House Underpinning Cost refers to the cost incurred in strengthening the foundation of any given construction. Underpinning may be necessary for a various reasons, which also have a bearing on the house underpinning cost, such as the original foundation is simply not strong and stable enough, the usage of the structure has changed, the property of the soil supporting the foundation may have changed possibly through sinking or changed during building construction, the construction of nearby structures requires the diggings of soil supporting existing foundations, to increase the depth or load capacity of existing foundation, to support the addition of another storey to the building above or below.
It is more economical to work on the present structures foundation than to build a new one due to land price or many other reasons, and Earthquake, flood, drought or other natural causes have caused the structure to move, thereby requiring maintenance of foundation soils and/or grips.
Underpinning may be accomplished by encompassing the foundation in penetration or in extent so the foundation rests on a more supportive soil layer or allocates its load across a larger area. Use of micro piles and jet grouting are common methods in underpinning, an alternative to underpinning is the strengthening of the soil by the introduction of a filling, which includes increasing urethane based engineered structural mastics. Underpinning may be necessary where p-class problem of soils in certain areas of the site are faced.
Types of Underpinning Methods
There are a few different methods used for house design underpinning and each result in varying house underpinning cost.
Traditional Underpinning: Traditional underpinning is the concrete underpinning method, which is nearly 100 years old underpinning method with the same procedure, as earlier. This underpinning method toughens an existing structure of the foundation by digging boxes by hand underneath and consecutively pouring concrete in a tactical order. This underpinning method is applied when the existing foundation is at a low depth and can work well for up to 15 meter depth. This is the method with the least house underpinning cost.
Mini-Piled Underpinning: Mini-piled underpinning is used when the loads from the foundation need to be transferred to stable soils at considerable depths, usually in excess of 5 meters. Mini-piled may either be augured or driven steel-cased
Beam and Base Underpinning: Beam and base underpinning in this is more progressive method of underpinning than traditional mass concrete underpinning. In this steel-clad concrete beam is built underneath, overhead or as a replacement of the existing foothold. Design of beam depends upon the configuration of the building and the load applied on it.
Expanding Resin Injection: In this method, the foundation ground beneath footing is vaccinated with a mixture of structural resins and hardener. When this mixture enters the ground, the resin and hardener mixture starts expanding due to chemical reaction. This helps in fixing any vacuums and cervices, if dense feeble soil injection continues it levels the above soil.
Factors influencing House Underpinning Cost:
- The cost of underpinning depends upon the size of your house.
- If your sinking is insured, then the cost of stabilizing your property will be covered in your insurance, but if the need of underpinning is required because of the changes done by you to the structure of the building, then it will not be covered under insurance.
- If you’re in a newly built house, which is under warranty and is experiencing sinking, then you will not get the insurance claim and in this case, you’re the builder of your home, who will be responsible for stabilizing your building.
- Cost will be according to the type of underpinning method used for your house.
- Cost also depends on how much work do take place in underpinning your building, and even the location of the building plays a major role in determining the cost of underpinning.
To know the exact cost of underpinning, you can consult your builder or you can search on the internet. Get the house underpinning done at the right time, so that the foundation of your building stays strong and there is no serious damage caused to your property.