Cedar Roof Conversion in Nanaimo, BC | Replacing Aging Cedar Roofing Systems
Nanaimo Elite Roofing provides cedar roof conversion backed by 20+ years of experience, replacing ageing cedar shakes and cedar shingles with modern residential roofing systems while addressing the different deck assemblies beneath them. Older cedar roofs may be installed over skip or spaced sheathing rather than continuous decking, so conversion can require a plywood overlay or new solid sheathing before architectural shingles or standing seam metal can be installed with their specified underlayment and attachment system.
Converting cedar involves more than removing the wood covering and installing a different material in its place. The exposed structure must be evaluated for sheathing configuration, substrate condition and compatibility with the new roofing system, while flashing transitions at walls, valleys, chimneys and penetrations may need to be reconstructed for the thickness and water-shedding characteristics of the replacement material. Establishing a continuous substrate also creates the appropriate surface for modern underlayments and manufacturer-specified fastening patterns that were not part of the original cedar assembly.
Cedar conversions are particularly relevant across central Vancouver Island, where older homes can combine legacy wood roofing construction with prolonged seasonal moisture exposure. We convert residential cedar roofs throughout Nanaimo and surrounding communities including Protection Island, Gabriola Island, Cedar, South Wellington, Extension, Cassidy, Yellow Point, North Oyster, Ladysmith, Saltair, Chemainus, Crofton and Honeymoon Bay, adapting the conversion scope to the existing sheathing, roof structure and replacement system found at each property.
Get a Free Nanaimo Roofing Quote
✓ 20+ Years of Residential & Commercial Roofing Experience
✓ Roof Replacement, Roof Repair & Emergency Roof Repair
✓ Asphalt Shingle, Metal Roofing & Roof Inspection Services
✓ Built for Nanaimo's 1,100+ mm Annual Rainfall
✓ Wind-Driven Rain, Moss Growth & Moisture Protection
✓ Strait of Georgia Exposure & Roof Durability Solutions
We'll contact you within 24 hours to discuss your roofing project, evaluate repair or replacement options, review roofing materials and drainage concerns, and help you maximise roof durability, weather resistance, curb appeal, and long-term property protection.
Why Aging Cedar Roofs Eventually Require Conversion
Loss Of Cedar's Natural Weather Resistance
Cedar contains natural extractives that contribute to its resistance to moisture and biological deterioration, but decades of ultraviolet exposure, rainfall and repeated wet-dry cycling gradually reduce this protection. As shakes or shingles age, surfaces can become increasingly porous and brittle, making individual pieces more susceptible to splitting, erosion and moisture absorption during Nanaimo's prolonged wet periods.
Splitting, Cupping And Physical Deterioration
Wood roofing continually expands as it absorbs moisture and contracts as it dries. Repeated dimensional movement can eventually produce longitudinal splits, curled edges, cupping and fractured cedar pieces that no longer maintain their intended overlaps. Once deterioration becomes widespread across multiple roof planes, replacing individual shakes or shingles does little to restore the remaining material's overall serviceability.
Reduced Protection At Cedar Keyways
Traditional cedar roofing relies on overlapping courses to prevent the vertical joints, or keyways, between individual shakes and shingles from providing a direct water path. As pieces shrink, split or shift with age, these drainage relationships can become less dependable. Deterioration becomes particularly consequential when defects in successive courses align closely enough for wind-driven rain to reach the underlying assembly.
End-Of-Life Conditions Across The Roof
A properly installed cedar roof can provide several decades of service, but lifespan varies considerably with cedar grade, shake or shingle thickness, roof slope, ventilation, tree cover and moisture exposure. When widespread deterioration indicates that the wood covering has reached the end of its useful life, conversion allows the ageing cedar assembly to be removed rather than continuing to replace individual pieces within a progressively declining system.
Preparing Cedar Roof Structures For Modern Roofing
1. Assess Existing Skip Or Spaced Sheathing
Traditional cedar shakes were often installed over horizontal wood boards with gaps between them, allowing the underside of the cedar to dry while providing fastening points for each course. Modern asphalt shingles generally require a continuous, structurally sound deck, so removing the cedar exposes whether spaced sheathing can remain beneath an approved overlay or whether sections must be reconstructed. Board condition, spacing, fastening and the underlying rafters or trusses all influence the appropriate conversion method.
2. Create A Continuous Plywood Deck
Where the replacement material requires solid decking, exterior-grade structural plywood can be installed over a suitable existing roof structure to create a uniform fastening surface. Panel thickness must be selected for the framing spacing, loads and applicable requirements rather than chosen solely to cover the old boards. Panels also require appropriate support, fastening and spacing to accommodate normal wood expansion without creating raised joints beneath the finished roof.
3. Rebuild Flashing For The New Assembly Thickness
Removing thick cedar shakes and adding solid decking changes the dimensions at chimneys, sidewalls, skylights and other roof transitions. Existing step flashing, counter flashing and penetration details therefore need to be evaluated against the elevation and profile of the new assembly. Reworking these interfaces during conversion prevents legacy flashing designed around the cedar thickness from becoming a weak point in the modern roofing system.
