Pressure‑Treated vs. Non‑Pressure‑Treated Cedar Roofing Shingles
Cedar roofing is one of the most architecturally appropriate and long‑lasting choices for historic and high‑value homes across Coastal Rhode Island and Southeast Massachusetts. But homeowners often face a key decision early in the process:
Should I choose pressure‑treated cedar shingles or non‑pressure‑treated cedar shingles?
Both options perform well when installed correctly, but they behave differently in coastal environments where salt air, humidity, and organic growth pressure are constant factors.
This comparison breaks down the differences clearly — and explains how copper strips support non‑pressure‑treated cedar by helping manage moisture and suppress biological growth.
Pressure‑Treated Cedar Shingles
Pressure‑treated cedar shingles are infused with preservatives that penetrate deep into the wood. This treatment significantly increases resistance to:
Moisture absorption
Rot and decay
Mold and mildew
Insect activity
These shingles are ideal for homes exposed to:
High humidity
Prolonged wet conditions
Dense tree cover
Limited sun exposure
Because the treatment stabilizes the wood internally, pressure‑treated shingles typically require less maintenance over time.
Availability
Pressure‑Treated Western Red Cedar — Widely available.
Pressure‑Treated Alaskan Yellow Cedar — Available, but much less common.
Oil Treatment?
Not needed. Pressure‑treated shingles already have enhanced moisture resistance and do not require oil treatment for protection.
Non‑Pressure‑Treated Cedar Shingles
Non‑pressure‑treated shingles rely entirely on cedar’s natural oils and tannins for protection. They are often chosen for:
A traditional, natural appearance
Historic‑district compliance
Homeowners who prefer the authentic aging of cedar
These shingles generally require more regular maintenance, but when properly cared for, they can add 10–20 years to a roof’s lifespan compared to untreated commodity cedar.
Optional Oil Treatment
Oil treatment is recommended when the homeowner wants:
More consistent color over time
Reduced UV weathering
Slower fading
Less cracking and drying
A more uniform appearance during the first several years
Oil‑treated roofs typically require recoating every 3–7 years, depending on climate, sun exposure, roof pitch, and product choice.
Copper Strips: A Key Upgrade for Non‑Pressure‑Treated Cedar
Copper strips are an exceptionally effective enhancement for non‑pressure‑treated cedar roofs, where the wood naturally absorbs more moisture and is more vulnerable to organic growth. Because non‑PT cedar relies solely on its natural oils and tannins for protection, it benefits greatly from any system that helps stabilize moisture levels and reduce biological activity on the shingle surface.
When rainwater flows over the copper, it releases microscopic copper ions that wash down the roof. These ions create an environment that is hostile to algae, moss, lichen, mildew, and other organic growth, all of which thrive on moisture‑rich cedar. By limiting these organisms, copper strips help the roof dry more evenly, reduce surface moisture retention, and maintain a cleaner, more uniform appearance over time.
For homeowners choosing non‑pressure‑treated cedar — especially in shaded, humid, or tree‑covered coastal environments — copper strips are one of the most reliable long‑term upgrades for preserving both performance and aesthetics.
Which Cedar Option Is Right for Your Home?
Your choice depends on your priorities:
If you want lower maintenance, strong moisture resistance, and long‑term stability → Pressure‑treated cedar is ideal.
If you prefer a traditional, natural aesthetic and are comfortable with periodic maintenance → Non‑pressure‑treated cedar is an excellent choice, especially when paired with copper strips and optional oil treatment.
Both systems perform exceptionally well when installed with premium craftsmanship and maintained appropriately.
Protecting Coastal Homes with Premium Cedar Roofing
At Slate & Copper Services, we specialize in cedar roofing systems that respect the architecture of historic homes while delivering long‑term performance in harsh coastal conditions. Whether you choose pressure‑treated or non‑pressure‑treated cedar, our focus is always the same: longevity, craftsmanship, and architectural integrity.
