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:
- stability of walls above ground
- stability of walls retaining ground
- provision for movement
- 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