Legal Basement Drywall in Ottawa – What You Need to Know Before You Build

Ron Selmani
May 30
2 min read

Finishing a basement is one of the best ways to add value to your home—but if you're planning to rent it out, it needs to be done legally. That means following Ottawa building codes, meeting fire separation requirements, and using the right materials and methods—especially when it comes to drywall.

At R&G Walls, we’ve helped dozens of homeowners and property investors build legal basement suites that pass inspection and stand the test of time.

Here’s what you need to know before drywall goes up in a legal basement renovation in Ottawa.

🧱 What Is a Legal Basement?

A legal basement is a self-contained rental unit (also called a secondary dwelling unit or SDU) that meets local building code and zoning requirements. In Ottawa, that means:

Minimum ceiling height (6'5"–6'11", depending on area)
Egress windows in each bedroom
Fire separation between units
Soundproofing requirements
Independent entrance, kitchen, and bathroom

🔥 Drywall Requirements for Legal Units

1. Fire Separation

Ottawa code requires fire-rated assemblies between units—usually 5/8" Type X drywall on ceilings and shared walls. We ensure all fire-rated installations meet current standards.

2. Resilient Channels / Sound Barriers

To reduce noise transfer between the main floor and the basement unit, we often install resilient channel systems or soundproof drywall assemblies.

3. Moisture & Mold Resistance

We use moisture-resistant drywall (green board or purple board) in basements, especially in bathrooms, utility rooms, and slab-adjacent walls.

4. Air-Tight Drywall Approach

In many legal basement units, drywall acts as part of the air barrier system, especially around attic hatches or HVAC chases. Proper sealing and taping is critical.

🛠️ Our Legal Basement Drywall Process

1. Review Plans & Permits

We work with your designer or permit-ready drawings to make sure every wall meets city code.

2. Material Selection

We source the right drywall types: fire-rated, moisture-resistant, or sound-deadening as needed.

3. Framing Adjustments

If framing needs minor tweaks for compliance, we handle it before drywalling begins.

4. Drywall Install + Fire Caulking

We install drywall per code, adding fire caulking where required at penetrations and gaps.

5. Finish Work

Taping, mudding, sanding, and priming for a paint-ready finish—plus trim, doors, and paint if requested.

🧾 Costs & Timelines

Legal basement drywall costs more than a standard job—but it’s worth it for peace of mind (and passing inspection).

💰 Ballpark price:

~$2.25–$3.50/sqft depending on specs
Includes taping, sanding, and materials📆 Timeline: 3–7 days for typical 800–1,000 sq ft units

We’ll quote your project accurately after reviewing drawings and permits.

🏆 Why R&G Walls?

✔ We’ve completed legal basements in Orleans, Barrhaven, Kanata, and downtown Ottawa✔ We follow Ontario Building Code and Ottawa-specific fire separation requirements✔ We work with homeowners, flippers, and property investors✔ We can handle framing, insulation, priming, painting, trim, and full finishing

📞 Call or text 613-869-7391 to book a free consultation📍 Serving Ottawa & Surrounding Areas