Types of Roofs- Flat Roofs Washington DC Maggio Roofing

Types of Roofs- Flat Roofs Washington DC Maggio Roofing

Flat and low slope roofs are among the most popular styles of roofing in Washington DC, and are gaining popularity in Maryland, and Northern Virginia. Due to space constraints and cost of construction, a flat roof is a good choice for both residential and commercial use in the city. But the design, installation, and repair of a flat roof requires special expertise and skills.

With more than 30 years of successful experience, Maggio Roofing has become the experts in flat roofs in DC, MD, and VA. Our team of professional roofers knows the best methods for the installation, repair and maintenance of flat and low slope roofs, so that we are able to provide our commercial and residential customers with quality products and outstanding service.

Free Estimate on Repair & Installation of Flat Roofs in MD, DC or VA

Call us at (800) 766-3495 or fill out our contact form today for a no obligation quote on having a new flat roof installed or for flat roof repair, or read below for more information about flat roofing.

Everything You Ever Wanted to Know About Flat Roofs

Flat roofs are not necessarily flat. Most have a slight slope to allow water to runoff toward the edges where it can be drained away. However, compared to the steeply pitched roofs evident on some homes, it is easy to see why they are called “flat” roofs.

If a roof is perfectly flat, a mistake has been made in its installation, or it has “settled” over the years. With no slope or pitch at all, water can pool on a roof and cause all sorts of problems, including leaks, seepage, and even collapse due to excess weight.

What Type of Roofing Works Best on a Flat Roof?

We normally suggest installing a single-ply membrane roof system on flat roof applications. Single-ply roofs have been proven to be durable, reliable, and easy to maintain over the past 30 years they have been in service.

Although many people think that all single-ply membranes are alike, there are really several varieties, each with their own strengths. The most common types are:

  • TPO (thermo-polyolefin)
  • PVC (polyvinyl chloride)
  • Elvaloy membrane
  • Types of Roofs- Flat Roofs Washington DC Maggio Roofing
  • EPDM (ethylene propylene diene monomer)
  • Modified Bitumen

TPO (thermo-polyolefin)

PVC (polyvinyl chloride)

Elvaloy membrane

EPDM (ethylene propylene diene monomer)

Modified Bitumen

Maggio Roofing installs FiberTite Roof Systems single-ply membrane roofs. This manufacturer has one of the best track records of any roofing material manufacturer. In fact, this manufacturer has not changed their formulation of their membranes since introducing them over 30 years ago. FiberTite is a unique DuPont™ Elvaloy® (Ketone Ethylene Ester – KEE) based roofing system that was invented over a quarter century ago. The membranes use a flexible solid polymer, Ketone Ethylene Ester (KEE) as their foundation of their coating. The costing is bonded to a heavy polyester fabric. This results in a high performing membrane that remains flexible and retains its physical attributes despite being exposed to UV, standing water, and environmental contaminants. The seams are fused together using a hot air welder, which will not pose a fire risk like a torch. The seams are actually bonded on the molecular level and are 10 times more secure than those created with a mechanical seaming process. Today, over 99% of FiberTite roofs ever installed are still performing well.

TPO is the most common single ply roofing material but is also the worst performing among those listed above. TPO came on the market in the early 90s and has had a bad performance record. With several manufacturers having failures of this type of material, it is a wonder that it is still produced. Several industry studies have warned of failures due to high heat, welding difficulties, and other effects from standing water (just to name a few). We strongly urge homeowners with flat roofs to stay away from this material or at least know that they are installing a roofing product with a poor performance record and an uncertain future. The upside to the material is that it is the cheapest flat roofing membrane on the market today (remember, you get what you pay for).

PVC membranes require a chemical called plastisol to be applied to a lightweight fabric to create a flexible membrane. Over time, however, this chemical is drawn to the surface by UV rays, heat, and environmental contaminants and then washed away by the rain and wind. The reduced plastisol reduces the membranes flexibility and leaves it susceptible to damage from thermal shock, hail impact, and foot traffic. The other effect of the reduction of plastisol is that the membrane becomes very difficult to repair and impossible to maintain.

EPDM is a good material but can be difficult to maintain due to field seams that must be glued onsite. The average roof in Washingotn DC, is relatively small and has many penetrations (hatches, skylights, and pipes) which require many field seams to ensure water-tightness. This system is dependant on a mechanical seaming process (either glue or tape) and requires these products to stick together in order to be leak-free. Water, UV rays, and environmental elements all degrade these glues or tapes, which can compromise the roof and cause ongoing maintenance costs.

Modified Bitumen, arguably the most dangerous roofing system for residential use, is made using polyester or fiberglass felts costed with a “rubberized” modified asphalt coating. These roofs are damaged by the UV rays and must be kept coated or installed with a granular coating. Probably the biggest problem for DC homeowners is that most of the modified membranes are installed with a torch. Imagine a relatively inexperienced person installing a roofing membrane on a highly combustible structure (75 year old wood and insulation) with a torch that sends out a flame that is 3 feet long! It’s no wonder that the largest insurance company for roofing contractors require that all torch technicians go through a certification class if the company wants to remain insured. Also be aware that contractors are supposed to notify the local fire department and provide a fire safety plan before installation starts. In addition, they are supposed to keep a “fire watch” for a minimum of 30 minutes after the last torch is extinguished. Ask yourself if you really want someone playing with a torch and having to have something called a “fire watch” on your home while they are installing your roof!


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