How You Should Avoid the ‘7 Deadly Sins’ of Construction
This photo shows an example of head and jamb fasteners not being used as required.
Construction defect claims have had a significant impact on the industry. Some claims are legitimate, and some are a result of deferred maintenance or customer service-related issues. There are many factors that can influence the quality of construction and the success of the project. Common ones include lack of skilled or trained labor, workload and accelerated schedules, turnover of key field team members as well as poor site management, building material availability and weather. The seven deadly sins are presented here, along with corrective measures suggested to remedy the problems or prevent occurrence in the first place.
There have been improvements over the past 25 years in field quality, plan details, building material products and quality assurance processes by builders, contractors and insurance carriers. Additionally, third-party peer review and quality assurance firms’ procedures have also improved oversight to supplement municipal building inspections. Combined, these efforts help ensure performance standards are met and risks of rework, added costs, delays and subsequent defect litigation are greatly reduced. Quite simply, a well-designed and implemented quality assurance program is a vital part of a construction process, establishing a deeper level of detail and understanding about various elements and interactions of the building components and systems.
Construction defect claims typically hit the books in year eight or nine, and even earlier with poorly managed projects. This makes for some inconsistent performance metrics over the long term. Based on our analysis of many hundreds of projects nationwide and the data stream generated by our quality assurance app, there appears to be no single dominant issue. Our primary research shows that three key elements — deviations from architectural plans, deviations from approved materials and deviations from standard field quality — contribute equally, though this pattern varies across the many U.S. markets, depending on region and building types.
“A well-designed and implemented quality assurance program is a vital part of a construction process, establishing a deeper level of detail and understanding about various elements and interactions of the building components and systems.”
Outlined in this article, are common problems with mid-rise and high-rise construction that can lead to rework, failure, litigation and sometimes disaster. The LJP team has experience with towers constructed around the United States, including Seattle, San Francisco, Los Angeles, San Diego, Dallas, Houston, Denver, Chicago, Boston, Washington D.C., Miami, Fort Lauderdale, Tampa and Austin, Texas. We have observed good construction practices and not all the 150-plus towers had problems. There are many issues that can arise during construction on large complex projects. This is because not every detail can be drawn in the architectural or engineering plans to anticipate design conflicts between building systems, and not all trade contractors are equally trained, skilled or experienced with these issues. The order of topics presented below follow the construction sequence rather than severity of problems observed:
- Below-grade waterproofing assemblies can be challenging depending on geological and soil conditions, depth to the water table and structural designs. Fortunately, chemistry of waterproofing membranes has improved dramatically in recent years leading to better control of subsurface moisture movement around the structural assemblies at grade or below grade. Failures can manifest in the horizontal sub-slab waterproofing membranes as well as the vertical blind side moisture barriers. Rebar penetrations through sheet membranes and pin holes in spray applied barriers can lead to moisture penetration into building elements such as conveyance systems. Bentonite clay blankets and draping exterior below-grade assemblies may not perform as intended, leaving open gaps in the system. In some locations, towers are designed with multiple levels of below-grade parking. These can be more prone to failure than buildings with above-grade parking.
- Below-grade structural system design and installation will directly follow the limitations of geological and geotechnical conditions of the building site. Subsurface borings combined with field and laboratory testing are necessary precautions to validate design and installation methods which contractors use. The New Millennium Tower in San Francisco is an example of foundation design choices which led to excessive settlement, compromising the integrity of the building. Numerous studies have explored the causes and proposed solutions to rectify the settlement and tilt of the structure. For buildings like this, field monitoring by the structural engineers of record during the construction process is a necessary scope of work. General contractors of new towers will also routinely have a dedicated field superintendent to oversee the structural aspects of the building as it goes vertical. In fact, it is common to have a lead superintendent on all major tower components — such as building structure, exterior skin and interior build-out.
- Exterior skin assemblies pose a unique set of challenges depending on the height and configuration of the building. Considerations include climatic conditions of the building locale, such as wind patterns, solar performance of the glazing, waterproofing components, technology designed into the skin, ease of construction and post-construction maintenance. For example, in Boston many years ago wind vortexes around Copley Square were reportedly contributing factors to 4×8 glazing panels popping out of the 62-story John Hancock Tower and crashing to the ground, clearly a safety hazard for pedestrians below. Extensive wind simulations are now routinely conducted to test building performance in advance relative to its skin and roofing assemblies. And with the increasing complexity of our thermal performance requirements for buildings, energy modeling has become critical to understand solar radiation and internal heat gain variables. Double and triple skin facades have helped to reduce these impacts, but if improperly designed and installed can lead to building performance failures.
