A Complete Guide to Commercial Flat Roofing Systems

How do you install a commercial flat roof?

After the Roof Design and Estimate is accepted, we order the materials and schedule the flat roof Installation.

Based on the scope of work, installing a flat roof often entails the following:

• Ballast Removal (if required)

• Delivery of materials (Membrane, Insulation, etc)

• Existing Roof Removal (if required)

• Rigid Insulation Installation (Isocyanurate, HD Coverboard, Tapered Insulation, etc)

• Membrane Installation (EPDM, TPO, PVC, Modified Bitumen, etc)

• Inspection and warranty award

When installing a flat roof, the commercial roofing installation is always compared to manufacturer’s specifications and inspected by the manufacturer to ensure the roof was installed to specifications. If the roof system was not installed properly, the warranty will not be issued until all errors are corrected. For some contractors, this means never requesting or receiving receiving a warranty. We are happy to offer warranties on our work as a flat roofer.

What is the best flat roof insulation?

Flat roofing insulation will have a huge impact on the energy efficiency of your property. The type of insulation required will depend on the immediate environment in your area and specific building regulations.

Implementing the right level of protection will help to maintain the other materials used in the construction of the flat roof, which means it will fulfill its projected lifespan. If this is your first time thinking about insulation, then our guide will help you understand the basics of insulating a flat roofing system.

What is flat roofing insulation?

Insulation for flat roofing is used to make a structure more energy efficient and minimize heat loss.

As a rule, any roof with a pitch below 10° is classified as a flat roof. In most cases, there will not be a loft in a building that features flat roofing. This means that your approach to insulation will differ from a standard pitched roof.

There are two main types of flat roof that require different approaches to installation:

• Warm Flat Roofing: Insulation material is placed on top of the roof, rather than in-between the ceiling and the decking.

• Cold Flat Roofing: Insulation is placed in-between the joists underneath the roof surface above.

Warm and cold flat roofs

• Warm Flat Roof: One of the main benefits you will receive from installing a warm flat roof is condensation will not become an issue because of the positioning of the insulation. At least 100mm of rigid board insulation must be positioned on top of the vapor control layer (the vapor control layer stops any moisture within the building contaminating the insulation). The waterproofing system is then applied over the top of the insulation.

• Cold Flat Roof: Many properties use this option, as there are no additional costs for scaffolding or organizing how to gain safe access to the roof exterior. The insulation material is placed between the supporting joists, leaving a gap of 50-60mm between the roof and insulation. This will enable the airflow to circulate freely. If insulation is being added to an older building, then it is common practice for the ceiling itself to be taken down. For properties that only have shallow joists above the ceiling, spray foam could be the best alternative, depending on the judgement of the installation company.

What types of flat roof insulation are available?

Here are commonly used materials for flat roof insulation:

• Wood Fiber: This is an organic board compromised of wood or cane, mixed with several binders and fillers. To enhance its water resistance, asphalt can sometimes also be coated onto the surface.

• Perlite: Similarly, perlite is mixed together with organic fibers and binders, along with air cells which are trapped into the material to insulate the roof. An asphalt coating is also applied to reduce absorption into the insulation material.

• Polystyrene: There are two options available for polystyrene insulation – expanded and extruded. A foaming agent is mixed with polystyrene to produce the expanded version, while extruded polystyrene is comprised of heated polystyrene that has been heated and then expanded.

• Polyisocyanurate: This is placed between the non-organic and organic felt within the flat roof. Using a blowing agent, the foam material is expanded which then creates a high level of thermal resistance.

• Cellular Glass: Crushed glass is heated after being placed into a mould and can be bought in flat or tapered blocks for use in insulation on flat roofs.

If you're unsure which material would best suit your flat roof project, please feel free to contact our commercial flat roofing experts.

How much does it cost to insulate a flat roof?

Flat roofing insulation is included in the estimates in flat roof replacement. Or, existing insulation material may be reused when a new roof is installed if it's still in good enough condition.

We will be able to supply a specific cost for insulation materials if that is your only requirement, as Commercial Flat Roofing Contractors.

What is the lifespan of flat roof insulation?

The insulation used for warm flat roofs will degrade faster than those used for cold roofs. This is due to the insulation being positioned closer to the outside elements. Not to worry, however. Insulation materials are particularly robust and will last at least as long as the waterproofing material itself. That can be anywhere between 25-40 years.

Commercial flat roof maintenance

(RoofOptions adheres to the major manufacturers required maintenance for flat roofs)

• Natural debris such as leaves and tree branches

• Foreign debris such as bottles, fasteners and materials left by others

• Clean out stormwater roof drains and strainers to prevent clogging of drain heads that will impede water flow. In some cases a plumber may be required for repair.

