Brick Acid Cleaning in Hawthorn

We use multiple dilutions depending on brick type: 1:10 for fresh red clay brick mortar smear, 1:20 or weaker for cream and buff brick, and often non-acid chemistry for heritage brick. The dilution is never a default — it is chosen after assessing the brick type and age. We tell you the dilution we plan to test before we come on site.

Brick colour and texture vary even within the same area — a "red brick" in one subdivision may have different iron content than a "red brick" two streets over. The test panel confirms the specific brick on your site will not yellow, streak or show any colour shift with the proposed dilution. This single step prevents acid burn.

We inspect the test panel 24 hours later in dry weather. If it has passed (no colour shift, no yellowing), we'll then confirm the timing for the production work with you. If the test panel shows any concern, we drop the dilution or switch to non-acid chemistry before touching the rest of the wall.

After the acid has dissolved the mortar smear, a final rinse with bicarbonate or alkaline solution stops the acid reaction at the right point. Without this step, residual acid continues to work inside the brick and mortar, sometimes causing salt blooms or efflorescence to re-emerge weeks later. The neutralising rinse prevents this.

Fresh mortar smear lifts cleanly with acid within 4–6 weeks of laying. Older stains that have been on the wall for months or years — especially if they are not pure mortar smear but are organic growth, pollution film or embedded dirt — may not respond to acid alone. A pre-treatment detergent, longer dwell time or combination soft-wash approach may be needed.

Every acid wash is quoted as a written fixed price from your photos, based on wall area, storeys, access and brick type. A test panel is part of every job and is essential on cream brick. Send wide shots of each elevation and a close-up of the staining.

Yes, when done by licensed professionals with proper safety equipment, protective measures and chemical handling certification. Hydrochloric acid is caustic and must be handled by trained professionals. DIY acid cleaning carries significant risks of personal injury and acid burn to the brickwork. Always hire a professional for acid-based cleaning.

Fresh mortar smear comes off completely with acid. If staining persists after acid cleaning, it is usually not mortar smear — it is algae, pollution film, or embedded grime that needs a different treatment. We assess the stain type from photos before quoting and tell you what to expect.