Shop Drawings on Building Restoration
By: Jose Santos
During the process of building envelope restoration, all contractors are provided with plans and specifications that reflect the project scope of work. The drawings graphically detail the required repair work at each elevation, while the specifications detail the repair work in writing. The specifications also outline the materials required to perform the work and the submittals that the Contractor is to submit to the Design Professional. Shop drawings are part of these submittals.
Shop drawings are detailed construction drawings provided by the Contractor that graphically depict the proposed materials, including, their size, shape, and more critically, their proper assembly. This allows the Design Professional to understand how the Contractor intends to implement the design in compliance with the plans and specifications. Contractors are ultimately responsible for the means and methods of construction, as well as verifying that the dimensions shown depict the actual field conditions. It’s crucial that the construction documents contain sufficient details to ensure the Contractor understands the design intent, along with the proposed materials for the project.
During the construction phase, the Contractor prepares the shop drawings for items such as parapet railings, replacement cornices, windowsills, decorative stone work, etc. Depending on the item being detailed in the shop drawing, they are often prepared by licensed professionals with specific experience relating to the item system or components. Structural calculations that are typically signed and sealed might also accompany the drawings. For example, the shop drawings for a railing replacement should depict the railing profile design, post and picket spacing, top and bottom rail spacing, attachment to substrate, and dimensioning of the overall assembly. The railing shop drawings should also be accompanied by structural calculations to reflect that the railing will meet the required regulatory design loads.
It is of the upmost importance that the shop drawings be carefully reviewed by the design professional to confirm they meet the design intent, design requirements and building regulations. Once reviewed, the shop drawings are either approved, returned to the Contractor for revision, or rejected. It’s important for the design professional to stamp and sign the shop drawings with the company’s submittal stamp, which serves as a record for the project.
The preparation, review and approval of the shop drawings is a critical juncture in the grand scheme of a project. Negative implications and schedule delays can be avoided if this aspect of a project is carefully managed.