Granny Flat Design
Buildana Siena
50m² · 1 bed · 1 bath · indicative $175,000 from
All floor plans and room sizes are fully customisable.
About this design
50m², 1 bed, 1 bath. Most granny flat buyers overthink this. The Siena has 1 bedroom, living space, bathroom and separate laundry — everything you need, nothing that'll blow the budget. Fully customisable if you want to make it yours.
Siena is warmth and heritage—Mediterranean refined. This 50m² design carries that sensibility. One bed, one bath, built with the kind of attention that makes it feel significant even at a smaller footprint. That's Buildana's discipline—bringing quality thinking to designs of every size. Compact doesn't mean compromised. It means everything is purposeful.
Room dimensions
What's included as standard
The Siena comes fully specced. Buildana doesn't do base-grade builds that look good on paper and cost twice as much to actually finish. What's listed below is what you get — no hidden upgrades required.
Bathroom Inclusions
- •Floor to ceiling wall tiles, including 300 x 600 ceramic tile options.
- •Stylus Banksia back to wall dual flush wc.
- •750mm polyurethane vanity with stone top, drop-in sink & mirror over.
- •Look vanity and shower mixers.
- •Look towel rail & toilet roll holder.
- •Framed shower screen.
- •Light, fan and heater combination.
Kitchen Inclusions
- •Sprayed polyurethane doors and panels (any colour of your choice).
- •10m cabinets includes upper, lower & overhead fridge cabinets & pantry.
- •600mm full length pantry with microwave space.
- •Laminate benchtop, tiled splashback – includes 300 x 600 options.
- •Westinghouse oven and ceramic cooktop (gas cooktops where available).
- •Ducted slide out rangehood (Euromaid), Clark 1 3/4 bowl with ‘look’ mixer.
Upgrade options
Tick what you want — your indicative total updates live. Final fixed price comes back in your formal proposal after a site assessment.
Exterior finish system
Choose the wall system for the external envelope. Pricing below is calculated against this design's external wall area — approximately 62m² (perimeter 27.0m × 2.7m wall height, less 15% for openings). Standard polystyrene-render is included; Hebel, face brick and brick-render are priced as upgrades over standard.
Foamboard polystyrene cladding system finished with cement render and texture coat. Included in the base price — light, fast to install, and the standard exterior on every Buildana granny flat.
Ceiling height
Standard ceiling height is 2.4m. Higher ceilings make small footprints feel larger and lift natural light through windows. Pricing below is calculated against this design's external perimeter 27.0m, covering the extra wall framing, plasterboard, render/cladding and cornice/painting needed to raise the envelope.
Standard ceiling height across all Buildana granny flats — already 100mm taller than the BCA minimum for habitable rooms. Included in the base price.
Doors & highlight windows
Door height and highlight-window upgrades. Tall doors are typically chosen alongside the 2.7m or 3.0m ceiling upgrade so the proportions stay right.
Slim 300 x 600mm highlight windows for natural light to bathrooms, ensuites, hallways, walk-in robes or above kitchen benches. Frosted or clear glazing. $1,100 each, supplied and installed. Pick how many you'd like below.
Premium fitout
Lift the standard spec to higher-end finishes.
Air conditioning
Choose how the granny flat is cooled. The standard living split is included in your base price.
Included as standard. Wall-mount inverter split unit to the living area, sized to the room load.
Outdoor & site
Pricing varies with site conditions, falls, and existing services. Final figures confirmed in writing after a site visit.
Compliance, services & metering
Almost always required for tenanted secondary dwellings. Pre-ticked by default.
Add-on rooms & layout changes
Layout extensions are quoted from your block survey — they may need a fresh CDC/DA pathway.
Common questions
Why pick Siena over Ilyas — they're both 50m² 1-bed?
Siena is the more refined of the two. Wider living window, taller front door, and the exterior carries render rather than poly-clad weatherboard as the default. If you want the 1-bed brief done plainly, pick Ilyas. If you want the same brief with a Mediterranean visual feel and a slightly more generous bathroom, Siena is the one.
What's actually included in the Siena base price?
The base price covers the dwelling itself — slab, frame, roof, exterior cladding, full internal fitout, all standard inclusions listed on this page, plus our fixed builder margin and warranty. What's not in it: site costs (excavation, retaining, rock removal), council/CDC fees, separate metering, BASIX upgrades beyond the minimum, and any structural alterations to the existing main dwelling. Site costs get quoted off a real assessment, not a postcode generic.
Can I rent the Siena out as a separate dwelling?
Yes — this is exactly what SEPP (Housing) 2021 allows for. The Siena is built to be tenanted independently of the main house. To do it cleanly you'll want separate water and electricity metering (configurator option above) so the bills sit with the tenant, plus the BASIX 7-star upgrade to keep their power bills competitive. We'll flag any council-specific tenancy conditions during the block check.
Is the Siena BASIX and SEPP-compliant?
Yes. Every Buildana design is built to current BASIX targets (5-star minimum as standard, 7-star available as an upgrade) and within SEPP (Housing) 2021 thresholds (50m² internal, single storey, single secondary dwelling per lot). We run BASIX modelling specific to your block's orientation and shading before lodging — not a generic certificate.
Request a formal proposal for the Siena
Pick your upgrades, send through your details, and we'll come back with a fixed-price proposal — usually within 3 business days.