Roofs shed water in layers
Steep-slope roofs such as shingle, tile, and metal shed water by overlapping. The visible roofing handles most of it, but underlayment and flashings do essential work beneath, particularly under tile and at every change in plane.
Low-slope roofs rely on a continuous membrane instead, whether built-up, modified bitumen, single-ply, or fluid-applied. Seams, terminations, and penetrations must hold out water that may sit on the surface. Slope to drains, and overflow provisions where required, keep that water moving.
Sheet metal ties the system together. Valley metal, step flashings, counterflashings, kickout flashings, edge metal, gutters, and scuppers handle the concentrated water that the field of the roof sends their way.
Why roofs leak
Most roof leaks start at flashings and transitions rather than in the open field. Roof-to-wall intersections without kickout flashings, short or reversed step flashings, sealant used in place of metal, and poorly flashed penetrations are frequent sources. Water often travels along framing before it appears inside, so the stain may sit far from the cause.
Material and installation also matter. Fastening, exposure, underlayment laps, and nailing patterns follow the manufacturer’s requirements, and departures can lead to blow-offs, slipped tiles, or water entry. Some failures trace to the product itself, which is a separate question from how it was installed.
Low-slope roofs add ponding, seam failures, and membrane damage from foot traffic or equipment. Clogged or undersized drains, scuppers, and gutters can push water over flashings that would otherwise perform. Attic condensation is sometimes mistaken for a roof leak, so ventilation and interior moisture sources belong in the picture too.
How a roof leak investigation proceeds
A typical investigation pairs interior observations with a careful survey of the roof. Investigators trace stains back toward likely sources, inspect flashings and transitions, and compare the installation with the plans and manufacturer literature. Controlled water testing, applied in sequence from low to high, can confirm a specific path.
We use state-of-the-art cameras and video documentation techniques to provide trial-ready exhibits. If roofing materials appear to have manufacturing defects, we are aligned with several laboratories that test and analyze product failure. We also keep field samples at our office in case they are needed at trial.
Gregg de Haan specializes in high alpine waterproofing, roofing, and general construction, and he is a member of the National Roofing Contractors Association (NRCA). Roofs in snow country face ice dams, heavy loads, and sliding snow that lower elevations rarely see.
Reports and repair scopes
Our field reports pair photo documentation with clear descriptions of each condition. We prepare conceptual repair scopes and cost estimates, which for roofs can distinguish local flashing repairs from partial or full replacement.
We are educated on past and current building codes, SB800, and building product performance testing. That context helps the parties understand which requirements applied to a roof when it was built.
Roof repairs also interact with other systems. Flashing work at walls can require removing siding or stucco, and replacement can affect gutters, vents, and rooftop equipment. A scope that accounts for these connections gives a more complete picture of cost.
Common warning signs
- 01Ceiling or wall stains that grow after rain
- 02Cracked, slipped, or missing shingles and tiles
- 03Rust, separation, or sealant patching at flashings and edge metal
- 04Staining or decay on walls below roof-to-wall intersections
- 05Ponding water on low-slope roofs days after rain
- 06Overflowing gutters or water bypassing downspouts
- 07Ice dams and heavy icicles along eaves in cold climates