Polyglass’ Guide to Commercial Roof Installation

With so many different roofing products and materials on the market, tackling a new commercial roof installation as either a contractor or a client can seem daunting. You’ll need to figure out which type of roofing products suit the particular needs of the building, how long it’s likely to last, and how much the project will cost.

That’s where this guide comes in. We’ll delve into the range of options that Polyglass offers when it comes to roofing systems. This guide will mostly be useful for contractors who are looking to plan their next client project. However, if you’re looking to hire a contractor to replace or repair the roof of your business premises, this handy guide can help you determine what you need.

Table of contents

Installation Prep

As a contractor, you should start by working with the client to choose the right roofing system for their particular needs. Advise them on what will work best for their building and create an in-depth plan for each project stage. This will help you quote an accurate time frame and provide a detailed estimate of the cost involved.

If you’re a client, take heed of the contractor’s advice regarding your particular roof needs. A good contractor will offer insights regarding the materials that will work best for your requirements.

To help you decide on the materials to choose for a commercial roofing project, the next few sections will explore Polyglass’ range of roofing products. We’ll cover what each product is, how it is installed, and what kind of roofing needs it suits.

Modified Bitumen Membranes

Modified bitumen membranes are a type of roof system that combines asphalt-based bitumen with additional materials such as polymers or rubber. This creates a versatile roofing system that can meet a wide range of roofing needs.

There are two main types of modified bitumen membranes; APP (atactic polypropylene) and SBS (styrene-butadiene-styrene). APP membranes are reinforced with plastic to make them more rigid. These membranes are easy to install and particularly suit smaller commercial roofs.

SBS membranes incorporate rubber to create a flexible elastomeric roofing layer. These membranes can react to changing temperatures, creating a roofing system that can stand up to more extreme weather conditions that some parts of the country face.

Polyglass offers a wide range of innovative APP and SBS modified bitumen membranes to suit different roofing needs. For commercial buildings situated in colder areas, the Elastoflex SA P Polar Cap membrane provides great insulation. For those looking for a more energy-efficient roof in sunnier climates, the highly reflective Polyfresko G SA membrane is a great choice.

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Modified bitumen membranes can be installed in two ways; torch-down application and self-adhering membranes. Each method has its strengths and weaknesses.

Torch-Down Membranes

Torch-down roofing membranes are installed using a gas or propane torch. The membrane rolls are gradually unfurled across the roof, with the bottom layers being heated by the torch. This welds the membrane into place, adhering it to the roof.

Torch-down membranes offer fantastic waterproofing because the seals are essentially fused together, creating strong watertight seams. However, the torch-down method does come with safety concerns as it poses a significant fire risk and can also release potentially harmful toxic fumes. They also take longer to install than self-adhering membranes.

Polyglass offers a range of torch-down modified bitumen membranes, including the Polyflex G APP cap sheet. This durable membrane can stand up to debris that can puncture or tear a roof and features FASTLap technology for easy application.

Self-Adhered Membranes

A self-adhered modified bitumen membrane features a durable dual-compound APP or SBS top layer to deal with weathering and a powerful adhesive bottom layer for quick and easy application. Self-adhered membranes were pioneered by Polyglass in the 1990s thanks to the development of innovative ADESO® technology. Polyglass has continued innovating and evolving its product range to include patented technologies likeSEALLap ULTRA and FASTLap end laps.

During installation, the self-adhered membranes are usually installed in at least two layers; a base sheet and a cap sheet. After allowing them to relax, the membrane sheets are cut into manageable lengths and placed on the roof. The protective film on the end laps is then removed, and the sheets are pressed into place.

Once a section is complete, pressure is applied in the form of a roller to make sure that the membrane fully adheres to the roof. This process is repeated for both the base sheet and cap sheet layers to create a dependable and durable roofing system.

Self-adhered membranes do not pose the safety risks that torch-down membranes do. No naked flames are required and no toxic fumes are released. This allows for much safer and easier applications.

What is ADESO Technology?

Polyglass’ industry-leading ADESO Self-Adhered modified bitumen membranes feature innovative technologies such as granule-free FASTLap end laps which allow for quick and easy installation. SEALLap Ultra technology creates unrivaled watertight monolithic seals along each seam, eliminating the risk of water leaks.

ADESO technology is available across most of Polyglass’ range of APP and SBS modified bitumen membranes, with a wide variety of surface colors and types to suit any roofing application.


Modified bitumen membranes will usually last for around 10 to 30 years. With some basic maintenance, the lifespan of a modified bitumen roof can be extended even further. Thankfully, these types of roofs are some of the easiest to maintain.

This makes modified bitumen membranes more cost-effective, durable, and versatile than other commercial roof installation methods such as EPDM cold-applied roofs, TPO single-ply roofing, and metal roofing systems.


In some commercial roofing installations, an extra layer will be needed underneath the roofing membrane. This is usually needed for extra water protection and is achieved by installing an underlayment layer before applying the membrane.

Underlayment sheets are fixed directly onto the roofing deck, which is usually a plywood frame that forms the first layer of a roof and covers the insulation. This is especially necessary for steep-sloped roofs. Underlayment sheets are typically made from asphalt-saturated felt, rubberized asphalt, or synthetic materials.

Polyglass offers a versatile range of self-adhered underlayments for steep-sloped roofs. Specialized underlayments can offer specific protection to meet a wide variety of building needs. Polystick TU PLUS is designed as a tile roof underlayment, for example. Polystick XFR underlayment is a dual-compound layer that provides unrivaled fire protection and waterproofing.


