Greener Structures

What if once a year, say at the start of a new year, a person could rant about stupid things that they have seen their colleagues do without worrying about the repercussions. If this were the case, I’d share stories about things I’ve seen architects and others do who obviously have no clue about how thermal building envelopes work. And maybe I’d post the stories in a blog…

I have this possibly radical opinion that if you are an architect and you don’t have a functional, working knowledge of how heat and moisture move through building envelopes, as well as familiarity with the Energy Code in the jurisdiction of your practice, then perhaps you should learn, or consider switching professions. Below are my ten favorite examples of what I would consider gross incompetence regarding thermal building envelopes. I’ve left out the names and identities of the people and buildings involved, in the hopes of not damaging relations. Kidding aside, I feel it’s important to share these stories. As ridiculous as they might seem, situations like these are way too common. They should be illegal – and in truth, they are.

1. Years ago when I knew little about building science and even less about the Energy Code, I visited the construction site of a natatorium renovation with my architect client. One of the things that I did know was that if the warm, humid and chlorine-filled natatorium air is able to exfiltrate, it can condense on cold surfaces like brick ties and cause corrosion and other types of deterioration. This had occurred at this building, which was why the exterior brick was being removed and replaced. Looking at the exterior walls being rebuilt, I noticed that although rigid insulation was being added to provide conductive thermal resistance, the new construction did not include any air barrier system. I pointed this out to the project architect with whom I was with. His response was to walk over to the contractor installing the insulation sheets and tell him to “Make sure the edges of the insulation sheets are tightly butted up to each other.” No tape, no sealant, no membrane – not even tongue-and-groove edges. In the architect’s mind, having insulation sheets that touch each other qualifies as an acceptable air barrier. That’s when I first realized that perhaps architects don’t know all that they should know about thermal building envelopes.
2. I popped up a suspended ceiling tile in an elementary school corridor so I could see the roof framing members and heard birds chirping as clear as if they were perched right next to my head. Curious, I traced the sound to the roof overhang along the exterior wall, where I could see daylight shining up through vents in the soffit. Some architects cannot resist the urge to ventilate all overhanging soffits, perhaps taking their cue from soffit vents for unconditioned residential attics. Air sealing and insulating the soffit between the roof edge and the top of exterior wall, or extending the thermal barrier straight up along the plane of the outside wall, would complete the thermal envelope – and silence the chirping of the birds.
3. A variation on the problematic soffit theme was the case of a brand-new school natatorium with a roof overhang that extended over an exterior sidewalk. The sidewalk could not be used in the wintertime due to heavy ice buildup caused by water dripping down from the soffit above and freezing. Looking from the inside, I saw that the interior air space extended out into the overhang, as did the steel roof joist extensions, which got cold in the wintertime and became wet with condensation of the warm, humid air. The condensed water dripped down onto and around the soffit panels, to the sidewalk below. If it weren’t for the sidewalk problem, this gross gap in the thermal envelope likely would have continued to dysfunction, possibly until the moisture created deterioration of the roof joists or the soffit assembly.
4. We didn’t know what we would find when we were sent to the one-story commercial building with a sloping roof that suffered from extensive roof eave icicles. We thought it likely that there were openings in the air barrier at the horizontal thermal plane at the base of the unconditioned attic. But removing one suspended ceiling tile instantly removed all mystery when we saw fiberglass batts suspended over the ceiling on chicken wire that stretched between the bottom chords of the wood roof trusses. Another room revealed batts supported by wood furring strips. So we were wrong – there were no holes in the air barrier – in fact, there was no air barrier at all! Warm air was free to rise up through the batt insulation into the attic space, warming the attic and melting the snow on the roof, with the meltwater freezing at the roof eaves. This was a simple diagnosis that would require extensive reconstruction to remediate the problem. The architect for the previous year’s renovation, when the ceilings were replaced, had had no clue that he had done anything wrong.
5. Construction of a hotel was nearly completed when I toured the building with the project architect. I was there for another matter, but asked to see the attic out of curiosity. Disappointingly, under the fiberglass insulation batts between the gable-pitched wood roof trusses was the familiar old polyethylene sheets – the anachronistic vapor barrier that so many architects still feel is necessary, even for air conditioned buildings – stapled to the bottom chords prior to installing the gypsum wallboard ceiling. The plastic sheets were interrupted by the tops of the interior partitions and cut to allow wires, pipes, and electrical fixtures to pass through. The architect with whom I was touring did not comprehend that the assembly required an air barrier, and the plastic sheeting did not function as an air barrier. Between the staples and screw holes, unsealed laps and edges, and penetrations, it never does. But the worst part was the corrugated cardboard boxes that were positioned on top of the drywall ceilings near the center of every room. At first I thought they were packing boxes left by the contractors, but actually the boxes were the product: They were designed to be placed over recessed ceiling lights to prevent insulation from getting too close to the fixtures. They were not airtight or air sealed to the ceiling drywall, so they created an as-designed gap in the ceiling air barrier continuity – a clear violation of the Energy Code that had been adopted several years earlier. Yes, they sell products that – intentionally or not – facilitate your noncompliance with the code.
6. Driving to a high school to assess the cause of a burst water pipe for an insurance company, I couldn’t help speculate on the cause. The front entry area of the building, where the failure occurred, was a recent addition. And the area had just experienced its first cold snap, with temperatures dipping into the single digits. Sure enough, the broken pipes were located in a wall chase that was open to the space above the ceiling of the front lobby. The lobby ceiling aligned with the ceiling over the entry vestibule and the exterior ceiling below a section of roof that extended past the exterior wall, forming an entry canopy. The absence of a thermal barrier in this area, defining a separation between interior and exterior, allowed cold air to come right in above the ceiling and down the chase, freezing the pipes. Showing the building thermal envelope on the construction drawings of a project isn’t just necessary to comply with an explicit Energy Code requirement (ECCCNYS C105.2.1) – it obliges the architect to deliberately define the continuity of the envelope, and helps them identify the envelope details that need to be included in the set.
