Roofing Historic and Older Buildings in Washington
Washington State holds a substantial inventory of registered historic structures, from Victorian-era commercial blocks in Port Townsend to Craftsman bungalows in Seattle's Capitol Hill neighborhood. Roofing these buildings involves a distinct intersection of preservation standards, state and local building codes, and material compatibility requirements that sets this work apart from standard residential or commercial re-roofing. The regulatory and technical constraints that govern historic roofing work are more extensive than those applied to modern construction, and the qualifications expected of contractors reflect that complexity.
Definition and scope
Historic and older building roofing in Washington encompasses roofing work performed on structures that meet one or more of the following classifications:
- Listed on the Washington State Register of Historic Places, administered by the Washington State Department of Archaeology and Historic Preservation (DAHP)
- Listed on the National Register of Historic Places, administered by the National Park Service
- Located within a locally designated historic district, as defined by municipal historic preservation ordinances
- Constructed before a threshold year specified by local code — commonly 1940 or 1950 in Washington jurisdictions — regardless of formal registration status
Formally registered structures are subject to the Secretary of the Interior's Standards for the Treatment of Historic Properties, published by the National Park Service. These standards define four treatment approaches — Preservation, Rehabilitation, Restoration, and Reconstruction — each carrying different obligations for material retention and replacement methodology.
Scope limitations: This page addresses roofing work governed by Washington State jurisdiction and applicable federal preservation standards as they apply within Washington. It does not address historic roofing regulations in Oregon, Idaho, or other adjacent states. Tribal historic properties on federally recognized lands within Washington may fall under separate federal review processes not covered here. Structures with no formal historic designation are subject to standard Washington roofing regulatory frameworks rather than the preservation-specific overlay described on this page.
How it works
Roofing a designated historic structure in Washington follows a multi-layer process that integrates local permitting, state review, and — where federal funding or tax credits are involved — federal oversight.
1. Determination of applicable standards
The first step is establishing whether the structure is locally designated, state-registered, nationally registered, or all three. Each layer adds review obligations. DAHP serves as the primary state authority. Local Historic Preservation Officers (LHPOs) administer municipal-level review in cities including Seattle, Spokane, Tacoma, and Bellingham.
2. Material matching and documentation
The Secretary of the Interior's Standards require that replacement materials match the original in visual character, profile, texture, and — where feasible — composition. For a structure originally roofed with wood shingles, replacing with asphalt shingles typically requires documented justification and often approval from the LHPO or DAHP. Substitute materials may be approved if they replicate the appearance of historic materials without causing additional damage to the structure.
3. Permit application and review
Standard building permits are required under the Washington State Building Code (RCW 19.27), administered locally. For registered structures, the permit application is typically routed to the LHPO for compatibility review before issuance. Projects receiving federal Historic Tax Credits undergo a three-part review process coordinated between DAHP and the National Park Service.
4. Structural assessment
Older roof structures frequently include framing members sized to pre-code dimensions (e.g., true-dimension lumber rather than nominal-dimension). Structural engineers familiar with pre-1960 construction practices are commonly engaged to assess load capacity before new roofing systems are specified.
5. Inspection and documentation
Post-completion inspections by the local building department confirm code compliance. For registered properties, photographic documentation of existing conditions before removal, and of completed work, is standard practice required by preservation guidelines.
Common scenarios
Replacing failed slate or clay tile
Washington's older civic and residential buildings in cities like Olympia and Walla Walla were frequently roofed with slate or clay tile through the early 20th century. When original slate fails, preservation standards generally require replacement with salvaged matching slate, new quarried slate of equivalent thickness and color, or — with approval — high-quality synthetic slate that replicates the profile. The Washington roofing materials guide provides comparative information on material types applicable to these replacements.
Cedar shake replacement on Craftsman-era homes
Cedar shake and shingle roofing was ubiquitous in Western Washington through the mid-20th century. Replacement-in-kind with new cedar is generally compliant with preservation standards. Fire code restrictions in certain Washington counties and municipalities may limit cedar use, requiring documented approval for exceptions on designated structures. This intersects directly with the considerations described in cedar shake roofing in Washington.
Flat or low-slope roofs on historic commercial buildings
Built-up roofing systems on early 20th-century commercial buildings — common in Pioneer Square in Seattle and in Spokane's historic warehouse district — present compatibility challenges when modern membrane systems are specified. Parapet heights, flashing profiles, and drainage configurations must conform to historic appearance standards at visible surfaces while meeting current energy and moisture codes.
Re-roofing older structures without formal designation
Structures built before 1940 that carry no historic designation are not subject to preservation review but may still present unique structural and material challenges. Roof framing member spans, ridge board dimensions, and rafter depths in pre-code structures often differ from contemporary equivalents, affecting load calculations and attachment specifications.
Decision boundaries
The critical decision point in any historic roofing project in Washington is whether preservation review is triggered. The following structured criteria define the boundary:
| Condition | Preservation review triggered? |
|---|---|
| Listed on National Register of Historic Places | Yes — NPS standards apply; DAHP review for state tax credit projects |
| Listed on Washington State Register | Yes — DAHP review required |
| Located in locally designated historic district | Yes — LHPO review required |
| Pre-1940 structure, no designation | No — standard code compliance applies |
| Federal funding or Historic Tax Credit involved | Yes — three-part NPS/DAHP review applies regardless of other status |
Preservation vs. rehabilitation: These two treatment categories from the Secretary of the Interior's Standards carry different tolerances. Preservation requires maximum retention of existing materials; Rehabilitation permits greater modification to accommodate compatible use. Most Washington roofing projects on occupied historic buildings fall under the Rehabilitation standard, which allows replacement of deteriorated materials with compatible substitutes.
Contractor qualification: Washington's contractor licensing through the Department of Labor and Industries does not include a specific historic preservation endorsement. However, DAHP and most LHPOs expect demonstrated experience with historic structures. Contractors performing work on federally tax-credit-eligible projects must align with documentation standards set by the National Park Service. The broader landscape of Washington roofing contractor qualifications applies as a baseline in all cases.
Safety standards: Work on older structures frequently involves fall hazards from steep pitches common to Victorian and Craftsman rooflines, as well as potential asbestos-containing materials in roofing cements and underlayments installed before 1980. Washington Industrial Safety and Health Act (WISHA) standards, enforced by the Department of Labor and Industries, apply to all roofing work regardless of historic status. Asbestos survey and abatement requirements under WAC 296-65 apply when suspect materials are present.
For a broader orientation to how Washington's roofing sector is structured and regulated, the Washington Roof Authority index provides sector-wide reference framing.
References
- Washington State Department of Archaeology and Historic Preservation (DAHP)
- National Park Service — Secretary of the Interior's Standards for the Treatment of Historic Properties
- National Register of Historic Places — National Park Service
- Washington State Building Code (RCW 19.27)
- Washington Department of Labor and Industries — Contractor Licensing
- WAC 296-65 — Asbestos Standards for Construction, Washington State
- Washington Industrial Safety and Health Act (WISHA) — Department of Labor and Industries