Soundproof garden music room for a flat by Garden Spaces
A 4.2m × 3.5m music room in the garden of a ground-floor flat in Hornsey, built with planning permission and the Gold acoustic package, its porch carried across the whole front.
If you are looking for a well-specified garden music room, one that holds up both in structural integrity and in acoustic tailoring, Garden Spaces is the name to look at. We have featured their work extensively over the years, and this project in Hornsey, Middlesex is another good example of how Garden Spaces tailor the design and specification to each client. Their turnkey service handles the whole process, from design conception through to a room that is ready to use.
The building measures 4.2m wide by 3.5m deep externally, giving an internal floor area of 11.1sqm, with internal dimensions of 3.8m by 2.8m. It is a compact footprint asked to do a demanding job, and the detail that follows shows how carefully the design has been resolved around the brief.
At a glance
- Size: 4.2m × 3.5m outside, 3.8m × 2.8m (11.1sqm) inside.
- Planning: Required, as flats don't have Permitted Development rights; Garden Spaces applied for it.
- Acoustics: The Gold package on a SIP core, an acoustic porch and a wall vent rated to 55dB.
- Glazing: Glazed porch doors and a back-to-back acoustic window, recessed under the canopy.
- Company: Garden Spaces, including the armoured cable back to the flat.
When Permitted Development is not an option
The room sits in the garden of a ground-floor apartment, and that single fact shapes the whole project. Flats do not benefit from Permitted Development rights in the way that houses do, so the building could not simply be designed within the usual height and siting limits, as would be typical at a property with PD rights. A planning application was required.
Rather than leave the owner to navigate that, Garden Spaces applied for planning permission on their behalf as part of their service. For anyone in a flat or maisonette considering a garden room, this is the practical reality worth understanding early: the route to approval is different, and having the company manage the application removes a significant unknown from the project.
An acoustic porch, extended across the front
The acoustic porch is one of the details most associated with Garden Spaces’ music rooms, and a popular choice with their customers. It creates a buffer zone between the garden and the room itself, so that sound passes through two separated thresholds rather than one. Here the owner chose to include it, and the way it has been handled sets this project apart from others we have written about.
Instead of stopping at the entrance, the depth of the porch has been continued across the full front elevation. That creates a recessed window detail, with the glazing set back beneath a canopy and wall cheek detail rather than sitting flush with the cladding. LED downlights are housed in the canopy above, washing the recess with light in the evening and giving the front of the building genuine architectural depth.
Getting the glazing right
Glazing is always a balancing act in an acoustic room. Every opening is a potential weak point for sound, so the instinct is to minimise it. But a room with no daylight or view is not a pleasant place to spend time, and that matters in a space built for hours of practice.
The answer here is to glaze well rather than glaze less. The owner chose glazed doors for the porch and a back-to-back, double-skin acoustically glazed window. Pairing two units of acoustic glass with specialist seals lets the room keep natural light and a connection to the garden without giving up the acoustic performance the brief depends on. The external door is PVC, with a separate internal door that is acoustically sealed, so the porch works as a true soundlock between inside and out.
Thermowood cladding
Garden Spaces offer a wide palette of exterior finishes, and for this room the owner chose Thermowood to all elevations. Thermowood is a softwood that has been heat-treated rather than chemically treated: kiln temperatures drive out moisture and alter the timber’s structure, leaving it more stable, more resistant to rot, and lower in maintenance than untreated softwood.
Left to weather naturally, it shifts from its warm honey-brown tone towards a soft silver-grey over time. That ageing is part of the appeal rather than a fault to be managed, and it pairs cleanly with the anthracite doors, window, and trims seen here.
A SIP core with a Gold acoustic package
Underneath the cladding, the building is built around a SIP (Structural Insulated Panel) core. SIPs give the structure its rigidity and a high level of thermal performance in a relatively slim wall, which is a sound starting point for any garden room. For music use, Garden Spaces then layer one of their acoustic packages over that core, tiered so the room can be matched to how loud it needs to be inside and how quiet it needs to be at the boundary.
This client chose the Gold package. Acoustic performance comes from combining mass, separation, and absorption rather than from any single product, and the Gold specification builds those principles into the walls, ceiling, and floor. The results are genuinely measurable: Garden Spaces’ own demonstrations show in the region of 60dB of noise reduction, even with ambient noise around 40dB, which is the difference between a full-volume rehearsal and barely registering it a few metres away.
Ventilation is part of the same equation. Air is brought in through an acoustic wall vent rated to 55dB of sound reduction, among the highest available on the market, so the room can breathe without that vent becoming the path of least resistance for sound.
Finished and connected, ready to use
Inside, the room is finished much like a new build, plastered and decorated throughout, with laminate wood flooring underfoot. The electrics are surface mounted rather than buried in the walls. In an acoustic build that is a deliberate choice: chasing cables and sinking back boxes into the wall would mean cutting into the very layers that are doing the soundproofing, so keeping the electrics on the surface protects the integrity of the acoustic envelope.
Heating and cooling are handled by an air-conditioning system, which keeps the room comfortable year-round without relying on opening a window. Power is supplied by an armoured cable run back to the flat, a properly rated connection required for a garden room building. The result is a music room that is complete on handover: structurally sound, acoustically tailored, and ready to play in from day one.
Learn more about Garden Spaces
Garden Spaces design and build bespoke garden rooms across mainland England and Wales, including highly specified music rooms tailored to different levels of acoustic performance. To explore more examples of their work, including video demonstrations of their acoustic rooms in action, or to discuss your own project, visit www.gardenspaces.co.uk, call 0845 387 9 387, or email info@gardenspaces.co.uk.
