PART 1: THE SINGLE-PLY ROOF

When it comes to commercial buildings, flat roofing almost always comes as the first choice, which is understandable given the long list of advantages that make it an attractive option. One of the most popular flat roofs around is the single-ply roof, a one-layer membrane that acts as a protective surface against the rain and other elements as well.

WHAT IT IS

There are several types of membranes considered as single-ply roofs. Generally though, they can be grouped into two: thermosets and thermoplastics. Thermosets are made from rubber polymers and require adhesives while thermoplastics (as their name imply) are more plasticized in nature and are welded together by hot air.

Though commonly used in commercial roofing, single-ply roofs are are also popular in residential applications. They can come in a range of widths between 6 and 18 feet but most of the single-ply membranes installed come in sheets 10 feet wide. In terms of thickness, a sheet should be ideally at least 50 mm thick but options typically come in a range between 45 and 99 mm.

PART 1: THE SINGLE-PLY ROOF

WHAT MAKES IT A GREAT CHOICE?

Durability

Depending on the membrane you choose, you can expect to get at least 15 to 25 years of service life from single-ply roofing. All single-ply roofing membranes are built to last through any kind of weather; but employ routine maintenance and you might be able to extend their lifespans by a few more years by catching problems early enough to keep them from being truly problematic.

Ease of Installation

Another one of single-ply roofing’s key selling points is its undeniably easy installation. With just one ply of membrane to install, single-ply roofing is easier to handle than other flat roofing types, speeding up installation.

Lightweight

Its lightweight design allows it to cater to unconventional architectural styles for roofs, making it a favorite among architects and designers. This also means additional structural support won’t be needed so you won’t need to reinforce your deck to take advantage of single-ply roofing.

Energy-Efficient

Coatings and surface materials may be added on top of a single-ply roof to enhance its ability to reflect heat. This reduces the level of heat absorbed by the roof, which is then transferred to the structure, keeping cooling load down so HVAC systems work more efficiently.

PART 2: MODIFIED BITUMEN ROOFING

There is no denying the fact that flat roofs dominate the commercial roofing industry. Aside from addressing roofing needs, flat roofs also open up space on top of a building a business can use to expand its operations. Interested in a vegetated roof? Flat roofing options may also be installed under green roofs as well, allowing you to do your bit for the environment while taking care of your roofing needs. Flat roofs do offer a number of advantages, as a modified bitumen roof would prove.

WHAT IT IS

Polymer-modified bitumen, more popularly called modified bitumen, was first developed in the 1960s. It later on found its way across the Atlantic and into the United States where it gained traction in the 1970s. It is said to be a combination of single-ply roofing and built-up roofing in that it harnesses the installation ease offered by former and the durability of the latter. How? Hot polymer-modified bitumen is poured over reinforcing fabrics, turning into a multi-ply roofing system with the durability of built-up roofing. But as it comes in a roll, it is easy to handle like single-ply roofing.

There are two kinds of modified bitumen membranes:

(1) SBS (Styrene-Butadien-Styrene) Polymer-Modified

• elastomeric extenders • more flexible than APP at cold temperatures • more complicated to produce than APP though, relying on bitumen-elastomer compatibility

PART 2: MODIFIED BITUMEN ROOFING

(2) APP (Atactic Polypropylene) Polymer-Modified

• thermoplastic extenders • heat-welded • requires higher temperatures for torching process

WHAT MAKES IT A GREAT CHOICE?

• It’s durable like multi-ply systems but easy to install like single-ply roofing.

• It can withstand a range of weather conditions, flexibly expanding and contracting with the temperature to adapt to the elements.

• It can help reduce energy costs, stabilizing indoor temperature by preventing excessive heat from being absorbed through the roof.

A QUICK NOTE

It’s easy to confuse modified bitumen and EPDM roofs because they are both colloquially referred to as rubber roofs. To avoid mix-ups, best to call roofs by their actual name when talking to a roofing contractor.

PART 3: THE BUILT-UP ROOF

Ever wondered why some roofs are covered in gravel? Well, that is what you call a built-up roof.

WHAT IT IS

Built-up roofing is a traditional system that has been around since the 1840s. It is called such because it is made up of built-up layers of bitumen and reinforcing fabrics. A four-ply system, for instance, will feature a four-layer roofing membrane. Base sheets, the bottommost layer, can sometimes be mechanically attached to a roof. If a BUR is directly applied to insulation or roof decks, it is considered as being fully adhered.

WHAT MAKES IT A GREAT CHOICE?

• BUR is highly durable, thanks to being made with several layers of material. This same feature also gives the flat roof excellent protection against leaks, allowing it to prevent moisture damage.

• Aggregate like gravel, mineral granules or slag covers the topmost portion of the roofing system, beefing up protection against impact. This makes the roof ideal in hail-prone areas.

• Depending on the surfacing used (aggregate, coatings or cap sheets) used, a BUR can reflect back a considerable amount of heat, reducing what a building absorbs to stabilize indoor temperature. This not only assures comfort but can help in cutting back on energy costs as well.

PART 3: THE BUILT-UP ROOF

• BUR is flat and solid, heavy enough to resist high winds and maintain its shape.

• It’s not unheard of for BURs to last 20 to 30 years. Given the long service life it offers, BUR makes for a great investment as it ensures you make the most out of your purchase.

• Plus, maintenance is easy. Aside from a routine check for wear and tear, most of the work involves just cleaning up debris that has accumulated on the roof.

DID YOU KNOW?

A BUR with two or three layers topped by a polymer-modified bitumen cap sheet is called a “hybrid” system. The National Roofing Contractors Association, however, counts this roofing system as a modified-bitumen type.

Arry’s Roofing Services, Inc.

401 East Spruce Street,Tarpon Springs, FL 34689

(727) 938-9565(727) 362-2230

ArrysRoofing.com