Underpinning is used to enhance the foundation of a building. Sometimes, the foundation is not stable or strong enough to support a building. A Residential Underpinning is therefore used to increase the depth of the original foundation. This is done by building new footings that enhance the previous footings. Footings can be made of concrete or of steel piers. Footings are constructed at more stable and stronger soil to better support the building. Stronger soils allow restricted movement giving rise to stronger buildings. A lot of times cracks develop in buildings over a span of time. This usually suggests the need for a stronger foundation and thus the need for underpinnings.
When to get Residential Underpinning
It is important to understand when to use Residential Underpinning. Usually, in cases where the shift in building footings is irreversible, an underpinning is required. Footings constructed on soft soil usually need residential underpinnings over time. Soft soils become loose gradually and can lead to unstable buildings. Shallow footings might need underpinnings too to level up your building to a proper height. A residential underpinning can be a lifesaver in such cases.
Know when Residential Underpinning is not required
Clayey soils usually differ in moisture content. Also known as ‘reactive clay movement’, the movement of buildings occurs due to changes in the moisture level of clayey soils. This change is usually irreversible and doesn’t require a Residential Underpinning. It is therefore important to analyse the type of soil on which your building is built to better understand whether to use a residential underpinning or not.
The process of building a Residential Underpinning
In short, the process of building a Residential Underpinning involves digging deeper holes for footings that go into stable and stronger soil, usually a few metres outside the perimeter of the house/building. The soil chosen is strong enough to support the building structure properly. The next step involves connecting the underpinnings to the main building structure. The new footings have to be constructed at a depth lower than the existing footings. Concrete is filled into the reinforcement bars.
The footings inside the house can be underpinned too which is then connected to the outside footings.
A residential underpinning takes time depending on the number of new footings constructed. Usually, it can take two weeks to a month.
Underpinning your house/ building
Constructing a Residential Underpinning is a step-by-step process and includes the following steps
- Getting your soil tested
- Contacting a Building Engineer who is experienced and understands your locality
- Record the damages to your house/building as assessed by the engineer
- Know which portions of your house/ building is damaged
- Take suggestions from the engineer whether your house/ building requires an underpinning or not
- Once your engineer suggests underpinning, make sure you get a solid design for your Residential Underpinning
- Getting hold of a reputed underpinning contractor
- Construction of the residential underpinning
A few more things to keep in mind while constructing a residential underpinning is whether to get building approval or not. A reputed structural engineer usually has a pretty good knowledge of the local building laws and can guide you throughout the process. Let the engineer decide which type of underpinning to construct for your house/ building.