Commercial Roof Replacements: Everything You Need to Know

Commercial roof replacements are huge projects with a wide array of factors that can influence the cost, project timeline, and how invasive or noninvasive the project will be. Some factors include the height of the building, access, whether the project requires a full replacement or an overlay, and the type of new roof to be installed. Just as important are the weather conditions and time of year it’s being replaced.

We’ll take you through Simpson’s battle-tested process of the roof inspection, estimating, planning, scheduling, and budgeting, and all of the major variables and considerations to keep in mind as you determine how and when to replace your commercial roof. (Learn more about Simpson Unlimited’s roof replacements and schedule an inspection here)

Unfortunately, there’s no “one size fits” all approach to commercial roof replacements, however a professional and experienced commercial roofing contractor should always conduct a thorough in-person assessment of the existing roof to review all existing conditions (i.e access, height of the building, etc.), as well as take core samples to provide customers with multiple options for the project’s scope.

Using a 3-part plan, they’ll build a timeline of your commercial roof replacement that details every aspect of their roofing services — from design to mobilization to crew size to footprint to closeout — all while taking into account the building type, the customer’s needs, and the building occupants’ comfort.

But there’s a lot of other supplemental information to take into account before committing to a commercial roof replacement, which we’ve outlined in detail below. Warranties, commercial roof types, and more are explained to give you a better understanding of everything the involved process entails.

What are the biggest factors I need to consider when replacing my commercial roof?

There are a bevy of factors and variables to consider when defining the scope and timeline of any commercial roof replacement.

For example, does the existing roof need to be replaced? Is there equipment currently on the roof that will need to be removed? The building height and access to the roof, as well as weather conditions and time of year (ie. temperature), will all have an impact on a commercial roof replacement’s timeline.

Other considerations include the number of layers, types of layers, and overall depth of the removal/replacement. Overburden, like pavers, furniture, or gravel, can add to the project scope. And, most importantly, the type of commercial roofing system being installed, whether it’s an asphalt roofing system or single-ply, traditional assembly or inverted, and the type of attachment method used for the insulation and membrane.

Given all the potential variables, Simpson puts together a 3-part plan for their customers that includes the following breakdowns:

Safety Plan: Outlining fall protection, personal protection, occupant protection, and public protection across the entire commercial roof replacement project.

Staging Plan: Outlining access of employees to the roof, the location of roofing equipment, and the staging areas for toilets, chutes, dumpsters, cranes, or other large on-site elements.

Phasing Plan: A working document that outlines the anticipated daily work area for coordination with building management and occupants. This will also detail the days and times that have the greatest impact on building users, such as when the roof is being actively removed overhead or drilling of concrete for mechanical anchors is taking place.

Lastly, the best commercial roofing system has a lot to do with the type of building being worked on, as well as the type of equipment within. A roof replacement over a hospital, for example, will be handled much differently from an everyday shopping center.

How long does a commercial roof replacement typically take and what does it involve?

Project timelines are one of the biggest considerations in any major project. Though it will vary largely by building type and scope (in addition to all of the factors we outlined above), the general timeline and process for any commercial roof replacement looks roughly like this:

Site Visit (1 week): Within a week, our contractors will visit your site to do a thorough walkthrough and roof inspection to examine the conditions, take a number of core samples, and communicate our findings to the customer.

Proposal (1-2 weeks): We’ll develop and build a formal proposal customized to your commercial roofing system and taking into account all of its unique complexities.

Approval & Permitting (1-3 weeks): Once the proposal is agreed upon and executed, we’ll obtain all necessary permits required for the project and hold a preconstruction meeting with the customer to discuss the details of the project and coordinate all of its logistics.

Commencement (1-2 weeks): Within a couple of weeks, and dependent on the weather conditions, roofing services will begin in line with the customer’s desired schedule mutually agreed upon.

The number of crew members for a commercial roof replacement varies, but generally speaking the roofing crew consists of roughly 8 members, as well as an on-site Foreman, Superintendent, and Project Manager to actively supervise the site. Third-party independent Safety Contractors will audit the job site intermittently to conduct randomized inspections and provide safety reports.

Inevitably, there will be a level of noise that’s disruptive. But those days will be limited to specific times when actual overhead work is being done, and there are a number of measures to reduce noise disruption, including performing those noisier tasks earlier in the morning, later in the evening, on the weekends, or whenever we can be flexible with the customer. Like every element of our roofing services, the timing will be based on the customer’s preference.

What should I know about a commercial roof replacement before I commit to the service?

