Which PlanExtend service option best suits my needs?

Whilst we have tried to provide you with all the information you need on our website to enable you to make an informed decision we understand that you might have some questions, or your requirement might not fit within the structure of our standard options.

So if you would like further information relating to any of our service options, if you wish to discuss your specific requirements or simply ask our advice, please do get in touch – we are here to help!

Call us on 0330 043 4142 or email or visit our ‘Get in Touch’ page and complete the form.

Can PlanExtend visit my property to undertake a survey?

Although the vast majority of our clients use our on-line service and download our simple Starter Pack, uploading their own measurements, sketch plans and photos, we appreciate that some clients are not comfortable generating this information.

If you require one of our team to visit your property to undertake a full dimensioned survey, take photographs and obtain your design brief we can offer this service as an ‘Add-on’. This can be selected when using out checkout process**

PlanExtend Survey & Consultation Fees are calculated as per the below:

£220.00 PlanExtend Property Survey & Design Consultation Fee

£0.50/per mile from PlanExtend Sheffield Office (S17 4NH) to location of client property (note return journey charges apply). Total mileage calculated using Google Maps.

Typical Fee: Property Address = Central Manchester (44 miles from S17 4NH)

  • £220 Property Survey & Consultation Fee
  • 44miles x 2 (return journey) = 88
  • 88 x £0.50 = £44.00

Typical PlanExtend Property Survey & Design Consultation Fee = £264.00

For survey and consultation visits where the property is in excess of 100 miles from our base we will need to review journey times and possibly charge for accommodation etc.

As a result we will not be able to confirm the cost of the survey and consultation until you have completed the checkout process. Feel free to contact us on 0330 043 4142 or email to obtain a price in advance.

*Please note that PlanExtend’s Property Survey & Design Consultation services are subject to the availability of our team.

How quickly can I expect my completed drawings?

Typical timescales relating to our standard service options can be found below. If you require drawings urgently we offer an accelerated turnaround ‘Add-on’. This can be selected when using our the checkout process:

Existing Drawings: PlanExtend – Option 1 Existing Drawings

  • Standard Service: 3 week turnaround (no charge)
  • Accelerated Service: 2 week turnaround (Optional Add-on).

Planning Drawings: PlanExtend – Option 2 – Planning Drawings

  • Standard Service: 4 week turnaround (no charge)
  • Accelerated Service: 3 week turnaround (optional Add-on)

Building Regulation Drawings: PlanExtend – Option 3 – Building Regs Only

  • Timescales differ dependant on extent of work.

Planning & Building Regulation Drawings: PlanExtend – Option 4 – Full Service

  • Planning Drawings Only – Standard Service: 4 week turnaround (no charge)
  • Planning Drawings Only – Accelerated Service: 3 week turnaround (optional Add-on)

The above timescales do rely on your prompt response to our queries and selection of design preferences etc as the design process progresses. Excessive time taken to respond to our queries or select design preferences may impact on our ability to meet the above timescales.

How much will it cost to build my new extension and alterations?

The cost of constructing an extension can vary significantly and depend on whether the you intend to employ a builder to do all the work, manage a number of subcontractors or undertake much of the work on a self-build basis.

The below is intended to provide a very rough guide to approximate extension costs:

Single Storey Extensions

The cost of a single storey extension can be anywhere between £1,000 and £1,500 per m2, in London and the South East this increases to anywhere between £1,500 and £2,500+ per m2:

  • 5m x 5m single storey extension average UK cost from = £25,000
  • 5m x 5m single storey extension London/South East cost up to = £62,500+

2 Storey Extensions

If the proposed ground and first floor of a 2 storey extension are the same size, it is an accepted rule that approximately 50% extra can be added to the single storey extension build cost. Again, London and the South East will see a further and proportional increase:

  • 5m x 5m 2 storey extension UK average cost from £25,000 + approx 50% = £37,500
  • 5m x 5m 2 storey extension London/South East cost = £93,750+

Kitchens & Bathrooms

Where the extension includes a bathroom approximately between £5,000 and £10,000 can be added to the the extension cost for sanitary ware, plumbing and surface finishes.

A Kitchen will be more than a bathroom, often adding around £10,000 to well over £30,000 to the extension cost depending on specification.

Costs for kitchens and bathrooms will vary significantly depending on size, style and specification of installations.

Planning Permission

Do I need planning permission for my extension and alterations?

