Liquid screeds can be laid as thin as 12mm bonded or 20mm over a membrane and as thin as 35-40mm over underfloor heating, though 50mm is recommended over underfloor heating pipes where possible to ensure full coverage, allowing for any deviations in the subfloor and insulation buildup, also this gives great efficiency for the system.
Common Questions...with Answers
Have more questions?
Contact Cempump today for expert advice, a personalised quote, or to discuss your screed and underfloor heating project
Can I lay screed upstairs?
Yes! Liquid screed is lightweight and ideal for going over upstairs floors and overlay underfloor heating systems, pumped directly for minimal disruption.
Thin Screeds Over Underfloor Heating on First Floors
How long will it take for my screed to dry?
On average: 1mm per day up to 40mm, with faster drying options available depending on the screed type.
What’s the fastest drying screed?
Gypsum-based and cement based screeds with additives can dry within 14-21 days for floor finishes, with light traffic after 24-48 hours.
Can I prepare the floor myself?
Yes, we can provide guidance if you wish to prepare the floor yourself or we can handle full preparation.
Can Cempump lay screed over underfloor heating installed by others?
Yes, we’re happy to work over third-party underfloor heating installations.
Do I have to sand my screed before tiling?
Yes, most anhydrite liquid screeds require sanding to remove laitance before tiling or applying finishes, we do offer this as an add on service. Some cement based liquid screeds do not require laitance removal, but we would still recommend a light sanding before adhering floor finishes.
What’s the best screed for underfloor heating?
Liquid anhydrite screed is usually best due to its thermal conductivity, but with product improvements over the recent years, cement-based liquid screeds also work very well in the correct conditions.
Is cement-based screed the best?
It depends: cement-based screeds can dry faster and work better in wet areas, and have less issues with laitance; anhydrite screeds offer better thermal performance and larger bay sizes.
How long will it take to lay my screed?
Typically most average size domestic floors are completed within one day, often within 2-4 hours depending on project size.
When can I walk on my screed?
Usually 24-48 hours after installation, depending on site conditions.
When can I turn my underfloor heating on?
After a minimum of 7 days for anhydrite screed, following a controlled heat-up protocol.
How much notice do Cempump need to book a job?
We recommend 1-2 weeks’ notice, although we may accommodate urgent jobs where possible.
Do Cempump have a depot in Wales?
No physical depot, but we have installation teams, management staff and very good supplier relationships that allow us to operate regularly across Wales.
Do I need to use a DPM before screeding?
Yes, a damp proof membrane is usually required, this can either be a physical DPM or sometimes a liquid DPM can be suitable.
What’s the difference between liquid screed and traditional screed?
Liquid screed is self-levelling, faster to install, dries quicker, and provides better heat transfer, it also enables larger areas to be completed in shorter timeframes.
Can I install liquid screed in my garage or industrial unit?
Yes, cement-based screeds can be used in these areas, although the materials sometimes have to be a slightly higher specification and where possible we would recommend a suitable wearing surface is applied to the screeds to give more longevity.
How do I know my screed is dry enough for flooring?
Through moisture testing with a hygrometer or carbide bomb test. We would always recommend that your finish flooring contractor carries out their own checks to ensure they are happy with the finish floor compatibility. We are happy to have discussions with the finish floor installer prior to our screed being installed and provide information data sheets for the products we are installing.
Is liquid screed suitable for wet areas like bathrooms?
Yes, but cement-based screeds are recommended for wet environments.
Can you screed over existing concrete floors?
Yes, provided the surface is clean, sound, and correctly prepared.
Can I lay tiles, laminate, or carpet directly onto liquid screed?
Yes, once dry and properly prepared, any floor covering can be applied.
When is the best time to install my screed?
We recommend installation of the liquid screed once the building is sealed and watertight, ideally when all the windows and doors have been installed. If windows and doors are not yet fitted, we recommend that the building is sealed up temporarily using boarding or polythene sheets over openings, 24hrs after the screed has been installed, the building can be opened up to allow for drying.
Will liquid screed crack?
Minor shrinkage cracks are possible but less common than with traditional screeds.
Do I need expansion joints with liquid screed?
Yes, in larger areas to manage shrinkage and movement. We are happy to advise on the best way to position these movement joints, and can also install joists where possible as part of the screed installation process.
How far can liquid screed be pumped?
We can pump the liquid screed upto 200m using our specialist high pressure pump, up tight driveways or footpaths, up scaffolds, through shopping centres, over walls, down basements, up lift shafts, over roofs, through hedges, up staircases………you name it, we’ve probably done it.
Is liquid screed more expensive than traditional screed?
Per m² on small floors It may be slightly more expensive than traditional semi-dry screeds, but overall installation time, labour savings, and performance benefits often make it more cost-effective. On larger floors liquid screed will normally work out a lot more cost effective.
How far will Cempump travel?
We cover Derbyshire, Nottinghamshire, Leicestershire, Staffordshire, South Yorkshire, Wales, Manchester, and can travel nationwide for suitable projects.
Do Cempump have a depot in Manchester?
No, we used to have a physical depot, we have found it to be more efficient to operate in this area and serve Manchester from our depot in Derbyshire. Our teams are happy travelling the short distances to our surrounding areas, we still cover the Manchester and Cheshire areas with our excellent working relationships with clients and suppliers.
Have more questions?
Contact Cempump today for expert advice, a personalised quote, or to discuss your screed and underfloor heating project
Services
Our services cover both commercial and domestic projects
Flow Screeding
Our flow screeding service includes screeding floors from 10m2 to 2000m2 using a range of suitable floor screeds and our expertise in preparing the screeding area.
Floor levelling & Thin screeds
We provide fast and professional thin screed layers, floor levelling and smoothing services, capable of covering areas ranging from 20m2 to 4,000m2 in one day.
Underfloor Heating Installation
We provide high quality triple core pipework and pre-manufactured manifold systems with all the necessary pumps, ensuring durable underfloor heating installation.
