fluid nature the screed fully encapsulates the pipework leaving no voids around the pipes.
- Thinner applications – just 25mm over pipework – means better heating efficiency as the screed is quicker to heat up and cool down.
- Improved heating efficiency means a saving on heating bills.
Who supplies cementitious flowing screeds?
- The three major products are Longfloor Integracure, Cemfloor by McGraths and Tarmac Topflow Screed C Belitex.
- The ready-mix concrete plants mix the cement binder with water and aggregates to batch the screed prior to delivery via concrete mixers.
- National ready-mix suppliers include Tarmac, Cemex, Marshall’s and Aggregate Industries.