E-Book, Chapter 5: The Impact of Building Envelope on the Renovation Cycle

In the broad scope of building systems, building facade systems are often out of mind for decades for many facility managers and owners. Masonry, concrete, metal, vinyl, steel, aluminum, and stucco are seen as materials that will last decades with minimal maintenance. For most buildings, this is substantially true. However, this does not and should not relieve building owners of doing reviews and maintenance of building envelope systems. With half of our building stock being over 50 years old, many of the façade systems are timing out and may need substantial refurbishment or replacement. Lightweight facades need regular joint sealant replacement, masonry walls need mortar maintenance, and window walls may need gasket refurbishment. When is the last time you did a study or assessment of your building’s façade? How long will your facades go without capital investment?

Facade Risk and Maintenance:

In decades of doing building condition assessments and forensics, I learned to ask clients what system, in the context of all building systems, kept them up at night. One of my clients surprised me by saying the building facade. He had recently used another consultant to give advice on the purchase of an office building for his portfolio. In the year after the purchase, discovered the façade had significant issues. The poorly performing façade had created stress on the building’s value and management. After that purchase, he insisted on a detailed assessment of building façades for each building that he considered purchasing.

Building facades, like many building systems, have gone through an enormous transformation over the last century, from traditional masonry and wood facades to a plethora of new, innovative and typically light-weight façade systems.  The introduction of steel and concrete framing, in the early part of the 20th century, allowed building heights to soar and façade systems to expand in-kind. Over the last 50 years, curtain walls, especially glass curtain walls, have allowed our buildings to be giant mirrors in the environment. Other experimental facades of the late 20th century include faux stone veneers, concrete tilt-up panels, EIFS, metal insulated panels, as well as vinyl and aluminum siding. Veneered facades were actually made famous in the Roman empire where sheets/slab of marble were used to cover masonry bearing walls of the Colosseum. In medieval Rome, the marble façade panels were removed and shifted to the Vatican for use in façade construction. In the US, veneer stone was invented in the late 1800s and introduced in mass in the 20th century. Historically, masonry and wood facades were a window into the structure of the building – ie the structure was often expressed in the façade features. Today, veneer facades often hide the structural realities beyond the veneer. Today, thin veneer panels are so common that sealants, instead of mortar are the key material that fills the gaps between façade elements. Many in the architectural community joke that modern buildings are held together by glue (joint sealants) made of silicone, polyurethane, acrylic, polysulfide, butyl, and foam.

EIFS:

In the 1980’s, EIFS (Exterior Insulation Finish System) was introduced as a system that could be applied to both new and existing buildings to insulate buildings on the exterior instead of interior. EIFS allowed retail centers to change their appearance every 20 years by removing or covering exterior facades with a new, fresh look. EIFS also has been successfully used as a retrofit to insulate older masonry buildings in order to prolong the life of buildings that were destined for the dust bin of history. The problem was that early attempts at EIFS lacked adequate drainage features and moisture problems ensued for a decade, or more, until cavity wall drainage and weeps were introduced. Also, In the 1970’s, masonry and wood frame wall design was revamped to include cavity walls with internal flashing and weep holes to help keep moisture out of the wall system. As structural systems became better engineered and more effective, building facades also became lighter and thinner as well. EIFS finishes have a natural coloration in the exterior coating. This trowel applied coating is known to have a 20-year useful life before fading occurs and recoating is recommended. EIFS has become so successful that it has also been introduced to high-rises, much to the dismay of buy and hold building owners. In the early 1990’s, I reviewed construction documents for a high-rise hotel in Washington DC to assist the lender with risk management. The original design had a stone veneer applied to a concrete frame building. Through cost engineering, the façade was changed to EIFS. This appeared to be a bad long-term decision due to future maintenance requirements. However, my client - the lender - was only invested with risk for 30 years of the loan term. Now 30 years later, the lender is gone but the owner is left with a façade on a high-rise that may need reconditioning and restoration. EIFS was not really intended to be a long-term solution as it is susceptible to impact damage, fading, and increasing levels of maintenance – over time.