Not all extensions and alterations require Planning Permission as some are covered under Permitted Development. Alterations to ‘houses’ requiring planning permission are summarised below:

  • A single storey extension taller than four meters
  • A single storey extension to the side of the property and more than half the width of your house
  • An extension more than six meters from the rear of a semi-detached house
  • An extension more than eight meters from the rear of a detached house
  • An extension that covers half the area of land surrounding your home
  • An extension or alterations that increase the overall height of the existing building
  • If proposals involve the use of materials that differ from the original style of the house
  • If proposals involve a balcony or raised veranda
  • If proposals involve extending towards a highway

Garages, Sheds & Other Out-Buildings

Outbuildings such as sheds, garages, greenhouses and some other structures are also considered to fall under permitted development. Generally a garage or outbuilding can be erected without planning permission as long as the proposed outbuilding does not exceed 4 metres in height. Also outbuildings should not occupy more than 50% of the land around the original property. 

Paving Over a Front Garden

if the proposed paving material is porous there is no need for planning permission whatever the size of the new hardstanding. If the material is impermeable however, anything above 5m2 requires planning permission.

Windows & Doors

In most cases there is no need for planning permission to repair or replace windows and doors. If your property is listed however, listed building consent will be required.

External Walls & Roofs

For minor maintenance works, or improvements such as painting your property or inserting a rooflight, planning permission is generally not required, although this is not the case if the property is listed. If the property is located within a conservation area or an area of outstanding natural beauty, planning permission will be needed to change the appearance of your home.

Wind Turbines & Solar Panels

Temporary wind turbines do not require planning permission but permanent wind turbines will. Solar panels do not require planning permission unless you live in a listed property.

Fences, Gates & Walls

Planning permission is necessary for any fence, gate, or wall:

  • Next to a road and over 1 metre high
  • Over 2 metres and not next to a road
  • If your house is listed
  • If it forms a boundary with a listed building

If you are unsure as to whether planning permission will be required for your ideal extension/alterations feel free to contact us – we are here to help.

What is permitted development?

Permitted development is the ability to undertake certain work to your property and use your property in a certain way, without needing to apply for full planning permission. These are called ‘permitted development rights’.

Permitted development rights are derived from a general planning permission granted not by the Local Authority but by Parliament. Many permitted development rights which apply to common projects for houses do not apply to apartments, maisonettes or other buildings. Commercial properties also have significantly different permitted development rights to dwellings.

Alterations falling under permitted development rights for ‘houses’ are summarised below:

  • Extension to the rear of a house
  • entrance hall or porch extension
  • internal alterations
  • conversion and occupation of a loft space
  • solar panels and other renewable micro generation equipment (excluding wind turbines)
  • satellite dishes, aerials and antenna
  • rooflights or dormer windows installed in an existing roof
  • replacement doors or windows.

All of the above are subject to specific design constraints, for example a porch has to have an area less than 3m³, rooflights and dormers windows installed in existing roofs must not face onto the highway, etc.

In some areas of the country, known as ‘designated areas’, permitted development rights are more restricted. In these area you will need to apply for full planning permission for certain work which would not need an application in other areas:

  • Conservation Area
  • National Park
  • Area of Outstanding Natural Beauty
  • World Heritage Site or
  • Norfolk or Suffolk Broads,

Permitted development rights also differ if the property proposed for development is a listed building.

Lawful Development Certificate (LDC)

The only way to be certain that that any proposed extension or alteration does not require planning permission and is covered by permitted development is by obtaining a Lawful Development Certificate (or LDC).

It is not compulsory to obtain an LDC for works falling under permitted development but we advise our clients to obtain this to avoid any risk of potential legal action by a Local Authority, to remove any ‘planning regulation’ ambiguity and ensure that the proposals are lawful.

PlanExtend will compile and complete the necessary documentation on your behalf and submit an LDC application to your Local Authority. This service is available as a free ‘Add-on’ which can be selected during the checkout process. You will be required to pay the planning fee’s directly to the Local Authority (we provide you with a web link for this at the time of submission), Typical LDC fees start from £86.

Planning application and lawful development certificate timescales?

Planning Application Timescales

For a typical house extension, Local Authority planning departments usually determine a planning application within 8 weeks. Large or more complex planning applications may take longer (approval periods do vary however, based on the volume of cases a particular department is dealing with).

Lawful Development Certificate (LDC) Timescales

For permitted development, Local Authority planning departments usually determine the Lawful Development Certificate within 8 weeks.

PlanExtend’s Free Submission Service

If you select PlanExtend our FREE Planning Application submission service PlanExtend will complete and submit your planning or LDC application to the Local Authority, including the production of your design & access statement (where required).

Whether your proposed extension and alterations require full Planning Permission or a Lawful Development Certificate (for extensions falling under permitted development) we will compile and complete the necessary documentation on your behalf.

Once the planning department receives a planning or LDC application PlanExtend will receive a letter acknowledging receipt of the application and any accompanying fee paid by the client. This letter will also explain the planning stages through which the application will pass prior to a decision being made.