7. Sometimes when reviewing an insurance loss, I’m less puzzled about the cause of the loss than by the lack of understanding by the architect that their design would result in performance problems. A newly built multistory hotel had a laundry room on the first floor and a laundry chute that ran up the full height of the building so that housekeepers could drop laundry from every floor down to the laundry room. Inexplicably, the laundry chute extended up through and above the insulated roof, terminating with a metal cap, with the top few inches of the chute just below the cap screened and open to the exterior. This created a wide-open penetration through the thermal envelope, connected to a vertical shaft that ran right down through the building. Worse, when the dryers were running in the laundry room they created negative air pressure that pulled outside air down the shaft. So when the sprinkler pipes adjacent to the laundry chute froze and burst, causing extensive damage, there was no mystery as to the cause. But what was bewildering was the lack of realization by the architect that this was inevitable, given the design. Their response to the loss was that the contractor should have realized that the laundry chute was to be insulated as part of the thermal envelope – despite the architectural drawings indicating no such thing. I hope this was not a prototype design!
8. A church built in 1960 (like me!) had a front entry vestibule set into a tall narthex, with an exterior porch roof running along the front wall just outside the vestibule. When the building was renovated in the 1990s the architect expanded the interior space by removing the vestibule and pushing the front wall out under the exterior roof with two new entry doors, one on each side of the addition. Since reroofing of the porch roof was not part of the project, the architect chose to install fiberglass batt insulation above the new gypsum drywall ceiling under the formerly exterior roof. But they also detailed open, screened horizontal vents above both of the new exterior doors to allow exterior air to flow in above the insulation. Apparently they were following some unwritten rule that the unconditioned space between the ceiling insulation and the roof deck must be ventilated. Years later, on a windy day, we noticed that outside air was blowing into the narthex through a soffit at the elevation between the entry ceiling and the low roof. It seems that that strip of wall had not been air sealed during the renovation. The remedy? Years later we reroofed the low roof over the entry addition with rigid insulation, and just this summer we finally we closed off, insulated and air sealed the vents over the doors with polyiso and plywood, sealing the edges and connection points with self-sealing tape. The lessons? Ventilating unconditioned spaces is not always as important as maintaining a continuous air barrier. Also, a building’s thermal envelope must be maintained along every plane of the three-dimensional volume of the conditioned space.
9. The use of OSB panels with factory-applied elastomeric coating applied to the exterior face of wall or roof sheathing, joints sealed with flexible tape, has caught on for both residential and commercial construction. If installed correctly, and perimeter transitions are handled well, it can be an effective part of a building’s air barrier system. So I wasn’t surprised when I visited a one-story wood-framed commercial building under construction and saw that these sheets were used on the outside walls. And it looked normal to see it as sheathing on the sloping roof. But – the architectural drawings called for batt insulation to be laid in the plane of the bottom chords of the wood roof trusses, creating an unconditioned attic. So what was an air barrier system doing several feet above the insulation? Certainly the “real” air barrier was the ceiling under the bottom chords of the trusses, upon which the insulation would lay, right? But the architectural drawings did not convey a continuous gypsum wallboard ceiling, or anything else that could be construed as an air barrier – the drawings were actually rather unclear regarding the ceiling construction. And the words “air barrier” were nowhere to be found in the drawing set, which was dated August 2020 – a full ten years after the NYS Energy Code first required continuous air barriers in buildings.
10. Moisture problems in the exterior walls of a newly-built high-rise, high-end apartment building had led to a nightmare of litigation for the architect, mechanical engineer, and contractors. By the time I joined the contractor’s defense team, experts had photo-documented the damage to the wall finishes, developed a time-study of the occurrence of standing water on the window frames, and performed two-dimensional thermal and hygrothermal analyses of the wall systems. Expert opinions had been established, supported by pages of calculations and references. But reading through the documents, three things jumped out at me. First, there was no mention of compliance, or lack of compliance, with the governing energy code, which the design and construction team was legally required to have followed. Second, the primary expert report gave little consideration to the effect of the continuous steel angles that extended through the wall insulation at every floor. Even though a THERM analysis of the wall section was performed, the “expert’s” interpretation was that the sheet metal flashing below the window was the primary contributor to the heat loss and condensation problem – not the thermal bridging of the angles that were about ten times as thick. Finally, the manufactured aluminum-framed windows had been submitted and approved for construction without indicating their overall U-factors. The term “thermally broken” was used in the window specification, but the specific U-factor required was not identified. Condensation of the thermally inefficient window frames and unbridled structural thermal bridging were the primary causes of the water damage. The ignorance of the basics of thermal envelope performance by the architects, the mechanical and structural engineer, the contractors, and even the forensic experts, was astounding. If the design and construction team had complied with the governing energy code – the law of the land – the problems probably never would have occurred.

Ironically, none of these stories were about saving energy – which is ostensibly the purpose of the Energy Code. Understanding and complying with the Energy Conservation Construction Code just might be the best way to minimize the potential for problems to occur in your buildings. Reducing thermal losses, saving energy and utility costs, and minimizing fossil fuel combustion for heating and cooling thereby cutting down ongoing emissions of global warming gases, are additional benefits. Pick your favorite reason. Or pick them all! Just please – if you design buildings, learn and follow the Energy Code, and we’ll all be better off.