We use only the best innovations in underpinning technology to bring you the services you deserve
Over time, your concrete will start to sink. The ground beneath our feet is fickle, which means that your house foundation or foundations elsewhere on your property will not always stand the test of time.
Say your home is suffering from sinkage. You might be familiar with underpinning, a process in which any weak spots in your foundation are reinforced by material poured or injected underneath. But it is important for you to know that all underpinning is not equal.
Traditional techniques used by most underpinning Melbourne companies — mass concrete underpinning, cement grouting underpinning and steel pile underpinning — are actually quite outdated.
Not only are they far more expensive, time consuming and disrupt your schedule, forcing you from your home or property for an extended period of time, but they also are not always guaranteed to work! Especially for a larger Melbourne home, you need more reliable and efficient underpinning services.
We can offer something better.
- A non-invasive and quicker process: You can see the slab moving as the resin is injected, so you know it is working right away. The resin takes 15 minutes to fully cure, ensuring that there is little to no disruption to the work area.
- Better results: Once hardened, the resin becomes stronger than concrete. The resin expands into the voids in the soil, creating a strong base that will prevent future movement.
- 25 year warranty on all materials used, giving you peace of mind
What is Polyurethane Injection Underpinning?
Also known as Chemical Underpinning, polyurethane underpinning is the process of injecting a 2-part resin under the affected area of the slab, causing a rapid expansion which fills any empty spaces (or voids) in the soil. This strengthens the soil and creates a strong base which ensures that the property will no longer sink. Using this solid base, more resin is then injected on top causing the property to lift back into the original position and returning it to a near new state.
Traditional concrete underpinning vs polyurethane underpinning
Traditional underpinning services use concrete and steel to reinforce the area under the slab. To achieve this, excavation is required. This creates a big mess, potential damage to the site by the excavation equipment and can take a long time to complete.
Unlike the methods used by most underpinning Melbourne companies, underpinning using chemicals such as Polyurethane is a non-invasive method and achieves a stronger outcome. 16mm holes are drilled in the ground under the slab for the resin to be injected having no contact with the existing footings. This process is cleaner, quicker and can be done in a considerably shorter period of time.
Causes Of Subsidence/Settlement Of Structures
Clay soils have the ability to absorb or dispel moisture. In a wet environment, clay will absorb moisture increasing its plasticity and expanding. This causes heave in footings and structures. In contrast, in hot and dry environments, it becomes hard, brittle and non-plastic shrinking in the process. During periods of prolonged drought, the clay shrinks to the extent that the structure supported by it subsides significantly. Any other cause for loss of moisture in clay will cause subsidence and settlement; this includes tree roots and vegetation, or the construction of a new structure which affects the impermeability of soil beside structure.
Poor site drainage can lead to water ponding against and seeping below a concrete structure, be it a house or a warehouse slab. The water weakens soil and washes away the silt/sands from silty and sandy clays. This leads to voids and weakening of soil causing subsidence. Cracked or leaking pipes (drainage or sewer) is another cause of poor site drainage. Therefore, we recommend regular checks of all pipes for any signs of leak.
A 150mm thick concrete slab can typically support a weight of 860kg/m2. However, the soil supporting the slab can have less support weight/bearing capacity. Once a structure or another type of load, such as a heavy vehicle, overloads this limit, the concrete begins to weaken and cracks can begin to form and soil underneath starts to settle. This creates openings for moisture to enter; weakening the underlying soil. A crack that is 5mm wide has the potential to reduce the weight capacity by up to half of its initial strength.
Waffle slab footing (edge and internal beams) can be supported on up to 300mm of ‘controlled fill’. The controlled fill has a strict method of laying, and is required to be of clayey materials with 97% of moisture. We recommend that all edge ribs are trenched through this fill and founded into natural clay. However, when the ribs are founded on fill, if it hasn’t been prepared as per requirements set out in AS2870-Residential Slabs and Footings, then the fill will settle over time and the slab will subside and show signs of distress.
If the adjoining land to your property is vacant, and during slab preparation your footing is undermined, that is the adjoining cut is below the bottom of your footing, this may loosen soil and cause subsidence.
Whatever the cause, our Melbourne underpinning services can help.
- Our engineers will do a site investigation to discover the reason for subsidence and any cracking so that we can ensure that the correct method of rectification is undertaken. If required, we will do a soil test to determine the soil profile and, by using the latest technology, we can track the site moisture and the full extent of subsidence beneath your Melbourne home or property.
- After identifying the cause, we will provide you with the best rectification solution. We will mark out the injection locations (both externally and internally) for our contractor to do a full survey of using a ground penetrating radar (GPR), locating all service cables/pipes to ensure that any existing services are not damaged.
- Once injection hole locations are confirmed as clear of existing services, 16mm holes are drilled approximately 1500mm deep at each injection location. This can either be in soil external to structure or internally. Ports are inserted to begin the chemical underpinning and injection process.
- Survey equipment is set up to monitor the lift process, to ensure adequate lift is undertaken. The injection process is started. Once finalised, the rods are cut, and holes re-grouted. Site is cleaned and any additional rectification works are complete.
We expect that the job should take a day at most.
Residential underpinning Melbourne
We have a wide range of experience working with Melbourne home owners to protect their property. With us, you will not have to move out of your home — you will not even have to leave while the underpinning job is being performed!
Underpinning your home or property in Melbourne is a must whenever damage is detected, so we believe that the experience should be as simple, effective and affordable as possible.
Get the underpinning Melbourne experts
Call us at 1800 18 20 20 today to find out more about our Melbourne underpinning services—our team is always willing to have a chat to discuss your job.
With a combined total of 50 years experience on the job, we consist of a registered building expert, structural and geotech engineer, and some of the best technicians in Melbourne. If you need underpinning Melbourne services, you’ve come to the right place!
We pride ourselves on our customer service, so feel free to reach out and we will strive to provide you with the best Melbourne underpinning experience.