Problem-Based & Residential Applications

Secondary Suite Soundproofing in Airdrie: Quieting the Floor Between Units

Footsteps overhead, a television through the ceiling, voices carried along the heating ducts: that is daily life on either side of a basement suite with an ordinary ceiling. We build the floor-ceiling assembly between units in Airdrie homes so it separates the two households properly.

(825) 475-1869 How the job runs

A basement ceiling with grey stone wool batts filling the joist bays and thin metal resilient channels screwed across the joists.

The Problem It Solves

Most Airdrie basements were never meant to separate two households. The floor joists above the basement carry the upstairs subfloor on one side and, at best, a single layer of drywall screwed tight to the joists on the other. Nothing in that assembly stops sound. Footsteps travel straight down the joists into the ceiling board, which acts like the skin of a drum. Voices and music pass through the empty joist bays and out through every pot light, heat register and gap around a plumbing drain. The tenant hears every chair scrape, and the owner hears the tenant’s late-night gaming.

Owners usually notice two different kinds of noise and assume one fix covers both. Airborne noise is talking, television and music: sound energy moving through the air, into the ceiling, and out the other side. Impact noise is footsteps, dropped objects and a washing machine on spin: energy put straight into the structure. Airborne noise responds well to absorption, decoupling, mass and airtightness in the ceiling. Impact noise enters the floor from above, so a better ceiling reduces it but rarely solves it on its own.

The other common complaint is noise that comes around the ceiling instead of through it. A single furnace with ductwork running to both floors carries conversation from one register to another almost as clearly as an open door. An unsealed stairwell door, a laundry chute, a rim joist bay left open at the exterior wall, or a drain stack boxed in with bare drywall will each leak sound past an otherwise good ceiling. Owners buy acoustic batts, still hear the other household, and blame the batts when the real problem was a flanking path.

How It Works

A quiet suite ceiling is a system, not a product. Stone wool acoustic batts in the joist bays absorb sound bouncing inside the cavity so it does not build up. Resilient channel, or clips with hat track, hangs the drywall slightly away from the joists so vibration in the structure has a much weaker path into the ceiling board. Heavier board, and sometimes a second layer, adds the mass that low-frequency noise needs. Acoustical sealant closes the perimeter gap and every opening, because sound finds air gaps the way water does. Batts alone typically add only a few points; the full assembly does the real work.

We also treat the paths around the ceiling. Ducts serving both floors can be fitted with acoustic duct liner where the mechanical design allows, or rerouted with offsets by your HVAC contractor so sound has to turn corners and lose energy. Pot lights are swapped for surface-mounted fixtures by your electrician, or boxed in, so they do not puncture the sealed plane. Rim joist bays at exterior walls are insulated and sealed, since they are both envelope and sound path. Upstairs, we tell owners plainly that a good underlay or soft flooring is what tames footsteps.

At a Glance

Cavity insulation: ROCKWOOL Safe’n’Sound stone wool acoustic batts filling the joist bays
Decoupling: Resilient channel, or sound clips with hat track, between joists and drywall
Ceiling board: 5/8" Type X gypsum is common; the permit drawings set the fire rating and layers
Air sealing: Non-hardening acoustical sealant at the perimeter, seams and every box or penetration
Flanking paths: Shared ducts, open stairwells, rim joist bays and plumbing chases addressed separately
Impact noise: Needs floor-side work upstairs (underlay, mass, soft finishes) as well as the ceiling
Performance: No STC or IIC figure promised; results depend on the whole assembly and the building
Permits: Suites inside Airdrie need City of Airdrie permits; the permit sets fire and sound separation

How the Job Runs, Step by Step

Walk both units and find the flanking paths

With someone talking and walking upstairs, we trace which sound comes through the ceiling and which comes around it: ducts, stair openings, chases, doors between units. We also check what the permit drawings or the City’s requirements call for, so the assembly we build matches the one that will be inspected.

Open the ceiling and prepare the joist bays

Existing drywall comes down where the ceiling is already finished. We check the bays for wiring, plumbing and ducts that must move, and mark joist locations so channel screws find wood. Any rim joist bays at exterior walls are air sealed and insulated before the acoustic work starts.

Fill the bays with acoustic stone wool

ROCKWOOL Safe’n’Sound goes into each joist bay, cut tight to the joists and around blocking, split around wires rather than crushed behind them, and fitted around pipes without leaving voids.

Install decoupling and seal the edges

Resilient channel or clips with hat track are installed perpendicular to the joists at the spacing the product and the permit assembly require, oriented correctly, and kept clear of the walls. The first course of drywall must hang from the channel only, with a small perimeter gap left for sealant. We mark the channel lines so nobody drives a screw through into a joist and bridges the decoupling.

Board, seal, and check before it is covered

The ceiling board goes up to the layers and type the drawings name, screwed only into channel. Acoustical sealant closes the perimeter gap, board seams where required, and every electrical box and penetration. Before taping we check for screws or cabinets that short-circuit the channel, leaving the ceiling ready for the permit inspection.

What Decides the Specification

The permit decides the floor. A secondary suite needs a fire separation and a sound separation from the main dwelling, and the drawings approved for your suite name how that is achieved, including the drywall type and number of layers. Many published fire-rated floor assemblies include resilient channel as a listed component, so swapping channel for clips, changing spacing, or dropping a layer can take the assembly off its tested listing even if it might sound better. When the drawings name a specific assembly we build that assembly, and any change goes back through the designer and the City first.

