Flat Roof Repair

Things to Consider for Commercial Roof Repair

No matter how skillfully it was constructed, every building’s roof will encounter problems throughout its life. This exterior feature constantly endures changing weather patterns and debris, which cause wear and tear. Additional factors like poor initial installation can make a roof deteriorate more quickly.

When you are considering a significant repair or even a full replacement, it can be difficult to know where to start. Getting a thorough understanding of the factors that influence repair or replacement is the first step, and evaluating the type of repair required is next. If you’re having trouble knowing where to start the process, you’ve come to the right place. We’ll go over what you need to consider when deciding on commercial roof repair.

Roof Repair, Replacement or Restoration?

Your first step is to decide whether your commercial roof needs a complete replacement, or if it’s a good idea to go for a repair or restoration. A full replacement of a commercial roof is a lengthy process that requires significant planning if you want to fit it comfortably within your budget. For most building owners, replacing a commercial roof is the last resort.

Commercial roof repair is a suitable option when the issue is small and located in a single area. Examples include impact damage to one spot while the rest of the roof is intact or weather damage on a roof that otherwise has many years of use left.

Commercial roof restoration is typically done by coating the roof. This process gives the building a new membrane and provides significant resistance to leaks. Applying a new roof coat is a cost-effective way to extend the roof’s life, and installation is simpler, as well as less disruptive to day-to-day business. As long as the roof is structurally sound and has not reached the end of its lifespan, repair or restoration are typically the most viable options for practicality and budgeting.


What is the best flat roof, or roof material for flat roof replacement? This is a question I get asked a lot, and to be honest there isn’t a right or wrong answer – But there is sometimes a type of flat roof that would suit a flat roof of a particular size, shape, detail level or budget. I have been fitting new flat roofs now for over 30 years, I have seen virtually every type of flat roof, from being installed on day one, to its final death. So if you want some impartial advice free from sales patter, read on. You can also find a link to average flat roof costs at the bottom of the page.

What is the best flat roof? Well let’s take a look at the main contenders, Felt v Asphalt v Fibreglass v EPDM rubber v Single ply membranes, let the fight begin, click on more info for a shortcut to that roof covering, or read the article as a whole.

Felt roof – Positives – low cost, proven results, suits roofs of any size – Negatives – not suitable for regular foot fall, requires heat to install, not DIY friendly, suffers from a poor reputation from older systems

Asphalt roof – Positives – Competitively priced, hard wearing, suitable for most sizes, long lifespan – Negatives – relatively heavy and requires a strong roof structure, not flexible, not DIY friendly

EPDM rubber roof – Positives – lightweight, flexible, hard wearing, no naked flames required, can be DIY installed – Negatives – not pretty and even ugly if overlooked, may shrink over the years, may not suit complex detailing, can attract poor installers

GRP fibreglass roof – Positives – lightweight, hard wearing, no hot flame, resists vandalism, truly jointless, pretty, long lifespan, can be DIY installed – Negatives – not very flexible, does not suit large surface areas easily, slippy when new

Single ply membrane like PVC, TPO, TPE, & PIB – Positives – lightweight, flexible, pleasant to look at, handles slopes and large areas, fairly durable, fire resistant – Negatives – Costs more to install than other flat roof systems in a domestic setting, may not suit regular footfall, or complex details


Before we begin… Sometimes the mere mention of a flat roof sends a homeowner into a spin. I’ve had customers spend 15 times the cost of replacing an old flat roof converting it to a pitch roof to save the cost of replacing it in another 20 years time. I know you want your next roof to last forever, but take a deep breath and think clearly.


This type of flat roof still has a bad reputation with some people, but I’m going to tell you why that perception is out of date. Most people have in mind the old ‘pour and roll’ felts of yesteryear, and these were thin bitumen felts glued together with a hot liquid bitumen between each layer. They had minimum internal reinforcing, with some containing natural hessian fibres which were prone to rotting. This type of felt, sometimes known as felt paper or tar paper, would effectively dry out and crack with age or UV damage from the sun. 10 years was pretty much the life expectancy.

Cool Things to Know about Flat Roofs

Flat Roof = Profit Center

If your property is a hotel, restaurant, motel, cafe, pub or similar establishment, consider a rooftop patio. Your commercial roofer can work with you to determine what modifications might be needed to transform all that square footage into a hip, cool, vibrant rooftop party place.

