Our Process

– Extensions & Alterations

Your Step by Step Guide

Wanting to progress your plans for an extension, it would be handy to understand the typical process that you will undergo. Afterall, what are you actually paying for and how long will it take?

We’ve outlined the typical six-step process that will get you from initial concept to signed handover documents. Whether you require our services for the full journey or only steps 1-4 you will get the same professional and approachable service.


Stage 1: Visualising your dream & the drawing of plans.

What Happens?

  • A clear understanding of the project is captured in a client brief
  • Survey of existing property is undertaken which includes a floor plan, elevations and section.
  • Conceptual designs are created in 2D for review & discussion
  • Client meeting to discuss initial layouts
  • 2D Layouts are updated for further review and discussion

What Do You Need to Do?

  • Provide a clear brief that helps us visualise your dream
  • Allow access to the property to enable survey to take place
  • Let us know your feedback so that we can update the layouts to fully suit your vision.


Approximately 2-3 weeks

Stage 2: Submission to planning

What Happens?

  • Prepare drawings to this stage only for submission with planning application
  • Submit planning application to the relevant council.

What Do You Need to Do?

  • Confirm that the design is to your satisfaction
  • Instruct us to submit the application for planning permission


Please note the regulation time for planning approval is approximately 8 weeks after the submission registration date.

Stage 3: Building Warrant / Technical Design

What Happens?

  • We provide a checklist for all information required to be included in building warrant drawings.
  • Prepare draft building warrant drawings on receipt of the above information
  • Prepare final building warrant drawings on instruction
  • Liaise with Structural Engineer if necessary
  • Prepare building warrant application & submit to Building Standards
  • When we are in receipt of the building warrant approval we will forward a copy of all documentation together with a copy of the stamp approved drawings to our client

What Do You Need to Do?

This is where we look more at the project in more detail working through electrical layouts and finishes. We need you to work through a checklist that we will provide, so that we can complete the drawings before submission.


Please note regulation time for building warrant approval is approximately 8 weeks from submission.

Stage 4: Construction Phase & CDM
(Construction Design and Management)

This stage happens after approval, but before work commencement.

Please note that as of October 1st 2015, projects must adhere to CDM 2015 regulations and require a Principal Designer and/or Principal Contractor to be appointed. This is in relation to health and safety regulations and is a legal requirement.

What Happens?

A pre-construction information pack needs to be produced in conjunction with our health and safety consultant. This is a document that details all health and safety measures to be adhered to on site.

We will provide the client with the following information to handover to the main contractor:

  • Stamp approved building warrant drawings and specification documents, including the structural engineers design package if applicable
  • Pre-construction information pack
  • CCNP (Construction Compliance Notification Plan)

Provide the client with documentation on the following for their own records:

  • Receipts from Local Authority for both the planning permission and building warrant lodging fees paid
  • A copy of the planning permission and building warrant consent

What Do You Need to Do?

Nothing at this stage – leave it all to us and the building contractors.

Stage 5: Post Contract/Construction Works

This stage also happens after approval, but before work commencement.

What Happens?

Local Authorty is required to be notified 7 days in advance of construction start date    (Form J)

What Do You Need to Do?

It is essential you ensure that the appointed contractor is in possession of the stamp approved building warrant drawings and specification documents, including the structural engineers design package if applicable, the pre-construction information pack and the Construction Compliance Notification Plan (CCNP).

  • Provide us with an anticipated start date so that form J (notice regarding start of work) can be submitted to building standards
  • Handover the CCNP to the main contractor before works commence

The CCNP is a checklist issued by building standards to confirm which stages of the works they require to inspect. It is the responsibility of the main contractor to notify the building standards case officer at the relevant stages.

Stage 6: Completion & Handover

Once all works are complete.

What Happens?

We will, when instructed, carry out a site visit to ensure no variations from the approved building warrant drawings prior to the submission of a completion certificate. (form 5)

Should there be any variations then an amendment to warrant application will be required to cover the changes.

What Do You Need to Do?

Provide us will all relevant paperwork which may include some of the following:

  • Electrical certificate
  • Boiler commissioning certificate
  • Smoke detection certificate etc.

We will confirm what documentation is required in advance.


Approximately 4 Weeks.

Uncomplicated. By Design.

This process can be daunting, but rest assured that we will take care of everything for you. You are in good hands with the expert team at Crawford.