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Tag: roof membrane

What’s the Difference Between a Shingle and Membrane Roof?

If you’ve been researching roofing repairs or replacements, you’ve probably come across several different roofing materials. The type of materials used for a roof depends on a lot of factors including the structure of the building, the building’s purpose and use, location, budget and local building codes. Two large categories of roofing materials are shingles and membranes. Both of these categories are made up of many different types of products and materials that are used for different purposes, so let’s dive in.

Steep Slope vs. Low Slope

The first factor in determining which of these two roofing methods will be used is whether the roof in question has a steep or low slope. Shingles are typically used on steep slope roofs, while membranes are used in flat or low slope roof situations. For the most part, membrane roofs are seen on industrial and commercial buildings, but can be found on residential properties as well, often as decks, over side and rear adjoining roofs. On residential properties, they are often found over sunrooms, utility rooms, or porches and can be used under decks and other walkable surfaces materials like pavers. Membrane roofs are quite common at waterfront properties and on new construction in the Hampton Roads/Tidewater area.

Types of Membrane Roofs

There are many different roofing membrane products on the market today, each with their own purposes and benefits. Below are four common flat and low slope roof membrane materials.

Thermoplastic polyolefin (TPO)

In the Mid-Atlantic region, TPO is becoming the low slope roofing standard. Because TPO is white, it is highly reflective, which means it’s efficient in keeping buildings cool. In fact, TPO roofs generally exceed the current energy efficiency standards and are a US Department of Energy, Energy Star rated roofing system, which some commercial structures may need to meet. TPO is also very durable thanks to its heat welded seams, and can last 20 to 30 years, making it a budget-conscious choice for businesses.

Ethylene Propylene Diene Terpolymer (EPDM)

EPDM is also a single ply membrane, but it is made of a rubber compound, rather than plastic like TPO. This material has been in commercial use for longer than TPO and has a strong reputation for durability. When properly installed, EPDM can easily last 30 years or more. However, if installed incorrectly or without proper maintenance, the adhesive treated seams can become vulnerable over the long term. Although EPDM roofs are usually black in color, meaning they are not as energy efficient as TPO, the material is 100% recyclable. There are also EPDM products that come in white, doubling their environmentally-friendly factor.

Polyvinyl Chloride (PVC)

PVC is a single ply membrane that is similar in appearance to TPO and is usually white, giving it similar energy efficient qualities. Other environmentally friendly aspects of PVC include its low petroleum content compared to TPO and EPDM. It’s also a recyclable material, even post-consumer, meaning it stays out of landfills. A PVC roofing system requires a slightly greater investment than that of a TPO roof, but it is also very durable and has a similar lifespan if installed and maintained correctly.

Modified Bitumen

The previous materials are almost exclusively used in industrial and commercial structures, but modified bitumen is perhaps the most common material for residential low slope roofs. It consists of five layers of asphalt that has had modifiers added to it to give it plastic or rubber-like properties. It is installed in large rolls and adhered with heat or with a factory applied self-adhesive. Modified Bitumen is designed to withstand very harsh environmental conditions, which makes it a good option for storm and heat prone areas of the Mid-Atlantic such as southeast Virginia.

Types of Shingle Roofs

Shingle roofs are seen on both commercial and residential structures, as long as the roof has a steep slope. There is a wide variety of shingle materials on the market designed for different purposes, styles and locations.

Asphalt Shingles

This is the most popular type of residential roofing material today. It’s also the most cost effective. Asphalt shingles consist of a fiberglass mat, top and bottom layers of asphalt, and mineral granules. There are three-tab shingles and architectural shingles, the latter being more costly but also more durable. Asphalt shingles are produced in a wide variety of colors to match myriad home styles and designs.

Synthetic Roofing

Whether they’re made to look like cedar shake, slate or any other type of upscale material, synthetic shingles are made with recycled materials and have a lower impact on the environment in part because of their lifespan which can be 40-60 years. These premium roofing systems should only be installed by roofing contractors who are experienced with these materials. They can be expensive, but their extended lifespan makes up for some of the upfront cost.

