# Cost Approach & Development Residual Appraisal

> Component slug: `valuation-cost-and-residual`. Researched: `2026-05-18T01:30:00Z`. Sources cited: `8`. Token usage: `18500`.

## 1. Summary (≤3 sentences)

The Cost Approach (Summation/DRC method) estimates property value as land value plus the depreciated replacement or reproduction cost of improvements, and is the primary valuation method for special-purpose assets—such as schools, hospitals, and heritage buildings—where market comparables are absent [ref: #26]. The Development Residual method works backwards from the Gross Development Value (GDV) by deducting all construction, soft, finance, and contingency costs plus a required developer margin to yield the maximum supportable land price [ref: #27]. Both methods are highly sensitive to construction cost assumptions; in the current Australian market, where build costs have escalated 15–25% since 2020, a 10% cost overrun on a $5M project directly erases $500,000 of residual land value [ref: #28].

## 2. Key Concepts

- **Depreciated Replacement Cost (DRC)** [ref: #26] — Current cost to replace an asset with one of equivalent utility using modern materials and methods, less accumulated depreciation.
- **Summation Approach (AU)** [ref: #3] — Australian application of the cost approach: land value + depreciated building value = total property value.
- **Replacement Cost New** [ref: #26] — Current cost to build a functionally equivalent building using modern materials and current design standards.
- **Reproduction Cost New** [ref: #31] — Current cost to construct an exact duplicate using the same materials, construction standards, design, and workmanship.
- **Gross Development Value (GDV)** [ref: #27] — The aggregate market value of a completed development scheme upon sale.
- **Residual Land Value (RLV)** [ref: #27] — The amount remaining for land acquisition after all development costs and required developer profit are subtracted from GDV.
- **Developer's Margin** [ref: #27] — Target profit expressed as a percentage of GDV; typically 15–20% for residential projects in Australia.

## 3. Methodology / Formulas / Process

### A. Summation / DRC Method

```
Property Value = Land Value + (Cost New − Accumulated Depreciation)
```

Land value is derived independently via the direct comparison (sales) method. Cost New is estimated by one of four techniques [ref: #26]:

1. **Comparative Unit Method** – Lump-sum per m² or m³.
2. **Segregated Cost Method** – Average costs by major component.
3. **Unit-in-Place Method** – Each component broken into sub-elements.
4. **Quantity Survey Method** – Most accurate; estimates every individual construction item.

### B. Development Residual (Land Residual) Method

```
RLV = GDV
    − Construction Costs
    − Professional Fees        (typically 8–12% of construction)
    − Finance Costs            (construction loan interest)
    − Marketing / Sales Costs  (typically 1–3% of GDV)
    − Contingency              (typically 5–10% of construction)
    − Acquisition / Stamp Duty Costs
    − Developer's Profit       (typically 15–20% of GDV, residential AU)
```

**AU-specific cost factors** [ref: #27]:
- GST margin scheme: applying wrong treatment can shift land value calculations by $200,000+
- State stamp duty on land acquisition: 4.5% (QLD) to ~5.5% (VIC) of site value
- Development contributions (council infrastructure levies): $20,000–$700,000/ha

### C. Sensitivity Analysis

| Input Variable | Standard Range Tested |
|---|---|
| Construction costs | ±5–15% |
| GDV / sale prices | ±5–10% |
| Finance / interest rate | ±1–2% |
| Development timeline | ±3–6 months |

## 4. Tools & Libraries

| Name | Type | Link | Notes | [ref] |
|---|---|---|---|---|
| Feasly | Online feasibility calculator (AU) | feasly.com.au | RLV calculator with state-specific cost presets, GST margin scheme handling | [ref: #27] |
| Excel (custom static models) | Spreadsheet | — | Most small-to-mid AU developers build custom static residual models | [ref: #28] |
| API Valuation Protocol (2025) | Standards document | api.org.au/knowledge-hub | IVS-aligned terminology and method selection guidance | [ref: #3] |