Built-Up Roofing Systems
Built-Up Roofing (BUR) is a great option for buildings with low slope and/or flat roofs and is particularly effective for large commercial buildings. One of the most common commercial roofing styles, it is also one of the oldest of the “modern” roofing styles, dating back to the early 19th century. Built-Up Roofing is a time-tested and true roofing method, and it’s only improving with all of the advances in technology that make it even more effective and efficient for large buildings.
- Base sheet – fiberglass, asphalt-coated organic sheet or asphalt-coated venting sheet, etc.
- Felts or fabrics – coal or tar saturated organic felt, cotton fabric or burlap (three or four layers may be used)
- Bitumen – asphalt, coal tar, lap cement
- Surfacing component – gravel, asphalt, minerals/coatings
Advantages of Built-Up Roofing
- Versatile: Built-up roofs can be installed over just about any type of roof deck, and can be used as part of a fire, wind, and/or hail-rated roofing system.
- Thermal Reflectivity: BUR surfacing materials can be coated with paint or other reflective materials to combat the heating effects of UV radiation, making it a strong “cool roofing” option.
- Longevity: When multiple plies are combined and sandwiched between layers of water-resistant asphalt, the result is a longer lasting, more durable roof.
- Durable: Built-up roofs can tolerate plenty of surface punishment and can withstand high amounts of foot traffic.
- Protection: Multiple layers of reinforcement offer more protection, and multiple opportunities to prevent leaks.
Repair and maintenance of built-up roofing:
While BUR’s generally require little maintenance, they are easily repaired, resulting in an extended service life.
Single-Ply System (PVC, TPO, EPDM)
Single-ply roofing membranes (sometimes referred to as PVC or TPO) have grown in popularity over the past 30 years for use on commercial buildings thanks to their flexibility, relative ease of installation, and competitive price. Single-ply roofing is composed of four basic elements:
- An insulation layer
- A single-ply membrane (usually made of plastic or rubber)
- An adhesive that melds the layers together
One big advantage of single-ply roofing is its cooling capabilities. With a proper coating, the light-colored roof surface reflects heat and can significantly reduce A/C energy use. This can lead to huge energy savings over the life of your roof.
The three main types of single-ply:
- TPO (thermoplastic polyolefin) – TPO roofing systems are made with a fire-resistant membrane that uses a polyester reinforcement to strengthen the bond. This membrane is also resistant to chemicals, grease, and punctures, making it a good material for rooftop areas with lots of foot traffic.
- PVC (polyvinyl chloride) – PVC is a great material for long-term flexibility of the membrane. PVC is pliable with excellent weathering characteristics and is resistant to harsh chemicals and industrial pollutants. This leads to a long service life with minimal maintenance needed.
- EPDM (ethylene propylene diene monomer rubber) – EPDM has the appearance and feel of an inner tube, and it rebounds when stretched. It is a highly durable roofing material that can last 40 years or more.
Advantages of Tile Roofs:
- Durable: Because air circulation is enhanced by the spaces under the curved tiles, tile roofs typically have excellent durability and can last upwards of 50 years.
- Tough: Thanks to their composition of stone or baked clay, tile easily endures harsh weather conditions, better than almost any other material in fact.
- Drainage: The natural curve of most tiles helps them to easily shed water.
- Fire Resistance: Because tile is made of clay or stone it is extremely fire-resistant.
- Low Maintenance: Tile roofs are very durable and require little to no maintenance over their lifespan.
- Resistant: Tile naturally repels insects and is immune to rot.
Modified bitumen (MB) is an excellent roofing method that is used regularly on both commercial and residential properties ranging from shopping malls to apartment complexes. Modified bitumen is an economical and flexible roofing material best suited for low-slope or flat roofs. One of the oldest of the “modern” roofing styles, it has been time-tested and has become a long-lasting and safe roofing material for almost any style of building.
Modified bitumen is made of asphalt with added modifiers that give it rubber-like properties, making it much more durable. The six basic layers that makeup modified bitumen can be assembled in a number of different combinations depending on the needs of the roof.
