Photography and Editorial by: Dr. Christopher Cooper
Many times I come across houses that have been painted and many of our subscribers ask what to do with the painted bricks and in some case, how you can remove the paint from the brick? The answer to the last question is there is really no way in removing the paint entirely from the brick without damage. Abrasive cleaners (for example any type of blasting or pressure washing) are never recommended as it simply destroys handmade bricks! Chemical cleaners are another real problem as it can chemically affect the brick itself causing problems in the future. The biggest problem with paint removal is that the final look is terrible as it is usually polka-dotted with paint that is deep in small fishers and dints in the original brick units!
It is also necessary to consider why the building was painted in the first place? Was the building painted to protect soft brick? Was it to cover poorly executed repointing or unmatched repairs? Or, was the painted masonry simply a fashion statement in a particular historic period (for example the Regency Period)?
The crumbling brick above is to the absolute extreme. If brick has spalled this badly, I would recommend wholesale removal of the paint (by scraping) a complete repointing with the possibility of turning the badly spalled bricks around (or replace the unit wholesale) and prime with a breathable primer and topcoat with several layers of high quality 100% acrylic latex.
One of the best protections against failing or spalling brick is to paint, there is no such thing as a water-proofer or sealer! Simply bricks must breathe, if they do not they will spall (in freezing temperatures) as a result of trapped water behind the so-called sealer caused by capillary action from ground source or from the interior of the building.
Water or moisture in a masonry system will generally hamper the satisfactory performance of the painted surface; therefore strict water management will have to be adhered to before any work is to proceed. Search for the water’s source and take the necessary corrective measures to keep water out of the wall.
The chemical property of masonry which may have a significant effect on paint durability and performance is the alkalinity of the wall. Bricks are normally neutral, but are set in mortars which are chemically basic. Paint products, which are based on drying oils, may be attacked by free alkali and the oils can become saponified (converts to soap). To prevent this occurrence, an alkaline-resistant primer is recommended.
The deposit of water-soluble salts on the surface of masonry, “efflorescence”, is another factor that can hamper the performance of painted masonry. Remove all efflorescence by scrubbing with clear water and a stiff brush.
The key to a good masonry paint job is preparation. Proper surface preparation is as important as paint selection. Thoroughly examine all surfaces to determine the required preparation. Remove all peeled, cracked, flaked or blistered paint by scraping. Like efflorescence, paint blistering is caused by water within the masonry. If alligatoring exists, remove the entire finish. There is no other means of correction.
Previously painted surfaces often require the greatest effort. Before painting, remove all loose paint. Take special care when cleaning surfaces for emulsion paints and primers (latex). They (latex paints) are non-penetrating and require cleaner surfaces than solvent-based paints (oil). Latex paint is preferred over oil because of latex’s ability to breathe! Be sure to follow directions accompanying the paint product.
After the wall is completely painted there are ways to mimic brick with mortar. Penciling is a technique of painting the mortar joints, which is a purely decorative process, often in a contrasting colour or mortar colour. A regular course of maintenance with periodic spot repairs can provide a very attractive and durable finish for years to come.
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