Owners should ensure that garden and boundary walls are 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 commonest causes of deaths by falling masonry. Insurance policies may
not provide cover 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 plating 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.
Things to check
- 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.
- Is the mortar pointing in good condition?
If the 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.
- 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.
- 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 e.g. more than 30mm
(half brick wall), 70mm (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
- Is the wall thick enough for its height?
The map and tables at the bottom of the page 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 e.g. walls incorporating piers, or walls supporting heavy gates
or retaining soil.
- Some climbing plants, like ivy, can damage walls if growth is unchecked.
Consider cutting them back and supporting regrowth clear of the wall.
- 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.
- 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 impact and be unsafe; in such
cases they should be rebuilt.
- 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.
One and a Half Brick