Short answer: soundproof drywall on its own does very little. What stops sound is an assembly built on four levers — mass (more or heavier board), decoupling (breaking the rigid path between the board and the framing), absorption (insulation in the cavity) and damping (a compound between layers that turns vibration into heat) — with sealing as the fifth thing that makes the other four count. The best value per dollar for a basement ceiling or a shared wall is insulation in the cavity, resilient channel or clips, and two layers of ⅝” board with the edges sealed. Sound assemblies are priced on site as material and labour on top of our Level 4 drywall rate of $3.00–4.25 per square foot. Below is where the noise is coming from, what each solution does, and what to avoid.
Where the sound is coming from
Two kinds of noise, and they need different fixes.
- Airborne sound — voices, TV, music. It travels through the air, hits a wall or ceiling, and vibrates the board. Mass, absorption and damping are the answer.
- Impact sound — footsteps, chairs scraping, a dropped toy on the floor above a basement. It enters the structure directly through the joists, and no amount of board on the ceiling stops it unless the ceiling is decoupled from those joists.
Both types also travel around a wall rather than through it — flanking — via ductwork, back-to-back electrical boxes, gaps at the floor and ceiling, and hollow doors. A well-built wall with an unsealed gap under it performs like a bad one.
What each solution does
| Solution | Works against | Relative cost | When to choose it |
|---|---|---|---|
| Second layer of ⅝” board | Airborne (mass) | Low | Any wall or ceiling being drywalled anyway; cheapest step with a real effect |
| Sound-rated board (damping layer built in) | Airborne | Medium | When there is no room for two layers, or on top of an existing wall |
| Resilient channel or sound clips + hat channel | Airborne and impact (decoupling) | Medium | Basement ceilings under living space; shared walls where the framing can be exposed |
| Mineral wool or fibreglass in the cavity | Airborne (absorption) | Low | Always, when the cavity is open; useless on its own, essential in combination |
| Damping compound between two layers of board | Airborne, especially low frequencies | Medium | Home theatres, music, bass-heavy neighbours; pairs with the second layer |
| Acoustic sealant, putty pads on boxes, solid-core door | Flanking — everything | Low | Every assembly; skipping this wastes the rest |
Performance is rated on the STC scale — sound transmission class — where higher is quieter. As general orientation only: a standard interior wall with ½” board each side and no insulation typically lands in the mid-30s, where normal speech is clearly heard; a decoupled, insulated, double-layer assembly built and sealed properly typically reaches the 50s, where loud speech is a murmur and most music is gone. Real numbers depend on the whole assembly and the flanking paths, so treat these as targets rather than guarantees.
Basement ceilings: footsteps from above
This is the most common request and the one most often done wrong. A basement ceiling gets impact noise from the floor above through the joists, so board alone — however many layers — does not fix it, and a drop ceiling with acoustic tile barely registers because it is light and leaky. What works is the combination:
- Mineral wool or fibreglass between the joists, filling most of the cavity but not packed tight.
- Resilient channel or sound clips with hat channel across the joists, so the ceiling hangs from the clips rather than the wood.
- Two layers of ⅝” board on the channel, joints staggered, with damping compound between the layers if the room above has a TV or a piano.
- Sealant at every edge and around every pot light and duct penetration. Pot lights are holes in the ceiling; use sealed, insulation-contact-rated fixtures or fewer of them.
Ductwork running through the ceiling is the flanking path that undoes all of this; where a bulkhead carries a duct, it gets the same insulation-and-board treatment. If the basement is being finished anyway, this is the moment to do it — the cavity is open and the labour overlaps with the basement renovation that is happening regardless.