4. Establish The Correct Underlayment Substrate
Once the deck is suitable, the new assembly needs a clean, continuous surface for its specified water-shedding layers. Synthetic underlayment or compatible self-adhered membrane must lie flat and integrate correctly with eaves, valleys and flashing rather than bridging unsupported gaps left by the former cedar construction. This substrate preparation is what allows a roof originally built around wood shakes or shingles to accept a modern roofing system according to its intended installation method.
Choosing A Replacement System For A Former Cedar Roof
- Architectural Shingles For A Traditional Residential Profile
Architectural asphalt shingles can replace cedar with a dimensional appearance while using a completely different water-shedding assembly. Laminated construction creates deeper shadow lines than traditional three-tab shingles, and modern product lines are available with algae resistance, enhanced wind specifications and manufacturer-matched accessory components. Once suitable solid decking has been established, the former cedar roof can support a conventional shingle assembly without retaining the installation characteristics required by wood roofing.
- Standing Seam Metal For A Longer Service Cycle
Standing seam metal can be an appropriate conversion option for homeowners prioritizing longevity and concealed attachment. Panels are joined at raised seams while clips secure the system without placing exposed fasteners throughout the primary weather surface. Depending on material, coating and exposure, quality residential metal roofing can provide roughly 40–70 years of service, potentially reducing the number of future roofing cycles compared with shorter-lived coverings.
- Account For Changes In Roof Weight
Changing roofing materials alters the permanent load carried by the roof structure. Cedar shakes, asphalt shingles and metal panels have different weights per square foot, and a conversion may also add plywood or another structural panel where the original roof used spaced boards. The complete assembly—including retained sheathing, new decking and finished roofing—should be considered when determining whether the existing framing is suitable for the proposed system.
- Match The New Material To Roof Geometry
The best conversion material depends partly on the roof's slope, complexity and architectural features. Architectural shingles can accommodate roofs with numerous hips, dormers and intersecting planes, while standing seam metal can be particularly effective on simpler roof forms where long panels can run continuously from ridge to eave. Nanaimo homeowners should therefore compare materials according to the existing structure and desired service life rather than selecting a replacement solely because it can physically be installed over a former cedar roof.
Cedar Roof Conversion FAQs
What is the difference between cedar shakes and cedar shingles?
Cedar shingles are generally sawn on both faces for a more uniform thickness and appearance, while traditional cedar shakes are typically split or partly split to create a thicker, more textured profile. Their different dimensions affect course exposure, fastening and the overall thickness of the roof assembly, which must be considered when transitioning flashing and perimeter details to a modern material.
Can architectural shingles be installed directly over cedar shakes?
Installing asphalt shingles directly over existing cedar generally does not provide the continuous, flat substrate required by modern shingle systems. The cedar covering should be removed so the underlying sheathing can be evaluated, with suitable solid decking established where required. This also prevents deteriorated cedar from remaining concealed beneath the new roof.
What is skip sheathing on an older cedar roof?
Skip sheathing consists of horizontal boards installed with spaces between them rather than forming a continuous deck. Traditional cedar shakes could be fastened to these boards while the gaps helped provide drying beneath the wood roofing. Its presence becomes important during conversion because many modern roofing products require continuous structural sheathing for proper fastening and support.
How thick does new plywood need to be during a cedar conversion?
There is no universal plywood thickness for every conversion. The required structural panel depends on factors including rafter or truss spacing, existing board configuration, panel span rating, roof loads and applicable building requirements. Using appropriately rated sheathing is more important than applying an arbitrary thickness to every former cedar roof.
Why might chimney or wall flashing need modification after cedar removal?
Cedar shakes can create a substantially different finished-roof thickness than architectural shingles or standing seam metal. Removing that thickness and introducing plywood, underlayment and a new roof covering changes where the finished drainage plane meets walls and masonry. Flashing that remains positioned for the former cedar surface may therefore require reconstruction to integrate correctly with the new assembly.
Can the gaps between old sheathing boards simply be covered with underlayment?
Underlayment is a water-shedding layer, not a structural substitute for roof decking. It cannot provide the fastener holding, panel support or continuous substrate required by roofing products designed for solid sheathing. Where the selected replacement system requires continuous decking, the underlying structure must first be brought into a suitable configuration.
Ready to replace an ageing cedar roof with a modern roofing system? Request a Nanaimo cedar roof conversion assessment using the contact form below.
Get a Free Nanaimo Roofing Quote
✓ 20+ Years of Residential & Commercial Roofing Experience
✓ Roof Replacement, Roof Repair & Emergency Roof Repair
✓ Asphalt Shingle, Metal Roofing & Roof Inspection Services
✓ Built for Nanaimo's 1,100+ mm Annual Rainfall
✓ Wind-Driven Rain, Moss Growth & Moisture Protection
✓ Strait of Georgia Exposure & Roof Durability Solutions
We'll contact you within 24 hours to discuss your roofing project, evaluate repair or replacement options, review roofing materials and drainage concerns, and help you maximise roof durability, weather resistance, curb appeal, and long-term property protection.