Cement residue with rust stains after construction

New stone floor or wall after tiling/grouting, where cement haze covers the surface and metal tools or rebar have left rust marks

Why order matters

When two problems appear together, the treatment order is critical. Using the wrong product first can spread stains, neutralise chemicals, or cause new damage. Follow these steps in order.

Treatment Steps

1. Step 1: Cement Residue

   Product: Lithofin MN Builders' Clean or Lithofin CEMENT-AWAY

   Why this order: Cement haze covers the surface - rust treatment cannot reach the stain through the cement layer. Cement removal also reveals the full extent of any rust stains.

   Method: Pre-wet the surface. Apply product diluted 1:3 to 1:10 (stronger on acid-resistant stone). Leave 5-10 minutes. Scrub with nylon brush. Rinse thoroughly.

   Wait: Rinse and dry completely - at least 4-6 hours

2. Step 2: Rust Stains

   Product: Lithofin Rust-EX

   Why this order: With cement removed, rust stains are now exposed and accessible. Rust-EX works by chemical reaction - it needs direct contact with the iron oxide.

   Method: Apply Rust-EX directly to rust stains. Leave 15-60 minutes depending on severity. For deep stains: poultice with cotton wool, cover with cling film, leave 4-12 hours. Rinse thoroughly.

   Wait: Allow to dry 24 hours before sealing

Warnings

• Never mix cement remover and rust remover - always rinse and dry between steps
• On marble/limestone: use diluted Builders' Clean (1:5 minimum) and work quickly
• Remove the source of rust (metal objects, iron filings) before treatment