Pro Limestone Consolidate + Protect
A water-based nano-consolidant and water repellent for friable limestone. Penetrates, re-binds, sheds water, stays breathable.
5 L and 15 L pails,
studio, raking light
We currently ship within Malta only.
For orders outside Malta, including trade and distribution enquiries, get in touch and we’ll arrange it directly.
How it works on the stone
Weathered franka loses its binder. The calcite that held the grains together dissolves and washes out, and what's left is a surface that powders under a thumbnail and comes away under rain.
Consolidate + Protect is carried into that damaged zone in water. It penetrates 12 to 18 millimetres, then cures to bind loose grains back to the sound stone beneath. Drilling resistance testing shows surface cohesion increasing by around 180%.
The same treatment leaves the surface water-repellent — capillary absorption drops by 87%, so driven rain sheets off rather than soaking in. Vapour permeability is unaffected: at Class V1 with an sd of 0.08 m, moisture inside the wall leaves through the face exactly as it did before.
That combination is the whole point. Most products do one or the other. Sealers protect and suffocate. Consolidants strengthen and leave the stone as absorbent as it was.
Supplied ready to use — do not dilute.
Living with it
No solvent, no odour, no fumes. Windows stay shut, the family stays put, and there is nothing to ventilate afterwards. Tools and overspray clean up with water.
Touch dry in an hour, rain-free after six, fully cured in seven days. There is no curing smell and no period where the wall cannot be touched.
Because nothing sits on the surface, there is no film to peel, crack, yellow or blister. When the water repellency eventually fades, you reapply over the top — there is nothing to strip first.
| Substrate | Suitable | Notes |
|---|---|---|
| Globigerina limestone (franka) | YES | Primary application. All conditions from sound to highly friable. |
| Coralline limestone (żonqor) | YES | Lower absorbency — expect coverage at the upper end of the range. |
| Sound lime render | YES | Must be fully cured, minimum 28 days. |
| Cement render | LIMITED | Test patch essential. Low absorbency limits penetration. |
| Painted or previously sealed surfaces | NO | Must be fully stripped first. The treatment cannot penetrate a film. |
| Walls with active rising damp | NO | Not a damp treatment. Address the source before treating the surface. |
| Gypsum or internal plaster | NO | Not formulated for internal finishes. |
| Stone condition | Per coat | 5 L covers | 15 L covers |
|---|---|---|---|
| Sound | 5–7 m²/L | 25–35 m² | 75–105 m² |
| Moderately friable | 3.5–5 m²/L | 17–25 m² | 52–75 m² |
| Highly friable | 2–3.5 m²/L | 10–17 m² | 30–52 m² |
Two coats standard. Figures are per coat — halve them for a two-coat job. Absorbency varies significantly across a single elevation. Buy to the upper figure.
Always test first. Here's why.
On highly absorbent stone the treatment can slightly lighten the surface. Measured colour change is typically ΔE 2.1 or below — not visible unless you're comparing treated and untreated stone side by side — but it can reach 3.4 on the most porous material, where it becomes perceptible.
So test. Half a square metre in an inconspicuous spot, two coats, left seven days to cure fully. Then look at it in the same light you'll see the finished wall in.
The 1 L test kit exists for exactly this. It covers 2 to 7 m² depending on condition, which is enough to test several areas of one elevation.
On a treated elevation with no ongoing water ingress, expect 10 to 15 years before the water-repellent effect needs renewing. The consolidation is permanent.
Only if that treatment has fully weathered away. Anything film-forming has to come off first.
Find out why, and fix that first. This product does not treat rising damp, penetrating damp or condensation, and applying it to a wet wall wastes the material.
Not with a conventional masonry paint — you’d undo the breathability. Mineral silicate paints are compatible.
Low-pressure spray or brush, wet-on-wet, until the stone stops absorbing. Full method in the application guide.