Flat Roof Leaks in Heavy Rain

Commercial Park, Aerial View with Several Large Structures.

A Low-Slope or Flat Roof Is Generally Chosen as an Economical Option for Large Structures.

A flat roof will always represent something of a gamble. While their economy and ability to cover large areas make them ideal for commercial roofing, building owners must practice a lot of oversight to ensure proper flat roof repairs. As a matter of fact, this oversight should ideally begin with the roof’s construction. Since flat roofs will always remain vulnerable to heavy rainfall, there must exist a proper, dependable drainage system. The roof must also have proper grading to prevent ponding, a highly troublesome issue that can become quite difficult to solve.

Homeowners who choose flat roofing tend to do so for aesthetic reasons, rather than economy. If the appearance of a flat roof provides the main justification for its choice, then the homeowner needs to fully understand the roofing’s vulnerabilities. If they do not, they risk a litany of problems that could include leaks with every heavy storm. For residential and commercial properties alike, a flat roof represents a compelling choice. Even though the reasons for this choice are drastically divergent, the responsibility for proper care and awareness remains the same.

Flat Roofing Systems and Rainfall

If you need to choose a new roof for your structure, or purchased a home or business that already had a flat roof, you should fully understand not just the advantages of this roof system, but also its drawbacks. A lack of dependable, functional, and effective drainage represents the main problem with many flat roofs. During and after storms, it can seem as if water simply refuses to leave the roof.

Flat Roof Advantages

  • Economical and Cost-Efficient
  • Rooftop Space for Storage
  • More Interior Space
  • Accessibility for Repairs and Installs

Flat Roof Disadvantages

  • Drainage Difficulties
  • Propensity for Leaks
  • Limited Choice of Roofing Materials
  • Short Lifespan Expectancy

The economy and cost-efficiency of flat roofing provides the top justification for its choice. Flat roofing materials generally cost around 80 cents per foot. This applies not only for installation, but any time new roofing material is needed for repair or maintenance. You should also not underestimate the advantage of a large rooftop storage area. While many companies and homeowners simply use the roof to store HVAC equipment, it can serve a variety of purposes, including space for a rooftop garden, deck, or leisure area, oran ideal expanse for the installation of solar panels. Furthermore, a flat roof makes it possible to take full advantage of your structure’s space, without the frustration of sloped walls created through a pitched roof. The accessibility of a flat roof also matters, as it makes it easier to both identify and make repairs.

As for disadvantages, drainage difficulties are, of course, the number one problem. Even well-designed drainage systems will operate slowly, and allow for the continued threat of ponding. This troublesome issue occurs when a portion of the roof has a lower grade than the surrounding area. While this can happen through faulty construction, it can also occur as a natural consequence of the roof’s age. Regardless of how it occurs, ponding creates the same problems as a place that will attract and trap water. Many people fail to realize the corrosive capabilities of water. As it sits on your roof, water will gradually eat away at seams and other vulnerable areas, and create the likelihood for leaks. Ponding will also grow worse over time, as the weight of the trapped water will continually cause the problematic section to sag further.

Flat Roof Materials

Modified Bitumen Roofing Material That May Need Flat Roof Repair.

Flat Roofs Can Become Vulnerable to Leaks at Their Seams.

Another disadvantage of flat roofing is the relatively poor choice of available materials. Since economy serves as the primary justification for many flat roofs, many building owners opt for rolled roofing. This category refers to roofing materials that are literally rolled on, then secured through adhesives, heat welding, or weight. Rolled roofing materials include EPDM, TPO, and bitumen. While easy and cheap to install, it’s not uncommon for these materials to last only 10 or 15 years. More durable options do exist, including PVC roofing, but the higher cost can serve as a major drawback when you need to roof a massive commercial warehouse.

Flat Roof Drainage

As discussed above, the lack of natural drainage is a serious drawback for many flat roofs. The precise reasons for this problem are as follows:

  • Ponding water contributes to leaks and overall damage.
  • Windblown debris will simply sit on the roof and trap more moisture.
  • Pooled water and debris will deteriorate caulking and adhesives.
  • Ice and snow become hugely problematic due to weight and drainage difficulties.
  • More likely to have leaks at flashing and other vulnerable areas.

Believe it or not, systems do exist for proper flat roof drainage. If you decide to make the investment in one of these roofing systems, or are forced to choose one out of financial necessity, make sure to fully employ the potential of each of these features.

Interior Drains: These work just like the drain of a shower. A drain is installed in an area that collects water, then sends it out via a system of pipes through the building’s interior and into a downspout.

Gutters: Flat roofs can also use gutters, which will collect water as it drips off the side of a roof, and channel it away from a building’s vulnerable foundation.

Scuppers: A highly effective drainage solution, scuppers are square openings installed along the roof’s perimeter to shoot water away from the building.

Will a Flat Roof Always Leak?

The answer to this question depends on one thing: the quality of the roof’s construction. Flat roofs installed by inexperienced or rushed roofers can very likely have permanent drainage issues. However, if the installation employed a skilled, expert roofer with plenty of experience in flat roofing, then leaks may only rarely develop. This all depends not only on the quality of roofing material installation, but also on the integration of proper drainage opportunities.

Can Flat Roofs Be Repaired

Like any type of roof, flat roofs benefit from regular maintenance and repairs. However, since a selection of problems can create the need for flat roof repairs, you must stay attentive to your roof’s needs. Since a lack of service can cause a flat roof to rapidly break down, preventative repairs provide the secret to long-term value. If you notice any of the following, make sure to call a trusted commercial roofer right away for an inspection.

  • Ponding
  • Rips and Tears in the Roofing Material
  • Mold Growth
  • Broken Flashing
  • Leaks

Common Questions About Flat Roofs

What Are the Different Types of Flat Roofs?

Flat Roof Housing Many HVAC Devices.

Flat Roofs Provide a Convenient Space to Store HVAC Units.

Built Up Roofing (BUR): Also known as tar and gravel roofing, this consists of layers of roofing felt topped with asphalt and gravel for waterproofing and impact protection.

Modified Bitumen: Similar to BUR, but with only two layers of material installed with rollers.

EPDM: Also installed via rollers, this type of roofing either adheres to a substrate, or has ballasting with stones. EPDM roofs are also known as rubber roofs, and appear like one would expect.

SPF Roofing: Spray foam is a seamless type of roofing applied as a liquid. Upon application, this liquid immediately expands and hardens for an airtight seal. It is usually covered with an elastomeric topcoat for added protection.

PVC and TPO: These are both thermoplastic membranes that consist of a single layer. Easy to install, these materials provide a range of benefits that make them a popular choice for flat roofing.

What Are the Problems with Flat Roofs?

Drainage difficulties and susceptibility to heavy rainfall represent the main problems with any type of flat roofing. There are also few choices in roofing materials, compared to the vast selection afforded to peaked roofs.

How Long Should a Flat Roof Last?

This depends on a number of factors, including the material chosen to cover the roof, the quality of its installation, the presence of proper drainage systems, the frequency of maintenance, the environment the roof exists within, and more. As a general rule, a well-maintained commercial roof can last for 20 years.

Do Flat Roofs Leak More?

If equipped with proper drainage systems, including internal drains, gutters, and scuppers, flat roofs leak no more than pitched roofs. If a flat roof lacks proper grading and has a poorly designed drainage system, then it will leak much more frequently than other roofs.

At Dimensional Drones, we provide unbeatable services for flat roofs. If your structure suffers from flat roof leaks, we can perform leak detection that will isolate each and every problem area to enable comprehensive repairs. If you need the inspection of a flat roof in Austin, TX, give us a call today at (512) 402-8877.