Benching, Battering and Shoring

To watch the video go to "Benching, Battering and Shoring"

Here in Australia the deepest excavation that a person can enter is 1.5m deep.

This height is set so that if a collapse was to occur you would not be buried any further than you waist. This is to try and eliminate a condition called Compressive Asphyxia, this is where the expansion of the lung is limited due to the weight of material on the chest of the victim.

If the excavation that you are getting into is deeper than 1.5m there is a couple of things that should be done before you bet in.

Benching

The excavation is cut in a series of steps. Each step should not be deeper than 1.5m and it should be set back enough so that if the top level was to collapse it would not fall into the bottom of the trench. This method requires a lot more material to be excavated however no shoring is required.

Battering

The sides of the excavation is sloped at the Angle of Repose so that the sides are self supporting. Again,this method requires a lot more material to be excavated however no shoring is required.

Benching and Battering

A combination of the above methods.

Shoring

Shoring is the act of physically holding up the sides of the trench to prevent it from collapsing. There are numerous methods of shoring, both permanent and temporary. A couple of temporary techniques are the shoring box and Sheet piling.

Angle of Repose - Zone of Influence

To watch the video on this go to "Angle of Repose - Zone of Influence"

The Angle of Repose

The angle of repose or the angle of rest is the angle that a material will naturally support itself at. Think of a pile of sand, when it is delivered out of the truck it sits up in quite a nice heap this is the angle of repose.

Over time the influence of the weather and people will cause the heap to spread and lower however generally speaking the weather will not affect the material when it is in the ground. 

The angle depends on the shape and size of the individual grains and how they move over each other.

Material	Angle Of Repose
Wet Sand	45o
Granite	35o - 40o
Dry sand	34o
Crushed Asphalt	30o - 45o
Loose Dry Gravel	30o - 45o
Dry Lump Clay	25o - 40o
Natural Gravel with Sand	25o - 30o
Water filled sand	15o - 30o
Wet Excavated Clay	15o

Zone of Influence

Therefore anything inside the Angle of Repose will support itself and not want to collapse into a  excavation. 

However any thing that is outside the Angle of Repose is in the Zone of Influence. Anything in this zone has the potential to collapse into a excavation if it is affected by weather, water, people or machines or anything else that could cause it to move.

Brick veneer, Slab on Ground Building Construction Part 3

To watch the video got too ‘Section through a Brick veneer, Slab on Ground Building Part 2’.

To go back a step go to 'Brick Veneer, Slab on Ground Construction Part 2'

Now we need to get the Bricklayer in just to run the first course of brickwork around the rebate. This will give the termite protection installers something to work with. There are 5 or 6 different methods of providing termite protection to your dwelling a couple of popular systems are ‘Termimesh’ and ‘GraniteGuard’ 

Other systems include, Kordon, Termguard, Termidor, and TERM-seal

Next the flashing is installed. It should be fixed to the bottom plate of the wall frame and bedded into the brickwork one course below. 














The course of brickwork above the flashing should have the perpends (perps) left out to allow any moisture in the cavity to get out. These are called Weep holes.













The sarking can now be put up making sure that it overlaps the flashing so any water will still run out of the building.

Once the Termite protection and flashing is in place the brickwork can continue. The Brick veneer is tied to the timber frame every 4th course using veneer ties. 

The ties are nailed to every stud slightly above the brick and then bent down so it can be bedded into the mortar. This will ensure that any moisture or water that runs down the back of the brick will stay against the brick until it hits the flashing and exits via the Weephole. The top row of ties should be a minimum of 2 courses from the top of the brickwork.

The brickwork should be laid to a ‘bond’ so that it finishes around 10mm below the ‘Drop Off’. 

Below the window the brickwork should finish 2 courses down to allow for the sill bricks and the flashing that is attached to the window should be embedded into the brickwork as well.

With the brickwork complete the eave frame can be built.

There are a few different styles of eave that you could have, the one shown here is a Boxed or Level Eave.

The finished eave should finish around 10mm above the brickwork to allow for the timber frame to settle overtime. 

A quad or similar moulding is used to cover the gap and still allow for the movement.

With the outside finished the work inside can really start. Internal linings such as Plasterboard can be installed. 

Plasterboard can also be used on the ceiling and the intersection covered with a cornice moulding again made from Plasterboard.

Architrave is used to cover the gap between the window jamb and the wall, 




















Skirting mould use to cover the connection between the wall and the floor.





The last few tasks are to fit off the Electrical and Plumbing Fittings as well as painting, floor finishes etc and landscaping.







The landscaping should finish with 75mm of the slab exposed for as part of the termite protection requirements.




Brick veneer, Slab on Ground Section