Demolition Cost in Markham

Before touching anything, test for asbestos and lead. Hire a designated substance survey (DSS) consultant to sample suspect materials — vermiculite insulation, floor tiles, drywall joint compound, pipe wrap, textured ceilings. Lab analysis takes 3-5 days. If asbestos is present and you're disturbing >1 m², hire a certified abatement contractor (O.Reg 278/05). Lead paint testing: XRF gun gives instant results, or send paint chip samples to a lab. Homes built before 1960 assume lead is present. Encapsulation (covering with new drywall) is cheaper than removal; removal requires containment, HEPA vacuums, and certified disposal.

If removing or altering walls, hire a structural engineer to assess load paths. The engineer will identify load-bearing walls, calculate loads (dead + live + snow), and design replacement beams and support posts. Expect drawings showing beam size (W10x22 steel or 3-ply 2x12 LVL), bearing points, footing sizes, and shoring plan. Cost: $800-$2,500 for a typical residential beam design. Submit drawings with building permit application — structural modifications require permits and inspections.

Demolition permits are required for: removing load-bearing walls, structural modifications, full building demolition, and asbestos abatement in some municipalities. Non-structural interior demo (cabinets, drywall, flooring) typically does not require a permit unless it's part of a larger renovation. Submit engineer's drawings, pay permit fee ($200-$800), wait for approval (1-3 weeks). Emergency demolition (unsafe structure) can be permitted retroactively in some cases.

Set up containment if working in occupied space — plastic sheeting barriers, dust control, HEPA air scrubbers if asbestos or lead work. Protect floors with Masonite or ram board (drywall on floor tears easily). Cover HVAC registers to prevent dust spread. Set up debris chute or bins — 10-yard bin for small demo, 20-40 yard for full gut. Shut off utilities if needed: electrical (panel breaker), plumbing (main shutoff or fixture shutoffs), gas (main valve or appliance valves). Verify shutoff before cutting — cutting a live wire or pressurized pipe is dangerous.

Work top-down, perimeter-in. For load-bearing wall removal: install temporary shoring first (Acrow props spaced 4-6 feet apart, bearing on strongback beam above and below), then cut and remove drywall, insulation, studs, top and bottom plates. Install new beam (steel W-shape or LVL) on bearing plates at each end, jack into place, secure with bolts or straps, then remove shoring. For non-bearing walls: cut drywall, pull studs, remove plates. For flooring: pull carpet/vinyl/tile, remove subfloor if needed (plywood or OSB screwed or nailed to joists). For cabinets: disconnect plumbing and electrical first, remove screws securing to walls and floor, lift out. Dispose of debris in bins — separate recyclables (metal, wood) if possible to reduce dump fees.

If you removed a load-bearing wall and installed a beam, call for a framing inspection before closing walls. Inspector will verify beam size matches drawings, bearing plates are in place, posts and footings are adequate, and shoring was done correctly. If no permit was required (non-structural demo), skip this step.

Sweep and vacuum (HEPA vac if lead or asbestos work), remove containment barriers, haul debris to bins. Asbestos waste must be double-bagged, labeled, and disposed of at approved facilities (not regular landfills). Lead-contaminated waste (painted wood, drywall) is usually accepted at municipal landfills but check local rules. Metal (steel beams, copper pipe, aluminum siding) can be sold to scrap yards — offset disposal costs.