2021 TPO Roof Cost and Pros & Cons of TPO Membrane Roofs

Updated on January 13th, 2021

Say it with me: Thermoplastic polyolefin. Yes, TPO is much easier. According to Firestone Building Products’ white paper, TPO is technically a polypropylene based plastic combined with ethylene/propylene rubber.

So, plastic and rubber, mixed is what comprises a thermoplastic roofing membrane designed primarily for low-slope roofing applications with energy-efficiency in mind. Much of the information online boasts how TPO is increasingly popular in commercial flat roofing. The thing is, we aren’t concerned with commercial buildings, and instead focus on the membrane options available, along with the costs, for adding this material to a residential roof.

Understanding TPO Roof Options

Like all synthetic roofing options, no two companies produce the same formula of TPO. Instead, they alter it just enough to create their own brand. All of it results in a membrane material, between 40 and 100 millimeters thick that gets attached to a roof deck.

TPO is known as a single-ply application, meaning one sheet is sufficient to achieve the benefits (see the “Advantages” section below). It competes each year directly with EPDM, and PVC membranes (PVC is similar in application methodology to TPO) with some of the same benefits, but with each system having its unique pros and cons.

TPO is purchased in rolls that are generally 6 to 12 feet wide and vary in millimeter depth. The typical thickness is in range of 45 to 65-mil, yet it is really an architect’s and builder’s preference that determines the membrane performance and thickness needs for a particular project. Sheets of TPO membrane are rolled out, and cut to fit a roof, based on the roof deck’s dimensions and any objects penetrating the roof structure. The material is attached in one of three ways:

  1. mechanically – nailed or screwed into the deck
  2. fully-adhered – glued
  3. ballasted – after the entire material is spread out, river rocks or ballasts are strategically situated to hold it in place

In over 90% of applications, TPO membrane is applied to flat roofs, but not always. Any sloped roof can handle the material. Costs are likely to increase though if TPO membrane is applied to a sloped roof.

TPO manufacturers boast the resulting roof will be monolithic, or without noticeable seams. This is wonderful for waterproofing the upper most layer of a roof. To achieve this seamless look among various sheets, the actual seams are hot air welded together, which is possible given the type of plastic TPO is made of. PVC is another material that is hot air welded at the seams. Both types of membrane are flexible.

All roofs need to allow for thermal movement, either from weather / temperature changes or impact by humans walking on it. PVC uses additives to its base material to promote flexibility, while TPO is naturally flexible.

Color options include white, light gray and black reflectivity. It used to be that only white was thought to reflect UV and infrared rays, but the material in synthetic roofs (namely a laminated top) can achieve this reflective option in darker colors, yet with higher temperature gain (less energy efficiency).

Cost and Value

The main thing with effectively estimating the price to install a TPO roof is finding a qualified professional who can do the job. Mechanically attaching the material, or even gluing (fully adhering the membrane to the roof deck), is something most roofers can probably do.

via Atlanta Roofing Specialists

Effectively hot air-welding the membrane seams takes special care, skills, tools, and experience. If the hot air welding of the membranes’ seams is not done properly, then the entire TPO roof system could be compromised at the seams, and hence be subject to costly roof leaks.

In our research, RoofingCalc.com lists residential TPO roofing costs at $6.50 to $12.50 per sq. ft. for materials and professional installation, however some residential and commercial contractors will install it for as low as $5.50 to $7.50 per sq. ft., but only on either larger or very simple and easily accessible residential projects that can be completed in a day or two.

A word of caution needs to be noted. This is touched upon in our “Disadvantages” section below but needs special mention.

Back in 2010, the Midwest Roofing Contractors Association issued an advisory against TPO, which obviously impacted the market. Some of the TPO manufacturers responded to this advisory by noting that no two TPO materials are the same, meaning some brands avoid the problem stated in the advisory.

Our take is that TPO is constantly undergoing changes and improvements in formulation and that is a good thing, even if the currently available TPO formulations have not been fully perfected yet. Many currently available TPO formulations are believed to be good and adequate, but only time will truly tell.

The industry is aware of the perceived problems with older TPO formulations with the new formulations aimed at addressing the old issues and ultimately having a better overall product, yet the flip side is that the TPO membrane using newer and improved formulation may need some “field time” to establish a proven track record of performance that can stand the test of time.

If you are looking to go with a TPO membrane for your low-slope roof application material, it’s best to stick to products from manufacturers that have been in the space since the beginning (read as in before the year 2000), to ensure the warranty of the reformulated products will be honored, if need be.

Most manufacturers’ warranties for TPO membranes are a minimum of 10 years, and as much as 25 years. The material itself ought to last much longer, so the installation quality is the key area to focus on, especially with respect to the quality of the seams including roof flashing details.