There are a number of misconceptions surrounding commercial roofing replacements, as well as a number of questions we’re repeatedly asked by potential customers, which we’ve listed below:

We always replace what’s being removed. In other words, everything we take off of the roof is replaced that very same day. We never take out more than we can replace in a day so the roof remains waterproofed at all times.

There’s no ‘one size fits all’ approach. Sadly, there’s no perfect roof or universal roof type. The best commercial roof replacements are custom-designed to fit the building, the occupants, and the owner’s budgetary considerations.

It’s a big project. The scope of a commercial roof replacement is quite large and requires an extensive mobilization, a vast setup with a large footprint, and an array of utilities like equipment, protection, dumpsters, toilets, etc. for a large-scale multi-week job.

Warranties can be complex. “System Warranties” (ie. “Labor and Material Warranties”) cover the materials installed and the quality of workmanship. But manufacturer warranties are not created equal and a lot of building owners are surprised when they learn that oftentimes their roof leaks aren’t covered. Similarly, “No Dollar Limit” warranties do not have coverage limited to the cost of the initial roof replacement/installation.

What’s not covered? Accidental punctures by rooftop HVAC servicing, occupants on the roof, satellite dish installations, standing water from drainage point blockage, and a host of other variables that could be avoided during bi-annual inspections and standard preventative maintenance. You’ll also be liable for any damage, punctures, abuse, or service by unqualified roofing companies, or wind damage above the stated coverage in the warranty, which is generally 55 MPH unless you have a roof system with enhanced wind speed warranty coverage. In addition, there are many details on a roof that are deemed “owner maintenance,” which include sealant at pipe penetrations, exposed termination bar, and pourable sealer pockets.

No ‘roof overs’ for soaked roofs. If your existing commercial roofing system is more than 25% saturated, then a “roof over” will not be an option and your hand will be forced to do a full replacement for warranty coverage. Depending on the level of saturation, it may also damage your structural decking, which is another immense cost.

Waiting for a leak means it’s already too late. Waiting until there’s a noticeable disruption in your roof can damage your relationship with your tenants and jeopardize the building’s overall integrity. Preventative maintenance, on the other hand, can save you a significant amount of money and prolong your commercial roof’s lifespan by years, often past its warranty period.

Why can’t I just waterproof or reseal leaks and punctures myself? Not only are leak sources difficult and complex to identify, but store-bought materials that are incompatible with your commercial roofing system can do significant harm to its integrity. No matter how much you pride yourself in your DIY abilities, these industry-grade and manufacturer compatible materials can’t be found at your local store.

What are other major considerations, curveballs, or elements involved in a commercial roof replacement?

Like our above list of common questions and misconceptions, we also want to detail all of the potential curveballs or potentially unforeseen elements that can affect a commercial roof replacement’s timeline, scope, or budget.

Budget determines design. How we determine the scope and design of a commercial roof replacement is dictated by the customer’s predetermined budget. The customer’s desired length of roof system warranty coverage is an important factor as well since a 10-15 year old roofing system will have a different design from a 20+ year old roofing system.

Drainage by design. The proposal introduced early in the process will outline all design elements, including industry-standard drainage to ensure it fits your building’s existing drainage system. If it doesn’t meet today’s requirements or best practices, Simpson will augment their replacement system to ensure it works properly.

Energy (and cost) conservation by design. Commercial roof replacements must be designed to meet the current energy code for the jurisdiction that the building is located in. Proper energy design can greatly aid in reducing energy costs for the building owner.

No change orders unless required. Most people don’t expect change orders because most contractors do not appraise their customers of potential contingencies before the commercial roof replacement operation begins. Simpson makes a point of being completely transparent and making the customer aware of potential variables before project commencement.

You can’t overlay a wet roof. If more than 25% of the existing roof is saturated, it’s more cost-effective to do a full tear-off. Similarly, if there are two roofs, they’ll need to be torn down to their decking.

Maintenance is (always) key. Your new commercial roof needs to be serviced and inspected just as much as your old roof. It’s in your best interest to protect your investment!

How do I know if my commercial roof needs to be replaced?

Most often, a commercial roof replacement is part of a building’s long-term plan and mandated by the building owner. But outside of a general timeline, knowing exactly when to replace your roof depends greatly on the condition of the roof itself and the type of commercial roofing system you have installed.

Your roof’s age is an important consideration, not only because of the warranty period (most roofs today offer a standard 20-year warranty, whereas 20 years ago warranties lasted for only 10-15 years) but because of its history of leaks or repairs. Any repairs or replacements we conduct are sized to budget, and typically repairs are designed to last roughly 2-5 years.

