A practical guide to the most commonly missed upgrade costs and budget items that catch new home buyers out — from site costs to post-handover essentials.
7 min read·Compare My Build — Independent Resource·No ads · No rankings
Cost estimates only: Any building, material or upgrade figures on this page are indicative, not fixed prices or quotes. Confirm current written costs, specifications and inclusions directly with your builder, supplier or relevant trade.
Overview
One of the most consistent experiences among new home buyers is discovering costs they didn't anticipate. The advertised "from" price of a builder's home is typically a starting point — the total cost to build and settle into a new home is almost always higher.
This guide identifies the most frequently overlooked costs — from site cost variations to post-handover essentials — so you can budget accurately from day one.
Watch Out
A realistic contingency buffer of 10–20% above your base build price is recommended for most new home builds. Buyers who don't budget a contingency are most at risk of financial stress during construction.
Site-Related Costs (Most Commonly Missed)
Soil test variation
$2,000–$25,000+
If your soil classification is higher than what the provisional sum assumed, a significant variation is common. Most likely single largest budget risk.
Retaining walls
$3,000–$20,000+
Sloping lots or adjacent higher ground may require retaining walls. Often a provisional sum — can vary enormously.
Service connections
$1,000–$6,000+
Power, water, gas, sewer, and stormwater connections vary by lot. Corner lots or rural properties can be significantly higher.
Council crossover / kerb cut
$1,000–$3,000
The connection from your driveway to the road. May or may not be included. Confirm with builder.
Fill material / cut and fill
$2,000–$15,000+
Required when your lot needs to be levelled. Cost depends on site slope and volume of fill material.
Front yard landscaping (turf, edging, mulch)$2,500–$8,000
Full yard landscaping (front + back)$15,000–$40,000+
Perimeter Colorbond fencing$5,000–$15,000
Clothesline + letterbox$400–$800
Garden irrigation / reticulation$2,000–$6,000
Electrical & Technology
Extra power points throughout home$500–$2,000+
TV/data points (additional rooms)$100–$250 per point
Smart home / home automation pre-wire$1,500–$5,000+
Security alarm system$1,500–$4,000
CCTV / camera installation$1,000–$3,000
Garage door motor$600–$1,500
Post-Handover Surprises
Beyond the build itself, many buyers don't fully account for the cost of moving into a brand new home:
Window furnishings (blinds or curtains)$3,000–$12,000
Light fittings (if builder includes bare batten only)$1,000–$5,000+
TV antenna and NBN connection$300–$800
Furniture for new floor plan$10,000–$40,000+
Stamp duty, legal fees, and mortgage costs$15,000–$50,000+
Appliances not included in build$2,000–$8,000+
Tip
Use a dedicated spreadsheet to track every cost category from the moment you start planning. Group costs into: build contract, builder upgrades, site costs, landscaping/external, electrical extras, post-handover essentials. Revisit and update it monthly through construction.