How much does it cost to build an oversized garage for RV or boat storage in Stittsville?

An oversized garage designed to accommodate an RV or boat in Stittsville typically costs between $85,000 and $160,000 depending on the dimensions, ceiling height, and level of finishing. The defining feature of these builds is height — most Class A motorhomes and larger boats on trailers require a minimum 14-foot interior ceiling clearance, which pushes the overall building height to 18 to 20 feet or more. That is a fundamentally different structure than a standard two-car garage with an 8 or 9-foot ceiling, and the cost reflects that difference.

The most common configuration Stittsville homeowners choose is a deep single bay (14 to 16 feet wide by 40 to 50 feet deep) dedicated to the RV or boat, combined with a standard two-car bay for daily vehicles. This gives you a total footprint in the range of 1,200 to 1,600 square feet. The oversized door alone is a significant cost driver — a 14-foot-tall by 14 or 16-foot-wide insulated commercial-grade door runs $4,000 to $8,000 installed, compared to $1,500 to $2,500 for a standard residential garage door. You will also need a heavier-duty opener rated for the door weight, adding another $800 to $1,500.

Foundation costs for oversized garages are higher because the deeper footings and taller foundation walls require more concrete and reinforcement. In Stittsville, where many of the newer subdivisions sit on clay-heavy soil, your builder may recommend engineered footings or a reinforced grade beam to handle the concentrated loads from taller walls. Budget $15,000 to $25,000 for the foundation and slab on a building this size. The slab itself should be poured at a minimum 6 inches thick (compared to 4 inches for a standard garage) if you plan to park a heavy motorhome on it, and many builders use fibre-reinforced concrete or welded wire mesh to prevent cracking under the point loads from RV jacks and stabilizers.

Framing an oversized garage requires engineered trusses designed for the wider span and taller walls. Standard residential framing crews can handle the work, but the materials cost more and the trusses need to be custom-ordered. Budget $20,000 to $35,000 for framing and roofing on a building this size.

Stittsville's location is actually favourable for oversized garage builds. Many properties in the newer developments west of Hazeldean Road and along Fernbank Road have larger lots (50 to 60-foot frontages or wider) that can accommodate the footprint without running into lot coverage issues. However, you still need to confirm compliance with the City of Ottawa zoning bylaw, particularly the maximum building height for accessory structures and the lot coverage percentage. Call 3-1-1 early in your planning to verify what your specific lot allows. Some Stittsville properties in older sections near Main Street have tighter lots where an oversized garage may require a minor variance.

One cost-saving approach is to build the oversized bay as a cold storage shell (uninsulated, no drywall, basic lighting) while fully finishing the standard bays. This can save $15,000 to $25,000 on insulation and finishing for the tall bay, and most RVs and boats do not need a heated environment for winter storage.

Connect with experienced garage builders through Ottawa Garages to get site-specific quotes for an oversized build on your Stittsville property.

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Looking for experienced contractors? The Ottawa Construction Network connects Ottawa homeowners with qualified professionals:

• 613Bins
• JC Carpentry
• Vanguard Environmental
• Ottawa Caulking
• JMY Renovations