Knowledge Base

Surface Preparation

Every Raised Access Floor Requires a Sound Foundation

No pedestal adhesive, regardless of its quality, can compensate for a poor concrete surface or unsuitable pedestal.

The performance of any bonded system is ultimately determined by the condition of the surfaces being joined. Even the most advanced adhesive will only perform as well as the substrate to which it is applied.

For this reason, correct surface preparation should always be considered one of the most important stages of any installation. Spending a little extra time preparing the substrate will maximise bond strength, improve long-term durability and help prevent costly failures later.

Achieving the Correct Surface Profile

A clean surface alone is not always sufficient and whilst rare, a surface that has been finished with a power float or a vibratory compactor can also result in adhesion problems.

For optimum adhesion, smooth concrete should be mechanically prepared to provide an appropriate surface profile.

Typical preparation methods include:

Diamond grinding
Shot blasting
Mechanical abrasion
Acid etching (where appropriate and carried out safely)

The aim is to produce a clean, sound surface with a Concrete Surface Profile (CSP) of approximately 2–3, providing sufficient texture for the adhesive to achieve maximum mechanical and chemical bonding.

If there is any question about the suitability of a surface, the standard T42 Swing bag test should be conducted prior to any installation.

Remove Contamination

Pedestal adhesives are required to bond to the surface beneath them—not to contaminants sitting on top.

Any contamination should be completely removed before installation, including:

Dust
Oil
Grease
Paint
Existing coatings
Bitumen residues
Adhesive residues
Surface laitance
Release agents

If contamination remains, the adhesive may bond to the contaminant rather than the concrete itself, significantly reducing bond strength.

Repair Defects Before Bonding

Surface preparation is also the ideal opportunity to identify any defects within the concrete.

Cracks, spalled areas, weak concrete or damaged sections should be repaired using appropriate concrete repair products (Such as StarPolymers LEVEL-FIX) before pedestal installation begins.

Adhesives are designed to bond structurally sound materials together however, they are not intended to compensate for poor-quality or deteriorating substrates.

Preparing Steel Pedestals

The underside of each steel pedestal should also be inspected before installation.

Pedestal bases should be completely free from:

Oil
Grease
Rust
Dirt
Dust
Manufacturing residues

During the manufacturing process, some pedestal finishes can leave microscopic conversion coating residues on the metal surface. These residues may reduce the ability of the adhesive to achieve maximum bond strength if left untreated. In this instance, the adhesive will bond to the concrete but not bond to (or leave much adhesive on) the base of the pedestal. Modern trivalent chromium and zinc-nickel phosphate conversion coatings generally provide excellent adhesion characteristics and are considered the preferred finishing treatment for raised access flooring pedestals.

Dust Control with StarFix SEAL-ZERO

Concrete floors, particularly older subfloors, can often produce loose surface dust that interferes with adhesive application.

StarFix SEAL-ZERO has been developed to penetrate and bind residual surface dust, helping to create a cleaner working environment while improving the consistency of adhesive application.

However, it is important to understand what StarFix SEAL-ZERO is—and what it is not.

StarFix SEAL-ZERO is:

A penetrating dust suppressant
A concrete dust sealer
A surface stabiliser for otherwise, sound concrete

It is not:

A concrete repair product
A method of strengthening weak or deteriorating concrete
A way of bonding to unsound substrates

If the concrete is weak, contaminated or damaged, the underlying issue must always be corrected before StarFix SEAL-ZERO is applied.

A useful rule to remember is:

"An adhesive bond is only as strong as the surface to which it is bonded."

If the concrete surface fails, the adhesive will remain attached to the concrete that has broken away. Likewise, if contaminants remain between the adhesive and the substrate, the bond can only ever be as strong as that contamination layer.

Proper surface preparation ensures the adhesive bonds directly to clean, structurally sound material, allowing it to deliver the exceptional performance for which the StarFix range has been engineered.

In the very rare event of a bonding failure, the reason for a failure is often easily identified:

The pedestal adhesive remains stuck to the pedestal but not the concrete:

Likely cause - The concrete base does not meet the minimum specification for an adhesive or coating.

The pedestal adhesive remains stuck to the concrete but not the pedestal:

Likely cause - The pedestal is contaminated with grease or manufacturing conversion coating residues.

The pedestal adhesive remains stuck to both the pedestal and concrete base:

Likely cause - The adhesive has failed and is not performing as expected.

Best Practice Checklist

Before applying any StarFix product, always ensure:

✓ Concrete is structurally sound and fully cured.
✓ All dust, laitance, grease, oils and contaminants have been removed.
✓ Smooth concrete has been mechanically prepared to provide a suitable surface profile.
✓ Damaged concrete has been repaired using appropriate repair materials.
✓ Steel pedestals are clean and free from grease, rust and manufacturing residues.

By following these simple principles, you will maximise bond strength, improve installation quality and ensure your StarFix adhesive system delivers reliable long-term performance.