As I travel around the Melbourne Suburbs I see lots of brick fences……….. A problem with a large proportion is that they have obvious cracks.
If you don’t believe me just walk around your neighborhood and look at a few brick fences yourself!
So why are there problems with brick fences?
- The actual cost of the wall in both materials and labour is high resulting in people trying to minimise on wall and pier thickness.
- Although many people think of brickwork as an inert material it is still subject to expansion and contraction which needs to be accommodated with proper detailing.
- Unless the thickness of the wall is increased for taller walls the weight of the top portion of the wall acts against the overall wall stability.
- Brick work is actually a fairly brittle structural material which relies on its weight for a lot of its strength. The jointing material of mortar is much weaker than the bricks.
- Due to the considerable weight of brickwork it needs substantial (expensive) foundations which will not be subject to any settlement.
- If it’s built on clay there is more chance of movement……The soil below the narrow foundation can gain, or lose, moisture more readily than under a house slab.
- Although it ‘feels’ as solid as a concrete wall it may only have a tenth of the structural strength of a well designed reinforced concrete wall.
Here are a few recommendations;
- Don’t try to save money on the foundation. After all that’s what all those expensive bricks are standing on. A 500mm wide x 300mm deep concrete with trench mesh should be the minimum.
- Brick piers a minimum of 320mm x 320mm with vertical steel reinforcement.
- Minimum wall thickness should be 210mm (double brick)
- Have articulation/expansion joints at 5m intervals.
- Use horizontal steel reinforcement every 6 courses.
- It you are retaining soil get the wall properly designed.
All sounds too expensive?,,,,,,,,,,,,,,,Perhaps brick piers with infill timber or steel panels may be the way to go!
Remember – “There is no such thing as a cheap brick wall”.
For sizes of brick walls see Brick Dimensions