Stronger Cement Mixes. Better Plaster Adhesion. Natural Wall Finishes.

BONDPRO

Plaster Primer & Bonding Liquid

Appearance

White
Dries Near-Clear

Covarage

5-8m² per litre per coat

Available Sizes

A multi-purpose co-polymer bonding liquid that makes cement and plaster mixes stronger, prepares newly plastered and repaired walls for painting, and seals steel trowel concrete walls to a natural near-clear finish — without the sheen.

What sets BondPro apart from standard bonding liquids:

BondPro is a co-polymer bonding liquid formulated at half the strength of SealPro's Penetrar — purpose-built for wall and plaster applications where a lower-strength, near-clear-drying product is needed. Unlike standard PVA bonding agents that re-emulsify when wet, BondPro remains stable once cured and is specified for both interior and exterior use.

Usage

Added to cement and plaster mixes as an admixture — replaces part of the gauging water to improve adhesion, strength, and flexibility of the mix

Priming newly plastered walls before painting — binds the surface, normalises absorption, and reduces alkalinity so paint bonds evenly

Preparing repaired plaster sections before painting — consolidates the repair and prevents differences in absorption between old and new plaster from showing through

Sealing steel trowel concrete walls and polished concrete feature walls to a natural near-clear finish — no sheen, maintains the raw concrete look

Priming smooth, non-porous, or previously painted surfaces before replastering — reduces the need for hacking and chipping

HOW IT WORKS

Specialised Plaster Primer for strong adhesion

BondPro is a multi-purpose co-polymer bonding liquid with three distinct, well-defined uses in plastering, wall preparation, and decorative concrete finishing. In each application it works the same way — by introducing flexible polymer chains into the cement or plaster matrix, or onto the substrate surface, to improve adhesion, increase strength, and control how the material above it bonds and cures.

As a cement and plaster admixture, BondPro replaces part of the gauging water in the mix. The polymer integrates into the cement matrix as it hydrates, improving the bond between the mix and the substrate, increasing tensile and flexural strength, reducing shrinkage cracking, and improving workability. The result is a plaster or repair mortar that bonds more reliably, is less prone to cracking, and achieves a more durable finished surface — all without changing the mixing or application method.

As a plaster wall primer before painting, BondPro is applied to newly plastered or repaired wall surfaces before any painting system is applied. Fresh plaster is highly porous and alkaline — two conditions that cause paint applied directly to it to absorb unevenly, bond poorly, and peel prematurely. BondPro penetrates the plaster surface, binds loose particles, normalises the absorption profile, and reduces surface alkalinity so that paint bonds evenly across the entire wall. On repaired sections in an existing painted wall, it eliminates the suction difference between old and new plaster that would otherwise show through the topcoat as a visible patch.

As a steel trowel wall sealer, BondPro is applied in diluted form to polished concrete and steel trowel feature walls to seal the surface against dust, moisture, and minor staining — while drying to an almost completely clear film with virtually no added sheen. This makes it the right product for the growing market of interior designers and homeowners who want to maintain the raw, natural look of a steel trowel or polished concrete wall without altering its character with a glossy or semi-gloss sealer.

Application tip:

As a plaster primer, apply BondPro to the damp plaster surface and allow to dry before painting — do not apply to bone-dry plaster without first lightly wetting the surface. As a steel trowel wall sealer, apply in two thin coats in opposing directions to ensure even coverage without pooling. As an admixture, replace 20–30% of the gauging water with BondPro — do not over-add as this can over-plasticise the mix.

KEY BENEFITS

Why BondPro Is The Preferred Choice

BondPro addresses three common building and finishing problems that standard PVA bonding agents, cement admixtures, and wall primers each solve partially — but rarely all together in one product.

1/ Stronger, More Adhesive Plaster Mixes

BondPro integrates into the cement matrix as it hydrates, forming flexible polymer chains that improve bond strength between the plaster and the substrate. On smooth or difficult surfaces — painted walls, glazed concrete, precast panels — this improved adhesion eliminates the need for hacking or chipping before replastering.

2/ Reduces Shrinkage Cracking in Plaster

Polymer-modified plaster shrinks less during curing than a mix gauged with water alone. BondPro adds flexibility to the set plaster matrix, reducing the micro-cracking that commonly appears as plaster dries in South Africa's hot, dry conditions — particularly relevant for exterior plastering in summer months.

3/ Normalises Absorption on New & Repaired Plaster

Fresh plaster absorbs paint at a very different rate to older, cured plaster — causing visible patches, uneven sheen, and poor coverage wherever repairs have been made. BondPro applied as a primer to new and repaired plaster sections normalises the absorption profile across the entire wall so paint dries evenly with no visible join between old and new.

4/ Reduces Alkalinity — Prevents Paint Failure

New plaster and fresh cement are highly alkaline. Paint applied to untreated new plaster is attacked by this alkalinity, causing saponification, colour change, and peeling. BondPro reduces the surface alkalinity of new plaster before painting begins, protecting the paint system from alkali attack and extending its service life.

5/ Dries Near-Clear — No Sheen Added

BondPro is specifically formulated to dry to an almost completely clear film with virtually no sheen — unlike Penetrar, which can leave a low sheen, and unlike most standard bonding liquids which can create a glossy film on smooth surfaces. This makes BondPro the right choice wherever the natural look of the substrate needs to be preserved, particularly on steel trowel and polished concrete walls.

6/ Improves Bond Without Affecting Mix Design

BondPro simply replaces part of the gauging water in the mix — no change to mixing method, application technique, or materials is required. Plasterers and repair teams work with their existing process; BondPro makes that process produce a better-bonding, stronger result without adding complexity or specialist skills to the job.

