Installing cedar shingles over existing siding can refresh a home’s exterior while adding natural beauty and durable protection. This guide covers the planning, preparation, and step-by-step process to help homeowners and contractors achieve a high-quality, weather-resistant result. It emphasizes safe practices, proper ventilation, and the importance of matching fasteners and underlayment to cedar’s properties.
Assessing Suitability And Regulatory Considerations
Before starting, evaluate whether existing siding, framing, and climate conditions support cedar shingle installation over it. Load-bearing capacity, wall ventilation, and moisture history impact long-term performance. In many cases, a weather barrier and a furring strip system are required to ensure proper drainage and air circulation. Local building codes may mandate vapor barriers, soffit vents, and drip edges. If the existing siding is severely warped, moldy, or structurally compromised, addressing these issues first is essential to avoid premature failure of the cedar layer.
Materials And Tools You’ll Need
Choosing the right materials affects durability and appearance. Core items include:
- Cedar Shingles: Choose grade and thickness suitable for exterior use; common choices are sawn shake or tapered hand-split shingles.
- Underlayment/Weather Barrier: A breathable, moisture-resistant barrier designed for use behind cedar siding.
- Furring Strips Or Lath: Typically 1×2 or 1×3, installed to create a vented cavity between shingles and existing siding.
- Fasteners: Exterior-grade stainless steel or galvanized nails sized for cedar and the chosen fastener pattern.
- Starter Strips And Spacers: Ensure uniform gaps and alignment along the base.
- Water-Resistant Backer Board Or Caulking: For sealing edges and joints where moisture may intrude.
- Ventilation Accessories: Drip edge, flashing, and soffit vents to promote air flow behind the cedar.
- Tools: Tape measure, level, Chalk line, Hammer, Nail gun with appropriate nails, Saw, Caulk gun, Safety gear.
Preparing The Existing Siding
Preparation ensures a solid, long-lasting installation. Steps include:
- Inspect the existing siding for rot, warping, or insect damage; repair or replace compromised areas.
- Clean the surface and remove loose paint, debris, and protrusions that could affect shingle fit.
- Plan the layout to avoid aligning cedar seams with existing siding joints, which reduces staggered gaps and water infiltration risks.
- Install a moisture barrier, if required by code, and ensure there is a continuous air gap behind the cedar system.
Constructing A Ventilated Furring System
A ventilated cavity helps manage moisture and temperature behind cedar shingles. Key steps include:
- Attach horizontal furring strips to the existing siding using corrosion-resistant fasteners, ensuring flat, even spacing to maintain plumb alignment.
- Leave a consistent gap between the back of shingles and the wall to promote airflow; typical gaps range from 1/4 inch to 3/8 inch depending on product specifications.
- Install a breathable barrier over the furring strips or directly over the existing surface, following manufacturer instructions for overlaps and sealants.
- Seal penetrations and joints with flashing and compatible sealants to prevent water intrusion.
Shingle Installation: Step-By-Step
The installation sequence balances aesthetic appeal with performance. A typical process includes:
- Start with a straight, level starter course at the base of the wall, using a starter strip or pre-cut edge to ensure even exposure and alignment.
- Place first row of cedar shingles with the long edge parallel to the ground; stagger joints between rows to reduce water penetration and create visual texture.
- Embed shingles into the barrier with appropriate fasteners at the nailing line, avoiding overdriving which can crush cedar fibers.
- Maintain uniform exposure for each course; use spacers to ensure consistent gaps and ventilation paths.
- Continue rows upward, ensuring each shingle aligns with the underlying furring system and that corner and window trims receive proper flashing and sealant.
Fastening Patterns And Cedar Characteristics
Fastener selection and placement significantly affect durability and aesthetics. Consider these guidelines:
- Use corrosion-resistant nails or screws suited for cedar and exterior conditions; common choices include stainless steel or hot-dipped galvanized fasteners.
- Nail through the prescribed nailing zone on each shingle; avoid nailing through the broad face to prevent splitting.
- Avoid overtightening, which can cause cedar to crack or warp as it expands and contracts with climate changes.
- Acclimate cedar in a shaded area before cutting to reduce warping during installation.
Insulation, Ventilation, And Moisture Management
Proper insulation behind the cedar and an effective ventilation strategy are essential for long-term performance. Consider:
- Maintain an air gap to allow moisture to escape and to help prevent wood rot and mold growth.
- Ensure attic or wall cavities have adequate intake and exhaust ventilation to balance humidity levels.
- Address any existing insulation gaps that could trap moisture near the cedar layer.
- Use flashing around doors, windows, and penetrations to direct water away from the wall system.
Finishing Touches And Maintenance
Finish options and ongoing care extend the life of cedar shingles. Practical steps include:
- Apply a water-repellent, breathable coating or stain if desired, following cedar-specific product recommendations and reapplication schedules.
- Inspect the roofline and drip edges annually for signs of moisture intrusion or misalignment.
- Clean the cedar surface with a soft brush or low-pressure wash to remove dirt and mildew; avoid high-pressure techniques that can damage the wood.
- Address any warped or damaged shingles promptly to prevent cascading issues in adjacent courses.
Common Pitfalls And How To Avoid Them
Recognizing frequent mistakes helps ensure a successful installation. Common issues include:
- Inadequate ventilation leading to trapped moisture and wood rot.
- Using incompatible barriers or sealants that trap water behind cedar shingles.
- Improper fastener choice or placement causing splitting, loosening, or corrosion.
- Failing to stagger seams or align starter courses correctly, resulting in a less durable and visually uneven finish.