Q. What is the best roof system for a flat roof?
A. There is no one flat roof system that is best for all applications. Keep in mind that even if you are using the best materials, your flat roof system still can be installed improperly and you could end up with a leaky roof. Good workmanship and proper attention to detail (e.g., flashing and drainage issues) are just as important as material selection. Also, maintenance plays an important role in roof system integrity and service life.
To assist you in your decision-making, property owners should be informed of what is available. It is critical you work with a professional flat roofing contractor and get a detailed, thorough proposal.
Q. I received three significantly different proposals from contractors. How should I decide which contractor to select?
A. Clearly written proposals that are detailed and broken down into separate line items are a good sign that the contractor is being thorough and has prepared an accurate estimate. The following is a partial list of items your estimate or proposal should include:
- The type of roof covering, manufacturer and color
- Materials to be included in the work, e.g., membrane, insulation, etc.
- Scope of work to be done
- Removal or replacement of existing roof
- Flashing work, e.g., existing flashings to be replaced or re-used, adding new flashing, flashing metal type
- Who is responsible for repairing/replacing exterior landscape or interior finishes that are damaged during the course of the work
- Installation method
- Approximate starting and completion dates
- Payment procedures
- Length of warranty and what is covered, e.g., workmanship, water leakage
Q. I received several estimates to replace my flat roof system and the prices vary greatly.
A. If one estimate seems much lower than the others and it sounds too good to be true, it probably is. Many fly-by-night contractors’ below-cost bids seem attractive, but these contractors often are uninsured and perform substandard work. If an estimate is confusing, ask the contractor to break down the estimate into items/terms you can understand.
Q. Should I repair or replace my flat roof?
A. When the area of wet roofing exceeds about 25 percent of the total flat roof area, the cost of patch-ups and flat roof repairs will begins to approach the cost of a full flat roof replacement. If the subsurface moisture is extensive — 30 to 35 percent or more of the entire roof area — it usually makes no economic sense to repair or recover the existing roof because all the wet materials must be removed before reroofing.