Garden walls

Garden walls can be unsafe if not regularly inspected and maintained.

Use this clear and simple advice from the Government "Building Research Establishment" to keep your garden's walls safe.

Garden and boundary walls should be inspected from time to time to see if any repairs are necessary, or whether a wall needs rebuilding.

Such walls are amongst the most common forms of masonry to suffer collapse, and they are unfortunately one of the most common causes of deaths by falling masonry. Your insurance may not cover you if the wall has been neglected.

Besides the general deterioration and aging of a masonry wall over the years, walls may be affected by:

  • an increase in wind load or driving rain if a nearby building is taken down.
  • felling of nearby mature trees or planting of new trees close to the wall.
  • changes leading to greater risk of damage from traffic.
  • alterations, such as additions to the wall or removal of parts of the wall e.g. for a new gateway.

Note. Rebuilding your garden's walls may require planning permission.

  • If you wish to raise the height of your walls above two metres (6 foot 6 inches).
  • If you are building walls for the first time around your garden.

However, garden walls are exempt from control by the Building Regulations.

Please do check your own garden walls and if rebuilding or building a new wall, do make sure you use the design guidance of the following diagrams, so as to build safe and long lasting garden walls

Things to check

  1. Is the surface of the brickwork crumbling away? 
    If restricted to a few bricks this may not be serious but walls can be weakened by general crumbling across either face.
  2. Is the mortar pointing in good condition
    If the hard surface layer can be picked out from the joint, or if the mortar can easily be scraped out with, say, a door key, then this is a good indication that the wall may need repointing.
  3. Is there a tree near the wall?
    As trees mature, there is a risk of the wall being damaged by the roots, and from wind-blown branches. Damaged sections may have to be rebuilt, perhaps with 'bridges' incorporated to carry the wall over the roots. Removal of
    large trees can also lead to problems because the soil accumulates more moisture and expands.
  4. Is the wall upright?
    Walls lean for a variety of causes, due for example to failure below ground caused by tree roots, a cracked drain, frost damage to the foundations or inadequate foundations. If your wall leans to an extent that could present a danger for example more than 30mm (half brick wall), 70mkm (single brick wall) or 100mm (brick and a half wall) it is recommended that expert advice is sought. This may involve checking of the wall foundations.
  5. Is the wall thick enough for its height?
    Click here to access the map and tables which give guidance on how high walls should be in different parts of the UK relative to their thickness. Seek expert advice if your wall exceeds the recommended height, or in circumstances whereby this guidance is inapplicable for example walls incorporating piers, or walls supporting heavy gates or retaining soil.
  6. Some climbing plants, like ivy, can damage walls if growth is unchecked. 
    Consider cutting them back and supporting regrowth clear of the wall.
  7. Is the top of the wall firmly attached?
    Brick cappings or concrete copings may be loose or there may be horizontal cracks (frost damage) in the brickwork a few courses down. Loose or damaged masonry near the top of the wall will need to be rebuilt and should include a damp proof course.
  8. Has the wall been damaged by traffic?
    Minor scratch marks or scoring of the surface may obscure more significant cracks. Piers at vehicular entrances may have been dislodged by impact and be unsafe; in such cases they should be rebuilt.
  9. Are there any cracks in the wall?
    Hairline cracks (0- 2mm across) are common in walls and may not indicate serious problems. For wider cracks seek expert advice; some may indicate a need for partial or complete rebuilding. Seek advice on any horizontal cracks which pass right through a wall or any cracks close to piers or gates. Repointing of cracks can lead to problems. Do not repoint without establishing the cause of the cracking.

How thick should my garden wall be?

The following diagrams offer you the "Building Research Establishments" considered advice on safe heights for different wall widths. Especially in relation to the normal and storm wind forces of your region.

Garden wall zones

Zone 1
Wall thicknessMaximum height (.mm)
Half brick525
One brick1450
One and a half brick2400
100mm block450
200mm block1050
300mm block2000
Zone 2
Wall thicknessMaximum height (.mm)
Half brick400
One brick1300
One and a half brick2175
100mm block400
200mm block925
300mm block 1850
Zone 3
Wall thicknessMaximum height (.mm)
Half brick400
One brick1175
One and a half brick2000
100mm block350
200mm block850
300mm block1650
Zone 4
Wall thicknessMaximum height (.mm)
Half brick375
One brick1075
One and a half brick1825
100mm block325
200mm block775
300mm block1525

Half brick = 100 mm  one brick = 215 mm  one and a half brick = 325 mm

This information is based on the guidance given in Good Building Guides 13 & 14. These guides are available from:

BRE Bookshop, Building Research Establishment, Garston, Watford, WD2 7JR

01923 664262

Contact us  

Development and Public Protection
Building Control
Gateshead Council
Civic Centre
Regent Street

0191 433 3144

Share this page