Flat roofs are commonly installed on commercial properties like warehouses, office buildings, retail stores, and industrial complexes. Unlike sloped residential roofs, these roofs need special treatment for lasting performance, weather resistance, and cost efficiency. One of the most common features of flat commercial roofs is that they have a layer of gravel.
So why do flat commercial roofs have gravel? Let’s dive into understanding this in the blog below.
Benefits of Gravel on Flat Commercial Roofs
1. Protects Against UV Damage
Flat commercial roofs are usually made of materials like modified bitumen, built-up roofing (BUR), or single-ply membranes like EPDM or TPO. While all of these materials are long-lasting, they can wear and tear due to prolonged exposure to sunlight.
Gravel adds an additional layer of protection against harmful UV rays which can dry out, crack, or damage roofing membranes over time. Gravel protects this membrane from direct sunlight, extending the lifespan of your roof and reducing the need for repairs.
2. Ensures a Stable Roof
Flat roofs are more likely to uplift during strong winds as compared to pitched roofs. The roofing material can shift or peel away if not anchored properly. Gravel adds weight and stability to the roof, anchoring down the roofing material underneath it.
This is even more important in the case of single-ply roofing systems such as EPDM which are usually laid loosely over insulation.
3. Effective Fire Resistance
Gravel on a flat commercial roof improves fire resistance. It acts like an effective fire retardant. Commercial roofs often house electrical lines, mechanical units, or HVAC systems that can pose fire risks. Adding a non-combustible gravel layer prevents flames from spreading.
In areas with strict fire safety standards such as urban areas or industrial zones, having a layer of gravel on a flat commercial roof not only provides protection against fire but also meets compliance requirements.
Also Read: Commercial Roof Repair Guide: Fixing Flat Roofs and Storm Damage Efficiently
4. Preventing Water Pooling by Ensuring Proper Drainage
Flat roofs are also slightly sloped or pitched to ensure proper drainage. However, you need to know that water can still accumulate in low spots leading to leakage or severe structural issues over time.
By adding gravel, roofs have better drainage as it creates a natural path for water to flow toward drains or scuppers. It also ensures that your roof’s drainage systems remain free from debris and unclogged as leaves, branches, and other materials usually get trapped in the gravel layer.
5. Protects Against Foot Traffic Damage
Flat commercial roofs often ensure regular foot traffic. It can be from maintenance crews, HVAC experts, or inspections. Walking straight on roofing membranes can lead to punctures, cracks, or general wear and tear.
Gravel on flat commercial roofs acts like a protective barrier that absorbs the pressure of foot traffic, thereby reducing the risk of membrane damage. It also provides a better grip, preventing tripping hazards for anyone working on the roof.
6. Enhanced Energy Efficiency and Temperature Regulation
Another lesser-known benefit of gravel on flat roofs is it helps in regulating temperatures. The gravel layer reflects sunrays, providing insulating properties and protecting from extreme heat during the summer. This reduces the energy consumption and bills.
Furthermore, during winter, gravel retains internal heat and maintains a cozy indoor temperature.
7. Increases Roof longevity and Reduces Maintenance
Gravel protects against UV rays, punctures, and drainage issues, prolonging the lifespan of commercial flat roofs. When the roofing membrane is protected, it is less likely to be damaged by strong winds, heavy storms, and rains. This eventually reduces the need for repairs.
Even when minor issues arise, flat commercial roofs with a layer of gravel on top generally need localized repairs. So, repairs are easy to manage and you don’t need to replace entire sections.
8. Affordable Roofing Solution
With so many roofing material options in the market, business owners strive to achieve a balance between cost and performance. Gravel-topped roofs offer a high return on investment as they are easier to install and low maintenance in the long run.
Gravel ballast roofing also has lower labor and material costs. It also avoids premature damage, aging, and repairs.
Also Read: Why Flat Roofs Dominate Commercial Buildings: Function, Cost, and Design Explained
9. Easy to Upgrade or Rework
Gravel on flat commercial roofs provides flexibility when it's time for upgrades, repairs, or replacements. Roofers can easily sweep aside to examine or repair membranes beneath the roof without dismantling the entire system.
If business owners later decide to upgrade roofing systems, such as from BUR to single-ply), a gravel-topped roof offers a non-invasive point. This flexibility makes it perfect for commercial facilities.
Hire Us for the Best Roofing Solutions for Your Commercial Facility
Looking to install flat roofs on your commercial facility? Trust our experts at 911 Exteriors Roofing and Solutions for the best roofing services. Whether you want to install it in a new building or upgrade the existing one, we are here to help. Book an appointment with us today.
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