Underground garages and car galleries in Cheshire

The Golden Triangle has the land a gallery needs

Alderley Edge, Prestbury and Wilmslow are known together as Cheshire's Golden Triangle. Cheshire East Council's appraisal of the Alderley Edge conservation area describes heavily wooded streets and substantial Victorian villas in spacious, well-planted gardens.

A BELOW gallery is a single level, about 4.5m deep, for around 16 cars. It has a drive-through lift in a garden pavilion and an independent drive-out ramp. A house with a long garden or a few acres has the length for both, without crowding the house.

Much of this country is Green Belt

The North Cheshire Green Belt was first drafted in 1961, to stop the Manchester conurbation spreading further into Cheshire and to keep the breaks between towns. The draft covered land around Knutsford, Wilmslow and Alderley Edge, and Green Belt control has applied there ever since.

Cheshire East Council lists Wilmslow, Knutsford, Alderley Edge, Prestbury and Mobberley among the settlements inset within or next to the Green Belt. An inset town or village is drawn out of the Green Belt, but the countryside around it is in. So the first question for any house is which side of the line it sits on.

Cheshire East's Green Belt rules

The Cheshire East Local Plan Strategy was adopted in July 2017. Its Policy PG 3 says inappropriate development in the Green Belt will not be permitted except in very special circumstances. An extension is allowed if it is not a disproportionate addition over the original building. Engineering operations are not inappropriate if they preserve openness.

The council's Site Allocations and Development Policies Document, adopted in December 2022, adds the detail. Its Policy RUR 11 covers extensions and outbuildings in the Green Belt and open countryside. In the Green Belt, additions of more than 30% over the original building will usually be judged disproportionate. The original building is the one that stood on 1 July 1948, or as first built if later.

RUR 11 allows exceptions to that figure. One is extra floorspace with no significant change to the outside of the building, and the policy gives basement extensions as its example. A gallery under the grounds is a different case from a basement under the house, so we argue it on openness and on how little shows. National policy, GB6 and GB7, sets the same tests. Our planning permission guide covers them.

Conservation areas in Alderley Edge, Prestbury and Wilmslow

Cheshire East lists several conservation areas in this country. Alderley Edge has four: Alderley Edge, Davey Lane, Elm Grove and Trafford Road. Prestbury, Mobberley, Knutsford, Legh Road in Knutsford and Nether Alderley have their own. Wilmslow has Hawthorn Lane, Highfield and St Bartholomew's.

The Alderley Edge conservation area was designated in September 1974. In a conservation area, the council must pay special attention to its character or appearance. The pavilion is designed to suit the house and its street, and the gallery below changes nothing anyone can see.

A listed house needs listed building consent for works that affect its character, and its setting is protected. A gallery under the grounds leaves the house itself untouched.

Hale and Bowdon fall under Trafford

Hale and Bowdon sit in Trafford, in Greater Manchester, not in Cheshire East. Trafford's development plan is Places for Everyone (2024), its Core Strategy (2012) and saved policies from its older plan. Places for Everyone set the Green Belt boundary there.

So Cheshire East's 30% figure does not apply in Hale or Bowdon. Trafford is preparing a new Local Plan, due for submission in December 2026 and adoption in 2027 or 2028. We check the policies in force at feasibility.

Trafford has four conservation areas south of Altrincham: The Devisdale, Bowdon, Ashley Heath and South Hale. The same duty to their character applies.

Sandstone, clay and groundwater

East Cheshire sits over the Sherwood Sandstone, part of the Permo-Triassic sandstones that form the second most important aquifer in the UK. The British Geological Survey and the Environment Agency record that here it supplies public water, industry, farms and golf courses. Its harder Helsby Sandstone forms the high ground of Alderley Edge itself.

Much of the area is covered by glacial deposits, more than 70m thick in places. These are mostly boulder clay, with sands and gravels in places. Hale, for example, sits on glacial drift, with sand and gravel along the Bollin valley and boulder clay elsewhere. Water can also perch above thin mudstone bands in the sandstone.

So two plots a mile apart can behave very differently. A site investigation comes before any design. The gallery is then built as a dry box to BS 8102 Grade 3, with two independent forms of protection. Our waterproofing guide explains how.

Source Protection Zones and dewatering

The Environment Agency defines Source Protection Zones around boreholes and springs used for drinking water. The inner zone is at least the area within 50m of the source. Where a scheme could pollute or harm groundwater, the developer may need to check whether the site lies in one. In East Cheshire, zones have been defined around public water supply sources.

The Agency also extends some zones under protective clay, because deep works could open a path for pollution into the sandstone. So we check the map for each site and choose a dig, a wall and a pile design to suit.

Groundwater may need pumping while the dig is open. An abstraction licence is likely above 20 cubic metres a day. Small-scale dewatering for building works can be exempt if it lasts less than six consecutive months and does not use wells or boreholes.

Mature gardens and protected trees

These gardens are full of fine trees. The Alderley Edge appraisal notes a large number of Tree Preservation Orders in the conservation area. In a conservation area, most tree work needs six weeks' notice to the council.

A Tree Preservation Order makes it an offence to cut down, top, lop, uproot or wilfully damage a protected tree without consent, and cutting roots counts. Each tree gets a root protection area under BS 5837, normally a radius of 12 times its stem diameter. The gallery and its working space are planned outside those areas. Our guide to a garage under the garden explains how.

What a Cheshire gallery can include

• A drive-through car lift inside a garden pavilion. Our residential car lift guide explains how it works.
• An independent drive-out ramp as the second route.
• Around 16 cars on a single level, about 4.5m down.
• Climate control, fire detection and security to insurer standards, as in our car vault guide.

Size, depth and ground set the budget. Our underground garage cost guide explains each driver.