Even the highly durable walls need to get regular inspection to identify problems
and the replacement of old materials.
While the brick units used in the walls assembly may last 100 years or longer, sills, parapets, chimneys, copings, and other elements with more severe weather exposure typically have a significantly shorter service life. Mortar joints may last 25 years before needing repairs, whereas sealants and plastic flashings could require replacement in as few as five years.
To evaluate the behavior of different materials in various weather conditions, inspect seasonally, noting potential problems and needed repairs. Items to look for include: Masonry: cracks, spalls, loose brick, mortar cracks, deteriorated mortar, clogged weeps, vegetative growth, deteriorated sealant, efflorescence and stains, out-of-plumb units, water penetration. Flashings: damage, open lap joints, stains, missing areas. Caps, copings, sills: inadequate slope, cracks, mortar hairline cracks, loose or open joints, out-of-plumb units, missing drips. Once any of the above problems have been observed, the underlying cause should be identified and corrected, as well as any outward effects of the condition.
Ideally, the original mortar composition should be replicated. If this is not possible, a mortar with a similar or slightly lower compressive strength is recommended for repointing. The existing mortar should be removed at least to a depth that is twice the joint width, or until sound mortar is reached. To prepare the joint, dust and debris should be removed by brushing, blowing with air, or rinsing. Joints should be dampened, but the brickwork should absorb surface water before new mortar is placed. Mortar should be packed tightly in thin layers and tooled to match the original profile.
A note on water-pepellent coatings. Properly designed and constructed masonry walls provide water infiltration protection without the aid of water-repellent coatings, and, in most cases, the addition of such a product causes more problems than it solves. Water-repellent coatings are no replacement for design details that resist water penetration. However, there may be isolated instances in which a breathable coating can be used successfully, such as for masonry subject to extreme exposure. A design professional can work with the manufacturer to determine when and where a vapor-permeable water repellent product might merit consideration.