Screeding is a vital component of a hard wearing flooring solution but its durability can vary from project to project. Steve Foster, CCF Flooring Category Director, discusses how going the extra mile to source and test products can benefit both the contractor and customer. 

The resilience of screeding can vary for a number of reasons and matching the right product to an application can have a definite impact. Finding the best solution is crucial as the challenges of screeding become increasingly difficult; specifications are more demanding, deadlines are becoming tighter and budgets are often restricted. Despite this, the result must be a smooth, resilient and impermeable surface.

Overcoming these obstacles requires a screeding solution that is both fast drying and durable. A flexible and hard-wearing solution is especially essential in areas that are going to be consistently busy. A good example is the work completed by High Wycombe based CSC Screeding, who came to CCF during the construction of Terminal 2 at Dublin Airport.

The original specification asked for a lightweight concrete which would provide a strength of 35N for the new terminal and the large Pier E extension. Cost efficiency was key, with CSC eager to provide a fail proof solution to such a high profile project. To meet all these requirements, the CSC team decided that they needed to find a credible alternative to the specified product.

Having used Knopp products in the past, CCF stepped in to provide specification support as the manufacturer’s UK distributor. CCF recommended Duremit 50 – a Knopp product which is widely used throughout Europe but is lesser known in the UK. Despite its suitability, its low profile in this country made it difficult to find a live reference site. At least 100,000m2 exposed surface area was required to provide the necessary technical data.

To gain this data, CCF’s specialist flooring solutions division flew representatives from CSC and its client P J Hegarty to Luxembourg to meet Knopp directly. The team visited a live site and conducted a number of tests at various stages of hardening.

The integrity of screeding can be comprised by the level of compaction in the mix, the binder content, the aggregate grading, water content and curing – demonstrating the range of factors that can result in a floor that needs repair or maintenance sooner than expected. Independent tests are essential to ensure that the final product will perform as planned.

Core samples and drop hammers tests were extensively taken at the specification stage.  Examining a core can assess factors such as compaction, density, permeability or any occurrence of cracking.  If required, a closer examination via microscope can provide details on carbonation depth, micro cracking or other deterioration of the aggregate.

Other methods to define whether crushing might occur, how it will withstand imposed loads and high levels of footfall also need to be carried out. Drop hammer tests were completed to meet the BS Code of Practice which measures overall soundness.

Hammer testing subjects the screed to four repeated blows by dropping an annular weight of 4kg down a cylindrical guide rod, onto a hardened steel anvil placed in contact with the screed. The depth of indentation on the screed after four blows is measured with the depth measuring device to assess the soundness of the screed. The tests carried out showed that strength of up to 55N was being achieved.

Duremit 50 passed both tests and as a result, CSC were chosen to screed around 56,000m2 of the 90,000m2 terminal area.  Due to the performance and efficiency of Duremit 50, the project also met sustainability targets with CO2 emissions reduced by approximately 1000 tonnes.

The Dublin Airport project is an ideal example of how specifying a screeding product needs to take more than the original specification into account. To make your service stand out from the crowd, you need to recommend solutions that will bring long term savings whilst environment benefits are an added plus. Furthermore, CCF believes it has a responsibility to be actively involved in value engineering to ensure a complete solution is provided to customers.

CCF is an exclusive supplier of Knopp screeding products. To discuss your specification needs, contact the specialist CCF flooring team on 08707 550686 or email You can locate your nearest branch by visiting