Many of the modern veneer facades also require regular maintenance. Unfortunately, facades for many building owners are out of mind for decades under the assumption that facades should be a long-term system.  The reality is that modern facades require regular maintenance and review. For instance, exterior painting is typically required every 5 to 10 years depending on environmental conditions and stability of the façade materials. Wood siding should be painted and re-caulked every 5 to 7 years. Stucco and painted CMU walls should be painted every 8-10 years.

Sealants:

Structural sealants, referenced above, are most common in steel frame construction with curtain wall or concrete tilt-up facades. Sealants need regular inspection and should be replaced every 10-20 years. Like comprehensive painting, sealants dry out and crack creating points of moisture entry. Sealant replacement, like painting, can be quite expensive and time consuming. Glass curtain walls, common in post-modern buildings of the last 30 years, not only require sealant maintenance but also have latent issues with rubber gaskets. Window gaskets typically fail over prolonged exposure to ultra-violet light and other forms of weathering. Gaskets typically have a 30 to 40 year expected useful life.

The true life-span of most modern façade systems is 40 to 60 years. Even in historic masonry buildings, mortar begins to fail at 40 years. Pointing and inspections should be planned, thereafter, on a 5-year cycle. In fact, older cities around the country, especially on the East Coast, have local laws that require an engineering inspection of facades over 6 stories tall, on a 5-year cycle, to help avoid problems with falling masonry or stone materials from the facades of urban buildings. Now that the average age of a US facility is more than 50 years, the issues related to building facades are becoming increasingly more important. There are issues of normal fatigue and maintenance. There are also issues of catastrophic failure that are entering the news. In the last decade, news stories involving catastrophic building envelope issues have become more common. Some recent stories of catastrophic façades (including water-proofing underground building envelope systems) have included:

Surfside Tower Collapse:

In 2022, Surfside Tower in Florida collapsed due to inattention to waterproofing above an underground parking garage. Moisture protection is one of the effective elements of modern building structures and is considered a necessary part of modern building facades. Engineers had known for years that Surfside Towers had water penetration problems affecting the waterproof membrane over the underground parking garage. Over-time, water penetration caused such distress in the top deck of the underground parking garage that the parking garage collapsed, bringing the above ground tower down as well. Engineers had warned the residents of defects in the water proofing, but the cost of making necessary repairs led the residents to delay necessary repairs and maintenance.

Inspection of 5-Story Masonry Facades:

In 2019, NYC architect – Erica Tishman – was hit and killed by falling masonry from a highrise 17-story building located at 729 7th avenue in mid-town Manhattan. Eight months prior, the building was slapped with a construction violation for “failure to maintain building wall(s) or appurtenances.” The violation — dated April 29, 2019 and listed as still open — described “damaged terra cotta at areas above 15th floor in several locations which poses a falling hazard for pedestrians.”

Since that fateful day, NYC has revised it’s law to require more timely resolution of dangerous façade elements, instead of postponing the repair and lining the streets with protective canopies. In 2012, there were 190 miles and 6,000 protective sheds installed over city sidewalks due to delays in making façade repairs.

Grenfell Tower Facade Failure

In 2017, the Grenfell Tower (Grenfell), Great Britan fire was found to be the direct result of the improper installation and use of an ACP which contained a 100 per cent polyethylene core and did not meet the local building codes. Polymer insulation (phenolic and PIR) used behind the rainscreen was also incorrectly installed as part of the rainscreen facade system, and for this reason contributed to the spread of the fire. 72 residents died in this fire, which was blamed on a faulty exterior façade system. USA building standards have long avoided this type of building façade as being too dangerous. However, standards in other countries have been more lax.

What to look for in masonry walls structural assessments?

Architects and engineers should have a keen eye for structural, foundation, and veneer conditions that may suggest construction fatigue or structural failure. The following examples are a limited list of observations and conditions that should be familiar with.

1. Bowing in the wall

a. Possible cause, rusted or missing wall ties.

a. White chalky stain that indicates moisture has been trapped in the wall cavity. White stains is caused by lime content in mortar.

