Preservation by Prevention: Paint and Historic Brick

Paint flakes and fails when trapped water cannot escape naturally from historically-unpainted brick.

Paint flakes and fails when trapped water cannot escape naturally from historically-unpainted brick.

Winter has arrived! Though this season brings opportunities to celebrate and make merry indoors, it also brings sleet, snow, and ice outdoors. For an owner of a historic brick house, this freeze-thaw cycle can be a cause for concern – particularly if the house’s exterior is painted when it should not have been.

Modern waterproof sealants, coatings, and paints significantly decrease the brick’s natural breathability. Water saturation and decreased breathability trap water in the material, and as the water freezes in the material it expands causing stress cracks and eventually spalling, and ultimately, failure. In unpainted or appropriately-painted brick houses, the porous brick absorbs water from sleet, snow, and ice, and with the material’s proper, natural breathability, the water evaporates, leaving the brick intact despite years of exposure to this cycle.

Some brick houses were supposed to be painted. That said, not all historic brick houses that are currently painted were meant to be painted, let alone covered in some of the waterproof coatings available today. So then, how does one determine which houses were supposed to be painted and which ones were not?

Generally speaking, in the United States, historic brick houses that needed paint were built prior to the 1870s, when the use of strong, machine-made brick became a more widespread practice. Bricks in the U.S. were first made by hand, with clay, sand, and water pressed into molds, then dried and fired. Eventually, brickmaking technology advanced from hand-power to animal-power to water-power to steam-power, and eventually, to the uniform machine-made. The mineral content of the clay and sand determined the color, while application of glazes affected the bricks’ finish.

Houses made from the weaker, softer, and more porous handmade brick of the early periods often required the use of a protective coating for an added layer to combat natural elements, such as the sleet, snow, and ice in the winter months.

By the mid-nineteenth century, advances in brickmaking offered stronger brick options that did not require paint for protection. They featured harder “dress” faces that served as both the construction material and the decoration, never meant to be painted.

Painting Flemish-bond with glazed headers (l) obscures the intended decorative patterning (r).

Painting Flemish-bond with glazed headers (l) obscures the intended decorative patterning (r).

Glazes were used more widely and creatively, forming decorative patterns in the walls. A prevalent example of glazes in brick patterns is with the Flemish-bond. Though the bond type itself dates back to the Colonial period in the U.S., its use with specially glazed bricks became a popular ornamental device in the late-nineteenth century.

Brick houses that were meant to be painted also do not usually feature the non-glazed decorative patterning that many late-nineteenth and twentieth century brick homes have, such as corbelling (stepped pattern below a projected element) and dogtoothing (bricks laid at an angle, so they project diagonally, resembling teeth). If a historic brick house features these types of brick detail, they were most likely not meant to be painted in the first place.

The Secretary of the Interior’s Standards for Rehabilitation expressly do not recommend the painting of historically unpainted brick. Historically unpainted brick was not coated because the materials had sufficient strength without paint and had decorative applications. Because of the damaging effects of water saturation and freeze-thaw cycles, painting historically unpainted brick can eventually destroy the brick. Additionally it requires long-term maintenance, a huge expense best avoided.

For a brick house that should not have been painted, there are a few methods of removal for returning the brick to its historically appropriate state:

  • Let the paint deteriorate naturally. The paint will flake and chip because of the water trying to escape, so make sure you remove paint chips from the ground below. The house may appear unattractive for a period of time, but eventually, the brick will reappear with renewed breathability.
  • Very gently scrape the chipping paint by hand. If the paint does not come off with gentle hand-scraping, do not increase pressure or speed – you want to avoid chipping or removing any of the bricks’ hard outer surface.
  • Sometimes, gel or paste paint removers are appropriate. As with any paint removal method, the guidance of a technical preservation specialist and spot testing are necessary.
Dogtoothing (l) and corbelling (r) with unpainted tan and yellow brick.

Dogtoothing (l) and corbelling (r) with unpainted tan and yellow brick.

If you have a painted brick house that would have been painted historically (i.e., one with weak bricks built before mid-nineteenth century and devoid of brick decorative detail), do not remove the paint. Appropriately-painted historic brick houses require the paint for protection, and there are options for responsible maintenance. While it is usually recommended to paint the painted brick with the same kind of paint it already has, even if it is modern, it is best to avoid fully waterproof coatings. The brick needs protection, but it also needs to breathe.

Historically painted brick would have been painted with wholly natural paints, such as lime-based whitewash and milk paint. Historical-recipe, natural paints are breathable and environmentally safe. If the appropriately-painted brick house is already painted with historical paints or if the house is unpainted but should be painted, then historical paints are the most responsible option.

In this row of late-nineteenth century brick rowhouses, the painted brick shows signs of efflorescence (second from left) and flaking (r).

In this row of late-nineteenth century brick rowhouses, the painted brick shows signs of efflorescence (second from left) and flaking (r).

Though sometimes charming and lovely, paint on historic brick houses is only appropriate when the house required paint for exterior wall protection in its initial, non-machine-made brick construction. Painting historically unpainted brick – particularly with the modern waterproof paints – involves intensive long-term maintenance and the destruction of historical materials. With historically unpainted brick, let the decorative brick details and fancy glaze be the charm and the beauty – and leave the modern waterproof paint on the shelf.

For More Information:

Butler, Mary. “Eco Paints and Plasters a Good Fit for Older Homes,” Old House Web.

Crews, Ed. “Making, Baking, and Laying Bricks,” Colonial Williamsburg Journal.

Kibbel III, William. “Brick Houses,” Old House Web.

Milk Paint,” Old House Journal.

Milk Paint

Virginia Lime Works Lime Wash

Weaver, Martin. Conserving Buildings. New York: John Wiley & Sons, Inc., 1997.

Young, Robert E. Historic Preservation Technology. Hoboken, NJ: John Wiley & Sons, Inc., 2008.

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