Replacing a Flat Roof: 4 Options

Roof repair or replacement on a flat roof is not a simple decision.

But it's a crucial one, since your roof provides critical protection for your business.

While a flat roof is often easier to build and provides additional usable space, it is also more susceptible to issues like water pooling and leakage.

In this article, we'll discuss your four primary options for replacing a flat roof: Layover, Tear-Off, Roof Restoration with Elastomeric Coating, and Spray Foam Roofing. Each comes with its own set of advantages and drawbacks, and the right choice depends on various factors such as the condition of your existing roof, your budget, and your long-term plans for the building.

Table of Contents

• Option 1: Layover
• Option 2: Tear-Off
• Option 3: Roof Restoration (Elastomeric Coating)
• Option 4: Spray Foam Roofing

Option 1: Layover

What is Layover?

A layover, also known as a roof overlay, is the process of installing a new layer of roofing material directly over the existing roof. Instead of tearing off the old roof, contractors simply add a new layer on top, effectively 'overlaying' the existing structure. This method is often quicker and less labor-intensive compared to completely removing and replacing the old roof.

Advantages of Layover

1. Cost-Effectiveness: One of the most significant advantages of a layover is that it's generally less expensive than a full tear-off. You save on labor costs and disposal fees associated with removing the old roofing material.

2. Speed of Installation: A layover can usually be completed much faster than a full roof replacement, as you are skipping the time-consuming removal phase. This is especially beneficial if you're on a tight schedule or want to avoid weather-related delays.

3. Less Disruption: Because there's no need to remove the existing roof, there's usually much less noise, dust, and general disruption to your daily activities or business operations.

Drawbacks of Layover

1. Underlying Issues: A major downside of opting for a layover is that it doesn't address any underlying issues your roof may have, such as water damage or structural weaknesses. Any problems with the original roof could continue to worsen over time, potentially leading to more significant issues down the line.

2. Increased Weight: Adding another layer of roofing material increases the overall weight on the building's structure. This can be a concern, particularly for older buildings not designed to handle the additional load.

3. Shorter Lifespan: Generally, a layover won't last as long as a completely new roof. If the existing roof has any issues, they can affect the new roof's performance, leading to a shorter lifespan for the roof as a whole.

When to Choose Layover

1. Budget Constraints: If your primary concern is budget, a layover is usually a more cost-effective option in the short term.

2. Time Sensitivity: If you need the job done quickly, such as before the arrival of harsh weather, a layover can be completed in a shorter timeframe.

3. Structural Integrity: If an inspection reveals that your existing roof is in relatively good condition with no major issues like water damage or rot, a layover can be a viable option.

Option 2: Tear-Off

What is Tear-Off?

A tear-off involves completely removing the existing roof down to the decking before installing a brand new roofing system. This method is more comprehensive and often seen as the 'gold standard' of roof replacement.

Advantages of Tear-Off

1. Longer Lifespan: Because a tear-off involves installing a brand-new roof, it often results in a system that will last longer than a layover would.

2. Higher Resale Value: A completely new roof is often more appealing to potential buyers and can increase the resale value of your property.

3. Better Energy Efficiency: With a new roof, you have the opportunity to improve insulation and, in turn, your building's energy efficiency.

Drawbacks of Tear-Off

1. Cost: Unsurprisingly, tearing off the old roof and installing a new one is generally more expensive than a layover because of the added labor and materials.

2. Time-Consuming: A tear-off is a longer process, as it involves not only installing new material but also removing the old roofing. This could be an issue if you're on a tight schedule.

3. Disruption: The process can be noisy and disruptive, particularly if the building is occupied during the renovation.

When to Choose Tear-Off

1. Poor Condition of Existing Roof: If your current roof is in poor shape, a tear-off is often the better long-term solution.

2. Multiple Layers: Building codes often limit the number of layers a roof can have. If you already have multiple layers, a tear-off may be your only option.

3. Long-Term Investment: If you plan to stay in the property for an extended period and want a long-lasting solution, a tear-off is often more suitable.

Opting for a tear-off gives you the opportunity to address any underlying issues and typically results in a longer-lasting, more durable roofing system. While it's usually more expensive and time-consuming than a layover, the long-term benefits often outweigh the initial costs and inconveniences.

Option 3: Roof Restoration (Elastomeric Coating)

What is Roof Restoration with Elastomeric Coating?