• Owner’s representative will be made aware of condition

• Reseal pitch pans as needed with materials compatible with existing roof system and manufacturer

• Reseal all sheet metal rain collars, as needed using a class “A” urethane sealant

• Inspect all drain heads, strainers and clamping rings. Clamping rings will be retightened as needed.

• Snow Removal Available

Commercial flat roof repair near me

We are happy to offer commercial flat roof repair or emergency flat roof repair. RoofOptions LLCs serves commercial roofing and industrial roofing clients nationwide with offices in Chicago, Twin Cities of Minneapolis and St. Paul, Indianapolis, Charlotte, Dallas, Fort Worth, Milwaukee and Philadelphia with a service presence in all 48 contiguous USA states.

Types of roof membranes for flat roofs

The two most common types of flat roof membranes are EPDM and PVC. While modified bitumen (modified flat roof)  is also still used, most owners are moving away from asphalt based products due to the environmental and health hazards.

Flat roof membrane life expectancy

A typical commercial flat roof membrane should last on average 20-25 years before needing to be replaced. On the shorter end it could need replacing in 10 years, and on the longer end, it could last even 50 or more years.

Flat roof materials you can walk on

Making the roof of your facility accessible to walk on can allow more usable space for tenants to take advantage of your roof (and bring in revenue) or allow a safe surface for workers. Before occupants and staff can get on the roof, it needs to be prepared for foot traffic and properly protected.

Traditionally for people to be able to walk on the roof, there’s a roofing surface and one or more layer on top, so it can be an approved walking surface. In a single ply, it is done in all one coat.

Safety roofing for flat roofing

RoofOptions LLC follows OSHA Flat Roof Safety Guidelines, and our roofing experts will walk you thru all that you need on your properties. All of our lead techs are required to have OSHA10 safety training. A majority of our techs have lift training and many are Open Flame safety trained. We follow all CDC Guidelines.

Commercial flat roof snow removal

RoofOptions LLC has commercial flat roof snow removal services. Learn more….

8 signs of flat roof damage

1. Rips in EPDM Membrane — EPDM rubber roofs are one of the most common types of commercial flat roofs on the market. If the protective rubber roof membrane of your EPDM flat roof is visibly ripping, that means it is no longer watertight and won’t be offering the same protection. If you see this type of commercial flat roof damage, serious roof leaks are next!

2. TPO Roof Coating Cracks — White TPO roofs offer energy efficiency as well as lightweight roof protection. As your TPO roof ages, the TPO coating can crack. If you see cracks in your white roof, call us for repairs before serious damage can occur. This is one of the most common causes of failure on TPO roofs and tends to happen at around the 15-year mark. 

3. Ponding Water — To look for ponding water on your commercial roof, you’ll need to climb a ladder and examine your roof after a heavy rain or Contact Us For A Free Inspection. If you see puddles of water across your roof — called ponding water — that’s a sign the built-in roof drainage system has failed. This needs to be addressed by a skilled roofer immediately, otherwise, that ponding water can eventually infiltrate your roof and cause damage.

4. Flashing Separated from Roof — Roof flashing does an important job on commercial flat roofs. Since the seams of most roofs can potentially act as an area of water infiltration, flashing is added to cover them. If the protective flashing looks or feels loose, that means water is infiltrating the vulnerable roofing seams. If you catch this issue early, it can be solved by a fairly minor repair. If you miss or ignore loose flashing, it can result in the entire roof rotting out.

5. Membrane Waving in the Wind — Another clue that your EPDM roof membrane is not providing sufficient protection. To look for this sign of commercial roof damage you’ll need to get on your roof when the wind is blowing — just be careful. If you see the rubber membrane catching or waving in the wind, that’s a sign it’s not giving sufficient protection and water can be infiltrating. Once again, this is often simple to repair, but catastrophic to ignore.

6. Loose Fasteners — One of the hardest signs of roof damage to identify on your own, when roof fasteners come loose they show up as bumps on the roof membrane itself. If you see or feel the fasteners through your roof membrane that is the first sign that the membrane will need a repair down the road.

7. Water Spots on the Ceiling — If you see water spots on the ceiling, that’s a clue your commercial flat roof might need some assistance. While water spots can come from other sources like air conditioner condensation, the most common reason is a leaking roof. Seeing water spots should encourage you to examine the roof closely or call a professional.

8. Roof Leaks — The number one, tell-tale sign your roof is damaged. If water drips from your roof after a rainstorm, that’s the only proof you need to see your roof is damaged. Don’t wait — contact a professional immediately.

Wind damage to flat roofs

With a flat roofing system, the areas prone to wind damage are on the corners and around the edges of the roof. This is due to the uplift pressure of the wind, which can actually be much faster than the horizontal wind speed itself. The problem with these vulnerable areas is when the perimeter of the roof gets damaged, it can start peeling back and lift up. In worst case scenarios, the wind pressure can get under the roof and essentially blow it off of the building.