Liquid screed vs traditional screed: which should you choose?
Reviewed by Spencer Warner, former BSI committee member. Established in 1987
CSC Screeding · Last updated
Liquid (flowing) screed usually wins on large, open floor plates and over underfloor heating, because it lays fast, self-levels and can often be thinner. Traditional sand and cement screed usually wins on small or broken-up areas, falls, bonded toppings and floors where moisture-sensitive finishes and cement compatibility matter, and it is more forgiving of imperfect site conditions.
CSC lays both, so we have no reason to push either. This guide sets out the differences, the honest downsides of each, and how to decide for your project.
Key facts
- On average our crews lay about 400 m² a day of flowing screed and about 120 m² a day of traditional screed. These are averages, not guarantees.
- We can pump flowing screed up to 120 m and traditional screed up to 150 m.
- Our Maverick batches flowing screed on site. It produces flowing screed only. Traditional screed is mixed and pumped with separate equipment.
- Over 2,900 projects since 2010. Isocrete (Flowcrete) Approved Contractor.
What is the difference between liquid and traditional screed?
Traditional screed is a semi-dry mix of sand and cement, placed, compacted and hand finished to level by screeders working from datums. It is the long-established method and covers bonded, unbonded and floating constructions.
Liquid or flowing screed is a fluid mix that is pumped into place and levelled with a dappling bar, so it settles to an even surface. Most flowing screeds are calcium sulphate (anhydrite) based; cement-based flowing screeds also exist. Each product has its own data sheet for thickness, drying and finishing.
Side-by-side comparison
| Flowing (liquid) screed | Traditional sand and cement | |
|---|---|---|
| Laying speed (CSC average) | About 400 m² a day | About 120 m² a day |
| Pumping reach (CSC) | Up to 120 m | Up to 150 m |
| How it levels | Self-levels, dappled | Compacted and hand-finished to datums |
| Thickness | Often thinner, per product data sheet | Generally thicker for the same construction |
| Underfloor heating | Fully surrounds pipes; good heat transfer | Works well if compacted properly around pipes |
| Drying | Per product data sheet; calcium sulphate commonly quoted at about 1 mm a day to 40 mm in good conditions (manufacturer data sheets) | About 1 mm a day up to 40 mm, then about 0.5 mm a day thereafter, based on lab conditions; site conditions vary |
| Laitance removal | Usually needed on calcium sulphate before finishes | Not normally |
| Falls and small areas | Not suited to falls; small areas less efficient | Handles falls, steps and small rooms well |
| Site requirements | Area sealed and tanked, edge strip fitted, pipes fixed down | More tolerant of an imperfect envelope |
| Cost | Material usually costs more; labour and programme often less | Material cheaper; labour-heavier |
Product claims vary, so the product data sheet always takes precedence for thickness and drying figures.
Advantages of liquid screed
- Speed. On average our crews lay about 400 m² of flowing screed a day, against about 120 m² for traditional. On a large floor plate that can take days off the screed programme.
- Even surface. It self-levels, which helps meet surface regularity on big open areas.
- Underfloor heating. It flows around pipes with no air voids, which is why it is popular in apartments and houses with UFH.
- Often thinner. Many products allow a thinner section than traditional screed for the same construction, which saves weight and depth.
- Less manual handling. Pumped and dappled, not barrowed and compacted.
Downsides of liquid screed (the honest list)
- Site has to be ready. The area must be sealed so screed cannot leak through gaps, edge strip and membrane must be fitted carefully, and UFH pipes and insulation must be fixed down or they can float.
- Laitance. Calcium sulphate screeds usually need the surface laitance removed before floor finishes. That is a cost and a step that is often missed in quotes.
- Moisture-sensitive finishes and cement products. Calcium sulphate screed needs the right primers and adhesives, especially for tiling, and is not suitable for wet areas without the right protection.
- Not for falls. It finds its own level, so it is not suited to falls to drains.
- Small jobs. On small or broken-up areas the set-up cost and minimum order can outweigh the speed benefit.
