ENGINEER’S CORNER: What to Consider Before a Window Replacement Project


By Rebecca Reilly, Sullivan Engineering

During the design phase of a window replacement project, building owners must consider many factors and make decisions that can impact costs, aesthetics, timelines, building occupants, and future repair/maintenance. Enlisting the assistance of an experienced design professional to make project specific recommendations is the prudent way to proceed.


Design professionals can assist owners with choosing he right windows to meet performance standards and energy requirements while still being cost-effective. (Photo: Sullivan Engineering)

Building owners should consider the appearance of the windows to be installed. An architectural rendering showing the expected appearance of the building after replacement may help owners and building occupants envision the aesthetic outcome. If the existing windows are not a standard style or size, the lengthy design and fabrication process for custom window replacement can be very expensive.

There are many window manufacturers with various price points to choose from. Owners must consider the effectiveness, reliability, lifespan and energy efficiency of the proposed materials and finishes. Design professionals can assist owners with choosing the right windows to meet performance standards and energy requirements while still being cost-effective.

Mockups should be installed to ensure that owner’s expectations with regard to appearance and performance are met or exceeded. This is especially helpful before a full-scale window replacement project is performed at a large building. In some cases, a window or two might be installed for one year prior to commencement of a window replacement project to track performance in all seasons.

DOB Permits and LPC

Typically, obtaining DOB Work permits for a simple window replacement project is not necessary. However, a permit would be required if the size of any window opening is changed. Additionally, there are added complications and requirements when performing window replacement at landmark buildings or at buildings within landmark districts. Approval of a smaller project at a building in a landmark district can often be made at the “staff level”, while the commission needs to approve a project at a landmark building or a large-scale replacement project at a building within a landmark district.

Establishing a master plan with the LPC is an efficient means of performing window replacement in landmark districts. A master plan includes specifications for future repairs, maintenance and replacement of a building’s windows that is subject to a full LPC review. Although the process of establishing a master plan can be lengthy, it’s especially helpful when windows are sporadically replaced. Set requirements for the replacement windows eliminate the need to initiate a full application process.

The impact of construction on building residents should always be considered. Ideally, any individual window should be replaced in one working day. A window opening should never be left open overnight for obvious reasons such as: potential water infiltration, heat/air conditioning loss, security reasons, etc. With the help of a building exterior consultant, property management and ownership should properly vet window replacement contractors to confirm that they have the workforce, knowledge and experience to accomplish one-day window replacement. Additionally, building occupants should be made aware of how interior finishes might be impacted by the replacement project.


The views and/or opinions contained within are those of the drafter and may not reflect the views and/or opinions of Skyline Restoration Inc.

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