How to Project Manage Your Own House Extension: Step-by-Step

Managing your own house extension might sound daunting—but with the right guidance, it’s absolutely doable. In fact, project managing your build can save you thousands in professional fees, give you complete control, and ensure every penny is spent exactly where it matters most.

At Klyra, we help homeowners take charge of their projects without the stress. Here's a high-level look at how to manage your own extension from start to finish.

1. Start with a Solid Plan

The best builds begin long before a shovel hits the ground. You’ll need:

• A well-defined brief

• Accurate architectural drawings

• Planning permission (if needed)

• A realistic budget

Don't skip this stage—mistakes here cost more to fix later.

2. Build the Right Team

You’ll need to source:

• A builder or main contractor (or trades if you’re subcontracting)

• Structural engineer

• Party wall surveyor (if applicable)

• Building control inspector

The right people are worth their weight in gold. Vet thoroughly, get multiple quotes, and make sure everyone understands your expectations.

3. Create a Schedule and Stick to It

Timelines are key to managing trades, deliveries, and cash flow. Use a simple Gantt chart or calendar to map out:

• When each trade is needed

• Key milestones (e.g., foundations, roof on, first fix)

• Lead times for materials

It doesn’t need to be perfect—just practical and reviewed regularly.

4. Track Costs Like a Hawk

Budget overruns are one of the biggest stress points for homeowners. Keep a live spreadsheet of:

• Quoted vs actual spend

• Payment stages

• Contingency use

Knowing your numbers gives you confidence to make decisions and stay in control.

5. Communicate Like a Pro

You are the glue holding it all together. Set up:

• A weekly site meeting with your builder or sub-contractors

• A digital paper trail (emails, notes, drawings)

• Clear instructions and timely decisions

Proactive communication helps avoid misunderstandings and keeps everyone accountable.

6. Know What to Look For On Site

You don’t need to be a builder—but knowing what should be happening each week can help you spot problems before they escalate. Understanding the sequence of work (and what's "normal") makes a big difference.

💡 Not sure what to look for? Our homeowner site inspection checklists are coming soon.

7. Stay Legal and Compliant

Don’t get caught out—make sure you’ve:

• Notified building control

• Covered party wall obligations

• Kept warranties, certificates and manuals

Getting this right from the start avoids stress at the end when it’s time to sign off and move in.

Final Thought

Managing your own extension is entirely possible—with the right systems and support. You’ll be amazed at what you can achieve (and how much you can save) when you approach it like a pro.

👉 Want expert guidance without the project manager price tag?

We’ve built Klyra to give homeowners like you the tools, templates, and support to manage your project with confidence.

📩 Join our mailing list to get our free starter checklist

🛠️ Browse our digital toolkit for step-by-step guides, templates, and inspection forms

📞 Or book a consultation to discuss your project