An architect with experience repairing hundreds of masonry walls reflects on deferred maintenance and shares tips on assessing masonry walls to maximize their lives and avoid major headaches.
At a job site, I ran into a contractor who was laughing. Knowing he was replacing the roof flashing for the second time in a short period, I asked him why he was laughing. “Because,” he said, “I’m getting paid twice.”
What that contractor and I knew was that the second replacement could have been prevented. The problem, which I’ll get into shortly, comes back to masonry.
The Perils of Deferred Maintenance
Encountering a masonry problem can be stressful for buildings and grounds professionals — and if the discovery is made too late, remedying it could have costly repercussions.
The good news is that many of these frustrations can be prevented if facilities professionals make it a point to periodically assess masonry and have problems fixed in the early stages. A minor investment of time and money now can pay building owners huge dividends in the long run.
Following are a few masonry-related tips based on my experience as a building envelope design professional.
Lack of control joints can cause vertical masonry cracks like this.
An entire parapet wall shifted at the roof deck to cause the horizontal crack shown above. In this case, rebuilding the parapet wall should be done before roofing work.
Look to Masonry Before Roofing.
A year and a half before I ran into that laughing contractor, I did a masonry and roofing assessment for the building’s owner. The inspection revealed that most of the roof was in decent condition. The parapet walls (walls built along the perimeter roof edge), however, were shifting about half an inch at the roof line and allowing water to enter the building.
In the interest of saving the client time and money, I encouraged the owner to fix the parapet walls and reflash the roof onto those walls before fixing the roof. The owner, however, chose to replace the roof and ignore the parapets and flashing.
One year later, the owner still had problems with moisture intrusion despite the new roof. It was because of those parapet walls. This brings us back to that contractor laughing while watching one of his employees cut away all the new flashing to fix the parapet walls.
If the building owner had fixed the masonry first, that would have taken care of the moisture intrusion … and a roof replacement wouldn’t even have been necessary.
A key lesson emerges from this story: before committing to replacing a roof, do a thorough masonry assessment and fix related problems.
A minor investment of time and money now can pay building owners huge dividends in the long run.
Tom Kikta, Building Envelope Director, Legat Architects
Take Advantage of Warranties and Monitor the Sealant.
Whereas roofing material warranties often extend for 20 years or longer, masonry warranties typically run for two to three years but might go as high as five. Additionally, most roofing warranties require at least annual inspections, but this is not necessarily the case for masonry restoration work. I advise building owners to talk to contractors or design professionals and get a service agreement for an annual or semiannual masonry inspection.
Thanks to UV radiation, the sealant is usually the first part of the masonry wall to degrade. When that happens, the brick and mortar get saturated, and water penetrates and starts to deteriorate the wall (a major problem). Degraded sealant also exposes the wall to critters — I’ve even seen birds’ nests embedded in walls.
In extreme cases like this, birds can nest in gaps caused by degraded sealant and masonry deterioration.
Installing contractors typically warranty sealant work for one to five years. If a warranty has expired or does not exist, facilities professionals can remove and install it themselves — it’s one of the easiest parts of masonry maintenance. What’s important is to get the sealant replaced quickly to take a lot of other, costlier damage out of the equation.
UV radiation and exposure to elements degrade sealant and allow water to penetrate masonry walls. Facilities professionals should regularly inspect walls to avoid this. Typically, sealant should get replaced every five years.
Don’t Assume Sealant Is the Best Answer.
Cracks develop in masonry walls for many reasons (settlement, movement, etc.), and when they do form, it is important to address them quickly. Sealant, right or wrong, is often the quickest and easiest “fix” for most building owners (although I’ve seen duct tape and other, more inventive means used). While it may be an appropriate short-term remedy, sealant is not always the best solution for a more permanent fix. Settlement cracks, for instance, are better addressed with tuckpointing (more below). Cracks stemming from building movement (expansion/contraction) may require tuckpointing and the addition of movement joints.
Sealant used in settlement cracks may work in the short term, but tuckpointing will be necessary to avoid costly repairs later.
Watch for Plugged Weepholes.
When doing one masonry restoration project, I discovered that the 30-foot-tall brick wall had no weep holes, which are small holes that allow water to drain from the wall cavity. When the contractor started grinding out the mushy mortar along the wall’s bottom, water poured out of the joints. It turns out there was three feet of water sitting within the masonry cavity. The wall’s north-facing position compounded the problem — had the wall faced south and therefore received more direct sunlight, the problem would likely have been less prominent.
Though a complete absence of weep holes is rare, this anecdote shows how important they are. When weep holes get clogged, water accumulates inside the walls, which leads to deterioration and interior leaks. Water will always find the easiest pathway both in and out of walls. As design and construction professionals, we want to make the easiest pathway out of the wall toward the exterior of the building. But if this avenue gets blocked (or doesn’t exist), that pathway may very well be toward the building’s interior.
Many weep holes in older walls use rope wicks, which are meant to prevent pests and help “wick” water to the outside. The ropes, however, tend to soak up water within new mortar and draw in a mortar slurry. As the water evaporates, the slurry and wicks harden, eventually clogging the holes.
A more effective alternative to the rope wick is the cell vent, which looks like a piece of corrugated plastic in the head joint between bricks. The cell vent allows more ventilation in the wall system but is much less likely to clog.
Facilities professionals should intermittently examine the bottoms of masonry walls. If it looks like the brick is wet, the cause could be clogged weep holes. In that case, call a contractor or design professional.
An incompatible hard gray mortar was used on top of the original softer tan mortar on this historic building. The harder new mortar prevents water from escaping the joint. The water degrades the old mortar, giving it a powdery appearance. In this case, water has also rusted the steel reinforcements.
Don’t “Butter” the Mortar Joints. Do Tuckpoint Them.
When water gets into the joints, the mortar that bonds masonry starts to disintegrate.
Building owners often contact me with masonry problems after they’ve paid contractors to inexpensively “fix” their mortar. Too often, these contractors have “buttered” the joints, meaning they have simply smeared new mortar over the old. It looks like they took care of the problem; in reality, they hid it — when the new layer gets wet, it starts falling off. Before long, owners are right back where they started and a few thousand dollars poorer.
The longer-lasting and far more cost-conscious (in the long run) solution to deteriorating mortar is tuckpointing. Contractors grind out the joint (usually half an inch to three quarters of an inch) and replace it with new mortar.
A related tuckpointing problem that I encounter has to do with the incompatibility of old and new mortar. Early 20th century and older buildings used a softer mortar. If contractors apply harder mortar over the softer, it does not allow water to drain. The water stays trapped behind the wall and slowly causes more damage. For buildings of this vintage, I recommend testing the new mortar to ensure it is compatible with the old.
Stumped? Contact a Design Professional for a Cost-Effective and Efficient Fix.
If facilities professionals notice mortar falling out or other severe masonry problems, it might be time to make a call. Consider contacting a design professional.
Tuckpointers focus on masonry. Roofers focus on roofs. The design professional, however, looks at how roofs and walls impact each other. This knowledge of the entire building envelope allows design professionals to solve masonry problems efficiently and cost effectively. They can also help building owners avoid unnecessary and expensive repairs down the road.
In my next post, I will share tips on ensuring a long roof life.
Contact us with your masonry or roofing challenges, or comment below to share your thoughts on this post.
