How we phase a big garden

Almost every large garden we design gets built in more than one go. That is entirely normal and usually sensible. What is not sensible is phasing without a master plan, which is how people end up digging up a two-year-old terrace to run a cable.

Design the whole thing first, always

The master plan costs a fraction of the build and it is the only thing that makes phasing safe. It fixes levels, drainage runs, service routes and tree positions across the entire site. Once those are set, any individual phase can be built in isolation without compromising the next one.

We have never regretted spending longer on a plan. We have frequently been called in to fix the consequences of not having one.

Get the invisible work done early

The right order is rarely the order of visual impact. Our default sequence is:

1. Demolition, earthworks and drainage. Heavy plant needs open access, and it will never be easier than on day one.
2. Services. Irrigation mains, lighting conduit, gas and power to every position on the master plan — including positions you are not building for another five years. Empty conduit is cheap.
3. Structural hardscape. Retaining, levels, primary circulation.
4. Finishes, planting and lighting. The parts people actually see.

Run the conduit to the future pool house in phase one and phase four costs a morning. Skip it and phase four means cutting a trench through a finished terrace.

Phase by outdoor room, not by trade

The instinct is to do "all the paving" then "all the planting". It is the wrong axis. Splitting by trade means the garden is a building site everywhere for the whole programme.

Splitting by room means each phase ends with something genuinely finished and usable, which keeps morale up across what might be a four-year programme. On Pool House Estate the family had a complete, planted terrace at the end of the first summer while the pool was still a year away.

Budget for the seam

Two things always cost more than clients expect at a phase boundary: protecting completed work while the next phase is built, and re-mobilising a crew and plant. Allow around 8–12% on later phases for both. It is not padding — it is the real price of building in stages.

When not to phase

If the earthworks are substantial and interconnected — a hillside, a pool with retaining, anything needing engineered walls — phasing usually costs more than it saves. Sites like The Hillside Terrace are cheaper built once, because the excavation and the structure are the same operation.