Repair Systems — 03 — Facade & External Envelope
Phosphoric acid brick cleaner
Technical product reference for phosphoric acid brick cleaner for masonry facade remediation on Australian Class 2 strata buildings. Gentler than hydrochloric acid — suitable for clay brick and calcium silicate brick — removes lime bloom, calcium carbonate staining, and efflorescence. Pre-wetting mandatory; PPE required; flush thoroughly to remove phosphate residue before any subsequent coating.
What is phosphoric acid brick cleaner?
Phosphoric acid brick cleaner is a gentler alternative to hydrochloric acid for removal of lime bloom, calcium carbonate staining, and efflorescence from clay brick, calcium silicate brick, and concrete masonry on Class 2 strata buildings. Lower fuming, slower acting, and less corrosive than HCl — making it more appropriate where occupied areas, calcium silicate substrates, or limited ventilation preclude the use of hydrochloric acid. Pre-mixed formulations with surfactant additions are available from trade and hardware supply nationally.
Product Reference
2 product systems — phosphoric acid brick cleaner — scroll to view all
Phosphoric acid brick cleaner — pre-mixed formulation
Phosphoric acid masonry cleaner — pre-mixed — external brick and concrete
System Description
Parchem Construction Supplies offers a pre-mixed phosphoric acid brick cleaner for removal of lime bloom, calcium carbonate staining, and efflorescence from clay brick, calcium silicate brick, and some concrete masonry on Class 2 strata buildings and commercial structures. Phosphoric acid is significantly gentler than hydrochloric acid — lower fuming, less corrosive, and slower acting — making it more appropriate where occupied areas, delicate masonry surfaces, or softer substrates preclude HCl use. Safer on adjacent materials than HCl but PPE remains mandatory and pre-wetting is still required before any acid application. The pre-mixed formulation eliminates on-site dilution and provides a consistent working concentration with surfactant package to improve wetting and surface contact. Suitable for calcium silicate brick where HCl is prohibited. After dwell time of 2–5 minutes, scrub and flush with large volumes of clean water. Confirm that phosphate residue is fully flushed before applying any paint, sealant, or coating — residual phosphate deposits affect adhesion. Still prohibited on sandstone, limestone, and reconstituted stone.
Technical Properties
- Acid type: Phosphoric acid — pre-mixed at working concentration with surfactant addition for improved wetting
- Application: Brush or low-pressure spray onto pre-wetted masonry — dwell time 2–5 minutes, scrub and flush
- Compatible masonry: Clay brick, calcium silicate brick, and concrete masonry — gentler than HCl on all substrates
Limitations
- Still an acid — PPE mandatory; prohibited on sandstone and limestone which dissolve in acid
- Slower reaction than HCl — may require longer dwell time (2–5 minutes) or repeat applications for heavy mortar smear
- May leave a phosphate residue film if not flushed adequately — check that residue is fully removed before applying paint, sealant, or coating
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
Phosphoric acid masonry cleaner — hardware merchant supply
Phosphoric acid masonry cleaner — hardware supply — external brick and concrete
System Description
Bondall and RLA Polymers manufacture phosphoric acid masonry cleaners distributed through hardware merchants and trade supply outlets nationally for removal of lime bloom, calcium carbonate staining, and efflorescence from clay brick, calcium silicate brick, and concrete masonry on Class 2 strata buildings and residential structures. Phosphoric acid provides a safer alternative to HCl for general facade cleaning where heavy mortar smear is not the primary defect — lower fuming, slower acting, and less damaging to adjacent materials. Pre-mixed at working concentration for trade and hardware supply — available in 2 L, 5 L, and 20 L containers through Bunnings, Mitre 10, and merchant outlets. The same safety requirements apply as all acid cleaners: pre-wet the masonry before application; PPE mandatory; flush thoroughly after treatment to remove phosphate residue before any subsequent coating or sealing. Suitable for calcium silicate brick where HCl would cause substrate damage. Prohibited on sandstone, limestone, and reconstituted stone.
Technical Properties
- Pre-mixed at working concentration — hardware and trade merchant distribution nationally in 2 L, 5 L, and 20 L sizes
- Phosphoric acid with surfactant — gentler than HCl on substrate and adjacent materials while still dissolving calcium deposits
- Suitable for calcium silicate brick (Hebel, Siporex) where HCl is prohibited — confirm with manufacturer TDS before applying
Limitations
- Prohibited on sandstone, limestone, and reconstituted stone — phosphoric acid dissolves calcium-based masonry substrates
- Phosphate residue must be fully removed by flushing before applying paint, sealant, or waterproof coating — residual phosphate affects adhesion
- Not effective on oil, rust, or organic staining — different cleaning chemistry required for these stain types
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
System Comparison
Side-by-side comparison of phosphoric acid brick cleaner supply options. Confirm substrate suitability and flush thoroughly to remove phosphate residue before any subsequent coating.
| Supplier | Product | Concentration | Compatible | Distribution | Key feature | Primary use |
|---|---|---|---|---|---|---|
| Parchem Construction Supplies | Phosphoric acid brick cleaner | Pre-mixed with surfactant | Clay brick + calcium silicate + concrete | Trade / specialist supply | Trade-quality formulation with surfactant | Lime bloom + efflorescence |
| Bondall / RLA Polymers | Phosphoric acid masonry cleaner | Pre-mixed RTU | Clay brick + calcium silicate + concrete | Hardware merchants nationally | Wide hardware availability | General efflorescence + lime stain |
Do not confuse phosphoric acid brick cleaner with:
- Hydrochloric acid (HCl) brick cleaner — significantly more aggressive than phosphoric acid, higher fuming, faster acting; for heavy mortar smear on fired clay brick; never use HCl on calcium silicate brick where phosphoric is the correct choice
- Sulphamic acid efflorescence remover — milder than phosphoric acid, solid crystal form, very low fuming; for light efflorescence only; do not substitute sulphamic for phosphoric when calcium silicate cleaning or moderate staining is the defect
- Alkaline cleaners (TSP, sodium hydroxide, bleach-based) — different chemistry for biological, organic, and carbon staining; do not mix alkaline cleaners with phosphoric acid cleaning products
- Poultice cleaning systems (attapulgite, kaolin, proprietary) — entirely different application method for deep stain extraction; poultice systems are used where surface acid wash cannot remove embedded staining
- Phosphate residue must be fully flushed after phosphoric acid treatment — do not proceed to paint or coating application without confirming the surface is free of phosphate film, which will degrade adhesion
Disclaimer
This page provides general technical information only. Phosphoric acid cleaner selection and application method must be confirmed for the specific masonry type and stain. Never apply acid cleaners to sandstone, limestone, or reconstituted stone. Flush thoroughly to remove phosphate residue before coating. OH&S requirements for chemical handling must be complied with.