When a new commercial or residential building is designed, the roof system is more than a layer of materials placed over the structure. It is a critical building assembly that must provide weather protection, drainage, durability, energy performance, fire resistance, and resistance to environmental loads. The architect plays a central role in specifying the roof system, translating the owner’s goals and the project’s design requirements into clear construction documents that contractors can price and build.
Selecting the Right Roof System
The architect typically helps determine which type of roof assembly is appropriate for the project. Depending on the building, climate, slope, use, budget, and performance requirements, options may include modified bitumen, TPO, PVC, EPDM, built-up roofing, metal roofing, or other approved systems.
The selection should consider factors such as expected service life, maintenance requirements, thermal performance, appearance, drainage, fire classification, and compatibility with the building structure. The architect may also coordinate with roofing consultants, engineers, manufacturers, and other specialists when the project requires additional technical expertise.
Defining Roofing Materials and Performance Requirements
During the construction-document phase, architects develop drawings and specifications that establish the required quality and performance of building materials and systems.
For roofing, this can include specifying the membrane or roof covering, insulation, vapor retarders, cover boards, primers, adhesives, fasteners, flashing, edge metal, sealants, and other components. A good roof specification should describe not only the desired product or system but also relevant performance requirements, installation standards, testing, compatibility, and warranty expectations.
This level of detail helps prevent contractors from interpreting an unclear specification differently and provides a more consistent basis for competitive bidding.
Coordinating Roof Design With Other Building Systems
A roof rarely exists independently. Architects must coordinate the roof assembly with structural elements, walls, parapets, HVAC equipment, skylights, roof hatches, plumbing penetrations, electrical equipment, and drainage systems.
For example, roof penetrations must be properly detailed so that flashing and waterproofing can be installed without compromising the roof assembly. Drainage locations and slopes also need to work with structural framing and plumbing design.
Clear coordination between drawings and written specifications is important because inconsistencies can lead to RFIs, change orders, delays, and rework.
Addressing Code and Environmental Requirements
The architect also incorporates applicable building-code requirements and project-specific performance criteria into the construction documents. These requirements can include fire resistance, insulation values, wind uplift resistance, drainage, energy performance, and other applicable standards.
For example, roof system designers should not simply leave wind-load determination to the roofing contractor or manufacturer. The roof assembly needs to be designed around the building’s applicable wind conditions and project characteristics.
Reviewing Roofing Submittals During Construction
The architect’s involvement does not necessarily end when the drawings are issued. Depending on the owner-architect agreement, construction-phase services may include reviewing contractor submittals such as product data, samples, shop drawings, and other information.
Under typical AIA-based project arrangements, the architect reviews submittals for general conformance with the design concept, while the contractor remains responsible for the means, methods, and detailed execution of the work.
This distinction is important: the architect specifies and coordinates the design intent, while the roofing contractor is responsible for properly installing the specified system according to the contract documents, manufacturer requirements, and applicable standards.
Why Proper Roof Specification Matters
A well-written roofing specification gives everyone on the project a clearer understanding of what is required. It establishes the intended roof assembly, performance expectations, materials, installation requirements, and quality standards before construction begins.
For building owners, this can mean fewer surprises, more comparable bids, better coordination, and a roof system designed around the building’s actual requirements rather than simply the lowest initial cost.
The Bottom Line
The architect’s role in roof system specification is to define and document the design intent and performance requirements of the roofing assembly, coordinate it with the rest of the building, and help ensure that the specified system meets the project’s functional, code, aesthetic, and durability requirements. The architect does not normally perform the roofing installation; instead, the architect establishes what the roof should accomplish and documents those requirements so qualified roofing professionals can execute the work correctly.
For complex commercial projects, early coordination between the architect, owner, roofing consultant, manufacturer, and qualified roofing contractor can help ensure that the specified roof system is practical, code-compliant, durable, and properly suited to the building.
Related Questions
- What is the difference between a prescriptive and a performance specification?
- Should I use design-build or design-bid-build for a roofing project?
- What is RoofNav and how is it used during specification?
- What roof commissioning is recommended on new commercial buildings?
- What is building envelope commissioning and does it include the roof?
Commercial Roof Replacement / Re-Roofing