Any commercial roof with long term, chronic leak issues should be considered for replacement or major repairs at a minimum. But without a commercial roofing professional, it’s impossible to determine how much a building leak is caused by the roof itself.

Choosing the right time to replace your roof is a balancing act. Generally speaking, it’s best to follow a 2-5 year maintenance plan following any repairs to allow yourself time to budget for a replacement. Most customers are reactive and won’t do anything until there’s a visible leak, but maintenance is always cheaper to start sooner.

Below is a breakdown of the most common commercial roofing types we deal with and the recurring issues we face for each:

Modified bitumen gets killed by the sun. The sun is any commercial roof’s worst enemy but that’s especially true for modified bitumen roofing systems. Granules on the top ply protect the asphalt from long term heat aging/UV’s, but when granule loss occurs, it’s only a matter of time before the roof begins to break down.

EPDM is worn down similar to a tire. Like tire treads, you can read the wear of an EPDM roof based on its cosmetics. As a single ply roof, it telegraphs problems differently than others. Bridging/tenting is a common issue, because the EPDM shrinks over time, pulls the flashing, and creates tears or holes. EPDM roofing systems are chemically bonded together at the seams, so generally speaking, open seams are a clear red flag and a sign the roof might need to be replaced.

TPO/PVC roofs need to be replaced when you see the scrim, feel the bitterness, or see the seams open up. A weathering layer on top of these roofing systems erodes roughly 1mm each year. Once the scrim is exposed, it can no longer be waterproofed and needs to be replaced. Like EPDM, TPO and PVC are single-ply, so installations are quicker and easier than multi-layered roofs like BUR and Modified Bitumen.

Built-Up Roofing (BUR) systems are the hardest to read. BUR roofing systems very clearly show their repair histories.

Metal roofs are very expensive to replace. That’s why more often than not we’ll conduct extensive coating or retrofitting repairs to metal roofs, rather than a full replacement.

How does Simpson Unlimited uniquely handle commercial roof replacements?

When we’re approached by a potential customer about conducting a commercial roof replacement, rarely do they have a firm understanding of what they’re actually asking for.

First and foremost, Simpson offers absolute pricing transparency. If there are discrepancies about the price during the bidding process, we’ll ask to compare our project scope to the scopes of the other bidders. Chances are the cheaper jobs offer a smaller scope of work, or it could simply boil down to the cheaper contractor being smaller (or less reputable) or maybe more desperate for work.

We strongly suggest that all potential customers interview their commercial roofing contractors and hold their bidders accountable. Ask why they have the best solution for your commercial roofing system. Ask for references and copies of manufacturer certification letters. Thanks to our long track record, Simpson understands all of the unforeseen conditions beforehand and will bring them to the owner’s attention to outline any and all contingencies that need to be considered.

Simpson prides itself in minimizing change orders as much as humanly possible. That’s why we make 5-6 core cuts on our initial walkthrough to make informed recommendations to the owner. Every once in a while, rotted or rusted decking, buried conduits, or deep rot or water intrusion won’t be found until later in the process. But much more often, change orders arise when owners decide to add scope to their project because they’re happy with the work we’ve completed thus far.

We also pride ourselves in matching the final product to the initial presentation; what we show you beforehand is exactly what you’ll get. We ensure all of our commercial roofs are properly sloped. We’re also certified with virtually every major commercial roofing manufacturer and are required to maintain those certifications, so you can enjoy the peace of mind of working with an industry-approved standard-bearer.

One last word to the wise — don’t replace your commercial roof unless you can also afford the coverage and maintenance. Otherwise, it’s a lost investment. There’s no greater or more costly waste than replacing your roof and failing to maintain it.

Most manufacturers require some level of basic proactive roof maintenance to maintain their warranties, and that maintenance can prolong your roof’s lifespan by years.

Your commercial roofing system is a unique beast, and there’s a lot of information to keep in mind before, during, and after the process to ensure the longest possible lifespan for your roof, the comfort and peace of mind of your building tenants, and the short and long term costs for you as the building owner or engineer.

A majority of that responsibility rests on your commercial roofing contractor’s shoulders. As long as they’re certified, reputable, safe, and transparent, all you need to ensure is that you have the proper amount budgeted for regular maintenance and the diligence to follow through on bi-annual inspections to maintain your warranties.

Otherwise, the biggest to-do is finding a commercial roofing contractor you trust.

And hopefully, Simpson Unlimited’s 25+ years of standard-setting experience and proven track record establish us as the only call you need to make.

In need of a commercial roof inspection, repair, or maintenance? Click below to learn more about our services and schedule a free commercial roof inspection today!


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