Brick Veneer Platform Floor Section Part 1

To watch the video got too ‘Brick Veneer Platform Floor Section Part 1‘

This method of construction incorporates a raised platform floor so we need to start with the a Footing system. The system will consist of a Strip Footing running around the perimeter of the building and a grid of Blob Footings through the centre of the building.

The Strip Footing reinforced generally with 2 layers of Trench Mesh, detailed in the plans and specifications. 

While the Blob footing just mass concrete poured into an excavation.

Both the Strip and Blob Footing should be finished level with a rough finish to allow the mortar to adhere to it. They should also finish approximately 1 course of brickwork below the ground so they can be covered up when the landscaping is done.

Next the Dwarf Wall is constructed on top of the Strip Footing. The Dwarf wall is a single skin of brickwork which is built up to the level of the underside of the bearers.

Ventilation is built in to the Dwarf Wall to allow air flow to occur in the sub-floor space. These vents should be placed roughly every metre.

The Dwarf wall is reinforced with Engaged Piers which also act as the bearing point for the Bearers.

On top of the Blob Footing is a Isolated Pier, also known as a Sleeper Pier. The Isolated Pier supports the Bearers through the middle of the building and therefore the spacing of the Isolated Pier is equal to the maximum span of the Bearers and the Joists.

Now we are ready to place our first timber member. Because the brickwork is porous (will adsorb moisture) and we don’t want the timber frame getting wet we need to separate the Brickwork from the timber. This is done using a DPC ( Damp Proof Course) or DPM ( Damp Proof Membrane). Nowadays embossed black polyethylene plastic (Plascousre)  is most commonly used although you can also use products like Alcor and Lead.

Then comes the Termite protection in the form of Ant Capping. A continuous length on the Dwarf Wall, a Half Cap on the Engaged Pier and a Full Cap on the Isolated Pier. These used to be joined together with solder however nowadays there is a special adhesive that can be used. Termite Proof Silicone

Now it is time for our first timber member the Bearer. The Bearer is the lowest timber member in the building. It is set 40mm from the inside of the Dwarf wall centred on the Engaged Pier. The Bearer usually runs along the length of the house. Traditionally the Bearer is not fastened down it relies on the weight of the building to hold them in place however nowadays in high wind areas they can be held down with Builders strap embedded into the Engaged Pier or Threaded Rod cast into the Footing.

The Bearer must be a minimum of 400mm off the ground to within 2m from the Dwarf wall from there is may slope up to a minimum of 150mm  from the underside of the bearer at the wall. This is to allow for good ventilation and good access under the building for inspections.

The Joists are next. They are spaced to suit the flooring that is going to go on top, commonly 450mm centre to centre (c/c) or 600 c/c. They are laid at 90 degrees to the Bearer. Double joists are required under the external load bearing walls where the wall runs parallel to the joists. When you have a platform floor like the one I will show here these joist can sit side by side. See ‘Platform Floor System’ for more information.

With a Platform Floor Sheet Flooring is generally used, ‘Structaflor’ is a common brand. The flooring should be installed in accordance with the manufacturers recommendations. Sheet Flooring is not designed to be exposed to the elements and should be protected is they will be exposed for an extended period.

To see what happens next go to 'Brick Veneer Platform Floor Section Part 2'