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EPDM Rubber Roof Cost, Plus Pros & Cons in 2021

Updated on January 13th, 2021

Welcome to the default, or old school, material for flat roof installations. It’s technical name: Ethylene Propylene Diene Monomer is a mouthful. While it is simply a rubber material, we’ll go with EPDM since everyone else does. This product competes directly with TPO and PVC as membrane type roofing material. This one though tends to only be used on flat roofs.

Some might be wondering why not just use the more traditional roofing materials like asphalt shingles. Well, traditional roofing materials normally come in a shingle or tile form designed for sloped water-shedding roofs, not waterproof ones.

If you were to use roofing shingles on a low-slope or flat roof, then any accumulated pooling water would rise underneath the asphalt shingles and seep through inside the house (similar to what happens with ice dams on asphalt shingle roofs), leading to severe issues like mold, rot, and damage to the roof deck and interior of the house. Thus, a waterproofing membrane approach has been in place for nearly a half century to provide an impenetrable waterproof barrier that can reliably protect the structure with a low-sloped roof.

EPDM Pricing and Value

EPDM is the least expensive of the three primary membrane types, but it isn’t cheap. The material is very durable.

Since the early 1960s, EPDM has been the material of choice in canals and other irrigation systems prior to becoming a successful material for waterproofing roofs.

It’s estimated to have 1 billion square feet of EPDM rubber membranes installed throughout the world’s roofs. This is partially due to its relative durability, ease of installation and its competitive pricing.

Average Cost Per Sq. Ft. Installed

On the low end, you can plan to spend around $4.50 to $6.50 per sq. ft. for the installation of an EPDM rubber membrane on a flat roof. — The low-end pricing, although not very common, would be on par with asphalt shingles pricing, which tells you how affordable it can be. $6.50 to $10.50 per sq. ft. installed would be the high-end pricing and would likely be for a thicker or solar-reflective rubber membrane, with the job done by experienced flat roof specialists.

What about DIY for EPDM?

The DIY approach is viable, because installation is not complicated. With TPO and PVC roofs, you need special skills and tools like hot air welders (whether hand-held or robots) for proper installation.

With EPDM, you need the sheets, which are sold in as large as 50 feet wide by 200-foot-long pieces, some glue and preferably some experience in achieving a successful installation.

Home Depot and Lowe’s sell rolls of 10 x 25 feet for around $170 and $225 respectively. Add another $80 for the glue, or bonding adhesive (sold in 3-gallon containers) and $25 for long armed roller and you’re set to go.

When it comes to value or return on investment, that’s another matter. Our Advantages and Disadvantages section below help identify the balance of lasting value vs. known issues.

The reality is EPDM roofs last 7 to 15 years on average before requiring a replacement (less likely) or resealing (more likely). With EPDM liquid roof coatings, repairs and resealing can extend the lifespan of the rubber membrane roof and re-institute the waterproof barrier properties from the original installation.

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PVC Roof Options and Costs – PVC vs. TPO Membrane in 2021

Updated on January 12th, 2021

PVC, technically known as Polyvinyl Chloride is really vinyl roofing, though is routinely referenced as PVC roof.

PVC competes with TPO and EPDM in the synthetic roof membrane arena, and indirectly with all other roofing materials including BUR, modified bitumen, and structural standing seam roofs designed for lower sloped roofs.

Membrane roofs are usually applied to flat or low-slope roofs but using a single-ply membrane on a sloped roof is also possible and common on roofs with slopes between 1:12 and 3:12.

Why not just use traditional roofing materials (asphalt shingles or other tiles) on a low sloped roof? Because they are very likely to leak unless a minimum specified slope for shingles or tiles has been met.

When used with a slope, the overlap of those materials is designed to shed water away from the roof deck. Whereas flat roofs have only a slight pitch, and any standing, or pooling water, could lead to immediate leaks and rotting soon thereafter.

PVC membrane is a kind of roofing material that can withstand pooling or standing water — puddles of water that accumulate on roofs with low slopes.

Cost

Of the three primary membrane roof types, PVC is the most expensive. EPDM is the least costly option, and TPO is somewhere in the middle.

TPO allegedly offers the benefits of both the other types, yet that material keeps undergoing formula changes, and so compared to PVC and EPDM is considered less reliable, particularly when it comes to warranties.

Prices for residential installs can vary greatly. A roofer is likely to quote differently than a professional PVC installer, probably less, but also likely to not have the proper tools. A fair range is between $6.50 and $12.50 per sq. ft. if installed by a PVC expert. On the lower end if going with less thick material.

In terms of value, durability, and ROI, PVC is arguably the best, or longest lasting of the three. EPDM will go 7 to 15 years before needing replacing or re-coating.

TPO is thought to go for as long as PVC, but that information is either suspect or unknown for sure just yet.

PVC has been in the field for decades and unlike TPO isn’t constantly undergoing changes to the formula to address performance issues. Warranties are usually ‘lifetime’ and with proper installation, it ought to retain solid performance for 20 years or more.

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