House extension step by step guide
Many homeowners require a step by step guide to their own house extension proposal. It is quite usual
for a home extension designer or architect to explain the various stages of a home extension as part of their
standard service which could also be viewed as a step by step guide.
Below is our suggested step by step approach to designing and implementing your own house
extension in the UK:-
1 - Make a list of your own requirements
2 - Interview several house extension designers or architects. Select one that will be the most pro-active for
you and has the experience and resources required. Ensure that their final documents presented for Building
Regulations can be used as the main contract documents for engaging the builder for an all inclusive fixed
3 - Agree fixed fees with your home extension designer establish what all the other costs may be
(consultants, reports, engineers etc.)
4 - Split the design process into 3 distinct stages - build up of design proposal, planning scheme then
upgrade for Building Regulations. This will reduce your exposure to abortive fees.
5 - Check all other issues that may affect start date & comply with the relevant requirements
(covenants, party wall act, main sewers etc).
6 - Obtain 4 recommended house extension builders to approach for tender pricing.
7 - Use you house extension designer or architect to handle the tender process if you are unable to install the
time and effort required.
8 - Complete you own due diligence tests on the builders and obtain references.
9 - Agree a form of contract, payment terms, programme, contract period and dispute resolution methods.
10 - Allow access for builder to complete the works.
11 - Be involved and pro-active yourself during the build to ensure fixtures and fitting are installed in the
correct locations the first time round.
12 - Retain 5% retention on all payments, release 50% of retention monies 6 months after practical completion
upon rectification of any defects.
13 - Never pay monies in advance of the works or materials being on site.
14 - Monitor and record all variations during the build with the builder and agree any add or omission costs per
item as quickly as possible to monitor contract budget.
15 - Use your house extension designer or architect for their contract administration services during the build
if you are unable to input the required level of involvement, time and paperwork yourself.
16 - Double check that the builder carries current insurance, check that his trades are being paid when you have
released monies, check that the project is being inspected and approved by the Building Inspector at the relevant
17 - Do not be too obsessive about finishing times and targets. It is better to take an extra few weeks to use
for a proper job than for the builder to take short cuts or rush the quality of work simply to hit a target
completion date. Obviously there are limits in extreme cases.
18 - Ensure you receive a Building Regulations completion certificate prior to releasing final payment.
19 - Never be afraid to thank your builder or their trades for good work, going the extra mile and accommodating
any issues that you may have. Everyone likes to be thanked for good service & work.
20 - Ventilate the house extension well for the first six months of use. Do not be too quick with
installing real wood flooring as it will warp, shrink or distort while the house is drying out.
21 - List any latent defects responsible by the builder any ensure they are repaired or fixed prior to releasing
final retention monies.
22 - Write a letter of thanks to the builder if they have provided you with a good job and service.