Roof restoration using elastomeric coatings is a method that involves applying a specialized, rubber-like coating over your existing flat roof. This coating cures into a tough, water tight membrane that protects your roof from rain, wind, hail, and the sun's uv rays. This can extend the lifespan of your existing roof almost indefinitely, and it is compatible with virtually any flat roof material, from built up roofs to metal roofing.

Advantages of Roof Restoration

1. Extended Roof Life: One of the major benefits of using elastomeric coatings is the extension of your roof's lifespan. The coating acts as a protective layer, preventing sun damage and reducing wear and tear.

2. Energy Efficiency: Elastomeric coatings often come in lighter colors that reflect sunlight, reducing the amount of heat absorbed by the roof. This can lead to a cooler interior and lower air conditioning costs.

3. Cost-Effective: Restoration is often cheaper than a complete replacement because it utilizes the existing roof. This saves you the costs of tearing off the old roof and installing a new one.

4. Quick Installation: Compared to other methods, roof restoration can be faster as it doesn't involve tearing off the existing roof.

Drawbacks of Roof Restoration

1. Not Suitable for Severely Damaged Roofs: If your roof has significant damage or structural issues, a simple restoration won't be sufficient. In such cases, a more comprehensive approach like a tear-off may be necessary.

2. Weather-Dependent: The effectiveness of elastomeric coatings can be influenced by the weather conditions at the time of application. For best results, the roof surface needs to be dry, and the application is ideal in warmer temperatures.

When to Choose Roof Restoration

1. Moderate Wear and Tear: If your roof has only minor damages or is showing signs of aging but is otherwise structurally sound, roof restoration can be an excellent choice.

2. Budget Constraints: When you're looking for a more budget-friendly option that still offers a range of benefits, a roof restoration can fit the bill.

3. Shorter Project Timeline: If you're pressed for time, the quicker installation process makes roof restoration a viable option.

Option 4: Spray Foam Roofing

What is Spray Foam Roofing?

Spray foam roofing, also known as Spray Polyurethane Foam (SPF), is a liquid material that expands into a foam when applied to a surface. This foam forms a solid, continuous layer that can serve as a durable roofing system for flat roofs. Much like an elastomeric coating, the spray application allows for a seamless roof covering, effectively eliminating joints or seams where water can penetrate.

Advantages of Spray Foam Roofing

1. Insulation Benefits: SPF is an excellent insulator, providing thermal resistance and reducing heat transfer. This helps in lowering your energy bills by making your building more energy-efficient.

2. Flexibility in Application: One of the advantages of spray foam is its versatility. It can be applied over various substrates and irregular shapes, offering design flexibility.

3. Environmental Benefits: Spray foam roofing can reduce your building's energy usage by up to 30%. Because it usually prevents a tear off, it also reduces landfill waste.

4. Waterproofing and Drainage: Because it forms a seamless layer, spray foam roofing is effective at keeping out water and can be sloped to aid in drainage.

5. Lightweight: Compared to traditional roofing materials, SPF is relatively light, putting less stress on your building’s structure.

6. Ease of Maintenance: SPF roofs are easier to repair and maintain. In many cases, small damages can be fixed simply by adding more foam.

Drawbacks of Spray Foam Roofing

1. Weather Sensitivity: The application of SPF requires specific weather conditions. The foam cannot be properly applied if temperatures are too low, or if the surface is wet.

2. Skilled Labor Required: The application process needs expertise to ensure the foam is applied correctly. Incorrect application can lead to problems like uneven thickness or poor adhesion.

When to Choose Spray Foam Roofing

1. Energy Efficiency or Environmental Concerns: If you're looking to enhance your building's energy efficiency and reduce landfill waste, SPF is a great choice.

2. Complex Roof Geometry: Spray foam can easily conform to different shapes and sizes, making it ideal for roofs with complicated designs.

3. Weight Constraints: If your building structure cannot handle much additional weight, the lightweight nature of SPF could be a good fit.

The Upshot

Replacing a flat roof is a significant investment, both in terms of time and money. As we've seen, there are multiple routes you can take: Layover for a quick and cost-effective solution, Tear-Off for a thorough revamp, Roof Restoration with Elastomeric Coating for extending your roof's lifespan, or Spray Foam Roofing for a lightweight and insulating option. Regardless of which path you choose, it's essential to thoroughly understand your options, or you could end up with a serious headache down the road. 

If you have specific questions about roof replacement, or need an inspection, give us a call. In a 30 minute, no-obligation call, our nationally-recognized roofing experts can provide you with customized guidance.