Roof Replacement Cost Calculator
Use Monolith Roofing’s roof replacement cost calculator Australia to estimate the price range for your new roof. It works for Colorbond® steel, metal, concrete tile and terracotta tile roofs across NSW, including roof replacement cost Sydney scenarios.
How to use the calculator
- Enter roof area (m²) — total plan area. The tool applies standard waste automatically.
- Select material — choose Colorbond® steel, metal (non-Colorbond), concrete tile or terracotta tile to see an accurate roof replacement cost range.
- Set pitch (degrees) — costs increase by $5/m² for each degree above 30°.
- Choose region — Sydney & Wollongong uplift is included.
- Add scope options — tick scaffolding and/or removal, then enter guttering (per metre), fascia (per metre), downpipes (each) and skylights (each) for a full new roof cost calculator estimate.
- Toggle GST — switch between ex-GST and GST-inclusive totals for quoting clarity.
Note: This tool is a guide only. Final quotation depends on site inspection, measurements, product selection and installation conditions.
What costs are included?
- Materials — pricing per m² by roof type (Colorbond roof installation cost, tile and metal options), with a built-in 10% materials reduction applied in outputs.
- Removal — old roof removal at $60/m² (if selected).
- Pitch surcharge — low/standard combined; each degree above 30° adds $5/m².
- Scaffolding — optional per-m² allowance (if selected).
- Guttering & fascia — guttering $45–$90 per metre; fascia $45 per metre.
- Downpipes — $150–$300 each.
- Skylights — $800–$1,800 each.
- Region — Sydney multiplier; Wollongong fixed uplift of $2,000–$3,000 on an average roof.
Roof types this calculator supports
Colorbond® steel
Durable, low-maintenance and fast to install. Use this profile for precise Colorbond roof installation cost estimates across gable, hip and skillion roofs, popular for energy-efficient re-roofs and modern designs.
Metal (non-Colorbond)
Alternative coated steel systems. The calculator estimates metal roof cost calculator Australia ranges using per-m² inputs similar to Colorbond tiers, adjusted for coating grade.
Concrete tile
Common across Sydney suburbs. Heavier dead-load but long-lived. Choose this when you need a tile roof replacement cost calculator Australia outcome for typical suburban homes.
Terracotta tile
Premium appearance with excellent colourfastness. The calculator models material and removal to provide realistic roof renovation cost ranges for terracotta replacements or upgrades.
Typical pricing signals (rule of thumb)
- Area: Larger roofs reduce per-m² overhead but increase total spend.
- Pitch: Over 30° adds labour complexity, captured as $5/m² per extra degree.
- Complexity: Valleys, dormers and penetrations increase flashing and time.
- Region: Logistics and trade availability vary (roof replacement cost Sydney often differs from regional NSW).
When to Request a Formal Quote
The calculator gives you a solid range, but a fixed, itemised quotation converts that range into a firm price, scope and timeline. Request a site inspection and formal quote if any of the following apply:
- You want price certainty and a confirmed installation window—even if the calculator range already looks acceptable.
- You’re planning a replacement within the next 3-6 months and need scheduling locked in.
- You’re budgeting/financing the project and need an itemised figure for approvals.
- You’re buying or selling and require a professional condition report and quote.
- You’re dealing with insurance (storm/hail/water ingress) and need a scoped estimate.
- Complex geometry or detailing (valleys, hips, dormers, parapets, box gutters, heritage flashings).
- Signs of underlying issues (sagging lines, soft spots, previous leaks, rust trails, loose ridge capping).
- Pitch above 30°, multiple roof joins, or many penetrations (skylights, chimneys, solar arrays).
- You’re comparing materials (e.g., Colorbond® vs tile) and want lifecycle/maintenance guidance.
- You need coordination with other trades (solar, air-con, insulation, gutters/fascia).
FAQs — Roof Replacement Cost (Australia)
What affects roof replacement cost the most?
Material choice (e.g., Colorbond vs tile), total roof area, pitch above 30°, removal scope, extras (guttering, fascia, downpipes, skylights) and region, especially for roof replacement cost Sydney.
Is this suitable for new builds as well as replacements?
Yes. For new builds, deselect removal, keep material and pitch, and add extras as needed to model the cost of roof installation.
How accurate is the calculator versus a site quote?
It provides realistic roof replacement cost ranges using current allowances. Final contracts depend on site inspection, product selection and measured quantities.
Can I estimate metal roof installation cost with skylights?
Yes. Select metal (or Colorbond) and add the skylight quantity. The tool uses $800–$1,800 each plus standard flashings.
Does the calculator include guttering and downpipes?
Guttering and downpipes can be included optionally. Guttering is calculated at $45–$90 per metre, fascia at $45 per metre and downpipes at $150–$300 each and are included when entered.