How much does it cost to replace my builder-grade hollow doors with STC 35 solid core doors?

Replacing builder-grade hollow-core doors with STC 35 solid-core doors typically costs between $500 and $1,200 per door fully installed in Ottawa, including the door slab, new weatherstripping, an automatic door bottom or threshold seal, and professional hanging. For a typical Ottawa home where you are upgrading four to six interior doors, budget $2,500 to $6,000 total. That pricing runs about 10 to 15 percent below equivalent work in the Greater Toronto Area, thanks to Ottawa's lower labour rates.
What Makes an STC 35 Door Actually Perform
The door slab itself is only part of the equation. A standard solid-core door — typically a particleboard or MDF core weighing 50 to 70 pounds versus 15 to 20 pounds for a hollow-core — costs between $200 and $500 depending on the style, size, and finish. Purpose-built acoustic door slabs from manufacturers like Overly, Ambico, or National Guard rated at STC 35 to 40 run $400 to $900 per slab, but for most residential applications a quality solid-core door with proper sealing achieves similar results at a lower price point.
Here is the critical part that many homeowners miss: a door's sound rating is only as good as its seals. A solid-core door hung in the original builder-grade jamb with the standard 3mm gap at the bottom will perform barely better than the hollow door it replaced. To actually achieve STC 35, you need compression weatherstripping on the jamb sides and head (not the flimsy foam tape from the hardware store, but kerf-in or surface-mounted neoprene seals at $30 to $80 per door), plus an automatic door bottom seal that drops down when the door closes and retracts when it opens ($60 to $150 each). The threshold or floor beneath the door may also need a small raised seal to meet the door bottom properly.
In many newer Ottawa homes across Barrhaven, Kanata, and Riverside South, the door frames are often sized for standard 1-3/8 inch hollow-core slabs. Solid-core and acoustic doors are typically 1-3/4 inches thick, which means you may need new hinges (heavier gauge to support the weight) and possibly minor jamb modifications. A good installer accounts for this in the quote, but confirm it is included rather than discovering it as an add-on during installation.
For the best value, prioritize which doors matter most. Bedroom doors, home office doors, and bathroom doors typically deliver the highest quality-of-life improvement. You do not necessarily need to upgrade every door in the house — closet doors and pantry doors rarely justify the investment. Also remember that if the walls surrounding the door are standard builder-grade single drywall on shared studs, the walls themselves may be the weaker link, transmitting more sound than even a hollow door. A soundproofing professional can help you identify where your noise is actually coming from so you invest where it counts — reach out through Ottawa Soundproofing's Sound IQ for guidance tailored to your home.Looking for experienced contractors? The Ottawa Construction Network connects homeowners with qualified professionals:Justyn Rook ContractingRenoMotion Inc.613PAINTING INCTH Custom WoodworkARTEXPRO Tile & FinishesView all contractors →