7/ Will Not Re-Emulsify When Wet

Unlike standard PVA bonding agents, BondPro does not re-emulsify when exposed to moisture after curing. This makes it suitable for exterior wall plaster applications, bathrooms, and wet areas where a PVA-based bonding agent would break down. Once cured, BondPro remains stable and water-resistant.

8/ Water-Based, Low VOC & Safe Indoors

Water-based, non-flammable, virtually odourless, and with a VOC content below 1%. BondPro is safe to use indoors on occupied sites, in bedrooms and living spaces, without requiring ventilation or site clearance. No solvents, no fumes, no disruption — ideal for occupied residential renovations and commercial refurbishment work.

GETTING STARTED

COLOUR & APPLICATION

STANDARD COLOURS

This product is white in colour and dries to an almost clear finish.

BondPro is a milky white liquid in the container. Unlike Penetrar, which can leave a low sheen on the surfaces it is applied to, BondPro dries to an almost completely clear film with virtually no sheen — designed specifically for applications where the substrate's natural look needs to be preserved. On steel troweled, polished, and off-shutter concrete walls, this means the raw concrete character is maintained after sealing.

(*) Disclaimer

While SealPro makes every effort to ensure that colours shown on this website, match paint colours as closely as possible, variations may occur due to a variety of factors. Always paint a test patch of the selected colour on your wall. For consistency of sheen and colour, always check that paint containers carry the same batch number.

APPLICATION

Brush, roller or airless spray. Touch dry in 1-2 hours. Re-coat after 6-12 hours

Where BondPro Is Used

REAL-WORLD APPLICATIONS.

BondPro is designed for three use cases in the plastering, painting preparation, and decorative concrete market — each with its own requirements that standard bonding liquids do not fully address.

01 · Cement & Plaster Admixture

Stronger Cement & Plaster Mixes

BondPro is added to cement and plaster mixes in place of part of the gauging water, producing a polymer-modified mix with improved adhesion to the substrate, increased tensile and flexural strength, better resistance to cracking, and enhanced workability. BondPro is the preferred choice due to it being formulated as a co-polymer product at the correct strength for wall plaster and repair mortar applications. Use it on smooth surfaces where the plaster would normally not adhere without cracking — BondPro eliminates the need to chip or roughen the surface.

BondPro Plaster Wall Primer · Before Painting

02 · Plaster Wall Primer · Before Painting

Newly Plastered & Repaired Walls Before Painting

Fresh plaster is highly porous and alkaline — painting it directly causes uneven absorption, alkali attack, and premature paint failure. BondPro is applied to newly plastered walls before the painting system begins, penetrating the surface to normalise absorption and reduce alkalinity. On repaired sections, it eliminates the suction difference between patched and original plaster, ensuring that the topcoat dries uniformly across the entire wall. This is the core function of Plasterkey in the South African market — BondPro performs the same role as part of the SealPro painting system.

03 · Off-Shutter Concrete Wall Sealer · Natural Look

Off-Shutter Concrete & Polished Concrete Walls

Off=Shutter Concrete and polished concrete feature walls are a growing trend in South African residential and commercial interiors. These walls need to be sealed against dust, moisture ingress, and minor staining — but most available sealers add a sheen that alters the natural look. BondPro is applied in a diluted form and dries to a near-clear film with almost no sheen, preserving the raw concrete character of the wall while providing practical surface protection. This use case has no direct South African equivalent at this price point and positioning — making it a unique market position for BondPro.

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SPECIFICATIONS

EVERYTHING YOU NEED TO KNOW.

1/ PRODUCT INFORMATION

Downloadable product information data sheets.

Product Information

Download PDF (0.60 Mb)

2/ APPLICATION METHOD

Downloadable product method statement.

Product Method Statement

Download PDF (0.54 Mb)

TIPS & ADVICE

Common Questions About BondPro.

What does adding a bonding liquid to cement do?

Adding BondPro to a cement or plaster mix in place of part of the gauging water improves the adhesion of the mix to the substrate, increases tensile and flexural strength, reduces shrinkage cracking, and improves workability — producing a stronger, more durable plaster that bonds more reliably to smooth or difficult surfaces.

Do I need to prime a newly plastered wall before painting?

Yes — always. Fresh plaster is highly alkaline and porous. Paint applied directly to new plaster absorbs unevenly, bonds poorly, and is attacked by alkali — causing colour change and peeling. BondPro primes the surface, normalises absorption, and reduces alkalinity so that paint bonds evenly across the full wall.

How do I seal a steel trowel wall without adding sheen?

Apply BondPro diluted 1:4 with water in two thin cross-coats. It dries to a near-clear film with almost no added sheen, sealing the surface against dust and moisture while maintaining the natural raw concrete look. Test a small area first to confirm the finish meets your requirements before full application.

What is the difference between BondPro and Penetrar?

BondPro is formulated at half the strength of Penetrar for wall preparation, plaster admixture, and decorative concrete sealing applications. Penetrar is the higher-strength product designed for deep capillary penetration in porous substrates before waterproofing, tile roof painting, or tiling. Each product has a different strength and finish — BondPro dries near-clear with no sheen; Penetrar can leave a low sheen on surfaces it is applied to.

Is BondPro safe to use indoors in an occupied home?

Yes. BondPro is water-based, non-flammable, virtually odourless, and has a VOC content below 1%. It is completely safe to use indoors on occupied residential and commercial properties without ventilation requirements, fire precautions, or disruption to occupants.

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