AL-Haitham LTD for Architectural services
The UK House Extension & ROI Calculator 2026
Welcome to the AL-Haitham Property Profit Portal. Whether you are a homeowner planning a dream rear extension, or a property developer calculating Gross Development Value (GDV) for an HMO or flat conversion, our AI-powered tool gives you instant clarity.
Use the tool below to generate a highly accurate, region-specific estimate based on live 2026 UK construction rates. Find out your build costs, required professional fees, and your estimated Return on Investment (ROI) in less than 60 seconds.
How to Use the Feasibility Calculator
1. Select Your Profile: Choose your role (Homeowner, Investor, Developer, or Estate Agent). The calculator will dynamically adjust to show the financial metrics that matter most to you.
2. Enter Existing Details: Input your project’s location and current property value. Regional multipliers will automatically adjust the pricing to your specific area.
3. Choose Your Strategy: Select one or multiple build types—from single-storey wraparound extensions to loft conversions and garden annexes.
4. Customise Your Finish: Add premium interior design styling, luxury bathrooms, or modern eco-upgrades like Solar Panels and Air Source Heat Pumps.
5. Generate Your Brief: Click "Generate" to instantly view your estimated costs and ROI on screen. Enter your email to download your comprehensive, phase-by-phase Architectural Brief.
What Are the Expected Results?
By using this tool, you bypass weeks of waiting for initial contractor quotes. When you generate your report, you will instantly receive:
A Phase-by-Phase Breakdown: Clear cost estimates split across Architectural Design, Structural Engineering, and actual Construction.
Financial Viability Metrics: Live calculations of your Estimated Added Value, Gross Yield %, and Break-Even Payback timeline.
Planning Permission Guidance: A smart indicator telling you if your project likely falls under Permitted Development or requires Full Planning Permission.
Exclusive Developer Data: Investors and Developers will receive a secondary CSV spreadsheet detailing the exact Labour vs. Materials split for their financial modelling.
FAQ Section
Are architectural fees included in the estimate?
Yes, you can toggle our ~8% fee inclusion
Does this include VAT?
Is this a final quote?
Yes, you can toggle our ~8% fee inclusion
No, this is an algorithmic feasibility estimate. Book a Free 3D Feasibility Study for an exact, site-specific quote