Best Basement Finishing in London (2026)
Framing, insulation, finishing and basement suite conversions.
Legal Basements London
Make your basement legal. Add value. Generate income.
Legal Basements London is London, Ontario's trusted specialist in legal basement apartment conversions, basement underpinning, waterproofing, egress windows, and full basement renovations, backed by 15 years of experience. The team handles every step from permit applications and 3D design renderings through to final inspections, ensuring full Ontario Building Code compliance. Their fixed-price model and two-year workmanship warranty make basement conversion projects predictable and stress-free across London, St. Thomas, and Woodstock.
Homeowner buyer's guide
Hiring a basement finishing contractor in London
Finishing a basement adds livable space, but it comes with permit, moisture and egress requirements that are easy to overlook. A contractor who understands these details up front avoids costly rework later, especially in older homes where foundations and ceiling heights vary.
What to look for
- A building permit pulled before framing begins
- Correct egress window sizing if any room will be used as a bedroom
- A clear plan for vapour barrier and moisture management against foundation walls
- Experience finishing basements in homes of a similar age
- A proper insulation approach for below-grade walls, not just interior framing
Questions to ask
- Will this project need a permit, and are egress windows required?
- How will you manage moisture and vapour barrier against the foundation?
- Is there any sign of past water intrusion we should address first?
- If this becomes a bedroom or suite, does the design meet code?
- What insulation type and R-value are you using on basement walls?
What it tends to cost
Basement finishing costs vary with square footage, ceiling height obstacles, whether a bathroom or suite kitchen is added, and how much moisture remediation the foundation needs first. A simple recreation room typically costs less than a legal secondary suite with its own egress, plumbing and fire separation requirements. Ask whether the quote already includes permit fees and any required foundation waterproofing work, since remediation found partway through can otherwise become a costly add-on.
Red flags
- Suggesting you skip the permit to save time or money
- No mention of moisture testing or a vapour barrier strategy
- Framing over walls with visible past water staining without addressing it