House Extension Time Scales - What should you be expecting from inception to completion?
Many homeowners seem to forget that there will be a long lead in time before that can start their house
extension on site. A generous allowance needs to be made for the time scales on a house extension anything
between four and eight months depending upon how you have broken the project down.
Assuming that you would want to play safe with your council applications and approvals by
only moving on from one design stage to another here is a typical example of a house extension time scales &
what you should be allowing:-
DESIGN STAGE 1:- Making your own schedule of requirements, viewing other extensions and
completing some basic research = 1 week
DESIGN STAGE 2:- Interviewing a few experienced house extension designers or architects for
assessment of their skills and charges = 2 weeks
DESIGN STAGE 3:- Engaging Professional home extension designer or architect an commencement of
their survey and collection of site data = 2 weeks
DESIGN STAGE 4:- Presentation of first design scheme proposal by your design agent issued for
your assessment and comments = 4 weeks
DESIGN STAGE 5:- Client assessment period and note taking. Meeting with house extension
designer to chat through queries, amendment of scheme & upgrade to Planning application standard = 4 weeks
DESIGN STAGE 6:- Submission to council planning Dept. for either a planning application or a
certificate of lawful development. Wait for decision notice = 8 weeks
DESIGN STAGE 7:- Upgrade of the planning scheme by your house extension designer or architect
to full construction scheme with specifications and details etc. ready for the Building Regulations application = 4
DESIGN STAGE 8:- Homeowners assessment of all details of the construction scheme presented.
Making notes and list of queries for any amendments = 2 weeks
DESIGN STAGE 9:- Submission of construction scheme to Council Building Control Dept. for
approval. Decision Notice arrives = 8 weeks
DESIGN STAGE 10:- Researching recommended house extension builders to approach for
tender. Making initial contact & sending tem the tender documents = 1 week
DESIGN STAGE 11:- Tender period. Return of all tenders for homeowners assessment of
prices = 5 weeks.
DESIGN STAGE 12:- Discussions with preferred builder to explore other contrast detail &
possible start date. Due dilligence checks. Formal engagement of builder = 2 weeks
DESIGN STAGE 13:- Period of waiting for builder to start on site = 8 weeks
DESIGN STAGE 14:- Contract period for the works. Finish snagging and move in for use of
extended house = 12 weeks
TOTAL TIME FOR FINISHED HOUSE EXTENSION:- from inception to completion = 63 WEEKS
Over a year I hear you ask? Well yes living in the real world and based upon 30 years experience. You
can compress this estimate typical time scale by conjoining several of the design stages above rather than adopting
a 'step by step' approach and this could remove about 16 weeks of time but you may be exposing yourself to a
greater level of abortive fees.