Questions covered in this guide
Treat drainage as an assessed system
GAF’s low-slope drainage guidance explains the purpose of roof drains and the problems standing water can create. Its commercial examples prompt a drainage review; they do not establish a diagnosis or repair method for your home’s roof.
Record the event from a safe location
If water is visible from a normal indoor window or other safe position, record when rain ended and when the photograph was taken. Mark the approximate area on a sketch without walking onto the roof or estimating its weight. Note any corresponding indoor leaks and tell the roofer promptly about active problems. Avoid puncturing a surface or trying to redirect water yourself; the professional must evaluate both the roof and its drainage arrangement.
Prepare an observation log
Use columns for date, weather description, observation time, photograph reference, visible location, and indoor symptoms. Leave a separate section for the contractor’s findings about drains, obstructions, slope, and the roof surface. Keep your observations and their conclusions distinct. Ask whether the proposed remedy addresses maintenance, drainage design, damaged materials, or more than one issue. A label such as ponding repair is not a complete explanation of what the contractor intends to change.
Evaluate the proposed result
Request a written scope identifying the areas addressed and how the contractor will check the completed work. If replacement is proposed, ask what drainage conditions the new assembly is intended to correct. Save the original log as a reference for that discussion, not as proof of a defect. The national roof calculator cannot assess standing water or price a drainage redesign. Obtain the site-specific explanation before comparing a coating, localized repair, or replacement proposal.
Putting it into practice
The event log gives a professional time-and-location observations without encouraging roof access. It separates drainage maintenance, assembly damage, and redesign so the homeowner can evaluate the actual proposed remedy.
Sources and supported claims
GAF explains that low-slope roofs use drainage paths to move water off the roof.
Source ↗ · national · Checked 2026-10-12
GAF identifies standing water as a potential source of deterioration or damage in roofing systems.
Source ↗ · national · Checked 2026-10-12