Should I Consider a Self Build House Extension?

For most ordinary people - NO!

Unless you have experience of building trades or have previous building management skills it is best avoided.

'The Building game' as it is commonly known is a set of 'wheels within wheels' especially at the local level.

Each 'wheel' or trade has its peculiarities and idiosyncrasies which any 'main contractor' or 'project manager' must understand and work with rather than against.

I have personally had a few 'office bound', middle management type clients who think that they can project manage their own home extension scheme & bring to the table a set of spread sheets, critical path analysis and target dates that will magically make the plumber turn up at 11am on a Friday.

It doesn't work that way and I think never will.

However, if you can afford the time, stress and have the person skills & thick skin that is often required, you may have a good shot at self building or managing your own home extension scheme.  If you get on well with the first set of trades (ground workers for example), they often know & recommend other follow on trades that you can approach for prices (wheels within wheels).

If you do take on your own home extension project then be prepared for long days on site maintaining quality control, long evenings on the telephone speaking to various trades & weekends sourcing materials. Is the 25% potential saving on the builders margin worth the cost of your marriage?

Any doubts - don't do it.