Extensions - what questions to ask?

[iamboudicca]

We are thinking of getting a single storey extension on the back of our 1930s semi. Its a pretty standard project - half the houses in our street already have them.

Neither me nor DH have ever done anything like this before and we are not great at managing workmen... for this reason we wanted to use a company that does a whole package, but what should we be asking them when they come to quote?

I work in construction - off the top of my head:
Will they do the job or sub it out to another company?
How long have they been trading (then check their accounts online).
Can you meet former clients?
What guarantees do they give?
Do they offer a retention for, say, three months for snagging?
How do they run their payment schedule?
Are they fully insured (they'll happily send you the certs if they are)
What hours do they work? What form of contract do they supply?
Are they members of any federations? Will they give Gas Safe/Part P certs? Will they liaise with building control? How will your existing house be protected? Portaloo or your loo? Can you live in your house throughout? How will the back be secured at night?
When it comes to the quote go through it line by line - literally walk around your potential space making sure everything is included - plastering, skirting boards, flooring, steels, downpipes, decorating, sub flooring, fit of whatever (take note of the words 'supply' and 'fit'; some contractors supply and fit downlights for example, others will quote just for fit.). Some of these questions are really just to see if you gel with the contractor and if they get defensive, you have your answer. For instance, subbing out isn't the end of the world, but if they do you want to ensure that team is insured/see their actual work etc. Membership of various federations is, again, open to debate but it gives you an idea. Oh, also, will you have one point of contact - who will be on site daily i.e Site Foreman, project manager etc. Don't forget as well as costs of the build you'll have: cost of drawings; planning fee; structural engineer and party wall surveyors. Anything else, just ask but hope this helps as a start.

wow thank you! excellent help!

Also confirm that they will take on the responsibility for CDM too .

If your not confident in managing the building, maybe ask an architect about overseeing the work as part of a contract. Their fee is generally a % of the contact value, but would include;

Sketch plans for the initial discussion
Submission of any planning drawings
Building regulation drawings and application
Contract working drawings
Full specification - which will quantify the scope of works, ie areas for plastering, sockets etc.
They can then approach a number of builders on your behalf to obtain competitive tenders.
You then enter into a contract with your builder, (JCT minor works) or something similar.
The architect will then complete inspections of the work, liase with you and the builder. The builder will complete valuations of the work completed, and the architect will certify this payment.
There will be a time period for the works agreed, a contract sum (with contingency) agreed and all extras will have to be authorised, you can fix penalties if the work over runs, there will be a retention period, snagging will be completed by the architect.