Screed systems & build-ups

Cement vs Calcium Sulphate Chemistry

A look at the binder chemistry behind the two main liquid screed families and why it shapes drying, finishing and site sequencing decisions.

Flowing Screed Explained

An explanation of the flowing screed process from batching through to the finished, self-levelled surface ready for flooring.

Bonded Screed Build-Up

A guide to bonded screed construction, where the screed layer is mechanically and chemically keyed to the substrate below it.

Unbonded Screed Build-Up

An overview of unbonded screed construction, where a separating membrane isolates the screed from the substrate beneath.

Floating Screed Build-Up

A breakdown of floating screed construction over insulation, the most common build-up for new-build underfloor heating floors.

Screed Over Insulation

A practical, site-focused guide to installing liquid screed over insulation, covering the details that often get overlooked.

Fibre-Reinforced Screed

An explanation of fibre reinforcement in liquid screed, what it contributes to performance, and how it differs from traditional mesh.

Screed Strength Classes

A guide to reading and understanding the C (compressive) and F (flexural) strength classifications specified under BS EN 13813.

Thermal Conductivity & UFH

An explanation of how a screed's thermal conductivity affects underfloor heating response time and overall system efficiency.

Acoustic Floating Floor

A guide to acoustic floating floor construction, where liquid screed sits over a resilient acoustic layer to control impact and airborne sound.

Screed Over Beam and Block

Guidance on installing liquid screed over beam and block suspended floors, a common ground floor construction in the South West.

Screed Over Metal Deck

What's different about specifying liquid screed on composite metal deck floors, common in commercial and multi-storey buildings.

Screed Over Timber Deck

A look at the additional considerations involved in specifying liquid screed over timber floor structures rather than concrete.

Thin-Section Bonded Screed

Bonded thin-section screed relies on full adhesion to a sound, mechanically prepared base to achieve reduced depths without a floating build-up.

Deep-Fill Screed Systems

Deep-fill liquid screed pours address uneven substrates, service ducting or level changes, but bring different shrinkage, drying and reinforcement considerations than standard depths.

Perimeter Edge Insulation

Perimeter edge insulation isolates the screed from walls and upstands, allowing thermal movement and reducing cold bridging around a floating floor.

Movement Joints & Bay Design

Movement joint and bay layout planning reduces the risk of uncontrolled cracking in liquid screed by directing shrinkage and structural movement to defined locations.

Day Joints in Flowing Screed

A day joint marks where one liquid screed pour session ends and another begins, and needs specific edge preparation to bond and perform correctly.

Primers & Bonding Agents

Primers and bonding agents are used to control absorption, improve adhesion or seal a substrate ahead of a liquid screed pour, depending on the design.

Surface Regularity & Finishing

Surface regularity in liquid screed is assessed against SR classes from BS 8204, and depends on both the self-levelling nature of the material and correct finishing technique.

Curing Regime

Curing protects a freshly poured liquid screed while it gains strength, which is a distinct phase from drying and is essential to avoid surface defects and long-term weakness.

Floor Protection Systems

Protecting a liquid screed from other trades and site traffic during the drying period reduces the risk of surface damage, contamination and moisture ingress before flooring is installed.

Wet Area Screed Systems

Wet area screed specification needs to account for falls to drainage, correct sequencing with tanking, and a binder choice suited to sustained moisture exposure.

Screed Under Resin Coatings

Resin coatings demand a fully dry, mechanically prepared screed surface, since any residual moisture or laitance beneath a coating can cause adhesion failure or blistering.

Screed Under Polished Finishes

A polished finish exposes the screed itself as the visible floor surface, so mix consistency, flatness and surface hardness all become finish-critical rather than cosmetic details.

Retrofit vs New Build Screed

Retrofit screed projects tend to be constrained by existing floor levels, access and occupied spaces, while new-build projects have more design freedom but different sequencing pressures.

Self-Levelling Compound vs Structural Screed

Self-levelling compound and structural liquid screed solve different problems, and confusing the two on site leads to floors that fail under load or fixtures.

Forced Drying Systems

Forced drying systems use controlled airflow, heat and dehumidification to accelerate moisture loss from a screed, but they depend heavily on correct sequencing and site conditions.

Testing and Handover by System

Testing and handover expectations vary between calcium sulphate, cementitious and modified screed systems, and knowing what to expect helps avoid disputes at practical completion.

Low Thermal Mass Screed Systems

Low thermal mass screed systems, typically thinner and lighter than standard structural screeds, are designed to heat up and cool down faster in response to underfloor heating demand.

Screed with Recycled Aggregate

Some liquid screed products incorporate recycled aggregate content as part of a wider sustainability strategy, though performance still needs to meet the same BS EN 13813 standards as conventional mixes.

Rapid Strength Cement Systems

Rapid strength cement screed systems are formulated to gain compressive strength and allow foot traffic more quickly than standard cementitious mixes, useful where programme pressure is high.

Screed Systems for Cold Stores

Cold store floors present specific challenges around thermal movement, insulation performance and moisture control that need addressing at the screed specification stage.

Screed Over Existing Screed (Overlay)

Overlaying a new liquid screed onto an existing screed floor is achievable in refurbishment projects, but depends entirely on the condition, bond potential and moisture state of the original substrate.

Screed Systems for Listed Buildings

Screed installation in listed buildings needs to work within heritage constraints on floor depth, existing structure and consented alterations, alongside the usual technical requirements.

Site-Batched vs Truck-Mixed Supply

Site-batched and truck-mixed liquid screed supply differ in how the mix is produced and delivered, with implications for consistency, logistics and access requirements.

Two-Layer Screed Systems

Two-layer screed systems combine a lower structural or levelling layer with a finer top layer, used where depth, programme or finish requirements can't be met with a single pour.

Acoustic Perimeter Strip Detailing

Perimeter strips isolate a floating liquid screed from surrounding walls and structure, and correct detailing at this junction is essential for both acoustic performance and preventing cracking.

Choosing a Screed System: Decision Guide

Selecting the right liquid screed system means working through a series of practical questions about heating, depth, substrate, programme and floor finish, rather than picking a product first.