- Supply timing. Ready-mix trucks bring delays on congested or restricted sites. On suitable sites we avoid this by batching flowing screed on site with the Maverick.
Advantages of traditional screed
- Flexible. Handles small rooms, steps, falls and awkward shapes.
- Tolerant. Less reliant on perfect sealing and tanking.
- Cement-based compatibility. Suits finishes and adhesives designed for cement bases, and needs no laitance removal.
- Bonded toppings. Well suited to bonded constructions on prepared slabs.
- Long pumping reach. We can pump traditional screed up to 150 m.
Downsides of traditional screed
- Slower. About 120 m² a day on average for our crews, so it uses more programme on large areas.
- Skill-dependent. The quality of compaction and finishing depends heavily on the screeder. Poor compaction leads to soft, hollow or crumbling screed.
- Curling and cracking risk if joints, curing and mix are not managed.
- Usually thicker, which adds weight and drying time.
Which is cheaper overall?
Neither is cheaper on every job. Flowing screed's material usually costs more, but on large open areas the speed, thinner section and smoother programme often close or reverse the gap. On small or broken-up areas, traditional screed usually costs less overall. Compare the total cost: material, labour, visits, laitance removal, drying time and the programme days the flooring trades are waiting. See How much does floor screed cost?.
How to decide: a quick guide by project type
| Project | Usually best | Why |
|---|---|---|
| Large open floor plates, apartments, shell and core | Flowing | Speed and surface over big areas |
| Housing with underfloor heating | Flowing (often) | Pipe encapsulation and speed per plot |
| Small extensions, individual rooms | Traditional | Set-up cost and flexibility |
| Bathrooms, wet rooms, falls to drains | Traditional | Falls and wet-area suitability |
| Bonded toppings on a slab | Traditional | Bonded detail |
| Tight city sites with no storage | Flowing with on-site batching, or traditional | Depends on area and access |
| Varying levels to suit different floor finishes | Either, set out from the drawings | Depends on the range of levels |
If the specification already names a product, we price that. If it does not, we will tell you which we would choose and why.
On site with CSC
- Brentford Waterside Phase 2a, Ballymore. Flowing screed batched on site by the Maverick, laid block by block, including over underfloor heating in the one-bedroom and studio apartments.
- Agar Grove Phase 2a, Camden, Hill. Mainly Isocrete K screed, with thickness varied across the floor plates so that each floor finish ends at the same finished floor level, and bonded areas at lifts and ramps.
- Marleigh, Cambridge, Hill. Traditional sand and cement fibre screed across five phases (1A, 1B, 1C, S1 and LLP2) for the same house builder.
When is CSC not the right fit?
If your job is a single small room and you only need a few square metres, a local screeder may be quicker and cheaper. We are best on jobs where programme, scale, access or the floor finish make getting it right first time matter.
Frequently asked questions
Is liquid screed better than traditional screed?
Not always. Liquid screed is usually better on large open areas and over underfloor heating; traditional screed is usually better on small areas, falls, wet rooms and bonded toppings.
Is liquid screed more expensive than sand and cement?
The material usually costs more, but faster laying and often thinner sections can make the total job cost similar or lower on large areas. On small areas, traditional is usually cheaper.
How much faster is liquid screed to lay?
On average CSC crews lay about 400 m² of flowing screed a day and about 120 m² of traditional screed. Actual output depends on the site.
Which screed is best for underfloor heating?
Flowing screed is a common choice because it surrounds the pipes fully. Traditional screed also works if compacted properly. Follow the UFH and screed manufacturers' guidance on heating up.
Does liquid screed dry faster than traditional screed?
Not necessarily. Calcium sulphate data sheets commonly quote about 1 mm a day to 40 mm in good conditions, and traditional screed is about 1 mm a day to 40 mm then 0.5 mm a day thereafter, based on lab conditions. Use the data sheet and test before laying finishes.
Can the Maverick mix traditional screed?
No. The Maverick produces flowing screed only. Traditional screed is mixed and pumped with separate equipment.
Send us your drawings and programme and we will price your job properly.
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