Before specifying replacement material, photograph and measure an intact area. If later roofing covers original material, attic access, selective openings or historic photographs may reveal the earlier pattern.
Record the material contract
Document:
- Material type and source when known
- Unit length, width and thickness
- Profile or butt shape
- Surface texture
- Exposure and overlap
- Coursing pattern
- Hip, ridge and valley treatment
- Fastener visibility
- Color and natural weathering
- Flashing metal and joint details
- Deck or lath configuration
This becomes the basis for comparing samples and mockups.
Wood shingles and shakes
A rough modern shake is not automatically a good historic match. The National Park Service wood-shingle brief warns that irregular, heavily textured products can alter historic character when the original roof used smoother split-and-dressed or sawn shingles.
Match the important visible features:
- Size and shape
- Butt thickness and taper
- Exposure
- Surface finish
- Hip, ridge and valley patterns
- Decorative butt shapes
- Spacing and coursing
The City of Phoenix wood-shingle guidance calls for documenting original material, configuration, detailing, exposure and nailing patterns and gives project-specific direction for preservation work. Its specific dimensions and requirements should not be copied onto a different roof without confirming that building's evidence and current approval requirements.
Slate
Slate is durable, but individual units, fasteners and flashing can deteriorate at different rates. A slate roof should be evaluated for:
- Percentage and distribution of failing slate
- Slate type, thickness, color and weathering
- Nail or fastener condition
- Headlap and slope
- Flashing life
- Deck condition
- Availability of compatible replacement slate
The National Park Service slate-roof brief emphasizes repair and timely maintenance and treats flashings, gutters and downspouts as part of the water-shedding system. Replacing sound slate while leaving exhausted flashing can be the wrong allocation of work.
Clay and concrete tile
Historic tile matching may involve profile, color variation, surface, dimensions, side laps and attachment. Salvageable tile can sometimes be removed and reset over a repaired underlayment, but breakage, discontinued profiles and fastening requirements must be planned.
Do not assume every reddish barrel tile is interchangeable. A mismatch can affect both appearance and water-shedding geometry.
Metal roofing
Historic metal roofs may use standing seams, flat seams, stamped shingles or specialty metals. Record seam spacing, pan width, edge details, soldered joints, coatings and visible fasteners.
When replacing metal, compatibility includes both appearance and galvanic behavior. Flashing, fasteners, gutters and roof metal should be selected as a coordinated system.
Asphalt shingles and substitutes
A later asphalt roof may be historically significant in its own right, or it may cover an earlier material. If a substitute is proposed because the original material is unavailable or impractical, compare:
- Profile and shadow lines
- Unit dimensions
- Texture at normal viewing distance
- Color range and weathering
- Edge and ridge treatment
- Weight and structural effect
- Fire and code performance
- Repairability and future availability
A product name such as “heritage” is marketing, not evidence of compatibility.
Repair pieces versus whole-roof replacement
Selective repair preserves more original material when deterioration is limited and compatible replacement units are available. Whole-roof replacement may be appropriate when failures are widespread or the underlying assembly cannot be restored through repair.
Ask the proposal to quantify repair areas and explain the threshold for additional replacement after materials are opened.
Samples and mockups
For visible or regulated roofs, approve physical samples before ordering the full project. A mockup can show:
- Exposure and coursing
- Surface texture
- Fastener visibility
- Flashing color
- Ridge and edge detail
- Transition between old and new work
Photograph the approved mockup and attach it to the scope.
Bottom line
Match the roof as an architectural assembly, not a color. Preserve sound material, reproduce character-defining details and coordinate replacement with code, drainage and flashing requirements. Start with the broader historic roof planning guide and document approvals through the preservation process guide. For a roof-specific assessment, request a free roofing estimate.
Primary references
Sources used for this guide
- The Repair and Replacement of Historic Wooden Shingle Roofs U.S. National Park Service
- The Repair, Replacement and Maintenance of Historic Slate Roofs U.S. National Park Service
- Wood Shingle Roofs City of Phoenix Historic Preservation Office