- Roofing assemblies are also part of the building skin, designed and installed to keep the weather out and the building water-resistant. Frequently, the roofing system is also required to carry an added burden of massive mechanical and plumbing equipment installed with numerous penetrations, which necessitate extensive and custom fabricated flashing systems. Due to weather exposures which vary regionally, adequacy of the roofing installation presents many potential failure points. Water intrusion is the most pervasive in our experience. Blown-off roofing assemblies, wind uplift and billowing also contribute to the water intrusion problem. Post-construction maintenance is also essential to maintain the roofing integrity on all structures. Sadly, improper repairs and unsatisfactory workmanship will lead to roofing failures. Whether the original flashing was improperly installed or seams with cold adhesives were not properly cured, wind uplift and moisture intrusion will manifest and damage the roofing membranes and interior components. This can occur on hot mop, torch down and EPDM roofing membrane types.
- MEP systems include mechanical, electrical and plumbing systems, which are highly complex in design, fabrication and installation. HVAC (heating, ventilation and air conditioning) and conveyance systems (elevators for people and freight as well as trash removal) are also critical components where failures can manifest. These systems and installations are typically unique design/build solutions for a specific project rather than a pre-packaged set of components ready for installations. System redundancy and emergency back-up solutions are necessary and part of the site specific design. These detailed designs require specific MEP engineering knowledge and experience and will likely include performance modeling of the proposed systems for functionality, efficiency, movement, thermal management, safety and comfort.
- Fire and smoke control systems, including insulation, cannot be over-emphasized in their importance whether in new construction or retrofit of an existing structure. Sadly, the Grenfell Tower fire in London proved a catastrophic disaster due to lack of attention to some of these systems during its recent retrofit. Choice of cladding materials, failure of internal systems and lack of attention to important fire protection details coupled with the local fire authority’s misguided directive to residents advising them to shelter in place resulted in an epic building failure and huge loss of human life. Newly constructed towers are either Type I with pressurized corridors or Type II, non-pressurized. The Type I pressurized buildings provide smoke-free exiting corridors, critical in safety planning. Taller residential buildings have higher densities of people, longer vertical distances on stairs to safely evacuate and require more protective systems. Fire spread is important to prevent, but smoke control is even more critical. Many construction materials and finishes in high rise towers may be non-flammable, yet the smoke from fires is still toxic.
- Exterior terraces and balconies present opportunities to bring the outside into the living spaces, capturing expansive vistas in many directions. The design of these exterior spaces includes installation of weather-resistant, high-impact window and door assemblies which will withstand major weather events such as south Florida tropical hurricanes. Glass railing systems have been prone to structural failure in some buildings requiring expensive retrofits after residents have moved into their luxury condos. Failures can also include excessive deflection or sag, loose railings or guardrails, and installing terrace finishes with a low frictional coefficient resulting in slips, trips and falls. Once constructed, routine inspections are necessary. In Boston, property owners are required to have certain facades inspected every five years. Clearly, a post-construction preventative maintenance program, with detailed inspections of all assets, will assure a building will live up to its design intent.
Raising the bar of construction quality is a complex endeavor. Pre-construction peer reviews of architectural and engineering plans is but the first step. Monitoring, evaluating and correcting specific assemblies prone to defect litigation during the construction process is the next critical step. And equally important is implementation of comprehensive maintenance manuals which provide the HOA Board of Directors with a practical recipe book of protocols by appropriate vendors on a routine and programmed schedule.
Designers and contractors face many issues during all phases of the construction process. It is important to establish protocols and procedures to prevent potential problems and rework from happening. New vehicles coming off the production line and later undergoing routine maintenance have been through this level of scrutiny for decades. Why not also apply the processes to buildings, which are a much larger investment? What’s in your tool box?
Don Neff is the president and CEO of LJP Construction Services. Headquartered in Irvine, Calif., LJP Construction Services has been at the forefront of the quality assurance movement on behalf of builder and insurance clients for more than 25 years.