Polished concrete floors: slab or overlay?

What is the difference between polished concrete and an overlay?

A conventional ground-and-polished concrete floor exposes and finishes the concrete slab. Its appearance depends on the concrete mix, aggregate and condition of that slab. An overlay adds a separate decorative surface over a supporting floor.

Puur PSR is a polymer-modified, fibre-reinforced cementitious overlay with a power-floated concrete-style finish. It is not a structural slab and should not be confused with Puur Mono resin flooring. Its natural shade and patina can vary with installation conditions.

How thick is a Puur PSR polished concrete overlay?

The standard PSR installation is approximately 6mm. This thin build-up can be useful when assessing a refurbishment, but it still adds material and height: thresholds, doors, transitions and structural loading need checking.

Puur’s product page and SD21 technical documents describe different permitted thickness ranges. Ask the technical team to confirm the applicable build-up for your substrate rather than treating a published range as approval for every project.

Can an overlay go over an existing floor?

Puur lists substrates including screed, tiles, ply and cement boards, subject to the correct preparation. Suitability depends on the condition, stability and moisture of the supporting floor, not simply its material name.

A survey should identify cracks, contamination, movement and transitions before a system is agreed. Overlaying a floor does not remove the need to address substrate defects or movement joints.

Which system suits retail and commercial office floors?

Consider an overlay where you want a concrete-style finish but cannot use the existing slab as the finished surface. Consider ground-and-polish where a suitable slab is already part of the design and its appearance is acceptable.

Puur’s product information describes seamless PSR pours of up to 1,000m². Actual layouts, joints and pour sizes require a project-specific design. The published SD21 data lists R12 dry and R11 wet slip ratings; these are not a blanket safety guarantee for every finish or environment.

What about colour, timing and cost?

PSR can be pigmented to RAL Classic or NCS colours. Approve a physical sample for colour, sheen and natural variation: a screen preview is not a colour standard.

Do not assume an overlay is always cheaper or faster. Preparation, repairs, access, area, sealing and protection all affect the quote and programme. Ask for an installation and handover schedule for your job, rather than relying on a touch-dry time.

What should you send for a specification?

Send drawings and floor areas, the existing substrate and condition, proposed use, desired colour and finish, movement-joint layout and any programme constraints. Request the current technical data and specification alongside your samples.

• Agree substrate preparation and moisture requirements.
• Confirm the complete floor build-up, finish and sealer.
• Confirm joints, transitions, slip requirements and cleaning regime.
• Agree protection and handover before follow-on trades arrive.