Basement
Lowering and Dig-Out
Many of Washington DC's row houses sit on basements that are too low to live in — six to seven feet of headroom, no natural light, no real use. A basement lowering and dig-out excavates the existing slab, underpins the foundation, and rebuilds the lower level with full ceiling height. The result is a habitable space you can use as a family room, home office, or a separate English basement rental unit.
Our Process
- Structural assessment — engineer review of the existing foundation, soil conditions, and load paths before any digging begins.
- Permits & approvals — we file with the DC Department of Buildings, coordinate with the Historic Preservation Office where required, and manage every inspection.
- Underpinning & excavation — sectional underpinning to extend the foundation downward, then careful excavation in stages to maintain structural integrity.
- Waterproofing & finishing — full perimeter waterproofing, drainage, vapor barrier, slab pour, and finished build-out to your specs.
Underpinning Expertise:
Sectional underpinning done in correct sequence — the proven method for DC row house foundations.
Waterproofing & Drainage:
Full waterproofing systems and perimeter drains so the new space stays dry through DC's wet seasons.
Permit Management:
We handle DOB filings, structural reviews, and inspections so you don't have to learn the permit process.
Income Potential:
Many DC homeowners use the new lower level as a legal English basement rental — we build to code so it qualifies.
A basement dig-out is one of the most cost-effective ways to add usable square footage to a DC home — no zoning variance, no additions visible from the street. If you're considering it, see also our historic home renovation and condo conversion services.
