spray foam is the best roof to install on a tight deadline

What’s the Best Commercial Roofing System To Install on a Tight Deadline?

Greg PalyaSpray Polyurethane Foam Roofing

A spray foam roof is the best roofing system to install on a tight deadline. Why? Because, in most cases, you can install it right over an existing roof, minimizing the timely tear-off. 

You’ll notice that I mentioned “minimizing tear-off.” This doesn’t mean there won’t be any roofing materials torn off.

There will be some tear-off in most cases (mainly because it’s probably leaking).

Which is fine. You want to eliminate the areas that allow water under the membrane. And you want to get rid of insulation that’s already wet.

Once the roof is dry, you can install a spray foam roofing system.

A real deadline killer is automatically going with a 100% tear-off.

In this article, we’ll go over:

  • Example projects that were completed on a tight deadline
  • What 3 variables shorten or lengthen a roofing project?
  • Do all roofing systems take the same amount of time to install?

And so you’re aware, West Roofing Systems has been in commercial roofing since 1979. Most building owners we come across want their roofing projects done ASAP. Some of them don’t realize they can significantly shorten the length of the project by which roofing system they choose to install.

This article has been reviewed, edited, and approved for publishing by a commercial roofing expert with more than 30 years of experience.

Let’s get started!

Example projects that were completed on a tight deadline

Project Name: Heskett Middle School

Existing Roof: Gravel Built-Up

Proposed Roof: Spray polyurethane foam

Days to Complete: 37

Days to Complete with an alternative solution: 75


gravel built up that needs repaired quickly


spray foam roofing over an existing gravel built up


One primary problem schools have is fixing roof issues on a tight deadline. They need the roof repaired while students and faculty aren’t on the premises. If the roofing project continues into the school year, it creates additional safety hazards.

This project was completed by wet-vacuuming the loose gravel off the roof. Then the roof was power washed to remove dirt and to provide a clean substrate. Spray foam was then applied over the roof. Many penetrations would’ve interfered with the installation of a traditional roofing system, such as TPO.

Spray foam and coating were installed in 37 days. An alternative solution, removing the rocks and installing a single-ply roof, would’ve taken at least double the time to install.

Read more: Complete case study – Heskett Middle School

Project Name: Oakview Elementary

Existing Roof: EPDM

Proposed Roof: Spray polyurethane foam

Days to Complete: 20

Days to Complete with an alternative solution: 40


commercial roof in poor condition


spray foam over a roof needing a repair on a tight deadline


Oakview Elementary had a similar problem. They needed a new roof installed when students were away on summer vacation. They got quotes from multiple contractors installing different roofing systems.

The only roofing system that could avoid a complete tear-off was spray foam. While other solutions could provide a dry and watertight roof, the cost was more than double, and it would’ve taken twice as long to install.

Roofs with lots of penetrations (HVAC units, exhausts, skylights, drains, etc.) are difficult to make watertight when not installing a fluid-applied product.

Read more: Complete case study – Oakview Elementary

Now that we’ve seen a few examples of projects installed on tight deadlines, let’s discuss what shortens or lengthens a roofing project.

What shortens or lengthens a roofing project?

Number of roofing systems

Per building code, the maximum amount of roofing systems you can have on a commercial building is two.

Suppose you already have two roofing systems installed. In that case, you’ll need to completely remove a roofing system before installing a new one.

You can do simple repairs and install any roofing system over the top if you have only one roofing system.

Complete removal of a roofing system will significantly lengthen any roofing project.

Amount of tear-off (1%, 20%, or 100%) – The 25% cutoff?

It’s simple to know that more tear-off will lengthen a roofing project. But how do you know how much tear-off will be (or should be) done?

25% is the industry standard for the amount of wet insulation a roof has when it should be 100% torn off.

A roof that’s 20% wet can be restored or re-roofed in most cases.

Some roofs have 1% wet insulation. These can be re-roofed, and the job can be completed much quicker than a job with 20% tear-off.

Application quickness, details, and scope of work

How fast a roof can be installed is a combination of:

  • how a roofing system is installed
  • the details of the roof
  • and the scope of work

For example, a roof with very little penetrations, a single-ply roof can be installed pretty quickly. Sheets can be 10 feet wide and 100 feet long. It’s not time-consuming to roll these out and fasten them down.

The same roof, but there’s a sloping issue that’s been causing ponding or standing water. A large amount of polyiso board must be tapered to create proper sloping. The added materials and the added scope of work significantly increase the length of this project versus the first one.

The same roof has 10 skylights, 5 HVAC units, 5 drains, and 100 feet of pipe on the roof. The single-ply or metal roof route would be very time-consuming to make watertight with all these interferences. A spray foam roof, which is fluid-applied, can be installed around penetrations much faster than a non-fluid-applied roof.

Do all roofing systems take the same amount of time to install?

No. Each roofing system takes a different amount of time to install. We beat up on the details in the previous section, but if you’re a building owner on a tight deadline, make sure you get the estimated installation time.

Better yet, get quotes from contractors installing different kinds of roofing systems.

Maybe one contractor can install it quicker, but it costs more. Perhaps you’ll hit the jackpot, and one contractor can install your roof faster, and it costs less!

Sometimes cost is important, and sometimes the project needs to get done on a tight deadline, making other solutions more attractive.


Schools aren’t the only buildings that need roofing projects done quickly. Strip malls and apartment buildings need roofs done promptly so they can continue to collect rent. Private companies need roofs repaired soon so the business can operate normally.

The best roofing system to install on a tight deadline depends on:

  • The roofing system you choose to install
  • The problems that need to be fixed to get the roof watertight
  • The number of penetrations/interruptions a roof has

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About the Author

Greg Palya

Greg Palya is the Digital Content Manager of West Roofing Systems, Inc. He has a B.S. in Marketing from the University of Akron and an MBA in Marketing from Walsh University. When he's not trying to teach others about spray foam roofing and silicone roof coatings, you can find him on the basketball court or golf course.