Extensions - bringing in a firm vs DIY

[TuesdayRuby]

We’re looking to extend out the back of our three bedroom terraced house. Had a few quotes for the extension all in the region of £50k (inc VAT) (London).
However, my brother in law is a brickie, husbands best mate is a plasterer and we could quite easily source an electrician and plumber. I guess the question is, how much would we save doing it ourselves? And is it worth it?
I’ve got two young kids and work full time from home. Am I being way too ambitious trying to project mange it myself? I don’t want to regret this decision 4 months in when I still have a massive hole in my kitchen!!

Have you engaged an architect (or architectural technician) and structural engineer? If you have the plans in place, it might be do-able, but I imagine it will be a lot of hassle...

Do you have plans? What about foundations and building regs? Structural engineer needs to get involved too.
You would save, but also have a massive job project managing it, including scheduling, sourcing materials and dealing with planning and hiring skips and so on. And the problem with relatives and 'mates rates' is when another job comes along you are put on the back burner, which has an affect on the other trades. And what if something goes wrong or you aren't happy?
Personally I think there's a good argument for getting tradesmen in without a personal connection.

A brickie and a plasterer wouldn’t be able to project manage all of it, I’d imagine. We have a master bricklayer (over 30 years experience) doing our extension and he only really knows his bit, though he is trying to learn more from the contractor we’re using.

We haven’t got any plans or anything yet. Tbh I’m thinking more along the lines of getting a firm in to manage it all. Working full time and with two babies, I think I’d need about a month in a health spa if I managed it myself so probably wouldn’t save anything

I would do it yourselves, you'll save a fortune.

We have just started something similar. Most builders so far, want to bring in their own bricklayer, carpenter etc etc and do the entire job. Like you, we already have some trades in place. DH and I both WFH currently, and no kids, so its been easier to organise skips, pick up equipment etc.

I'd speak to the builder who will actually do the extension and see IF they are happy to work with your traders, rather than their own? If they need a project manager or could recommend one. Do check the fees though. 1 company we approached to project manage, added on a 10% admin fee for every trade they brought in, on top of their own fees.

If your family/friends are in the business then diy OP.
I don't know why people are obsessed with architects as they are expensive and tend to over design!
A good builder is all you need as they/he/she will have a structural engineer that they use and trust and good builders draw plans, work to your specific budget, walk you through step-by-step and don't over design.

A builder often starts out as a trades specialist, but directing the whole project is an extra skill! Our builder was originally a joiner. I couldn’t have done what he did in terms of directing the work onsite. Who would be in charge? You? The brickie?

It depends on what your planning to build ? If you get some good plans draw up with detailed measurements and all the building specs it’s quite easy to follow,

I’ve just built a small extension on our house , it’s taken about 15 months due to mostly me working on it and waiting for materials due to COVID. A builder I know said to would be roughly 30k to build. It’s cost 8.5k up to now and will be about 10 when it’s totally finished inside.

when I had mine done, we used a builder who was a friend and he just used people he knew plasterers, electrician ect. Dp is a plumber so he did the plumbing.