Recent weather conditions highlight the importance of avoiding unintentional design responsibility. This first quarter of 2018 has seen persistent periods of wind-driven rain; which often expose building envelope weaknesses. Uncontrolled rainwater penetration, condensation, and moisture related damage commonly result and threaten both structural integrity and building envelope performance. Indeed, virtually 90 percent of such sources of intrusion are uniquely associated with only 1 percent of the interfaces between materials or building components in the building envelope.
Frequently failures of this sort result from the improper integration of related building components, such as windows, doors, and flashing from the design phase of a project. Things such as reduced fees and accelerated schedules can lead to less exhaustive detailing by the designer. But despite this growing trend, such exhaustive detailing is important, and in many cases necessary.
For example, Section 107.2.4 of the International Building Code mandates that construction documents include exterior wall envelope details, including flashing, intersections with dissimilar materials, corners, end details, control joints, intersections at roofs, eaves or parapets, means of drainage, water-resistive membrane and details around openings.
Yet, despite such requirements, and sound practices, some projects get released for bidding with increasingly less information. Instead, those designs attempt to shift design risk to bidding contractors (and their subcontractors) through the shop drawing phase.
The result can be disastrous, and expensive. Poorly conceived submittals or attempting to resolve the designer’s intent in-house can and often results with missed intent and requirements; resulting in widespread leaks and resulting damages to the building and other property. To avoid that, contractors and subcontractors must avoid proceeding without clear, documented direction from the designer.
Savvy contractors negotiate contractual terms to preclude such risk allocation to them, but sometimes that cannot be negotiated. If not, contractors need to proactively address related matters during the submittal process; at the earliest possible stage; and unsavvy contractors that proceed with the mentality of “this is how we always install these components,” proceed at their own peril.
One of the main ways to address unclear designs is effective use of the Request for Information (RFI) process. If there is any question, RFIs regarding design intention, clarifications, and instructions are appropriate for requesting specific guidance from the designer and/or owner. Follow the RFI process strictly, retain all records; and memorialize related discussions.
Additionally, follow-on contract requirements incorporating additional design input received should be formally entered as a contract requirement. Virtually every construction contract includes a requirement for written changes only, executed by authorized contract agents only. Without strict compliance with those requirements, unintentional risks can get assumed regarding not only performance but also design; along with the additional liabilities that follow.