Old brick in Mobile's historic districts

Mobile's historic districts sit around the downtown blocks. Church Street East and the De Tonti Square area are right by downtown. Oakleigh lies south of Government Street. Old Dauphin Way follows Dauphin Street west, and Midtown and Ashland Place spread out farther west, Ashland Place off Spring Hill Avenue.

These are the streets with the city's older houses: raised cottages up on brick piers, two story houses with tall brick chimneys, and brick buildings downtown with iron balconies. Big live oaks shade most of the blocks, and their limbs reach out over the roofs.

Old Mobile brick is softer than brick made today, and it was laid in lime mortar. Lime mortar is soft on purpose. It gives a little as the house moves, and it lets water leave the wall through the joints instead of trapping it in the brick.

The trouble starts when somebody repoints old brick with hard cement mortar. Now the joint is harder than the brick. Water that used to leave through the mortar goes out through the brick instead, and the brick faces crumble and pop off while the new mortar sits there looking fine.

Donald mixes the mortar to suit the brick, softer than the brick, and as close in color and texture to the old joints as he can get it. Some very old brick cannot be matched exactly. If that is the case on your house, you hear it before the work starts.

A lot of houses here sit up on brick piers, with brick skirting or lattice between them. Mortar low on a pier or a skirting wall takes splash from every rain and stays damp in the shade under the house, so it washes out first.

Donald repairs brick foundation walls and skirting: loose brick, cracks, and soft or washed out mortar. Work on the piers themselves is a separate question, so ask him about your piers when you call.

Up top, old houses often have more than one chimney, and some of them have not seen a fire in years. A chimney nobody uses still takes rain on all four sides and on the crown. Loose brick at the top, open joints and a cracked crown are where the water gets in.

• Sand in the joints when you scratch them with a key
• Brick faces flaking off low on the walls or on the piers
• White salts drying on the brick
• A stain on a ceiling or wall near the chimney

The live oaks that shade these streets are hard on the brick under them. Roots reach for foundations and walks and lift them. Shade keeps the walls that face away from the sun damp for days after a rain, and green growth and mildew settle in.

And the usual answer to green brick is a pressure washer. On old soft brick that is a mistake. High pressure cuts the lime mortar right out of the joints and can take the hard outer skin off the brick, and once that skin is gone the brick drinks up water. A gentle cleaning, tried on a small spot first, does far less harm. Ask Donald before anyone puts a wand on old brick.

Many houses in these neighborhoods are in a local historic district. Before changing anything on the outside, ask the City of Mobile about historic district review. Repairs that change how the brick and mortar look, or that take something off the house, are the kind of thing to ask about.

Donald can tell you what the brick needs and how he would go about it. What needs the city's OK is a question for the City of Mobile, and one to ask before the scaffold goes up.

• Historic OakleighHouse museum in the Oakleigh Garden District
• Washington Square ParkSmall park on Chatham Street in the Oakleigh area
• Old Dauphin Way Historic DistrictHistoric neighborhood along Dauphin Street, west of downtown
• Midtown Historic DistrictHistoric district in Midtown Mobile
• Ashland PlaceHistoric neighborhood off Spring Hill Avenue
• Boyington Oak TreeOld live oak beside the Church Street Graveyard