Home Improvement Tips

How much do External Consultants Cost? Creating a Realistic Budget (2020)

The surveyor will provide us with a digital CAD file of the data so that we can start detailing your proposals.

“How much should I pay for External Consultants?”

When budgeting for an upcoming renovation, refurbishment or home extension, people often forget to budget for the necessary external consultants and surveys.

Your contractor gives you a quote… your architect gives you a quote… and you hope that this is all you will need to put aside for your project.
Unfortunately this is not the case. There are external consultants, surveyors and organisations that you may need to instruct depending on the individual project. Your Structural Engineer, your Party Wall Surveyor, your measured survey and your planning permission are all going to be extra costs.
We’ve outlined a guide on what you can expect to pay for the potential consultants, surveyors and organisations you may require.

Structural Engineer

This will vary depending on the complexity of the design. Guide costs below (VAT not included):
Simple loft conversion or single storey rear extension
Combination of the above, side and rear extension
Combination of the above plus internal structural alterations
Major works to 4+ bedroom property

Party Wall Surveyor

You will need to notify your neighbours of any relevant works being carried out under the Party Wall Act 1996.
More information can be found here but in general, if you’re installing foundations within 3m of your neighbours property, or putting steel beams within party walls you will need to notify your neighbour and potentially draw-up Party Wall Agreement.
Cost: To serve notice, circa. £200.  From £900 up to £2000+ (if an Award is needed)
structural crack - Party Wall Agreement
CCTV Drainage

Drainage CCTV survey

If you do not know the routes and flow direction of your property’s drainage we’d suggest paying for a CCTV survey.
This will give us the location and direction of drainage, manhole invert (depth) and cover levels, and detail whether there is any damage to the pipes.
Cost: £300-400

Thames Water Build-over Agreements

If you’re building over or near a Thames Water sewer that is classified as ‘Public’ you will likely need to submit relevant drawings and details to apply for a Build-over Agreement. 
Most residential applications will be for pipes up to 160mm diameter. There will be additional work for us to generate the design documents and manage the application on your behalf. 
Cost: £343+
Tender Drawings

Full Measurement/Topographical Survey

To ensure we are working to accurate, measured data, you will need to instruct a Surveyor to provide a full measurement survey of your property.
This will include:
Room Dimensions
Window Locations and Measurements
Roof Ridge Height
Floor Levels
Eaves Heights
Ground Levels
And everything else we would need to work from.
Cost: £800+ (depending on size of property)

Planning Permission

Rates increased by 20% on 17th Jan 2018.

Householder Planning Application Fee:

Certificate of Lawful Development:

A full Planning Fee Schedule can be downloaded from the Planning Portal via the link

Earlsfield Planning Architect sketch
Project Management

Building control

We will generally recommend instructing a private Approved Building Control Body as opposed to the Local Authority Council (*our preference only). A Building Control application is split in two sections.
Plans Check 
This is where our drawings and the engineers calculations are submitted to the inspector and a desktop study carried out to check compliance with the Building Regulations Approved Documents. Payment for this is generally required on submission of the application.
Inspection Checks
These are carried out at various stages of the build to check progress on site. The inspector will check compliance with the Building Regulations and comment on any alterations needed. Payment for this is generally required following the first inspection.
Simple loft conversion or single storey rear extension
£300 ex.VAT
£350 ex.VAT
Combination of the above, side and rear extension
£400 ex.VAT
£500 ex.VAT
Combination of the above plus major internal structural alterations
£500 ex.VAT
Major works to 4+ bedroom property
£600 ex.VAT
£900 ex.VAT
Note: The above costs are for guidance only. Your local authority website will have a full fee schedule for you to download, alternatively an Approved Inspector will provide quotes on a project-by-project basis

Struggling to Calculate all the Costs?

We can you with your Home Design Journey.
To start… Create your Quick and Easy Online Brief. It should only take 15 Minutes.