Where you see only HVAC units, an engineer and the experts can envision weatherproof seating, railings, mood lighting and a panoply of stars above the heads of giddy guests.

Get a Charge

the number of sunny or partially sunny days in annually. Your roof, even if it is not conducive to the tourist trade, can be great spot for solar panels that deliver free electricity to your business. With 27 percent of days being completely sunny, you have plenty of opportunity to tap the free energy beaming down on your flat roof.

A solar array on a flat roof is easy to service, leaves a very small footprint on the existing roofing material, and can be installed with relative ease by coordinating with your commercial roofer and a local solar energy contractor

A Passive Punch

Another cool thing about your company’s flat roof is its ability to cool your building. With the right mix of rooftop insulation and reflective roofing material, your commercial roofer can install a cool roof, one that lowers cooling costs by reflecting sunlight away from the building.

What kind of flat roof material is better?

The TPO roof system is quickly becoming an attractive option for owners of commercial buildings and contractors alike. It is a type of single-ply roofing material which is durable and highly resistant to environmental hazards. It is also available in a variety of colors.

TPO is popular partly because it is economical. However, it is also durable, meaning it can resist a variety of threats ranging from mold to tears. We’ll discuss this in greater detail below.

Like any other material, TPO roofing has both advantages and disadvantages. On the plus side, TPO is priced reasonably. It offers some of the benefits of PVC including energy efficiency but at a more affordable cost. The roofing material also looks great on any type of building. Whether you get a grey, black or white roof, you benefit from UV resistance and a cooler building.

TPO roofing is also highly resistant to dirt and isn’t easily torn or punctured. The material withstands thermal expansion and contraction better than other single ply roofing products. And because TPO sheets are wider, the installation is quicker and there are fewer seams. There are also multiple options for installation methods allowing for greater customization.

The number of roofing options available on the market today can overwhelm any building owner. However, you should seriously consider a TPO roofing installation if you want a cost-effective solution which doesn’t compromise the integrity of your building.

PVC Flat Roof Installation

PVC Flat Roof Installation

There are many different types of flat roofs, but the two main types are PVC (vinyl) and TPO (thermal plastic). At Pro Roofing NW we prefer PVC over TPO because they are more water resistant – which is a must in the rainy climate. However, TPO is considered a “greener roof” option because it emits less gas when welded together. Flat roofs are notorious for being costly to upkeep due to their predisposition for springing leaks. However, PVC flat roofs are so watertight that even if water pools on your roof for an extended time it should not have adverse effects. PVC is also known for its strength – these types of roof can last more than 20 years!

Flat Roof Underlayment – What You Need to Know Before Hiring a Roofer

One of the most important parts of flat roof installation is the underlayment. Because is such a rainy climate, one of the most important things you should know is that when choosing a roofing material is that you should never install a single ply roof (such as torchdown). The biggest problem with single-ply roof types is the risk for condensation. Over time moisture from inside your home from normal activities (showering, boiling water, breathing, etc.) will begin to accumulate in your attic and under the single ply membrane. Condensation will manifest itself just like a leak, but it’s just water from inside your home that is trapped and can’t get out. To ensure this doesn’t happen to you it is imperative your roof has two proper layers of underlayment as well as proper venting. Every PVC roof must have both layers of protection under PVC.

Two necessary layers of protection for your flat roof include:

Leak barrier – In order to protect your flat roof it’s important to have a leak barrier that acts as a shield from water and ice. These barriers allow small amounts of water vapor to evaporate through them from the inside of your home but will not allow water drops from rain to pass through to the inside of your home.

Separation sheet – Additional protection for your flat roof includes the installation of a separation sheet. These sheets are felt-like and applied directly over the leak barrier. They will absorb small amounts of moisture under the membrane in case any water passes through the leak barrier.

Venting for Flat Roofs

The next important thing to consider during flat roof installation is proper ventilation. There are two basic types of vents – one lets the air out of the attic (RVO) and the other pushes air under the membrane and over the separator sheet to dry it (soffit).

RVO high neck vents – These types of vents are used to let air out of attic cavities. The necks are tall because water can build up and run into the house through the vents.

Soffit vents – are installed on the underside of your home’s eaves. Cool, dry air enters through these and then get pushed up and out through the RVOs.

Why Choose Pro Roofing NW?

Flat roofs are more individually unique than any other type of roofing. Pro Roofing NW has years of experience in providing these roofs in the rainy climate and can help guide you through the process as well as ensure that adequate measures have been taken to prevent future leaks.