10.1.5Garage walls

Walls for garages shall transmit all loads to foundations safely and without undue movement. Issues to be taken into account include:

  1. stability of walls above ground
  2. stability of walls retaining ground
  3. provision for movement
  4. adequate resistance to rain and ground water.

Garage walls will be acceptable where they are in accordance with:

  • Chapter 5.1 ‘Substructure and ground-bearing floors’
  • Chapter 6.1 ‘External masonry walls’
  • the guidance given below.

Stability of walls above ground

Walls for detached garages and external walls for attached garages should:

  • be not less than 90mm thick
  • have adequate lateral restraint against wind loading
  • in the case of walls up to 200mm thick, have piers at the corners (unless buttressed by a return) and at intermediate centres not exceeding 3m.

Stability of walls retaining ground

Garage walls retaining ground should be:

  • suitable for the ground conditions
  • structurally adequate.

Where garage walls act as retaining walls, they should be designed in accordance with Chapter 5.1 ‘Substructure and ground-bearing floors’ or by an engineer in accordance with Technical Requirement R5.

Provision for movement

Movement joints in garage walls, as described in BS EN 1996-2, should be provided:

  • between homes and attached garages
  • where there are movement joints in foundations.

Adequate resistance to rain and ground water

To protect the wall from rising ground moisture, a DPC should be provided at a level at least 150mm above the level of adjacent ground.

Garage walls constructed from a single leaf of masonry, such as brickwork or blockwork approximately 100mm thick, will not be impervious to wind-driven rain and consequently could become damp.

In areas of severe exposure, single leaf walls may require a high standard of workmanship and possibly surface treatment to prevent an unacceptable level of rain penetration.

Where a garage is integral or attached, the design should ensure that dampness cannot enter the home.

Where a wall is below ground level, precautions should be taken to prevent the entry of ground water by:

  • tanking (see Chapter 5.4 ‘Waterproofing of basements and other below ground structures’)
  • the use of DPCs and DPMs
  • drainage of ground behind the wall.