Building control helps you get your project on track and ensures it complies with all the necessary regulation.

You can find this service at your local authority and also privately.

This post sets out the basics that you need to know regarding your extension, its foundations, and the role of the Building Inspector.


Whatever sort of extension or improvement you have in mind, you need to obtain Building Regulation approval. This is when an inspector visits to ensure that the work has been carried out satisfactorily. They also visit after the footings are dug, on completion of the foundations.

You can choose whether to opt for a Building Notice Application or Full Plans.


The builder carries the full responsibility of the works and making sure they comply with the rules.


This is when the plans are checked by the Building Inspector.

It gives you the peace of mind to know everything is okay with the build.

Also, it gives the builder all the detailed information they need to give you an informed quote.


You have a choice of a private or public building inspector.


This is an inspector from a private company. They are registered with the Construction Industry Council.

Like the public inspector, they will check your plans comply with all the relevant regulations.

However, if they hit a problem, they may have to refer the matter to the local authorities.


The Local Area Building Inspector can also carry out inspector duties. Unlike the private inspector, they can enforce the regulations.

Whichever option you choose, you should do this as soon as possible – it will help determine the fees for the project.


Once your plans are approved, these are the ones that will be used.Discussing plans

Before submitting them, you should check them against the original plans carefully. This is because if they’re different, this matter needs rectifying before you begin the project.

In terms of inspections, there are usually eight in number and could be more besides.


This takes place about two days prior to any work commencing. You must have told the building inspector before the job starts.

The inspector makes their first inspection and can meet the builder in charge of the site, to discuss the project.

You will also pay a one-off fee for this service.


This inspection comes before the foundations are laid, in the excavation period.

It gives the inspector the chance to look at the site and ensure certain criteria are being met. These include;Building addition to residential house with new foundation

  • If the ground is manmade (made up).
  • The drain depth and the vicinity of any manholes.
  • The capacity of the ground for bearing a load.
  • Whether there are any trees in the area – or even trees that have been taken out.
  • What the depth of the current foundation is for the proposed extension.


This inspection is the oversite preparation.

Now the inspector makes sure that the sand blinding, the damp proof membrane (DPM) and the hardcore is correct.

The damp prove course is checked. This is to make sure the materials and joints are all okay.

The concrete used in the cavity must be 225mm beneath the DPC.

If there is sub floor thermal insulation going in, this is also checked over.

The foundation walls are also looked at.



This happens when the footing walls are at the level of the DPC.




Now the drainage is inspected before it is covered.


Everything is checked, such as the drains and that the correct materials are being employed.


Also, the material for the beds is checked, as well as access points and inspection chambers.




The drainage is checked – both below and above the ground, to ensure it is watertight and airtight.



You need to notify the inspector and local authority once more, if the project is not fully completed, but about to beBuilding Inspector Looking At New Property occupied.


This is the final check, which is supposed to take place at the end of the project. Although this is sometimes overlooked, it should still be done.

Things that are checked are;

  • That the ventilation to the roof voids and the rooms is adequate.
  • The roof coverings are okay.
  • The safety glazing is correct.
  • The geometry of the staircase.
  • That the fire safety regulations have been met.


These are not by any means the only checks that the Building Inspector will make. There could be others. They include;

  • The inspector might ask to see the joists in the ceiling and the floor, to check off against the approved plans.
  • An inspector might check the timbers or trusses of the roof and ensure they are the right size. They may also see if the timber used is the correct grade for the job.
  • Could check the grade, size and the centres of the joists.Roof insulation
  • They might carry out an inspection of the sound insulation, as well as the thermal insulation, for the adequate levels of thickness.
  • To check that the fire safety is up to scratch.
  • Check the regulations for the glazing.
  • May check the structural quality of the building.
  • To check that the staircase is correct and abides by all the regulations.
  • If the builder is either a beginner or an amateur – for example if it is the homeowner undertaking the work as a keen DIYer – then they might make more inspections than usual.




Check the approved plans carefully against the original drawings and make sure they tally. It will stop any potential problems from arising in the long run.


If you are not sure about any aspect of the job, take the opportunity to check it carefully with the Building Inspector.


We would advise maintaining a good working relationship with the Building Inspector, as it is prudent for the smooth running of your extension.


Having said all this, Inspector often do not make all of these checks if they know they are working with competent builders. We often find that most inspectors usually make around three visits during the build. In general, the Building Inspector is a useful ally and happy to help and give advice to your project. He often offers advice according to the specifications if the job so that you cannot go far wrong.


The next part of the build involves the brickwork and scaffold.

Please get in touch for a free quote.