Tuckpointing Mortar Joints in Masonry

Tuckpointing Mortar Joints in Masonry

Tuckpointing (also spelled as tuck pointing and/or tuck-pointing), used in Building Restoration, Historical Preservation and other masonry repair projects, is the process of removing old cracked, spalled, or failed mortar in the joints (both head and bed joints) between masonry units such as brick, block, stone, etc. It involves removing the old existing mortar, preparing the joints properly for re-pointing, tuckpointing, and finishing the joints to match as close as possible the existing joints in terms of type of mortar, color, and the finish of the joints. Because tuckpointing can be a very complicated matter when deciphering exactly what type of mortar mix is best for the re-pointing process and it is an elaborate process it is better termed re-tuckpointing or, simply, repointing.

Older buildings in the United States that pre-date the early 1900’s usually are lime based mortars, while after 1900 portland cement was widely used in mortars. For the last half century, modern mortars are made with more basic cement (and/or portland cement) and typically are ready-mixed and, while easier and cheaper for use, they typically do not last as long as lime based mortars found in older buildings. Type n, o, and m mortars are the most commonly used today. Type n mortar is, arguably, the best of the modern mortars to repoint with in most applications as it is usually softer than than the masonry units (i.e. brick, stone, block) and when there is movement in the wall/facade/structure it will move and crack before the masonry unit(s) will. This will save the owner the greater expense of masonry unit replacement while only having to repoint the mortar joints when they do fail. It is not a matter of if there will be failure in the mortar, mortar joints and/or masonry facade but when.

When doing a Building Restoration or Historical Preservation, if one wants to be certain about what the existing mortar is exactly composed of then removing a small section of the mortar and having it analyzed/tested by a lab is a fairly easy and inexpensive option. If it is a lime based (i.e. lime putty) or a mix with portland cement and/or a more modern mortar such as type n, then it can be matched exactly or very closely with that same mortar. However, it is not necessary to use the same exact mix/type of mortar nor finish of the joint as it may be too costly, an owner needing Building Renovation may change it at his/her discretion for a variety of reasons, materials may not be available, etc. Often times, it simply comes down to the owner’s preference, budget and timeline as to which exact type of mortar is to be used in the repointing process.

The good news is that even modern mortars (such as type n) will typically last most of our lifetimes if properly mixed, pointed, and finished. So, in order to have a building water-tight and look beautiful, even on an old historical structure, one need not have to repoint with the same old style, type of mortar and/or mortar mix to accomplish this goal. Granted, on important historical preservation projects it will be dictated by the local authority (state, federal, city, etc.) that the older original type of mortar will be used for the repointing and will be completed according to the Historical Preservation Briefs. This can be a very tedious process as there are many steps in tuckpointing.

The proper steps in tuckpointing are as follows:

  1. Determine what type of mortar is existing via testing or by a trained professional’s judgement
  2. Decide what type of mortar the owner wants to be pointed back if other than the existing (must discuss time frames, availability of materials, labor costs, color of mortar and type of finished mortar joint, etc.)
  3. Properly and carefully remove existing mortar via hand (hammer and chisel) and/or mechanical application (grinder) to a minimum depth of 3/4″ (referred to as “burying the blade” on a grinder) taking caution not to damage or cut any masonry units
  4. Prepare the joint by cleaning out all debris, loose mortar, dirt/sand (aggregate) and make the joint dust free via a blower and/or a brush
  5. Slightly wet the joint
  6. Mix the approved mortar to proper ratios of sand, mortar, lime, portland cement, dye, etc. for whatever type of mix necessary to get the style, texture, color and finish of desired joint,
  7. Point or “pack” the mortar in the wall via a small pointing tool in pointing hand from a mud board or “hawk” in the other hand
  8. Strike or rake the joint with a tool, handle, etc. for desired appearance/finish of joint,
  9. Lightly brush joint as needed to get excess mortar off of it and on masonry units, etc., and, lastly
  10. Frequently lightly wet joint to make certain it cures out slower and stronger, etc.

Tuckpointing is not easy by any means but once a trained professional gets the hang of it, it becomes natural like any highly skilled trade. This is why tuckpointing is never cheap if done properly as you get what you pay for.

“The sweetness of low price is soon forgotten, while the bitterness of poor quality long remains” — Ben Franklin.

However, tuckpointing is not expensive at all once you consider the consequences of neglecting to re-tuckpoint a masonry structure for a long period of time.

Tuckpointing is essential for the longevity of a masonry facade and structure’s lifespan and ease of use. Tuckpointing keeps the building envelope water-tight and mitigates water damage that can result in very costly repairs to the masonry structure. Some common examples include masonry bows in walls, masonry walls collapsing, steel supports such as shelf angles and/or lintels rusting, swelling, and failing, masonry units spalling (this occurs when the face of the brick “spalls” or pops off during freeze and thaw cycles from water getting in behind it) or cracking.

Water that penetrates the exterior facade will eventually cause damage to internal walls, ceilings, etc. If re-tuckpointing is ignored too long, it will make the structure unsound and uninhabitable. It can also lead to mold damage requiring very expensive mold remediation. Consequently, it is not uncommon when a older building’s masonry and need for re-pointing has been neglected far too long, the building ends up being condemned.

Building owners and property managers need to understand that water is evil and will wreak havoc on masonry structures if not held in check with routine exterior inspections and maintenance of the masonry including periodic tuckpointing. Often, a tenant will demand that any leaks into their leased space needs stopped before they will sign and/or renew a lease for office space as the leaks are a real annoyance. One note of caution, even a building envelope that is tuckpointed properly will sometimes allow water in due to high wind-driven rains and/or long steady downpours. So, pointing will not stop all leaks into masonry walls but it is one of the most important factors and is the first line of defense (assuming integrity of the masonry/masonry units are sound).

In order to stop such leaks, an experienced professional contractor that has the knowledge and experience in all facets of exterior building envelopes as well as tuckpointing needs to be hired to determine the source of the leak(s) and develop a plan to resolve the leaks. Ideally, this professional will have first-hand knowledge of the entire exterior of a building, home or church from the roof, masonry walls including brick, block, concrete panels or poured-in-place, stone, stucco, and/or EIFS (exterior insulated finish systems), glass/metal on windows, storefronts, curtain walls, and skylights, down to the foundation below-grade.

Finding such a rare professional with this vast amount of knowledge and experience can be difficult so it is recommended to begin your search at the local Better Business Bureau (BBB) for mason or masonry contractors with an A+ Accredited Rating. Also reference professional organizations such as Building Owners and Managers Association (BOMA), International Facilities Managers Association (IFMA), and International Real Estate Management (IREM).

Mark Huffer, is President of Utmost Consulting and Utmost Renovations. He is a BOMA (Building Owners and Managers Association) Instructor on building envelopes. Mark is a leading authority on Building Restoration and Historic Preservation.

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