Plan CHECK by MUSTARD
“Make sure your plans cut the mustard”
Thinking of building an extension? Already got drawings?
Before you spend thousands on building your extension, renovation, or new build—get our fresh expert eyes on your drawings.
Are you feeling:
• Rushed into a basic design?
• Unsure if you’re missing a trick?
• Worried you’re not getting the best design for your budget?
If so, get a second opinion!

An Expert Second Opinion Service
Introducing: MUSTARD’s Plan CHECK
Plan CHECK is a same-day design review service that gives you confidence, clarity, and a better plan. Whether we are your architect or not, it doesn't matter - you still deserve the best plan you can get.
We’ve visited hundreds of homes and heard the same thing:
“We wish we’d done
things differently”
Let’s make sure you don’t say the same.
How Plan CHECK works
01 Send us what you’ve got
Plans, drawings, renders, photos - anything your architect or builder has given you.
02 We give it the once-over
Our experienced architect will highlight what’s working, what’s not working, and will show you what could be better.
03 You get real design value
You’ll receive:
- Hand-drawn sketches & 3D ideasDesign tweaks & upgrade options
- Honest budget advice (including where to save)
- Product links, colour palettes & trade tips
Why it matters?
Sometimes it’s a simple tweak that transforms a space.
Other times, it’s catching a costly mistake before it’s built.
Either way, don’t feel that you have missed a trick, instead move forward with confidence—and a design you actually love.
Ask yourself...
• Are you 100% happy with your current plans?
• Do you know exactly what your home will look and feel like?
• Are you confident you’re getting the best design for your money?
If you’re even slightly unsure—get a second opinion.
Plan Check by MUSTARD
Smart. Fast. Totally worth it.
Plan CHECK
by MUSTARD
£395 ALL-IN
All our knowledge
All your questions answered
All in one day
It could save you thousands!
Connections
Builders
Don't leave it to chance, download our list of tried and tested builders who wont let you down
Professionals
Extending your home can involve lots of professional help. We know all of the good ones.