How Long Will It Take? 

The timescale for building work varies depending on scale and complexity. 
A straightforward internal kitchen/diner renovation can take 5-6 weeks whilst a two-storey extension may take 26 weeks or more. Ask your builder for a programme of works to help you see how the job will progress. 
As an idea, the programme for a basic, single storey extension would be as follows: 
Works to create the watertight shell 
Weeks 1-2 
Weeks 3-4 
Weeks 5-7 
Weeks 8-9 
Week 9 
Demolition, groundworks & foundations 
Structure below ground up to damp proof course. Drainage installed, lintels fixed in place and concrete floor & insulation laid. 
Build external walls above damp proof course, blockwork, brickwork/stonework & cavity wall insulation 
Internal walls, roof structure & covering 
Windows & doors – possibly just temporarily blocked-up initially to protect new glazing 
Break through into the existing & start connecting old to new 
Week 10 
Week 10 
Weeks 10-11 
This is when you will need to vacate part of the existing house to allow the knock through to take place. 
Strip-out existing rooms & disconnect electrics & plumbing 
Insert steels & demolish walls 
First Fix (everything up to finished plastered walls) 
Week 12 
Weeks 13-14 
First fix joinery, plumbing & electrics. At this point your builder will need to know where you want switches and sockets, lights and any plumbed items e.g. sink, washing machine, sanitaryware etc 
Plasterwork which needs to be left for about a week to dry 
Second Fix (connections are made) 
Week 15 
Week 16 
Week 17 
Second fix electrics i.e. switches and sockets made live, lights fitted. Second fix plumbing i.e. taps installed and connections made Flooring and kitchen units fitted, doors, skirtings & architraves fitted 
Snagging & completion i.e. finishing off any remaining items, builder’s clean & hand-over to the clients. Any faults or other problems should be reported to the builder as soon as possible so they can be addressed quickly. 
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