Colorado exterior material comparison · Reviewed August 2026
Compare thermally modified wood, acetylated wood such as Accoya, and cedar for Colorado decking, siding, soffits, screens, and outdoor structures.
There is no universal winner. Thermally modified wood can offer stability and a refined real-wood palette; acetylated products such as Accoya may offer product-specific warranties and stability; Western red cedar offers familiar fabrication, regional trade knowledge, and established weathering. The right choice depends on the exact product, approved use, wildfire context, moisture detailing, fasteners, finish expectations, supply, and replacement plan.
Owner comparison · Updated September 9, 2026
No. Accoya uses acetylation; Thermory describes its thermal modification as a heat-and-steam process. A modification method is not an installation specification. The manufacturer sources below explain their own products, not an independent ranking.
| Put this on both quotes | Why it changes the decision |
|---|---|
| Same use and profile | Name the application, board dimensions, finish and fixing system. A siding price does not establish the cost or suitability of a deck. |
| Installed work, not boards alone | Ask each bidder to identify substructure, clips or screws, coating, cut-end treatment where required, waste and labor. Mark exclusions separately. |
| Appearance and upkeep | Choose whether you want a maintained color or natural weathering. Ask for the exact product care instructions, access needed for recoating, and who will perform that work. |
| A repair you can actually make | Ask how one damaged board comes out, whether matching stock is available, and what spare material should be retained. |
There is no verified local installed-price comparison on this page. Use these questions to obtain comparable project quotes, then include ongoing care in the free ownership-cost planner.
Alternative-by-alternative
These are planning distinctions. Verify the exact source, product, finish, assembly, exposure, installer, and warranty.
| Option | Potential fit | Highest-attention questions |
|---|---|---|
| Thermally modified wood | Refined cladding, screens, soffits, ceilings, and product-approved decking | Brittle edges, product-specific fastening, ventilation, runoff, UV change, and future matching. |
| Acetylated wood / Accoya | Applications supported by the selected product system, dimensions, coating path, and warranty | Manufacturer rules for fabrication, adhesives, coatings, hardware, exposed ends, and warranty conditions. |
| Western red cedar | Cladding, screens, soffits, pergolas, gates, and selected decking where grade and detailing fit | Grade, grain, extractives, fasteners, moisture, wildfire context, UV change, and refinishing commitment. |
Decision criteria
| Criterion | Comparison | Owner action |
|---|---|---|
| Maintained brown color | All require an intentional coating and maintenance path | Approve maintained and naturally weathered samples. |
| Wet or horizontal use | Exact product approval and drained, ventilated assembly control | Do not generalize from cladding to decking. |
| Future replacement | Local availability, profile continuity, and matching vary | Buy attic stock and record exact source and profile. |
| Wildfire exposure | Material name alone does not decide compliance or risk | Review the complete assembly, location, clearances, and local requirements. |
Before approval
Specific records
Evidence boundary
These sources frame material-system behavior. They do not approve a product, assign the Registry's editorial comparison, or replace current manufacturer literature and project specifications.
Registry methodology →