digging a trench for wall foundation

[alexandra123]

Hello,

I am looking for some information please


Can someone tell me the average cost to just dig a trench to support an external brick garden wall - 32ft in length and 6 ft in height..using the normal 9 inch cavity blocks to build the wall ?

Also - what should the depth and the width be for the foundation?


My father is going to do it for me, but I wanted to give him some money for helping me out, so I wanted to know what the average price was.


Thanks in advance

 

[kceire]

Foundations for any structure really should be designed by an engineer.

As a rule of thumb for a boundary wall you could get away wit 3T. (3 = thickness of the proposed wall). In your case for a 215 cavity wall you would want a minimum of 600mm wide by 300-350mm deep.

You may have to lay a layer of sand blinding and may have to use some reinforcement, maybe A393 mesh but again, you may need someone to assess the ground conditions on site.

The width can also be determined by the digger that you use, if it has a 900mm bucket then just use that width.

To give an idea, I was quoted €1100 from a builder for everything for a boundary wall using cavity blocks also for a run of 10.5m here in Dublin. That was for everything, supplied and constructed.