10.1 Garages

10.1.5 Garage 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 any or a combination of the following:

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

If integral garages are formed within a timber frame building, the construction of the garage walls should be in accordance with Chapter 6.2.

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.

Piers should be located in single leaf walls:

  • up to 200mm thick
  • which are greater than 2.5m in length or height and which do not contain a major opening ie, garage door
  • at corners, unless buttressed by a return of at least 390mm
  • at intermediate centres not exceeding 3m
  • either side of a major opening ie, garage door.

Piers should also:

  • be built off the foundation
  • extend the full height of the wall
  • measure at least 390mm x 190mm or 327mm x 215mm depending upon masonry unit size
  • be bonded or tied to walls with flat stainless steel wall ties, 20mm x 3mm in cross section, placed in pairs and not more than 300mm centres vertically.

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 or worse, single leaf walls may require a high standard of workmanship and possibly surface treatment to prevent an unacceptable level of rain penetration.

Where a cavity wall is to be used as an alternative to surface treatment of a single leaf wall, it would be acceptable to use a cavity of less than 50mm in this instance.

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.

Last updated: 2nd January 2024

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