Architects & Specifiers
Although there is a huge variety of “specialist” screed materials allowing very specific types of installation (very thin, with wearing surfaces etc) the primary types of screed are for relatively thick sections of more than 20mm. The exact thickness will be dependent on the type of screed material chosen and the way in which it is used.
We will compare the use of three main screed materials in the various types of installation.
- Traditional Sand / Cement Screed (including modified versions)
- Flowing Screeds based on Calcium Sulphate (Gypsum)
RIBA Approved CPD – Guide to Different Types of Screed
This presentation examines the different types of screed used in the construction industry. Topics covered will include advantages and disadvantages of each type of screed, methods of installation, the drying process and factors effecting drying time. By the end of the CPD you should have a greater understanding of:
- The different screeds available on the market
- The benefits of various screeds
- How screed dries and potential problems that can be encountered on site
This CPD can be delivered to you live and remotely. Please follow the link to book a suitable time and date.
Traditional sand and cement screed is still substantially the most commonly specified and used type of screed in the UK. Its primary benefits are availability, relative simplicity and low cost. There are admixtures available that can improve specific aspects of the performance of this type of screed (usually drying time and strength) and the use of improved cements can achieve the same.
Flowing screeds based on calcium sulphate have been available in the UK for over 25 years but despite many obvious advantages over traditional screed have only gained a relatively small market share. Primary benefits are controlled quality, higher performance, speed and ease of application.
Cemfloor is a BBA approved cement based liquid screed. Since its introduction to the UK market, it has continued to grow from strength to strength. The primary benefits are similar to other flowing screeds but with quicker drying, there is no need for special preparations before applying floor finishes, and no risk of incompatibility with the range of cement based adhesives and levellers.
BBA certification is recognised throughout the construction industry as a symbol of quality and reassurance. The BBA provides independent, expert product approval and certification for manufacturers, so that they can be confident that their products and systems will be selected by architects, designers and specifiers who need to know that their chosen items are safe and fit-for-purpose. Cemfloor are delighted to have been the the first cement based liquid screed to be awarded BBA Certification in the UK & Ireland.
Underfloor heating has been growing in use over recent years and so it is becoming increasingly common for a screed to either contain or overlay an underfloor heating system. This may take the form of electric heating cables or warm water pipework. Almost invariably these screeds will be floating due to the need for there to be a layer of insulation under the heating system. In general, the screed would be installed as any other floating screed but it is likely that the inclusion of the heating system will necessitate a higher thickness. Often this will be defined as a minimum “cover” to pipework for example.
Underfloor heating systems are where the benefits of flowing screeds become even greater when compared to semi dry screeds. They can be laid thinner at typically 45 to 50mm for calcium sulphate or Cemfloor instead of 75mm for traditional screed. The screed will fully encapsulate the pipe, which is difficult to achieve with hand compacted materials, and the thermal conductivity is much better.