Category Archives: Launceston

Concrete Deck

This house in the Launceston area, required a total of 16 underpinnings. The concrete deck at the front of the house had pulled the wall out and had dropped in all areas. The deck was removed to make the work area more accessible and helped make the job more economical. The owner intends to build a new treated pine deck at a later date. The holes were founded on hardpan material at varying depths, ranging from 800mm to 2400mm. This was the main reason for such severe movement.

Worksite Images
Showing extensive cracking of wall and remnants of old concrete deck.

 

Worksite Gallery
Underpinning work has been completed. Owner to build new treated pine deck at a later date.

Pier Replacement

This house is in the Launceston area and required 40 new piers.

Tas Underpinning Site Gallery
Here you can see the old timber piers, sitting on the edge of the concrete pedestals. Most of the timber piers were rotten at the bottom and were tilted and unstable due to the concrete pedestals moving. The floor was propped prior to removal of old piers.

 

 

 

 

 

 

 

 

 

Tas Underpinning Site Gallery
New steel piers

Pier Movement

This house in the Hobart area, had a mixture of brick and timber piers that were sitting on the existing clay, without a concrete pad. We supported the existing floor and removed the sub-standard piers. We excavated and poured new concrete pads and fixed new galvanised steel piers in the concrete and to the timber bearer. Working height for this job varied from 900 mm to 300 mm.

photo_017
Excavating new pier holes.

 

New steel piers
Work completed using new steel piers

Underpinning

Underpinnings showing traditional bulk excavation,  which is our main method for doing underpinnings.

This is the most reliable method and we are happy to provide a 20 year guarantee on all our works. Owners can actually look in the hole and see what the house will be sitting on. Engineers can visually see and check that the new underpinning foundation will be sitting on rock or high kpa bearing capacity. Any floating rocks or hard crust layers can be penetrated and removed if hit during excavation.

This cannot be done with resin injections or steel bar techniques.

Concrete foundations have been the main material for house foundations for many years and will continue to be so. The main reason why houses with concrete foundations have failed, is because they did not have concrete piers put in during construction, or they were not put in deep enough.

Which is what traditional underpinning does.

Hole for Underpinning

Dry Rot

In this example, the owner’s freezer and bed had fallen through the floor. Due to the lack of ventilation in the sub-floor area, all supporting timbers had failed due to “dry rot”.  Photos of different stages of the job are shown below.

Existing floor with preparation holes cut and supports put in place prior to removing floor.
Existing floor with preparation holes cut and supports put in place prior to removing floor.
Removal of floor, with internal walls totally supported.
Removal of floor, with internal walls totally supported.
Completion of first concrete pour.
Completion of first concrete pour.
Preparation for final concrete pour.
Preparation for final concrete pour.
House back to normal with a new concrete slab.
House back to normal with a new concrete slab.