Unexpected Costs when Renovating


So, your home renovation is about to start, you have a budget in mind and a schedule to follow. Even with all your preparation, there are likely to be hidden renovation costs that may surprise you along the way.

For example, loft conversions don’t require formal planning permission, but did you factor in the cost for a certificate of lawfulness and for the work required to meet building regulations?

We have put together a lift of the typical unforeseen costs you have likely not considered to help you get ahead of renovation costs.

Planning Permission Fees

Renovation often includes needing planning permission. For certain types of work formal planning permission from your local authority will be needed.

The typical local council fee, which will need to be considered in your renovation costs, is around £170 for most types of planning permission and around £90 for a certificate of lawfulness. Your architectural designer will be able to advise you on what application you will need to put in.

For larger projects such as change of use the fees are higher and depend on the size of your project.

Structural Alterations

Structural works include knocking through supporting walls, adding sliding or folding doors etc. For this type of work, you will need to allow for a structural engineer’s fees to provide the calculations to support our project. Some structural works will require reports that are important for Building Control, at an additional cost to your renovation.

Building Control

It is required by law to have a Building Control Officer check over the work done by the builder. This is to advise you both on the current building regulations, fire provisions and health and safety and ensure they are adhered to all current requirements during the works and after completion.  The Building Control Officer will inform the council about the start date of the build and will provide the certificate at the end to say it has passed building control. You can choose between the local authority or a private inspector.

Additional Jobs

There are often other additional jobs that need factoring into your renovation costs. The typical ones are:

  • Electrical rewiring
  • Improving water flow and pressure
  • Levelling old floors
  • Plumbing costs
  • Insulation costs
  • Scaffolding costs
  • Skip hire

Garden Works

Some works will cause disruption in the garden. Not only that, but also underground work may need to be done for water drainage or having light, power and taps fitted. This will all need to be considered early on so that it is planned for accordingly. Depending on your garden, the costs may differ a lot to it is worth finding out.

Even if there are no great changes to your garden, protecting the area while there is building work going on will have additional costs so factor these into your budgeting.


It’s always a wise idea to retain part of your budget as part of a contingency plan. There are always going to be overlooked elements, no mater how detailed you plan. Having a back up fund will act as a good cushion when/if issues arise.