Building Enclosure Commissioning Overview, Part 2
Why Commission the Enclosure? Building Enclosure Commissioning Overview, Part 2
In the ideal world, all components of the building enclosure providing waterproofing and air leakage mitigation – air and water resistive barriers, flashings, primary and secondary membranes, sealants, coatings etc., would be thoroughly analyzed for compatibility and detailed with great care to maintain integrity at all possible conditions arising as a result of the building design. But in the real world this would result in very high design fees and be near impossible to accomplish within the project schedule. A firm understanding of the building enclosure commissioning can prevent potential problems. Please enjoy this Building Enclosure Commissioning overview.
The best that the architect can do, is provide representative details and specifications.
For the remaining issues, he kicks the can down the road and hopes for the best…
During construction, several issues routinely arise that bear close scrutiny and observation. For example, even if the construction drawings have details for specific conditions, the installer may install the detail the way he sees fit. Or if a detail has been provided, there may be a need to improvise it, to account for conditions in the field. In this case, the installer may proceed with improvising it as needed for ease of installation, rather than issue a request for information to the Design Team. Especially if these kinds of situations deal with the air, thermal or water barriers / waterproofing of the building, the energy and durability of the building could be compromised. And then of course, there are always plenty of conditions which are simply not detailed – as I mentioned above, the goal is to provide representative details and leave the variations for resolution during construction.
But isn’t that why we have architects involved with the construction phase?
They are paid for regular site visits, so wouldn’t they address these discrepancies? According to AIA B101 and A201 (the standard AIA contract documents used in the industry) “The Architect will visit the site at appropriate intervals to become generally familiar with the progress and quality of the Work completed, observing if it complies with the Contract Documents”. In other words, architects do NOT supervise the work nor do they closely scrutinize for quality and integrity of waterproofing and other critical installations. Their focus on workmanship is mainly aesthetic in nature and to ensure that the work installed, follows the drawings, submittals and shop drawings. They need a building enclosure commissioning overview!
Additional issues also arise as a result of sequence of installation followed by the general contractor. A very common example is that of leakage at the joint between the door assembly and balcony deck. Disabled access requirements necessitate that the difference in height between the floor and balcony deck cannot exceed ¼”. In case of concrete floors, balcony decks are cast at the same level as floor. Since the GC will want to enclose the building as soon as possible, the door assembly will be installed prior to the protective coating on the balcony deck. This practice also ensures that the protective coating does not get dirty/ damaged during construction. This means that the sealant at the base of the door assembly is installed prior to the balcony deck coating and the door assembly weep holes end up below the level of the balcony coating/ finish. Over time, as the water seeps under the balcony deck finish, it may cause the finish to fail or worse, impact the structural integrity of the balcony framing. To fix this issue, it would necessitate altering the sequence of installation or doing an additional intermediate step.
All of the above issues with details, observation of critical installations, review of construction sequencing prior to start of construction, are part of the enclosure commissioning agent’s scope of work.
The idea is to bridge the gap between the architect and the general contractor with a focus on water proofing, energy efficiency and longevity of the building. The enclosure commissioning agent not only reviews drawings in the Design Phase to ensure that the air, water and thermal barriers (a.k.a control layers) are continuous through various interfaces (e.g. openings, penetrations, material changes, etc.) but also undertakes extensive construction observations to ensure integrity of installation of the control layers and the building enclosure as a whole. Testing of the installation is another key aspect that I have not touched on. I will keep this for a later blog as it is a fairly extensive topic in and of itself.
I hope this blog has been helpful in shedding more light on the upcoming field of enclosure commissioning. Thank you for reading our Building Enclosure Commissioning Overview blogs.
Who is Healthy Building Science?
Environmental Testing Services at HBS
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