Beyond the permit minimum, the specification follows how much quiet the household actually wants and what the house allows. Ceiling height matters in older basements, because channel and a second layer each take space. Mechanical layout matters, because a single shared furnace limits what ducts can do. Budget matters, so we rank the steps: sealing and flanking first, decoupling second, mass third. Floor-side work upstairs is often the best money spent on footsteps.

Alberta Code Notes

Alberta enforces the National Building Code – 2020 Alberta Edition, in force since May 1, 2024, and a house with a secondary suite falls under Part 9. The code sets sound transmission and fire separation requirements between a suite and the main dwelling, lower for a suite within a house than between two separate dwelling units. We do not quote an STC figure as the requirement, because the approved drawings name the assembly the inspector checks. Suites inside city limits need City of Airdrie permits; outside it, Rocky View County or the City of Calgary. Where rim joist bays form part of the exterior envelope, Section 9.25 governs their insulation, air barrier and sealed 6-mil poly.

General guidance only. The authority having jurisdiction and the product’s own evaluation report decide what applies to your job.

Around Airdrie

Suites are showing up most in Airdrie’s newer family communities, where basements were left unfinished by the builder and owners want rental income or space for extended family. In Midtown, newer builds often have open, unfinished joist bays, which makes a decoupled ceiling easier, though the shared furnace remains a sound path. In Coopers Crossing and Kings Heights, many basements were partly developed by earlier owners, so it is common for ceilings, ducts and pot lights to need removing before a suite ceiling can be built to its permit.

Common Mistakes to Avoid

Batts alone, no decoupling: Stuffing acoustic batts between joists and screwing drywall straight back on typically adds only a few points. The structure still carries vibration into the ceiling board, so the owner hears little difference.
Screws shorting the channel: One drywall screw driven through resilient channel into a joist, or a cabinet fastened through it, bridges the decoupling. Several of them quietly undo most of the benefit, and nobody can see it once taped.
Ignoring the ducts: A shared furnace carries voices between registers. A beautifully built ceiling with an unlined duct connecting both units still leaks conversation, and it is usually the first thing a tenant notices.
Expecting the ceiling to stop footsteps: Impact noise starts in the floor above. A decoupled ceiling helps, but hard flooring laid without a suitable underlay upstairs will still thump through. Plan floor-side work as part of the job.

When to Choose Something Else

If the noise you want to stop is mostly footsteps and the basement ceiling is already finished and permitted, start upstairs, not downstairs: a quality underlay under new flooring, area rugs, or carpet in bedrooms may do more than tearing out the ceiling. If the suite has not yet been through permitting, do not build the separation first and hope it passes; get the drawings approved so the assembly is known. If you need a measured sound rating, hire an acoustic consultant for field testing.

Often Done Alongside

ROCKWOOL Safe’n’Sound Acoustic Batts

Safe’n’Sound batts for quieter interior walls, ceilings and floors.

Code-Compliant Vapour Barriers

Continuous 6-mil poly with sealed laps, plates and electrical boxes.

Cold Basement Walls & Rim Joists

Closed-cell foam on rim joists and foundation walls for warm, dry basements.

Where We Do This Work

Suite Soundproofing: Questions We Get

Can you guarantee a specific STC rating for our suite ceiling?

No, and you should be wary of anyone who does. Laboratory STC ratings describe tested assemblies built under controlled conditions. In a real house, flanking through ducts, stairwells and framing lowers the result, and the field number depends on the whole building. What we can do is build the assembly your permit names correctly, seal it properly, and deal with the obvious flanking paths. If a measured result matters to you, an acoustic consultant can test it.

Do we need a permit to soundproof the ceiling for a basement suite?

Suites inside Airdrie need City of Airdrie permits, and the fire and sound separation between the suite and the main dwelling is part of what the permit covers. The City, or Rocky View County or Calgary if you are outside the city, decides what is required. Soundproofing work in a home without a suite is a different question, and the authority having jurisdiction decides that too.

Is poly needed in the ceiling between the basement and upstairs?

Not normally across the interior ceiling, because both sides are heated living space and there is no cold side for moisture to condense on. The airtight seal that matters for sound there is acoustical sealant at the edges, seams and boxes. Poly and a continuous air and vapour seal matter where the ceiling meets the exterior walls, at the rim joist bays, which are part of the house envelope.

Will soundproofing the suite ceiling lower our basement ceiling height?

A little. Resilient channel or clips with hat track add some depth below the joists, and a second layer of drywall adds more. Where ducts and beams already hang low it can matter, and suite ceiling heights are part of the permit review. We check the numbers on site before you commit to an assembly.

How do you work out what my home actually needs?

We start by looking, not selling. That means getting into the attic or crawl space, checking what insulation is there and how deep it sits, finding the air leaks that matter, and looking at ventilation and moisture. In winter we can add a thermal camera, which shows cold spots and leaks as temperature differences on the surface. The recommendation that follows says what to fix first, what can wait, and when something is not worth doing at all.

Considering Suite Soundproofing?

Call Airdrie Insulation or send the details. We will look at the job, tell you whether suite soundproofing is the right fix, and price it in writing.

(825) 475-1869 Send the Details