Shared walls in townhouses and semis
You cannot change what the neighbour has on their side, but you can build a better wall on yours. If the existing drywall stays, the simplest upgrade is a second layer of board with damping compound between, and a full bead of acoustic sealant at floor, ceiling and corners. If the wall is being opened — a townhouse basement finish, a renovation — the better version is a new stud wall a small gap off the party wall, insulated, with double-layer board on the room side. That air gap plus decoupling is what turns a mid-30s wall into a 50s one. Either way: putty pads behind any outlet on that wall, no back-to-back boxes with the neighbour, and a solid-core door on any room you are trying to keep quiet. Older Toronto semis with a shared brick wall behave differently — brick is heavy and already does much of the work; the leaks are at the joist pockets and the chimney breast. See drywall installation in Toronto.
Between units in a legal basement suite
A second unit needs sound separation between the suite and the home above alongside its fire separation, and the two are built together: a rated ceiling assembly with insulation in the joists, resilient channel and fire-rated board is also a good sound assembly. That is why “sound insulation between units” is included in the Full Suite package on our legal basement apartment page rather than sold as an extra — with a tenant below and a family above, it is not optional. Pricing for the packages is in our guide to legal basement apartment cost in the GTA. Brampton’s large newer basements, with full-footprint ceilings under the main-floor family room, are where we build this most often — see drywall installation in Brampton.
What to avoid
- “Soundproof paint.” A coat of anything is a fraction of a millimetre; it adds no useful mass and no decoupling.
- Foam panels and egg-crate. They absorb echo inside a room — useful in a studio for how the room sounds — and do almost nothing to stop sound getting through a wall.
- One more sheet of board screwed to the studs. A little mass, no decoupling: the studs still carry the vibration straight through. Worth doing only with damping compound between the layers and sealed edges.
- Insulation alone. Filling the cavity without changing the board or the connection to the framing gives a small, disappointing improvement.
- A quiet wall with a hollow door. The door becomes the wall.
One limit on our side: we build sound assemblies in walls and ceilings. Acoustic design for a recording studio, and noise coming in through windows from the street, are different problems for an acoustician or a window contractor.
How soundproofing is priced
There is no per-square-foot soundproofing rate on our site because the assembly is chosen wall by wall. The logic is simple: the base is the drywall itself at Level 4, $3.00–4.25 per square foot turnkey — what that covers is explained in our guides to drywall installation cost in Ontario and drywall finish levels — and each sound element is added on top as material and labour: a second layer of board roughly repeats the board and hanging portion, channel or clips add a step before the board goes up, insulation is a material line, damping compound is a material line applied between layers, and sealing is a small labour line that we do not skip. Ceilings sit at the top of every band because the work is overhead. Tell us what you are trying to block — footsteps, a TV, a neighbour’s music — and we quote the assembly that fits, per room, in writing.
IntraBuild builds sound-rated walls and ceilings across Toronto, the GTA and Southern Ontario: one insured crew, a written price with the assembly spelled out, no travel fee. Get a drywall installation quote or call (647) 558-8723.
Frequently asked questions
Does soundproof drywall work?
Sound-rated board helps — it has a damping layer built in — but only as part of an assembly with insulation, decoupling and sealed edges. On its own, screwed straight to the studs, the improvement is small.
What STC should I aim for?
For a bedroom or a basement suite ceiling, the 50s is the practical target where loud speech becomes a murmur. A standard interior wall sits in the mid-30s. These are typical figures for well-built assemblies, not guarantees; flanking paths decide the real result.
Can you soundproof an existing wall without removing the drywall?
Yes, to a point: a second layer of ⅝” board with damping compound between, acoustic sealant at every edge, putty pads on outlets and a solid-core door. It will not match a decoupled rebuild, but it is a real improvement for a shared wall you cannot open.
Does insulation alone stop sound?
No. Insulation absorbs sound inside the cavity and matters in combination, but without mass on the surface and decoupling from the framing the difference is modest.
Is it worth it for a basement apartment?
Yes, and it is included: sound insulation between units is part of the Full Suite package, built together with the fire separation. A tenant hearing every footstep upstairs, or a family hearing the tenant’s TV, is the most common complaint in an unregistered suite and the easiest to prevent while the ceiling is open.
