Basement Renovations & Finishing in the Greater Toronto Area
Finishing a basement is the most cost-effective way to add livable square footage to a GTA home — but it is also where moisture, insulation, and code compliance quietly make or break the result. Blackstone General Contracting finishes basements as recreation space, home offices, in-law suites, and permitted secondary (rental) units, starting with the parts you can't see.
Every basement build begins with moisture management: assessing water history, sealing, sub-floor systems, and proper insulation against the foundation. From there we frame, run licensed electrical and plumbing, insulate for sound and warmth, and finish with drywall, flooring, trim, and paint. For income units we handle egress windows, fire separation, and the permit process.
The GTA's second-unit rules have made legal basement apartments a serious investment. We build to the applicable Ontario Building Code requirements so your unit is insurable, rentable, and safe — not a liability waiting on an inspection.
What's included
- Moisture control, foundation sealing, and sub-floor systems
- Framing, insulation, and sound-dampening assemblies
- Licensed electrical, pot lights, and dedicated circuits
- Rough-in and finished plumbing for bathrooms and kitchenettes
- Egress windows and fire separation for legal secondary units
- Full kitchens and bathrooms for in-law and rental suites
- Flooring, drywall, trim, and paint
- Permit applications and inspection coordination
Typical GTA cost · 2026
$35,000 – $80,000+
A finished basement with a bathroom, flooring, and lighting commonly runs $35K–$55K in the GTA. Legal secondary units with a full kitchen, egress windows, and fire separation trend higher. Underpinning or waterproofing needs add to the total.
Get a fixed quoteMoisture-first construction
We solve water and vapour before framing, because everything above depends on a dry, correctly insulated envelope.
Legal-unit expertise
Egress, fire separation, and ceiling-height requirements handled to code so a rental unit is insurable and inspectable.
Real added value
Finished basements add usable space at a lower cost per square foot than any addition — and a legal suite can add income.
From first visit to final walk-through.
Consultation & scope
We visit the space, listen to what you want, and turn it into a clear scope and honest budget range — no vague ballparks.
Design & fixed quote
Material selections, drawings where needed, and a detailed fixed quote so you know exactly what you're paying for.
Permits & scheduling
We handle permit applications, structural engineering, and trade scheduling before a tool touches the site.
Build & finish
Licensed trades, tidy job sites, and staged work that keeps your home or business usable — finished on the timeline we set.
Walk-through & guarantee
A final walk-through, a punch list closed out, and a 12-month workmanship guarantee in writing.
Basement Renovations, answered.
Yes — finishing a basement almost always requires a building permit, and a legal secondary unit has additional requirements for egress, fire separation, and ceiling height. Blackstone manages the permit applications and inspection scheduling as part of the project.
Structural & Open-Concept
Load-bearing wall removal, open-concept conversions, and layout changes.
Service — 02Bathroom Renovations
Ensuites, main baths, and powder rooms — waterproofing, tile, and fixtures done right.
Service — 04Flooring & Painting
Hardwood, engineered, and vinyl flooring plus premium interior painting.
Let's build something that lasts.
Tell us about your project. We'll visit the space, scope it honestly, and give you a fixed quote — no vague ballparks.