51 Engineering 1

Oamaru stone Walls

All perimeter walls and internal walls were build out of solid Oamaru stone blockwork.
(perimeter wall: 115mm / 50mm cavity / 115mm and internal wall: 125mm thick)
For quite a few reasons the house can not be rebuild as per the original Oamaru stone built. It won't comply structurally, there is no thermal insulation, no services and interior stones are painted and too many are damaged.
I have taken the opportunity to design a rebuild strategy by reusing the Oamaru stone.

Exterior perimeter walls:
Most important is the reinstatement of the three exterior Oamaru stone facades.
Since the perimeter wall is a cavity wall, the structural and architectural components can be separated easily.
The exterior (architectural) wall will be rebuild as per the existing layout of the Oamaru stone blocks.
Cavity requires to be 40mm minimum.

The interior wall of the perimeter walls will be replace by a steel structure with timber/insulation infill.
The steel/timber/insulation structure requires to provide structural and thermal security but will be designed as slender as possible.
Plan is to add a layer of 35/40mm Oamaru stone veneer to the interior side of the perimeter wall.

The total package of the proposed perimeter wall is only 5 to 10 mm thicker than the original built.
Provisions will have to be made at stones bridging the cavity like sills, lintels and corbels.

Internal walls:
While deconstructing the house I discovered a specific technic at the arch.
The stone masons had used a cemented (vertical) core inbetween/consealed by Oamaru stone to gain more strength from the stones surrounding the arch.
My plan is to use this technique through out all interior walls in the house.

So a 50mm concrete (reinforced concrete) core is going to be poured in-between 40mm Oamaru stone blocks.
Plan is to run all power cables in the core.
I am also looking into running warm water tubes, powered by solar panels, through the core to get the winter cold out of the house.

Bandsaw:
To execute this plan all existing (painted) interior stones will have to be cut over the length of the stones.
Stones measure 1230 x 250 / 330 x 125mm (L x H1 / H2 x W)
Few months ago I found a huge, 100 year old, cast iron band saw on Trade me and currently I am preparing this bandsaw for cutting the large Oamaru stones.
Once a stone is cut over its long side, the clean side of the stone is going to be the new face and the painted side of the stone will be set to the side of either the concrete core (internal walls) or glued to the timber framing (perimeter wall)