All Polyglass underlayments feature industry-leading ADESO Self-Adhered Technology for quick and easy installation. These are installed in a similar way to the self-adhered modified bitumen membranes above.

After acclimatizing, the underlayment rolls are cut into manageable lengths and laid out onto the roofing deck. The protective film covering the adhesive layer is removed and the underlayment is pressed into place. Once a section has been completed, a pressure roller is used to ensure full adhesion.


Depending on the exact material used and the specific conditions of the roof, the expected lifespan of a roof underlayment could be anything from 12 to 20 years. All Polyglass underlayments come with a 30-year warranty to give you and your clients peace of mind.

Roof Coatings

No matter how well a roof is maintained, it will eventually start to deteriorate. The expanding and contracting of the roof during temperature changes may eventually produce small cracks and tears that compromise the waterproofing of the system. Strong winds may blow pieces of debris across the roof, which can sometimes tear the membranes.

In these cases, many clients will assume that the roof will need a complete replacement. However, some products can patch up a roof’s wear and tear without changing the entire system. These products can add several years to the lifespan of a roofing system and are commonly referred to as roof coatings.

There are two broad types of roof coatings: asphaltic roof coatings and elastomeric roof coatings. Within these categories, different materials will be used to give the roof coating different properties. Polyglass offers a versatile range of roof coatings across these different types to suit any roofing application.

1. Asphaltic Roof Coatings

Asphaltic coatings are usually made of aluminum, asphalt, bitumen, or tar. They can only be used on roofs that are made from a similar material to the coating because asphaltic coatings cannot always adapt well to fluctuations in temperature. There are two main types of asphaltic roof coatings; fibered and non-fibered.

Fibered Coatings

Fibered asphaltic coatings mix different fibers, such as fiberglass, with the base material of the coating to increase the strength of the mixture. While this does make the coating less capable of adapting to temperature changes on the roof, it works well when the roof needs extra protection against abrasion from the elements.

Some of Polyglass’ innovative fibered roof coatings include the PG 650 aluminum coating that helps to boost UV reflectivity and the PG 300 coating, which enhances the durability of a roof when confronted with surface abrasions.

Non-Fibered Coatings

Non-fibered asphaltic coatings do not contain any additional fiber materials within the coating mixture. This doesn’t make the coating more resistant to tears, but it does allow the mixture to remain flexible enough to adapt to changing temperatures on a roof.

Polyglass’ range of non-fibered asphaltic roof coatings includes the PG 200 modified asphalt coating, which provides extra protection for metal and stone roofing systems.

2. Elastomeric Roof Coatings

Elastomeric coatings are commonly made using acrylic or silicone and can expand and contract with a roofing system as it responds to fluctuating temperatures. This makes elastomeric coatings more compatible with a larger array of roofing types than asphaltic coatings.

Polyglass’ range of white elastomeric coatings is part of the Kool Roof Solutions range to help reduce heat loss and increase UV resistance, leading to a more energy-efficient roofing system.

Acrylic Coatings

Acrylic roof coatings are a good choice if a roof requires more protection from ultraviolet rays, which can help to increase the energy efficiency of a roof. Acrylic coatings are applied as a liquid to create monolithic seals for strong protection against water. They are usually less expensive than silicone coatings but can be more brittle in extreme weather conditions.

Polyglass has a comprehensive range of acrylic roof coatings, including the Polybrite 55 coating designed for Sprayed Polyurethane Foam (SPF) roofs and the PG 700 coating that helps to keep a roofing system cool as well as defending it against ultraviolet rays.

Silicone Coatings

Silicone elastomeric roof coatings act as sealants that prevent air and water from penetrating cracks in the roof. This helps to increase moisture resistance. Silicone coatings are more durable than acrylic mixtures as they have a higher content of solids. Silicone coatings are usually brushed onto the roof.

Polyglass’ versatile range of silicone elastomeric roof coatings includes the Polybrite 90 and 95 coatings which help to enhance the reflectivity and UV resistance of a roof, making it more energy-efficient.


In addition to membranes, underlayment, and roof coatings, several other roofing products can be useful during a commercial roofing installation. Here are some examples of these accessories, using Polyglass’ comprehensive range to illustrate each product.

1. Cover Boards

Cover boards are additional layers of fire-resistant protection that are placed between roof insulation and the roofing membranes. They are particularly useful for protecting against the hot adhesives used during torch-down roof application. Polyglass offers three types of cover boards: the asphalt Polyboard E, Polyboard W and the polyisocyanurate Polytherm HD.

2. Flashing Strips

Products like Polyglass’ Elastoflex SA V flashing strips are often used to provide additional waterproof barriers around the frames of adjacent roofs, chimneys, vents, and windows. The Elastoflex SA V flashing strips feature an SBS compound and ADESO Technology for dependable durability and quick installation.

Flashing strips can be used in conjunction with a sealant such as PolyFlash 1C for extra waterproofing protection in vulnerable areas.

3. Granules

Granules, such as Polyglass’ PG granules, are usually added to mineral-surfaced membranes as an extra layer of UV and weather protection.

4. Insulation

Insulation is installed underneath the roofing membrane layers to help keep heat within the building. There are various types of roofing insulation, and Polyglass offers three main insulation products; the PolyPUF SPF insulation and the Polytherm and Polytherm G polyisocyanurate insulation.

5. Reinforcement Materials

Reinforcement materials can be used either to help repair a damaged roof and reinforce various seam mastics to increase the lifespan of a roof. Polyglass offers three reinforcement materials; Reinforcing Cotton, Reinforcing Fiberglass, and Reinforcing Polyester.

Other Polyglass roofing accessories are also available. To find out more about Polyglass’ roofing materials, contact us today.