- Insulation – A layer that helps keep heat out in the summer and in during the winter. The insulation also offers a stable base for the other layers.
- Base sheets – Sheets or plies used under the membrane. These can be modified to give the roof different properties.
- Modified Bitumen Membrane – A sheet of modified bitumen reinforced with either polyester, fiberglass, or some other composite.
- Adhesive – The bonding agent that glues all of the layers together.
- Surfacing – A surface coat applied to the outermost layer to protect against UV rays and weathering.
- Flashing – Provides protection around the edges of the roof as well as around perforations in the roof created by vents, AC/Heating units, etc.
Benefits of Modified Bitumen Roofing
- Resistance: Modified bitumen has superior fire-resistance and waterproof capabilities.
- Flexibility of application: MB offers a broad range of application methods while also offering a wide choice of top-surfacing options.
- Durable: Modified bitumen has a very high tensile strength and resists thermal shock and splitting can be made extremely resistant to fire, wind, and hail with the proper surfacing or coating.
- Cost: Modified bitumen is among the lowest cost-per-square-foot materials that you can use for commercial roofing.
Little to No Roof Maintenance
Modified bitumen has an average lifespan of twenty years. During this time it requires almost no maintenance, and at the end of the twenty years coatings can be applied to extend its serviceable life a bit more.
Standing Seam Metal
Advantages of metal roofing:
- Fire-Resistant: Metal roofing options are particularly resistant to fire when combined with a code-compliant underlayment.
- Attractive: Metal roofing offers many attractive options including steel, aluminum, copper, and zinc. Metal is available in a huge assortment of styles including shingle/slate, tile, shakes, vertical panels, and more.
- Tough: Metal roofs are extremely resistant to high winds, hail, and snow buildup. Metal roofs also shed rain extremely well.
- Long Life: Metal roofs have an incredibly long lifespan which can often reach over 50 years when installed properly.
Metal roofs are virtually maintenance free:
Metal roofing is just about as close to maintenance-free as a roof can be. All that is needed is an occasional hose-down. However, if the roof is damaged because of high winds, it should immediately be repaired by professionals to prevent water leaks or other damage.
Advantages of asphalt shingles:
- Affordable: A big advantage of asphalt shingle roofs is their relatively low cost. Because shingles are easy to manufacture and install, they are inexpensive compared to other roofing materials.
- Easy Installation: Asphalt shingle roofs are easy to install, provide flexibility, and are very sturdy, making them compatible with most roof designs.
- Look Great: Asphalt shingles come in dozens of designs and textures, including dimensional asphalt shingles. Asphalt shingles can be manufactured to look like other more expensive materials, including cedar shakes, slate, tile, or wood.
- Lightweight: Materials like slate are extremely heavy and aren’t suitable for certain styles of roofs. Although asphalt shingles are not the lightest material, they are compatible with most roof types.
Some roofing materials require regular maintenance, but asphalt shingles require almost no maintenance at all! While they aren’t as tough as tile shingles, they do hold up fairly well to most weather conditions. If asphalt shingles become damaged, they are easily repaired and it is relatively inexpensive to replace a few shingles at a time.
Elastomeric Roof Coatings
Elastomeric coatings offer effective and affordable solutions for fixing roof leaks. The coatings can be used to repair almost any type of roof leak and they can be used throughout the year because they stretch and contract easily to adjust to varying temperatures. Elastomeric coatings can be used to fix almost all types of roofs. Examples of common roof types that will work well with elastomeric coatings include; wood, polyurethane foam, single-ply roofing, modified bitumen, metal roofs, concrete and built-up roofing.
Elastomeric coatings are resistant to fungi and mildew among other common materials that cause damage to roofs over time. Another advantage of these coatings is that they are seamless, providing a uniform coating. The heat reflexive properties of these coatings also offer great energy use benefits such as lowering cooling costs. Elastomeric roof coatings are also simple to use, VOC compliant and nontoxic.