Trying to cut costs on a home extension – what can we realistically do ourselves?

[firsthomebuyerfirstreno]

We’re a family of 5 in a terraced house and are planning a ground floor extension—about 4.5m out to the garden. The rest of the house is livable and nice; we bought it a year ago. Some minor work like removing wallpaper and a new bath is needed, but my main question is about the extension.

We have around £50k to spend in build (know it’s probably not enough and are working on raising more). Builders only give rough, ballpark quotes (£50k–£80k-£100k), so it’s hard to know what costs what.

My husband is keen to do some of the work himself. He’s never done building work professionally, but used to be a hotel maintenance manager and did plumbing/electrics apprenticeships many years ago. He’s got the energy and desire, and we feel it may be the only way to make it affordable.

For those who’ve done similar projects (even if your layout is different), what types of work actually make a real difference to costs if you do them yourselves? If any.. thank you 😊

It might be helpful to give some details on what you are planning on doing exactly. Yes an extension, but will you be removing any walls in the existing rooms, will you be adding a utility room, another bathroom, a new kitchen? Will you be building over pipes, will you need to move a manhole?...It might help if you post a rough plan/layout of what you are envisioning.

If he did an apprenticeship in plumbing and electrics he can do most of that. Will need a qualified sparky to sign off. Papering and painting is easy. Are you fitting drywall? - not difficult. Most joinery work should be doable. That should keep him busy.

If we were going to do something like that the things we couldn't do we would find someone else to do it like brick work, plastering just hire someone on day rates for what you need.

We did an extension some years ago - side return and extend into the garden. My husband is brilliant at diy, including electrical and plumbing. There was no way he would have done this though - the house was a building site for the duration of the contract and it was covered by the builder's insurance. He would not have signed off on any electrical work that wasn't done by registered electrical contractor.
What we did afterwards ourselves was all the painting and decorating.

We've just finished a huge renovation of what had been a derelict property. For some jobs, it was better for us to continue to work and pay a professional to do the job in a fraction of the time. DH did act as a labourer some days, drove the dump truck, moved rubble the skip etc, but he works full time in a non trade job. It clearly depends what exactly do you building, will it have bifolds, bathroom, utility etc etc, but somethings (I'm by no means in the trade, these are just things we did):

-If you know the size/plans etc. Rather than a qualified architect, I 'think' its a draftsman or junior at an architects who can draw up plans cheaper.
-We got an account with the local builders merchants so in most cases, bought the materials ourselves and just paid day rates for trades
-We hired skips from a local company rather than via the trades
-We added a small 3x4m extension. It was double storey though, not single like yours. The main house is 100yrs old and on a 0.5m foundation, but for the extension, they wanted a 2.5m foundation! Do you have access for a digger if needed?
-We had bifolds put in, very wide access either side of the house so the lorry backed up and they used a dolly to get them in. The house across the road, they had to crane the steels over their house!
-If you have an existing toilet they can use, then no need to hire one in the garden.

-If your DH feels comfortable then he could do alot of the bits he has experience in.

You need to read the builder’s quote carefully: radiators, flooring, doors, windows, etc. Even if they say “flooring is included,” you should clarify exactly what that means and what type of material they will use.

Depending on your style, costs can easily escalate. For example, our extension (demolishing a conservatory and building a proper living room) went far over budget.

There are a million things you don’t think about that end up costing extra—light switches, skirting boards, special paint after plastering, and so on.

I would suggest having at least an extra £10,000 for unforeseen expenses. Many things can also go wrong—such as needing new electrical work—so I wouldn’t feel comfortable if the budget only covers the builder’s fee.

Be careful extending and creating a 'double depth' room... We have a kitchen extension (previous owner) which means we have a massive kitchen diner, but the room can be a bit dark.
At some point were going to put in sky lights and bigger doors to make it lighter.

I'm not extending but when I was considering it for another property my bf's mate quoted me £30k just for a box without plumbing or electrics.

What I've done here to try to keep costs down is fit in with trades (which takes longer as they fit me in when they can), source as much of the stuff myself (including on FB marketplace), buying what I can on offer or on sale and counting the pennies.

You need a complete breakdown of everything included and see if you can source anything cheaper

With that budget, it might be better to get a sun room/conservatory with an insulated roof. They can be lovely if done well, and it sounds like anything else will just be too expensive in the end.