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Mike McClintock: Home Sense

Tricks With Bricks

By Mike McClintock
Special to The Washington Post
Thursday, July 29, 2004; Page H02

Brick lasts longer and withstands severe weather better than wood and most other siding. But even this nearly indestructible material needs occasional work, such as repointing mortar joints and removing drips of paint.

Then there are two key (and often confusing) questions to consider: Should you remove clinging vines, and, once the wall is in good shape structurally, should you apply a protective, clear-coat sealer?

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Removing paint

This repair job often arises on houses with only some brick, on the first story for instance, with painted siding above. Also it's easy to accidentally drip paint when you're painting window and door trim on an all-brick building.

With many brick repairs, including this one, it's wise to try the fix on a small, out-of-the-way area to be sure it doesn't mar the wall. There are many different types of brick, variations due to the age of brick and mortar and no way to guarantee repair procedures for every type.

If you catch drips soon after the mishap, first wet the area with water and then try trisodium phosphate and water in a solution of two pounds per gallon. The mixture should soften the paint so you can scrape it off. You can also use a proprietary chemical stripper rated for brick. Gel-solvent types that cling to the area often work best on old, hardened paint, though several applications may be necessary.

Fixing eroded mortar joints

This basic and ancient maintenance job involves scraping away crumbling mortar between bricks and replacing it with fresh mortar. The repair, called tuck-pointing, provides necessary structural support and keeps water from further eroding the wall.

There are two basic rules to follow. First, be ruthless when scraping. Many do-it-yourselfers are not aggressive enough, realizing that the more they scrape out the more they have to fill in.

Second, to provide a good bite for new mortar, excavate old joints at least as deep as the joint is wide, and preferably twice as deep. Once the joint is clean, pack in fresh material and smooth out its surface, a process called tooling, normally with a slight concave shape.

For best results, dampen the joints for a better bond, mix dry mortar ingredients thoroughly before adding water and pack in the repair mix tightly to fill all voids.

According to the Reston-based Brick Industry Association, "An individual who is an excellent mason/bricklayer may not be a good tuck-pointing craftsman. Skills should be tested and evaluated prior to the selection of the craftsman." Maybe, but it's really not rocket science; you just have to be patient, thorough and test the mortar mix repair on one spot before tackling the rest of the wall.

Removing vines

Graceful green vines make an elegant dressing for brick. Unfortunately, behind that classic architectural image there may be massive, if gradual, deterioration.

Vegetation isn't strong enough to break masonry. But the clinging ends of individual shoots, called suckers, find even the smallest voids in mortar joints and transmit moisture into the wall. Once that happens, freeze-thaw cycles that cause expansion can erode more mortar, let in more moisture and weaken the wall.

On the plus side, a well-constructed brick wall with sound mortar joints can resist this intrusion for decades. And aside from the good looks, ivy vines can shed water and reduce the surface temperature of the wall on blistering summer days.

In many cases, removing vines is a tossup question -- and clearing a lot of vegetation that's locked onto a brick wall can be difficult. Pulling down tendrils can take out some mortar as well and reveal staining that requires yet more repair work. But if you rummage around under the leaves and find crumbling or missing mortar, you should remove the vines and patch the wall.

The best procedure, the association says, is to cut (not pull) vines from the wall. The suckers will remain and should be left until they dry out and die, generally in two to three weeks.

Then dampen and scrub the wall with a stiff fiber brush. The association says adding a small amount of laundry detergent or weed killer to the water will help, but then you have to rinse the wall. If the wall is old and the ivy has been there for years, it's likely that you'll need to repoint at least some mortar joints.

Sealing brick

Sealers protect brick walls by shedding water and can save maintenance and repair work. But in the process they typically darken attractive light-pink tones and blur some of the subtle variation among variegated brick. Some people think sealers make brick walls look better; others hate the change.

There are two main types: penetrating sealers that settle into masonry and coatings that form a surface film. Penetrating sealers last longer by creating a more thorough bond. They also allow more moisture in the building to escape without causing efflorescence and other problems on the way out.

You can brush, roll or spray sealers onto the wall. In all cases, check label cautions. For best results, apply the coating on warm, dry days. The association says walls should be cleaned and allowed to thoroughly dry before applying a water-repelling sealer.

© 2004 The Washington Post Company