Cleaning bricks with sandblasting techniques can be the perfect solution or a nightmare!
Dry sandblast cleaning is a relatively new method of cleaning recently built masonry, In spite the system has been used for many years in masonry restoration work.
Most experts prefer sandblasting over conventional wet (acid) cleaning because of possible adverse acid reactions with certain types of brick. Other designers are reluctant to permit sandblast cleaning from fear the blasting will erode the face of the brick and mortar joints. Nevertheless, with a qualified operator, proper specifications and good job inspection, sandblasting bricks is as good as any other system and is sometimes superior in many ways.
This is my recommended procedure for Sandblasting bricks:
- Wait for mortar to harden. Brickwork should be completely dry and at least seven days old, preferably 14 days.
- Remove all large mortar particles with hand tools before blasting. Use wooden paddle, the rough edge of a brick, or metal scrape hoe. Chisels may be used if necessary to remove hardened mortar or concrete. This “pre-cleaning” is a very important part of sandblast cleaning. Sandblast operator would irreparably damage wall if large droppings are left for him to remove by blasting.
- Provide adequate protection for all non-masonry surfaces adjacent to work areas, Use plastic sheeting and duct tape to protect windows, doors, etc. If possible, painting, caulking, etc. should be done after sandblast operation is completed.
- When all surfaces are prepared and protected, the operator can begin a first test cleaning.