New Build house costs SQM Thanks

[Colin3322]

Hi everyone,
I'm a general all-rounder in the building trade.

I'm planning to build a house for my parents on a small patch of land they own in West London.


I'm trying to decide whether to self-manage the project myself — basically, coordinating and bringing in the trades just like a general builder would, since I have solid contacts in the industry. The downside is that it would take me away from my regular paid work, where I've been for years, and don’t want to lose this job.

As a rough guide for West London in 2026:

• • If I self-manage using my circle of contacts, what's a realistic cost per square metre for a mid-range spec (decent finishes, standard modern systems, compliant with regs but nothing luxury)?
  • What do builders typically charge per sqm for a full contract/turnkey job (where they handle everything)

Thanks in advance for any realistic figures or advice — much appreciated!