2. Star – bolts

a. Evidence of previous bowing and repair – typical in urban masonry buildings b. Stars are placed on the exterior. A steel rod is inserted and secured to interior parallel joists and bolted together to secure the wall.

3. Weep holes

a. Weep holes shou/d be locate above lintels and at each floor line to allow moisture to escape wall cavity. Weep holes should be installed in conjunction with flashing in the wall cavity. b. Lack of weep holes or blocked weepholes can lead to moisture saturated walls.

4. Sealants at joints

a. Sealant– not caulk – is used at control joints. Typical at column line location to allow building movement. Steel columns on isolated footers and walls on spread footers settle differently and require control joints to relieve stress caused by normal building movement. High performance sealants are silicon or polyurethane.

5. Caulking at window/door openings

a. Sealants refer to high quality used at curtain wall application for control joints – Silicon or polyurethane b. Latex caulking is typically used for masonry “punched” openings at doors and windows.

6. Rusted lintels

a. Lintels should be painted regularly. Check for clogged or missing weepholes trapping moisture. b. Scrape and paint lintels with metal primer and finish coat.

7. Efflorescence

a. White chalky stain that indicates moisture has been trapped in the wall cavity. White stains is caused by lime content in mortar.

8.   Mortar Fatigue or evidence of mortar replacement

a.     Variation in mortar color suggests pointing and mortar failure

 9.   Non-matching brick

a.     Variation in brick color or pattern suggests history of masonry replacement

b. Variation in mortar color may suggest history of mortar fatigue and replacement

10.             Shear cracks            

a.     Vertical cracks typically caused by sudden movement and point load stress.

b.     Often observed after earthquakes when two materials collide due to inadequate control joint or spacing

11.             Step cracks

a.     Diagonal cracks typically caused by gradual movement of a foundation

        i.     Check for clay soils which expand and contract like a sponge in response to moisture

       ii.     Check for water ponding near foundation from downspout or lack thereof.

12.             Horizontal cracks

a.     Pointing of mortar joints should be preceded by cleaning the joint to a 1” depth

b.     Horizontal cracking suggests mortar fatigue or sudden movement of a foundation

13.    Evidence of post tension slab

a.     Post tension slabs can be identified by steel end caps on the exterior of the slab

b.     Post-tension slabs are common in TX, OK, LA to counteract the expansion and contraction of clay soils

14.     Interlocking bond at building corners

a.     Buildings sharing party walls - in older row house buildings, often the party wall was not interconnected to the front wall.  If the adjoining building is removed, a vertical line of masonry separation can be seen.

 15. Sloping sills and or sill replacement

a.     Sills in masonry construction should be sloped down and out away from the building

16. Flush or recessed mortar joints

a.     Mortar joints flush with the masonry wall can deflect water.

b.     Recessed joints can allow a “lip” on which moisture can collect

c.     Remove mortar a minimum of 1”.  Replace mortar with matching mortar mix.  Older buildings had high lime content and mortar strength should match by adjusting lime content.

  New regulations pertaining to property inspection for 2022 include:

1.     Masonry facades over 4 stories in height require inspection every 5 years in NYC. In 2020, a local architect was killed by falling masonry and NYC enacted new enforcement to ensure repairs are made without delay after inspection are completed.

2.     Parking garages in NYC are now required to be inspected annually. This is a result of underground parking garage collapse in Surfside FL in 2021.

3.     NYC and Washington DC passed a new energy laws that took effect in 2021, requiring annual energy audit reporting for properties over 50,000 SF.

In conclusion, façade issues need to be taken into account to address the age of the system, progression of fatigue, and construction flaws. For instance, most cavity masonry walls constructed before 1980 were not designed with adequate weep holes and flashing. The backup walls were not typically insulated to modern standards and may have inadequate moisture barriers. These issues need to be taken into account before renovation decisions are made.

Facility Condition Assessments are the first step to preparing for and prioritizing your asset management goals. Having consistent and defensible data will help you to plan for and budget for the coming landslide of renovation. This E-Book attempts to identify and explain the issues related to the coming renovation cycle. In the next chapter, we will look at “The Impact of Energy Laws and Regulations changing the Renovation Landscape."