Most roofs in Washington DC are flat or nearly flat with a slight pitch. Some flat roofs that are completely flat and do not have a pitch due to settlement of the home, improper construction, or deflection of the rafters must have a roof system installed that will either correct the pitch or be able to withstand the effects of ponding water. In order to correct a roof structure that has standing (or ponding) water, a tapered insulation system can be installed. Sometimes, though, this is not possible due to penetrations or other structures on the roof. When this is the case, a roof system that is not adversely effected by standing water should be used. The problem is that most flat roof systems are made from asphalt products, which do not hold up under these situations.
At Bradley Construction, we normally suggest installing a single-ply membrane roof system. The next issue is to decide which type of single ply roof should be used. Most people have the impression that all single-ply membranes are alike and nothing can be further from the truth. Just because they are called single-ply membranes does not mean that they will perform the same. Like most products, there are a variety of features from one manufacturer to another. Single-Ply roofing membranes have been installed on roofing projects for over 25 years. Some have performed well while others are doing poorly or are non-existent today, while others have recently come into the marketplace.
In designing performance characteristics in a single-ply membrane or single-ply system you have to keep in mind what elements the material is going to be subjected to. Roofing membranes need to perform 24 hours a day, seven days a week, without resting periods. Roofing membranes are exposed to UV Rays, rain, snow, hail, standing water, micro organisms, chemical pollutants, vast temperature changes, wind and dynamic flexing, etc.
The expectations of single-ply membranes should be that the membrane:
- It is a waterproofing sheet
- must remain waterproof throughout its warranty life
- must be non-flammable
- must comply with building codes
- must be easy to work with and repair
- be pliable at different temperatures (especially extreme cold)
The single-ply roofing market today is dominated by TPO, PVC & EPDM. TPO’s are relatively new and while some say they do not have adequate performance history to make a concise judgment, we have had no problems over the past 10-15 years. GAF recalled its’ TPO2 product, according to a newsletter article from the NRCA dated 6/8/01 “GAF Materials Corp. (GAFMC) has announced that it will temporarily discontinue production of its new EverGuard® TPO² Plus product… Subsequently, the product was reengineered to meet the company’s requirement for being “contractor-friendly.” The new product has proved to be excellent.
Other products such as PVC & EPDM roofing membranes have been around for over 25 years with an excellent, documented track record as well.
Bradley Construction uses both types of membrane, such as Mulehide’s TPO and EPDM Roof Systems. 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 20 years ago.
FiberTite is a unique DuPont™ Elvaloy® (Ketone Ethylene Ester – KEE) based roofing system that was invented over a quarter century ago. Today, over 99% of FiberTite roofs ever installed are still performing.
To compensate for deficiencies, many manufacturers continually alter their product formulas. Look for proof that the product you choose has already stood up to the tests you plan to giveit.
If you want your roof to last 20 years, withstanding exposure to harsh chemicals and intense sunshine, ask the manufacturer for examples of similar success stories. Be aware: many products that start out performing like champions, lose their original physical properties with age.
Figuring the cost of your roof requires looking far beyond the sticker price. The real value of a roof is calculated by factoring the system’s proven longevity, the energy savings it can bring if it is a reflective roof system, typical maintenance and repair costs, and also, if necessary, the cost of disposing the roof when it’s old.
According to the Department of Energy, in most regions of the U.S., reflective roof systems can save between $.07 and $.20 per square foot, per year – in some cases even over $.20 per square foot. Be sure to ask the manufacturer for life cycle cost data.
Don’t overestimate the value of a warranty. In many cases it’s a piece of paper used as a marketing tool. Warranties protect the manufacturer and with some, the proof of failure lies with the owner. A warranty for 15 or 20 years makes you feel safe the day you buy it, but first verify that the roof system will last that long. Will the manufacturer last that long? Take time to understand the warranty, especially its exclusions.
Many warranties are pro-rated and exclude common conditions like ponding water, hail, oil or grease. Definitions for wind speed can be vague.. Big company or small company, nothing is more important than their integrity and proven commitment to service and product performance.
The best roof system in the world put in the wrong hands will fail. The quality of the finished product depends on the experience of the installer, Bradley Construction has certified, factory trained installer with years of experience. Check to see if the product manufacturer provides installation training for the contractor. Ask the contractor for a complete project reference list to verify customers have been satisfied with the installation of the system you select.
|TPO ADVANTAGE:The performance of rubber with heat-welded seams The weathering and low temperature flexibility of EPDM with the superior seam strength of heat-weldable membranesWhite membranes reflect sunlight and cool building interior for energy savings.Wide sheets mean less seams and less labor compared to standard PVC sheets.More product on top of the scrim where you need it most – one of the thickest top plies in the industry.Minimal shrinkage for watertight integrity you can count on.
Call Bradley Construction 301-253-6087 for your free estimate and consultation on your flat roof in Washington DC Metro area.
Blog provide by David Bradley