Sensitive Substrates
The Proper Cleaning Process for Sensitive Substrates
Subject: Removing excess mortar (post construction)
Product: NMD 80 (new masonry detergent) or SOS-50 (Non-Corrosive new masonry detergent)
Use NMD 80 or SOS-50 to clean these surfaces at a 4:1 dilution ratio (4 parts water to 1-part product).
Apply the product with a low-pressure application through an EC Jet or low-pressure pump-up applicator. Always read over the specification sheet for details concerning the use of the EC Jet.
Exterior Application:
- Prewet wall with water (do not soak).
- Apply NMD 80 or SOS-50 (at a 4:1 dilution ratio) from the top down. Let dwell up from 3 – 5 minutes. Note that dwell time is determined by substrate and environmental conditions. Do not allow product to dry on the surface.
- If necessary, use a metal or plastic scraper to gently scrape wall after the first chemical application. Do not chip at or dig into the surface with the scraper. Keep scraper at a low angle to the wall. Do not brush surface-dyed brick or block because brushing can cause color bleed. Do not brush ground face and/or burnished block. The grit from removing the excess mortar will scratch the surface.
- Reapply NMD 80 or SOS-50 at a 4:1 dilution after a 3-5 minutes dwell time without rinsing. Let dwell for an additional 3 – 5 minutes without letting the chemical dry on the wall.
- Rinse making sure each pass is even. For optimal efficiency use a pressure washer in the 3 -5 gallons per minute range with a 40º tip using no more than 300 p.s.i. Hold wand 8-12 inches from the wall when rinsing. A space rod attached to the rinsing nozzle will help keep the rinsing distance the same. Never use a zero, 15º, or rotating zero-degree nozzle.
Important: Do not use high pressure or aggressive scrubbing on any sensitive substrates Use either a garden hose rinse or an equivalent with a pressure washer. Don’t use more than 300 p.s.i.. Another option is to close the shut off valve on the EC Jet to use it as low-pressure rinse tool.