What happens after obtaining planning permission for your home extension or new build?

August 6, 2021
by Sege Rosella

There’s a whole host of information out there about how to get planning permission, how to finance your build, and how to actually build your project.

But there’s precious little on what happens in the bit between being granted planning permission and actually putting shovels in the ground. I’m here to help you with that.

This stage of your building project is very important and I find that it is often overlooked. I know from first-hand experience that any errors in this phase can have a big knock-on effect with the rest of the build and can potentially cost you many thousands of pounds.

Here are the ten steps you need to take:

01. Obtain detailed working drawings

This step is crucial. The plans that you submitted to the council for planning permission likely won’t be detailed enough for you to get an accurate quote from a builder. You need a complete set of working/construction drawings, building notes, and detailed specifications (if applicable).

At this stage your architect (or architectural designer/technician) should engage a structural engineer to calculate the key structural aspects of your build, such as the correct design for your foundations, any steel beams required, roof truss specification etc.

I would always recommend that you dig trial holes. This is done to determine things like ground conditions and - if you’re building an extension - to determine depth and make-up of your existing foundations, which is particularly important if you are adding a storey to the existing building. Never presume. Skipping this step, or any errors here will cost you later down the road.

02. Meet with your architect

Now that the working drawings and engineering works are being prepared I recommend that you meet with your architect so that they can inspect any of the aforementioned trial holes to enable them to accurately complete foundations designs leaving you no surprises further on.

Don’t hold back here. Discuss everything from the exact types of bricks, render, tiles, and all the way down to the type of door handles, skirting boards, and paint.

03. Receive the full design specification from your architect

This should include everything discussed in the steps above. Note that the more detail included, the more likely it is you’ll get an accurate quote. This means your build has a much higher chance of being completed on time and on budget, and you shouldn’t have any nasty surprises.

04. Submit to local building control for building regulation approval

Once all the above is agreed your architect will be ready to submit the drawings for building regulation approval. It’s a formality and they should be able to do this quickly.

05. Invoke the Party Wall Act

This isn’t necessary for all builds, but the planners will have added this to your planning permission as a Condition if it applies to you. I can’t stress enough how important it is that you don’t skip this step if it applies to you. It has to be done by law.

06. Consult with an independent  quantity surveyor

You now have your working drawings and specifications and are almost ready to build.

If your architect hasn’t already included this in their service then I recommend that you consult with an independent quantity surveyor - preferably RICS registered. Their job is to give you a cost for your proposed build. It’ll be a full nuts-and-bolts breakdown that will include a bill of quantities (BOQ) and schedule of costs (SOC), and will include any and all statutory fees that might need to be paid.

I advise to have this done as quantity surveyors are not only very accurate (it’s literally their job), but they act as an impartial, trusted third-party, and are fully insured against any mistakes.

This may cost you an extra £200, but you’ll have something to check all of your quotations against as they come in from your builders, which has the benefit of saving you money in the long run. The builder you think that is the most cost-effective might not be.

07. Get quotes from builders

My strong advice is that you only begin this step once you’ve completed all the others above. Don’t be tempted to skip ahead. A builder will only give you a quote based on the information that you’ve given them. So neglect to include something important and you’ll likely end up with an unexpected bill later down the path.

The quotes you get should be roughly in line with what the quantity surveyor gave you. If they’re wildly under or over then there’s cause for concern. If you need help deciphering the quotations it may be worth asking your quantity surveyor to check the quotations for you.

Be sure to get in contact with us at this stage — we’d love to give you a no-obligation costing for your build.

08. Ensure your architect has met, and satisfied, all planning conditions

Before any work commences on site you should check with your architect to find out if they’ve cleared and met all of the conditions in your planning permission.

Your architect should write to you to tell you all the conditions (if there were any) have been met. 

You should have received confirmation in writing from your local planning authority to confirm this.

09. Meet with your builder

Once you’ve chosen your builder you should meet with them to discuss the finer details of your professional relationship. You should do your full due diligence, negotiate terms, and discuss contracts (get these checked by your solicitor).

10. Instruct your builder

That’s it — you’ve signed on the dotted line and are ready to get your build underway, with confidence. Good luck!