Water is behind many construction disputes
Water intrusion is among the most common sources of construction defect claims. It damages finishes and framing, can support mold growth, and often appears far from where it entered. Repairs frequently require removing finished materials to reach the source.
Waterproofing failures are often concealed. By the time staining, efflorescence, or decay is visible, water may have been entering for some time, and the path it took may not be obvious. Early investigation helps separate active leaks from old damage.
Waterproofing consulting is one of the services de Haan & Associates provides. Gregg de Haan, our founder and principal, specializes in plan reviews as they relate to waterproofing above and below grade, and in high alpine waterproofing.
Waterproofing above and below grade
Above grade, the building envelope relies on layers that shed water: cladding, building paper or another water-resistive barrier, flashings, and sealants at windows and doors. Each layer must lap correctly over the one below it, and each opening must be integrated with the layers around it. A single reversed lap can direct water behind the barrier it was meant to protect.
Below grade, walls and slabs face soil moisture and, at times, hydrostatic pressure. Subgrade waterproofing, drainage, and site grading work together to keep water away from the structure. Failures below grade are especially costly to correct, because access often requires excavation.
Decks and podium slabs sit between the two. They are horizontal surfaces that must carry water away while protecting occupied space beneath them, which makes their waterproofing details especially demanding. Drains, slopes, and edge details all have to work together.
Plan reviews for waterproofing
Many waterproofing problems begin on paper, when details are incomplete, conflicting, or difficult to build. Gregg de Haan specializes in plan reviews as they relate to waterproofing above and below grade. A detail that cannot be built as drawn will usually be improvised in the field.
Our associates can perform construction document plan and detail analysis for constructability and for code compliance. We also draw on a large library of present and past product literature and testing data to aid our analysis. Product literature shows what each manufacturer expects at transitions and terminations.
Common plan issues include missing transitions between materials, details that do not show how a membrane terminates, and drawings that leave flashing sequence to the field. A review can raise these questions before they become field problems.
Investigating waterproofing failures
Our investigative specialties include subgrade waterproofing, waterproofing and building paper installation, site drainage, decks, podium slabs, and roofing and sheet metal. When a waterproofing system fails, our field personnel identify and document the defects. Tracing water back to its point of entry is often the central task.
Where windows and doors are involved, our specialties include product and installation water testing. If a waterproofing material may have a manufacturing defect, we are aligned with several laboratories that test and analyze product failure. We also take field samples to store at our office in case they are needed at trial.
We generate comprehensive field reports, photo documentation, conceptual repair scopes, and cost estimates promptly. Those documents connect each failure to its cause and to a defined repair. They also give the parties a shared basis for discussion.
Waterproofing expert witness services
Waterproofing questions often reach settlement conferences, mediations, arbitrations, depositions, and trial. Our expert witness services cover each of those forums. These matters often turn on details measured in inches, such as a lap, a termination, or a missing piece of flashing.
Gregg de Haan’s background includes litigation and waterproofing consulting. His role includes attending expert meetings, mediations, and arbitrations, and appearing at trial as an expert witness for owners and builders.
We are retained by attorneys, insurance carriers, building owners, homeowner associations, and contractors in California, Arizona, and Montana. The questions in a waterproofing dispute are often the same whoever raises them: where water entered, why, and what repair will stop it.
What we examine
- 01Subgrade waterproofing
- 02Waterproofing and building paper installation
- 03Podium slabs and decks
- 04Windows and doors, including water testing
- 05Site drainage
- 06Roofing and sheet metal
- 07Plans and details for waterproofing above and below grade
- 08High alpine waterproofing
What you receive
- Plan reviews for waterproofing above and below grade
- Comprehensive field reports
- Photo documentation
- Conceptual repair scopes and cost estimates
- Expert witness testimony