Talk me through a big building project

[Thistledew]

We are in the process of finding a builder to do major extension works on our house. It is a two story extension and loft conversion, and will include a new bathroom and kitchen, and will need two new staircases.

Obviously, we will need a main builder who will do all of the structural work, and I would like them to project manage it in terms of scheduling the specialist trades, but I would appreciate some advice as to the pros and cons of sourcing some of the specialist trades myself.

For example, I think the following will need to be done by specialist contractors:

Windows
Staircases
Polished concrete flooring for kitchen and bathroom
Damp proof treatment of a problem wall

There will also be some specialist items that have to be bought in, but which either the builders could do or could be done by a specialist company:

Underfloor heating
Kitchen units and worktops
Bathroom fittings
Built in storage in the bedroom, loft and under stairs
Reclaimed floorboards to match existing.

I have some very clear and particular ideas on the design side in terms of the look of the kitchen, bathroom and stairs, and would be quite happy to source light fittings etc myself.

I don't have a huge amount of spare time but am self employed so have a bit of flexibility in terms of being able to source products and contractors.

I just feel quite uncertain as to the benefits of doing the sourcing work myself. Is it likely that I could get better value for money by, for example, sourcing a kitchen supplier myself? Would I then get my main builder to fit it, or would it be better to get the kitchen company to do this?

If I have a very clear idea of the particular look that I would like from the bathroom fittings, am I better off sourcing this myself or giving a clear brief to the builder and relying on them to find something that results in what I am looking for?

Is there a general rule of thumb as to the most cost-efficient way to do this?

TIA for any advice.

Here's my 'two penneths' worth as someone who's towards the end of a big build / refurb.

My view is that a prime contractor should be able to co-ordinate most if not all of that lot for you. They will be able to use their contacts to get contractors in at the right time in the schedule to minimise downtime. You will pay a premium for that (probably around 15% over what you could get them for direct) but if you manage the specialist contractors yourself, you run the risk of your build slowing / stopping whilst your main contractor waits for your specialist contractor to do their stuff. If cost is more important to you than hitting a specific deadline, you should manage the specialist contractors yourself and accept that your schedule might slip. If you're anxious about hitting a specific date (which you won't anyway as building isn't an exact science and things always crop up that puts the schedule back) you should get your main contractor to manage it. I've had numerous occasions where things cropped up and the prime contractor got onto a plumber, electrician or carpenter and someone turned up same day or following day to sort it. I don't believe that I would have been able to get the same result if I made the call.

Generally, I would let the builder supply, fit and manage 'building stuff' (and I would include windows, staircase, damp treatment, UFH and storage cupboards in that) but for personal things like bathroom fittings and kitchen, I would source it myself but make sure that the builder fits it all within their price. There are downsides to this however, anything that you supply, the builder (quite reasonably) isn't responsible for.

Kitchens are a great example - I started off with the Magnet type thing and to supply and fit was around £25k. I then did Benchmark / Howdens / B&Q and to supply only was around £10k - £15k. I ended up with DIY Kitchens for around £7k for the same number of units (and I think better quality). I don't know specifically how much the builder is charging to fit the kitchen (as I have a 'bottom-line price') but on the basis that he charges me £150 day + VAT for a carpenter or plumber and it's about a week's work, fitting is about £1,000.

I would get a specialist in to do worktops (I'm assuming granite) as they have a short lead time and can be flexible with your schedule.

I absolutely wouldn't rely on a builder to source anything relating to the final finish without my prior approval as you may get cheap naff stuff unless you've been very specific. For example, my brief to my main builder for some carpentry items was 'Internal doors, architrave and skirting to match existing. I will supply handles for you to fit. You will supply and fit hinges. Finished surfaces to be supplied primed (or primed by you) for me to paint'

My very general final comment is that you should supply the things that you care about but let the builder supply and fit everything else!

Hope this helps!

My advice is to stock up on gin

What Loumate said. Your builder should be able to sort all that out. For instance, we wanted Velfac windows, but it was our builder who got the Velfac people out to measure up and coordinated delivery dates etc. We also went with the underfloor heating they recommended on the basis that we wanted something they were used to fitting and reviews were generally good.

Our builder also used his carpenter for the custom internal bifolds but we specified the design etc.

If you want to use your own contractors be prepared for things to take much longer as you try and herd cats and get them to turn up when you need them. It also increases the scope for them all to blame each other when it goes wrong.

Give a clear brief to the builder and be onsite at the start and end of every day to check on what they have done.

VeryPunny - It also increases the scope for them all to blame each other when it goes wrong.

Absolutely 100% spot on...

Hi Loumate666

Thank you so much for your useful advice here. It really is a lot of help. I thought that I had posted my thanks before, but I have just come back to this thread and seen that it never posted - sorry for that .