Tuck-pointing is typically needed when exposure (of 25-30 years) causes mortar joints to crack, flake, or disintegrate. Large holes and washed out mortar are typical signs that tuck-pointing is needed.

Although the right material and technique are usually enough to deliver a water-tight job, it usually takes the skill of experienced professionals to use the proper mortar mix and tools to match existing mortar.

The U.S. Department of the Interior Office of Historic Preservation has established standards to preserve the appearance of older buildings and to avoid irreparable damage during repointing and in the future. Often modern hard cement mortar cannot be used in older buildings because applying modern mortar over old lime mortar can result in serious damage to the original building materials and may not last. It is important that new mortar match the original in porosity and compressive strength.

by Kathy Maynard, reprinted courtesy of HomeAdvisor.com