• Draw Plans

Building a House Extension - What Do I Need?

Updated: Oct 19, 2020


Draw Plans are London based Architectural Designers & Consultants that specialise in adding space and value. We provide Design & Building Plans for any type of House Extension or Loft Conversion within 7/10 days. Prices Start from £795 Plus Vat for a Single Storey House Extension.


Here is a summary of Architectural Services that you may need to build your own extension.



01: Extension Design Plans


Adding an extension to your home is a huge investment so it is crucial that you use an experienced and gifted architectural designer to create plans for your extension.


At Draw Plans, our Design Plans Package for a Single Storey Extension includes onsite client consultation, measurement survey, consultation with local planning, research, preparation of draft sketches, further consultation with client, preparation of design plans for your extension and layout changes to your existing floor plan.

Draw Plans Cost £ 795 Plus Vat



02: Planning Application Submission / Single Storey Extension


If you are building an extension you may also require a Full Planning Application, a Prior Approval Application or a Certificate of Lawful Development.


To make a planning application on behalf of the client to the local planning authority, prepare planning application plans, including any necessary supporting documents such as Design & Access Statement, CIL Levy Q&A, Biodiversity Statement etc, submit application and liaise with the planning authority to ensure validation of the application.


Liaise with the planning authority throughout the planning application process. Work with the appointed planning officer, negotiate and amend/tweak plans if required. Keep client informed and generally work towards a positive outcome.


Draw Plans Cost £ 295 Plus Vat (Additionally, you will have to pay the Planning Authority cost of the application.)



03: 3D ARCHITECTURAL VISUALISATION / OPTIONAL

3D Architectural Visualisation services are a great aid to the design process because they allow you to get a real feel of what your home is going to look like before you commit to the build.


If you are worried about how your extension or loft conversion is going to look like on the outside or how the new interior layouts will work out then 3D visuals will be an enormous help.


Draw Plans provide a full range of 3D Architectural Visualisation Services including Exterior 3D Views, Interior 3D Views, 360 Deg Internals and CGI Animation 3D Video Walkthrough.


Prices Start with £195 Plus Vat for 4 Exterior Views or 3 Interior Views.




04: Building Regulations Drawings / Single Storey Extension

To build your extension you will also require Building Control Approval and a full set of Building Drawings.


To create a full set of Building Regulations Drawings and Detailed Sections suitable for Building Control Approval. Work also includes for liaising with the local Building Control office or a client appointed Approved Inspector and making adjustements or tweaking the plans as necessary during the build process.


Draw Plans Cost £ 995 Plus Vat



05: Structural Design & Calculations

If you are making structural alterations to your property you will most likely require a Structural Design Plan and Structural Calculations for your project. It is not possible to provide a quote for Structural Design & Calculations until the Design Plans have been completed.


Draw Plans will be happy to arrange free quotes for Structural Calcs.



06: Party Wall Agreements

If you are building an extension within 3 metres of a neighbouring property you will most likley require a Party Wall Agreement with your neighbour.


Most extension projects require Party Wall Agreements. Depending on the layout you may need a PWA with more than one neighbour. You should also note that the neighbours are entitled to instruct their own surveyor and if they do, you would be expected to pay their costs also.


Draw Plans will be happy to advise and or deal with party wall issues for your project. If you know your neighbours we can also advise you how best to proceed and provide you with the necessary notice documents free of charge.


Draw Plans PWA Agreement / Award £750 Plus Vat Per Dwelling



07: SAP Calculations


Sap Calculations may be required if your extension design includes excessive amount of glass. Under the building regs you are allowed up to 25% of the floor area to be used for glazing to the walls and ceiling.


If you exceed 25% you may have to have SAP Calculations carried out which will allow you to use more glass in return for upgrading existing elements within the original part of the house.


Draw Plans SAP Calc Costs £ 350 Plus Vat



08: Specification & Schedule of Works / OPTIONAL


Having a costed Specification & Schedule of works done for your project is a great way of finding out at the early stages what the project is going to cost.


The schedule is also a big help when it comes to getting quotes as you can provide builders with an un-costed schedule and plans which means everyone is pricing the exact same job.


It is also a great negotiation tool because you will know if you are being overcharged on any of the works.


Draw Plans Cost £ 295 Plus Vat



09: Full Project Management Services / OPTIONAL


Draw Plans provide Full Project Management Service for house extensions and loft conversions across Greater London. Costs are generally based on a % of the build cost.


At Draw Plans we are open to all sorts of informal or flexible arrangements that will help you to bring your project to a successfull conclusion.



10: Key Stage Project Management Service / OPTIONAL


Our Key Stage Project Management Service is a more popular option for homeowners. Having an experienced Project Manager by your side for the entire project will ensure you get an on-time on-budget build with no nasty surprises in the final account.


Draw Plans Cost £ 995 Plus Vat



11: Fixed Price Build Contracts / OPTIONAL


A Fixed Price Build Contract can be a great option if you want to use one main building contractor to build your extension. It may cost a bit more but you know from the start where you are with regard to finances.


You can also opt for a Penalty Clause in your build contract to ensure that the work is carried out on time.


Retentions are also a popular option to ensure that defective or faulty workmanship is put right after the build.


Draw Plans will be happy to arrange a Service Provider Contract for specific trade services or for a Fixed Price Build Contract.


This a FREE Service for clients who have instructed Draw Plans for the Key Stage Project Management Service.


Draw Plans Cost £ 195 Plus Vat (To Prepare a Fixed Price Build Contract Ready for Signing)