Cleaning Blackened Clay Roofing Tiles

Procedure code:
732102S
Source:
Gra Research File - Clay Roof Tile
Division:
Thermal and Moisture Protection
Section:
Clay Tiles
Last Modified:
06/29/2017

PART 1---GENERAL

1.01 SUMMARY

  1. This procedure includes guidance on cleaning blackened clay roofing tiles.
  2. Clay tile may become discolored or blackened due to any of the following:
    1. Dirt build-up from air pollutants
    2. Organic growths such as lichen, algae or moss
    3. Industrial pollutants

PART 2---PRODUCTS

2.01 MATERIALS

  1. Household detergent, household ammonia, weed killer, or mixture of zinc or magnesium and water.
  2. Clean, potable water

2.02 EQUIPMENT

  1. Stiff bristle brush
  2. Ladder
  3. Garden sprayer/garden hose
  4. Medium or coarse long handled vegetable fiber brushes

PART 3---EXECUTION

3.01 PREPARATION

  1. Surface Preparation:
    1. Sweep down tile to remove dirt and debris. Use a long handle broom or brush with more rigid bristles which do not scratch the tile surface.
    2.  Pick up and bag the debris washed from the tile such as leaves, dirt, and other litter from the gutter and clean gutter at the same time.

3.02 ERECTION, INSTALLATION, APPLICATION

  1.  For Dirt and Pollutant Crusts: Scrub the tile by hand with water and a stiff bristle brush.
  2. . For Organic Growth:
    1. Remove growth with a stiff bristle brush and clean water.
    2.  Apply detergent, household bleach, weed killer or use a solution of zinc or magnesium and water.
    3.  Rinse thoroughly with clean, clear water.
  3. For Industrial Stains: Clean with a water-based household detergent and a stiff bristle brush.

END OF SECTION

Last Reviewed 2017-06-29