At the end of the process the planning decision notice will be issued advising whether planning permission has been granted or refused or in the case of permitted development rights a Lawful Development Certificate will be granted or refused.

Can planning permission be guaranteed?

Unfortunately not.

No one can guarantee that planning permission will be granted. However, PlanExtend’s knowledge of both planning legislation and the approval process ensures that your submission will have the optimum chance of success.


Building Regulations

Will I need building regulations approval for my extension and alterations?

Not all building alterations require Building Regulations Approval but the majority do and many changes that do not require Planning Permission will require Building Regulations Approval.

Meeting the requirements of the building regulations is the responsibility of the person carrying out the building work and, if they are not the same person, the owner of the building.

  • The following works generally require building regulations approval:
  • Erection or extension of a building
  • Any alteration involving work which will temporarily or permanently affect the ongoing compliance of the building, service or fitting with the requirements relating to structure, fire, or access to and use of buildings
  • Installing replacement windows using a builder or window company which is not FENSA registered
  • Installation or extension of a service or fitting which is controlled under the regulations
  • Application of insulation into a cavity wall
  • Underpinning of the foundations of a building
  • A fundamental change of a building’s use
  • Renovation of a thermal element
  • Change of a building’s energy status.

If your building work consists only of the installation of certain types of services or fittings (e.g. some types of drainage, fuel burning appliances, replacement windows, WCs, electrical installations and showers) you can employ an installer who is registered to self-certify the work. This means you will not need to formally apply for Building Regulations approval.

Do I need building regulations approval if don't plan to complete works?

Building Regulations approval is not required if you are not intending to complete the extension or alteration works or are considering using PlanExtend to obtain planning permission for an extension to your property with the sole purpose of increasing the property’s value.

Will I need a structural design & calculations?

When the alterations proposed to your property involve changes to the building fabric which will affect the stability of the building a structural engineer will need to be appointed to provide the necessary calculations and drawings.

This structural information will also need to be submitted to Building Control in order to ensure compliance with Building Regulations.

Each design project differs and the need for structural calculations for your alterations will depend upon the nature of the project. Structural design and calculations are generally required prior to completing the following works:

  • Building an extension
  • Removing or modifying internal walls
  • Modifications to existing door and window openings
  • Underpinning walls
  • Modifications to existing roofs
  • Loft conversions (generally)
  • Removing a chimney breast
  • Fitting solar panels

The above is not exhaustive but provides a general guide.

When selecting the ‘Structural Calculations’ Add-on, PlanExtend will engage with a number of partner Structural Engineers on your behalf and obtain the necessary calculations and design information for your project. Our prices are very competitive!

Full plans or building notice. What is the difference?

Full Plans Application

This type of application requires submission of detailed plans, specifications, and where necessary structural calculations. If commercial works are proposed a Full Plans Application will alway be required.

The details are checked to make sure they comply with the regulations. Once the application is checked and found to be satisfactory it will be approved. If not a letter will be sent, advising what amendments and or additional information are required to enable an approval to be issued. If no response is received or the revisions submitted are not satisfactory the application will be rejected.


  • The council must check your application and make a decision within a statutory timescale (
  • Your builder works from approved plans so there is less chance of work having to be corrected during construction.
  • A Full Plans application may be necessary when borrowing money from a bank or building society to pay for the building work, as they usually ask to see an approval notice before they advance any funds.
  • An approval notice is issued which can then be passed onto any future purchaser of the premises.
  • You will gain peace of mind that your project will be safe, secure and that the process of construction is being monitored by qualified and experienced surveyors throughout the build.


  • There may be a delay while your surveyor or architect, for which they will charge a fee, prepares plans. However, plans may already have been prepared for the planning application, where necessary, which may just require the addition of technical details and sectional drawings.

Building Notice

Building Notice applications should only be used for work which is not complex and by people experienced in construction. They can only be used for domestic and not commercial work.

A Building Notice application must be submitted at least 48 hours prior to work commencing. The notice will be checked and if found to be satisfactory a letter of acknowledgement will be issued confirming the application


  • Often planning drawings will be sufficient for this application, although sometimes detailed plans and calculations are required to support the application.
  • The time taken to process and acknowledge a Building Notice application is less than a Full Plans application.


  • Plans are not checked for compliance with the Building Regulations and no approval notice is issued, which may lead to work having to be altered on site if found to be non-compliant which is likely to lead to an increase in build cost.
  • The fees for a Building Notice application in most cases are exactly the same as a Full Plans application, but you should note that the plan and inspection fee are paid on deposit of the application. These are nonrefundable.
  • A Building Notice is not acceptable or appropriate for commercial buildings or complex projects.

By closing this window you are giving consent to cookies being used. If you would like more information click here.