Wood Shingles & Shakes

Made from cedar, redwood, southern pine and other woods, these shingles are machine sawn or hand hewn. Some local building codes limit the use of wood shingles and shakes because of concerns about fire resistance, but there are certain wood shingle products that incorporate a factory-applied, fire-resistant treatment. These shingles are not often installed on a new structure or total roof replacement, but because of the age of some homes in the Tidewater region, wood shingles are often needed for repairs of older roofs or to maintain the design of a historic home.

Find an Expert

Whatever type of material you choose for your roof replacement, Andrews Roofing has experience with nearly all of them. If you’re not sure what the best material for your project is, please contact us to set up an appointment with one of our knowledgeable cost estimators. We can help you determine the most appropriate, durable and cost-effective roofing solution for your needs.

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Why You Should Replace Rather than Roof Over Your Existing Roof

If you’ve been in the market for a new roof for your home, you have probably run across the option of roofing over top of your existing roof.

“Roofing over” is a method that leaves the current shingles and roof deck in place, and installs new shingles right over top of the existing ones. Alternatively, reroofing requires removing all existing shingles, doing any necessary repairs or replacement of the roof deck, membrane, and supporting structures beneath, before replacing the shingles with new ones.

Roofing over your roof requires that all the existing shingles are perfectly flat without any curling, that your roof deck be in perfect condition, that there are no leaks or ventilation issues that need addressing, and that the current roofing structure is able to withstand the additional weight of a second layer of shingles. However, if all of these things are true, you may not need a new roof at all. And even if those conditions are in place, a roof over existing roof can appear wavy and uneven. In most cases, a roof over does not make long term sense for homeowners, which is why we do not recommend this to our clients and do not guarantee this type of work.

We should note here that it is possible to roof over certain materials, like membranes that are in decent condition. This is done more often on commercial roofs depending on the core sample, decking, condition of insulation, etc. This type of project is only performed after careful inspection of the flat roof and an analysis and assessment of the materials and decking beneath the membrane.

Roofing over an existing roof is sold to homeowners as a cheaper alternative to replacing their roof. Often times, though, roofing over does not really solve the underlying issues the structure may have and can end up being a more costly option.  If you’re looking into replacing your roof, it’s likely because you’ve noticed leaks here and there, there’s damage to the shingles, shingles are missing or deteriorated or you’re noticing your energy bill is soaring. Putting new shingles overtop of existing ones doesn’t address any of these critical issues on the inside, which means damage may continue to occur. Putting another layer of shingles on top of existing ones that have issues also means it will take more time, money and material to get to and diagnose the problem, and more labor to repair the underlying issues.

Replacing your roof may cost more up front, but the return on investment is higher.

Over the long term, a new roof will look better, last longer, and protect your home better. When you allow a licensed roofing contractor to remove the existing shingles, they can properly assess any other repairs that need to be done to the roof decking, membrane, flashing, structural beams or ventilation systems. Having these issues addressed at that point means the overall lifespan of the roof will be longer. It’s also important to note that some roofing material manufacturers will not warranty a product that is put over existing shingles rather than onto a clean roof deck. While roofing over a roof may be cheaper upfront, the costs of uncovered warranty claims and an overall shorter lifespan don’t pan out in the long run.

Your roof is a major part of your home that you want to look good and function well. When you’re considering your roofing project, consider that your roof literally protects everything in your home beneath it. It’s not the place to cut corners. Before reroofing your home, research roofing contractors in your area, read up on their online reviews and ask around your neighborhood for recommendations. Get quotes from at least two to three reputable companies and research the materials they work with to ensure they are high quality and guaranteed with a manufacturer warranty.

If you live in the Hampton Roads region and your home needs a new roof, contact Andrews Roofing. We’d love to be one of the companies to provide you with an estimate. Our work is always guaranteed, we use some of the best products on the market, and we’ve been providing excellent customer service to Tidewater residents for years.

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