The method of providing a new foundation to an existing house without disturbing its stability is known as underpinning. This method greatly enhances and strengthens the weak foundation of a house and boosts its load conveying limits.
So, are you also planning to get the weak foundation of your house stabilized but confused about the methods that will exactly suit your house? Don’t worry.
The underpinning method varies from foundation to foundation. Take a look at the methods of Underpinning, so that you may select the most suitable one for your house.
Methods of Underpinning
Underpinning methods depend on:
- Age of the structure
- Type of work involved
So to start with, you have to first look at both these factors and select the best method from the following.
Methods of Underpinning
Mass concrete (Pit) Method
Here the existing footings beneath the house are moved to a greater depth where there is enough stabilized soil which can handle the required bearing capacity.
The Cantilever Beam Method
Here the already present weakened pit on one side is made stronger. The method is faster in comparison to other traditional methods.
Pier and Beam Method
In this method, reinforced concrete beams are placed below the house. This is done with the sole motive of transferring the load to piers. The method is suitable for ground conditions.
Mini piled Method
In here, steel cased piles are driven inside the ground and the load is then transferred on to the strata. The method is suited to areas where the soil is of a variable nature.
In this method, piles are driven at equal distances on both the sides of wall which are later interconnected with concrete or steel needles. This is an effective method for houses built on clayey soils.
Here the soil beneath the house is compressed. After this, a suitable method is employed to strengthen the foundation. The method is suitable for multi-story buildings.
The procedure of Underpinning in Foundation Strengthening
The ground beneath the shallow footings is first excavated. This provides an access to the underside of the basement
The existing foundation is extended by adding extra support. This can be done by the addition of:
- Resistance Piers: ideally suited for bigger homes.
- Helical Piers: The whole framework is screwed.
- By pouring a concrete mixture: concrete is poured over the piers to make it stable.
This makes the existing foundation rest on a stronger soil substratum and also helps in distributing the weight in a larger area.
The contractors do a usual inspection of the house, its foundation, and the surrounding soil before starting with the process. Only after a thorough inspection, the most suitable method is adopted to underpin the foundation of the house.
In many cases contractors adopt basement Underpinning; it is a general repair process that prolongs the durability of a residential building.
Many times the contractors use a combination of concrete and piers for basement underpinning.
Application of Underpinning in Foundation Strengthening
Besides strengthening the foundation of an existing house, underpinning has numerous applications:
- Underpinning provides you with more space, for you and your family to enjoy.
- It can be used to improve the structural integrity of the house and make the basement more usable.
- It can also be used to create more headroom in basements, thus giving you additional space to construct more rooms in your existing house.
- By this method, you can also add more doors and windows in the house and can also add better light fixtures into the ceiling.
- By getting your house underpinned, you can gain access to the mechanics of your home. You can update the existing plumbing, wiring, and insulation of the house.
- It makes the soil around your house compact and increases its holding and load-bearing capacity.
- An underpinned house adds positive value to your home; you get a good sum if you are planning to re-sell it.
It is recommended to take safety precautions while getting the house underpinned. Take care of rubble foundations, higher water tables and presence of silt and clay around the house.
Make sure you have informed the local authorities and taken permission from them to get your house underpinned.