Building a swimming pool in a UK garden

Concrete pools, built with sprayed concrete or blockwork and a rendered, tiled or lined finish, can take any shape and size and last for decades, but they take longest to build and cost most. Prefabricated pools come as one-piece shells, usually glass-fibre, or as panel systems with a vinyl liner. A one-piece shell is quick to install but needs crane or lorry access to lift it into place, which many back gardens do not have. Panel and liner pools can be carried in by hand and suit awkward sites.

Above-ground and semi-sunken pools avoid much of the excavation. Indoor pools in an extension or outbuilding are a different kind of project: the building has to handle humidity and condensation, which needs a dehumidification and ventilation system designed from the start.

Most outdoor pools in the UK are heated, and air source heat pumps are now the usual choice for that. Gas boilers and solar heating are alternatives. Whatever the heat source, a cover makes the biggest difference: an uncovered pool loses a great deal of heat from its surface, above all through evaporation. Automatic slatted covers are convenient; bubble covers are cheaper but must be taken on and off by hand.

Running costs include heating, electricity for the pump and filtration, chemicals, water top-ups and annual opening and closing. Ask the builder to estimate these for the season length you want, and to state the assumptions behind the estimate. Some water companies also have rules about filling a pool from the mains; check yours before the first fill.

In England, a swimming pool in the garden of a house can be permitted development under the rules for outbuildings and enclosures. The Planning Portal sets conditions: nothing on land forward of the principal elevation, and additions and outbuildings together must not cover more than half the land around the original house. An enclosure or pool building within 2 metres of a boundary is limited to 2.5 metres in height.

On designated land, which includes conservation areas, pools at the side of a house need planning permission, and any pool or outbuilding in the grounds of a listed building needs permission. Flats and maisonettes do not have these permitted development rights. Telescopic enclosures and pool buildings are structures in their own right, so ask whether yours stays within these limits. Wales, Scotland and Northern Ireland apply their own rules.

The wiring regulations BS 7671 treat swimming pools as a special location with stricter requirements for equipment, zones and protection. New circuits for pumps, heat pumps, lighting and covers are notifiable under Part P in England and Wales, and should be done by an electrician registered with a competent person scheme or approved through Building Control. Ask the pool builder who does the electrical work and who issues the certificates.

Excavation raises its own questions: soil type, water table, access for machines and where the spoil goes. A high water table can push an empty pool shell out of the ground, which is why pools should not be drained without advice. For families with children, discuss safety covers, fencing, alarms and gate locks early; they are easier to design in than to add.

• pool type, internal dimensions, depth profile and finish
• excavation, spoil removal and ground conditions allowed for
• filtration system, pump, and water treatment method
• heat source, its output and the expected season
• cover type and whether it is included
• electrical work and who certifies it
• planning position, in writing, and any enclosure
• warranty on the shell or liner and on the equipment

Older pools often need a new liner, retiling, new pipework or a modern filtration and heating plant. A survey should find leaks before anything is refinished, because a new liner over a leaking pipe only hides the problem. Replacing an old gas heater with a heat pump and adding a good cover are common upgrades that change the running costs more than any cosmetic work.

You tell us about the garden, the pool you have in mind and your timescale, and confirm your phone number and email. We offer the request, stripped of your contact details, to pool builders in your area. One company can buy it and then it is gone from our shop. You find out who it is by email, with name, address and phone number, before it sees your details. Offrano costs you nothing.

A request may not be bought; if not, we withdraw it after 21 days. You are not obliged to accept any quote. Offrano checks only that the buyer is a registered business, so visit a pool it has built and ask about guarantees and aftercare.