Substrates
Substrate Types
What types of substrate are suitable for epoxy resin flooring?
The substrate is the existing surface beneath the resin flooring. Its strength, rigidity, moisture condition and surface preparation all affect how successfully the coating will bond and perform.
Resafloor HB is designed primarily for concrete and cement-based substrates. These provide the most dependable base for a high-build epoxy coating and are the recommended choice wherever possible.
Timber and old bitumen-based screeds may sometimes be physically coated, but their performance is less predictable. Latex screeds, tarmac and steel are not suitable substrates for Resafloor HB.
Substrate suitability at a glance
Substrate | Suitability | Guidance |
Concrete | Recommended | The preferred substrate when sound, dry and properly prepared |
Sand and cement screed | Recommended | Suitable when sufficiently strong, cured and securely bonded |
Cementitious flowing screed | Recommended with checks | Confirm that it is cement-based, sufficiently dry and mechanically prepared |
Timber or timber mezzanine | Possible, but not advised | Movement, joints and deflection can cause cracking or loss of adhesion |
Legacy bitumen-based screed | Possible, but not advised | Condition, softness and compatibility can vary considerably |
Latex screed or smoothing compound | Not suitable | May not provide the strength, stability or compatibility required |
Tarmac or asphalt | Not suitable | Too flexible and potentially affected by oils or movement |
Steel | Not suitable | Requires a coating system specifically designed and prepared for metal |
Concrete
Concrete is the preferred substrate for Resafloor HB. It provides a strong, rigid surface capable of supporting a durable epoxy coating.
Before application, the concrete must be:
Sound and structurally stable
Sufficiently cured
Dry enough to receive an epoxy coating
Free from oil, grease, dust and contamination
Mechanically prepared to remove laitance and expose a clean surface
A resin floor can only perform as well as the substrate beneath it. Weak or contaminated concrete must therefore be repaired or removed before Resafloor HB is applied.
Sand and cement screeds
Traditional sand and cement screeds can also provide a suitable base. The screed must be strong, securely bonded and free from loose or friable material.
Weak screeds may break down beneath the coating even if the epoxy remains bonded to their surface. Cracks, hollow areas and damaged sections should be investigated and repaired before coating.
Cementitious flowing screeds
Some flowing screeds are cement-based and may be suitable for Resafloor HB after the necessary moisture, strength and preparation checks.
However, not every flowing or self-levelling material is a suitable cementitious substrate. The product type and composition must be identified rather than assumed from its appearance.
A suitable cementitious flowing screed must be:
Fully cured and sufficiently dry
Strong and securely bonded
Free from weak surface laitance
Mechanically prepared before coating
Timber floors and mezzanines
Timber and boarded mezzanine floors can sometimes be coated, but they are not recommended or tested substrates for Resafloor HB.
Unlike concrete, timber can flex, move at joints and expand or contract as environmental conditions change. A rigid epoxy coating may not accommodate this movement, potentially resulting in visible joints, cracking or delamination.
Successful previous examples do not guarantee that another timber floor will behave in the same way. Applying Resafloor HB to timber should therefore be regarded as an untested use rather than a standard recommendation.
Old bitumen-based screeds
Traditional bituminous screeds have occasionally been coated successfully, but their composition and condition can vary significantly.
They may be softer and more flexible than the epoxy placed above them. Oils, historic contamination or movement within the material may also affect adhesion and long-term performance.
Old bitumen-based screeds are therefore not recommended or tested substrates for Resafloor HB, even where coating them appears physically possible.
Latex screeds and smoothing compounds
Latex screeds and latex-based smoothing compounds are not suitable substrates for Resafloor HB.
These products can vary considerably in composition, thickness, strength and adhesion to the floor beneath them. A resin coating applied over a weak or unsuitable smoothing layer remains dependent on that layer’s bond and mechanical strength.
Where latex material is present, it should not be treated as a suitable base simply because its surface appears smooth and sound. The floor should be assessed and the unsuitable layer removed to expose an appropriate cement-based substrate before applying Resafloor HB.
Tarmac and asphalt
Tarmac and asphalt surfaces are not suitable for Resafloor HB. These materials are comparatively flexible and may move, soften or release oils that interfere with a rigid epoxy coating.
A successful initial bond would not remove the risk created by movement or instability within the substrate.
Steel
Resafloor HB is a flooring product intended primarily for cement-based substrates, not a protective coating system for steel.
Metal surfaces require their own preparation standards, corrosion protection and metal-compatible coating specification. Resafloor HB should therefore not be selected for steel floors or plates.
Choosing the right substrate for Resafloor HB
Concrete and sound cement-based screeds offer the best combination of strength, rigidity and predictable adhesion. They are therefore the recommended substrates for Resafloor HB.
Timber and legacy bitumen-based screeds may be physically coatable, but their variable condition and movement introduce risks that have not been tested within the standard Resafloor HB specification. Latex screeds, tarmac and steel should not be coated with this system.
If the existing floor is concrete or cement-based, properly assessing and preparing it creates the most reliable foundation for a durable Resafloor HB finish.