What Happens After Planning Permission Is Approved in London? (Step-by-Step Guide)
Getting planning permission approved is a big milestone—but in London, it’s only the beginning.
Most projects stall after approval because homeowners don’t realise there are still several legal and technical steps before construction can start.
This guide explains exactly what to do next so your project moves forward without delays.
1. Check Your Planning Conditions (Critical First Step)
Nearly all London approvals come with conditions.
Some are pre-commencement, meaning you cannot legally start work until they are approved.
Typical London conditions:
External materials (brick, cladding, windows)
Detailed junction drawings
Drainage strategy
Landscaping
Cycle and refuse storage (common in boroughs like Lambeth and Wandsworth)
2. Discharge Pre-Commencement Conditions
You will usually need to submit:
Additional drawings
Material specifications
Sometimes samples
London timeframe: typically 4–10 weeks (often slower than the official target)
3. Prepare Building Regulations Drawings
Planning drawings are not enough to build from.
You now need detailed Building Regulations drawings, including:
Wall, roof, and floor build-ups
Insulation (Part L compliance)
Fire safety (Part B)
Drainage design
Construction details builders actually use
This is where many low-cost providers fall short and where build issues start.
To understand the difference between planning and building regulations, see:
https://www.drawandplan.com/new-blog/2025/8/28/do-i-need-planning-permission-or-just-building-regulations-approval-a-complete-guide-for-uk-homeowners
4. Structural Engineer Design
If your project includes:
Open-plan layouts
Steel beams (RSJs)
Roof alterations
You will need:
Structural calculations
Beam and foundation design
These are required for Building Control approval.
For more info refer to our blog:
https://www.drawandplan.com/new-blog/2025/5/7/the-role-of-a-structural-engineer-in-home-extension-design-a-comprehensive-guide
5. Party Wall Act (Often Overlooked)
In London, most extensions trigger the Party Wall Act, especially if:
You are building near a boundary
Works affect the party wall
This is separate from planning and can delay projects if ignored.
Our blog contains further information:
https://www.drawandplan.com/new-blog/2025/3/21/how-the-party-wall-affects-loft-conversions-and-home-extensions
6. Build Over Agreement (If There Is a Sewer)
Common in London terraces.
You will need approval if:
A public sewer runs under or near your extension
This may involve:
CCTV survey
Drain protection details
Chamber relocation
Find more info in our blog:
https://www.drawandplan.com/new-blog/2025/4/7/build-over-agreements-for-extensions-a-complete-guide
7. Appoint Building Control
Before starting work, appoint:
Local Authority Building Control, or
An Approved Inspector
They will inspect:
Foundations
Drainage
Structure
Insulation
Final completion
8. Get Accurate Builder Quotes
With proper drawings, you can:
Get like-for-like quotes
Avoid underpriced (and risky) builders
Reduce variations during construction
Better drawings lead to better cost certainty.
You can view example drawing quality here:
https://www.drawandplan.com/drawing-samples
9. Start Construction Properly
Only start when you have:
Conditions discharged
Building Regulations drawings approved
Structural design complete
Party Wall matters resolved
Build Over Agreement in place (if required)
10. Completion Certificate (Essential)
At the end of the project:
A final inspection is carried out
You receive a Completion Certificate
This is essential for:
Selling
Remortgaging
Proving legal compliance
Final Thoughts
In London, the biggest delays do not happen at planning stage—they happen after approval.
Getting the next steps right—conditions, building regulations, and technical design—is what keeps your project on track.
Need Help Moving Forward?
At Draw and Plan, we help homeowners across London with:
Planning drawings and approvals
Building Regulations drawings
Measured surveys
Discharge of planning conditions
Start here:
https://www.drawandplan.com/
Or view services and pricing:
https://www.drawandplan.com/services-prices
Disclaimer: This article is for general informational purposes only and does not constitute legal or professional advice. Always consult relevant professionals and local authorities before undertaking any development or change of use
