Underpinning Melbourne.

Underpinning Houses in Melbourne, Australia.

Underpinning in Melbourne is best done with Uretek expanding resin injection, because it's fast, economical, minimally intrusive. 

The Drought: Why Many Melbourne Houses Require Underpinning

Many houses in Melbourne have been solid for a long time; until foundations began to subside as the result of drought which dried out the layers of reactive clay deep in the ground. As well as drought affecting clay soils there are also problems caused by sandy soil around Pt Philip Bay.

Subsidence can be caused by many things, but the recent 20 years of drought in eastern and southern Australia has affected many properties that had previously been perfectly stable.

The problem of subsidence has hit Melbourne particularly hard.

Unfortunately many fine houses to both the east and the west of the city have been affected by subsidence. The result: cracks in walls and sunken floors, with windows and doors not opening and closing properly.

Why Melbourne? The Volcano!

The reason why Melbourne has been so badly affected goes back to pre-history and the geological formation of the area. The area where Melbourne now stands is relatively flat, but perhaps amazingly, was once a huge volcano!

As this was weathered down over the millennia the surface was left with a wide variety of soils and some big soil differences! Very sandy around Frankston; much clay in the areas around Springvale; very dense basalt rock (Bluestone) from old lava tubes emerging to surface around Deer Park. 

The soils in many, many parts of Melbourne contain reactive clays. These are clays that shrink, often quite significantly, when they lose moisture content. And this clay soil is the culprit behind most of the foundation problems these days.

Why So Many Melbourne Homes Require Underpinning

Today most homes and commercial businesses are built upon concrete slab or concrete strip (perimeter) footings. These footings support the home or building structure and give it stability. In turn, the footing is supported by the foundation soil underneath.

Problems begin with changes in water content of the clay soils under and around concrete foundations in Melbourne. During protracted periods of hot, dry weather the clay soils will lose large volumes of water and shrink or contract. This shrinkage leads to the footings of the building losing support, which results in subsidence of the footings.

Such subsidence is usually uneven. Over the length of a house concrete footings will bend quite a bit. So walls may develop cracks, inside and/or outside. Doors and windows can cease to work properly, even jamming in some cases, if that part of the house goes “out-of-square”.

Sometimes gaps appear below skirting boards because the floor has sunk in one place but the wall and skirting board stays up being supported from other floor sections.

So the answer is to find the best way to raise, re-support and re-level the footings of the house for the long term.

The Best of Underpinning in Melbourne: The Uretek Method of injecting expanding structural resins.

Why is this the best? Compare:

The old, traditional way was to jack-up a house from concrete underpinning. That involved excavating under the house footings and pouring huge blocks of concrete into the holes, letting them set and then jacking the house up from those blocks.

1. Concrete underpinning is very hard and time-consuming work.

2. Concrete underpinning is extremely disruptive and creates a huge mess covering lawns, landscaping and gardens.

3. Concrete underpinning can produce major problems in the future of the house. It’s because concrete or masonry underpins, unless installed along every part of a building’s footing system, often contribute to future differential movements in the structure.

Generally concrete underpinning is used to re-support a footing down onto a different underground stratum not susceptible to movement. The problem is that whilst the corrected section is then rigid, the adjacent sections that have not been underpinned will continue to move with future ground movement. That often creates new cracking in your home - unless articulation joints have been sawn completely through your walls.

Uretek is different, addressing the nature of the foundation soils and any cracks and voids therein, improving bearing capacity, raising and restoring and maintaining a uniformity of bearing strata

The expanding resin injection technology of Uretek avoids this problem. This has been shown by empirical evidence, (university research plus 30 years of specific field application).

N.B.:  In relation to concrete underpinning, Australian Standard AS 2870 warns, “Underpinning should generally be avoided where the problem is related to reactive clay,” and  “Deep underpinning should only be considered as a last resort.”

In soft ground conditions, as in many parts of Melbourne, the added weight of concrete or masonry underpinning (at about 2400 kg per cubic metre) can make the situation worse, not correct it! With the exceptional stiffness-to-weight ratio of Uretek material, this is avoided.

Compared with concrete underpinning, the Uretek Expanding Resin Injection Method is like keyhole surgery!

• With Uretek most house re-levelling takes one day or less… hardly ever more than two days.
• You don’t need to move out.
• There’s no excavation. No water. No cement dust. Practically no mess or disruption.
• Minimal affect on your garden and landscaping.

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