Construction consulting services in California
de Haan & Associates is a full-service forensic construction consulting firm providing investigation, research, and litigation services for the construction industry. In California, we are retained by attorneys, insurance carriers, building owners, homeowner associations, and contractors. The firm is founded on two basic concepts, industry experience and integrity.
Our experience includes universities, community colleges, school districts, casinos, condominium associations, vacation resorts, single-family homes, commercial buildings, and restaurants. We are experienced in inspections of schools, commercial buildings, multi-residential buildings, and single-family homes.
Our services cover field investigation, forensic reports, photo and video documentation, project costing, property loss analysis, and product failure analysis. They also include waterproofing consulting, water testing, construction defect investigation, and expert witness testimony. These services apply across the building types and conditions found in the state.
From the Bay Area to Sacramento and Lake Tahoe
Our office is in Walnut Creek, in the East Bay. Gregg de Haan is qualified to testify in Sacramento County Superior Court, San Francisco County Superior Court, and Alameda County Superior Court.
His construction litigation support spans the Bay Area and the Sacramento region, mountain communities at Lake Tahoe and Truckee, and the Eastern Sierra. That work includes condominium and community associations, university and school district buildings, community college facilities, and casino hotel work.
We work throughout California, and in Arizona and Montana. Contact us to discuss a matter wherever the building is.
California’s range of building conditions
California buildings face a wide range of conditions within one state. Coastal fog and wind-driven rain test windows, plaster, and flashing. Inland heat and sun age roofing and sealants, and seismic movement stresses joints, finishes, and connections. Expansive soils in some regions also move slabs and flatwork.
Hillside sites add drainage and subgrade waterproofing concerns, and dense urban projects often rely on podium slabs over parking. Older buildings may predate current codes, which affects how their performance is evaluated. Each condition places different demands on the same building systems.
In the state’s mountain regions, buildings also contend with snow loads, ice dams, and freeze-thaw cycles. Roofs, decks, and entries there must manage snow, ice, and meltwater through long winters. We are snow country building specialists, and Gregg de Haan specializes in high alpine waterproofing, roofing, and general construction.
- Cement plaster, wood siding, and composite siding
- Windows and doors, with product and installation water testing
- Roofing and sheet metal
- Decks and podium slabs
- Subgrade waterproofing and site drainage
SB800, codes, and research
SB800 is California’s Right to Repair Act, which applies to residential construction. That makes it relevant to condominiums, multifamily buildings, and single-family homes. Our associates are educated on SB800, past and current building codes, and current and past building product performance testing.
Gregg de Haan provides code compliance reviews and SB800-related building inspections. He also specializes in plan reviews as they relate to waterproofing above and below grade, a frequent question on hillside and podium projects. Those reviews compare the drawings with field conditions.
We perform construction document plan and detail analysis for constructability and for code compliance. A large library of present and past product literature and testing data supports that analysis. Most of the 2025 California Building Standards Code (Title 24) took effect on January 1, 2026, and a building is generally judged against the code in force when it was permitted.
For residential construction covered by SB800, Civil Code § 941 generally limits actions to 10 years after substantial completion, and the Act sets shorter periods for some items. Outside SB800, Code of Civil Procedure § 337.15 generally sets a 10-year limit for actions over latent deficiencies in improvements to real property. Shorter statutes of limitations can end a claim sooner. This is general information, not legal advice; counsel determines which legal requirements apply to a given matter.
Investigation, reports, and testimony
Our field personnel identify and document defects promptly. We use camera and video documentation techniques to provide trial-ready exhibits. We generate comprehensive field reports, photo documentation, conceptual repair scopes, and cost estimates. Gregg de Haan specializes in preparing repair scopes, cost estimates, and complex defect reports.
If materials are found to have manufacturing defects, 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. Preserved samples keep physical evidence available after repairs are made.
We provide expert witness services for settlement conferences, mediations, arbitrations, depositions, and trial. Gregg de Haan is qualified to testify in Sacramento County Superior Court, San Francisco County Superior Court, and Alameda County Superior Court. He leads field investigations, gathers field data, and attends expert meetings, mediations, and arbitrations. Our aim is accurate, organized information and a balanced, educated opinion for fair resolution.