Building a garden bar on a sloping garden

A sloping garden can give a bar the best seat in the house: a view back across the lawn, a natural sense of arrival and a raised terrace for evenings. It also brings two problems flat gardens don't have, height and water.

Find the level

Measure the fall across the footprint. A string line and a spirit level, or a laser level, will show how much the ground drops. Even a gentle slope adds up across a few metres.

Three ways to deal with it

Dig in

Cut into the slope to create a level platform. This keeps the building low but means moving soil and often building a retaining wall behind. Retaining walls holding back significant soil are structural, and taller ones need proper design.

Build up

Raise the base at the low side with a timber frame, posts or ground screws. This avoids digging but increases the height of the building above ground on the low side.

Cut and fill

A mixture of the two keeps both the digging and the height down.

Height and planning

Raising a building on the low side increases its height measured from the ground. In England, outbuilding planning limits are measured from ground level, and the Planning Portal explains how to measure on sloping ground. Check before committing to a raised base. See planning.

Water runs downhill

A slope sends rainwater towards whatever is in the way. If you dig in, water will collect against the uphill wall. Plan drainage behind retaining walls and around the base, and keep cladding clear of soil.

Steps and access

People will walk to the bar in the dark, sometimes after a few drinks. Steps must be even, lit and with a handrail where needed. Gravel on a slope can be slippery. See lighting and the hosting checklist.

Deliveries

Carrying panels, sleepers or a fridge up or down a slope is hard work. Plan the route and get help. See delivery and assembly.

Set a string line level across the proposed footprint and measure the gap to the ground at the low corner. That single number tells you which approach makes sense.