Underpinning foundations safely can help with compliance
Construction refurbishments that involve underpinning foundations could be in the spotlight in the weeks to come as the Health and Safety Executive clamps down on Greater Manchester sites that do not meet the necessary safety standards.
The coming crackdown is focused particularly on sites where refurbishment and repair work is being carried out – such as underpinning foundations to help stabilise older buildings.
Legal requirements state that any work on the structure of a building should be carefully planned in order to avoid unplanned collapse.
As such, underpinning foundations without the right equipment from specialist providers, and without temporary supports in place for the rest of the building, could leave construction firms at risk of breaching their safety obligations.
“The refurbishment sector continues to be the most risky for construction workers, but small changes to working practices can make all the difference,” says HSE principal inspector for construction Neil Jamieson.
Our specialists can offer foundation piling where traditional underpinning is not possible, safely strengthening your foundations through a combination of piling and needle beams in the poorest of ground conditions.
Underpinning foundations can help prevent heaving
Underpinning foundations can help deal with all kinds of soil conditions – and as the cold of winter gives way to the rainy days of spring, ‘heaving’ is one issue that you might encounter.
Soil is subject to a lot of weather-related effects, and we recently told you about expansive soils, which can become unpredictable in particularly dry conditions.
However, when it is especially wet, all types of soil can experience heaving – this is when the level of moisture in the ground becomes high enough that the soil expands significantly, and can literally push foundations upwards out of the earth.
By underpinning foundations, you can tackle this effect by strengthening the position of your structure within the topmost layers of soil.
Alternatively, if you are working on a new construction project, concrete piles can give support to your foundation or basement levels from deeper underground.
When weather conditions are less than favourable, there is the option of using pre-cast concrete piles delivered from off-site.
These offer the strength of reinforced concrete, but are not subject to the vagaries of the weather during their drying time, ensuring that the necessary chemical reactions can take place to make them strong and reliable.
Underpinning foundations can tackle expansive soils
Underpinning foundations is a good way to create stability in soils that are not stable enough to support structures on their own.
Expansive soils are a particular cause for concern – these are where changes in moisture content can make the ground expand or contract by quite a large amount.
Following a fairly dry 2011, soils in many areas are likely to be much drier than they would ordinarily be, making some construction projects unpredictable.
In England, for example, Met Office estimates for the whole of 2011 are that rainfall was just 84% of its normal level.
Even in December, England’s rainfall was down, at 99% of its expected average for the month.
With this in mind, builders could find dry soils are unable to support foundations as well as they ordinarily would do – and some already-completed buildings may well develop foundation problems, too.
By underpinning foundations to help improve their stability, construction projects can be kept on track, and completed structures safeguarded.
With the Met Office forecasting a warmer-than-average year for 2012 as well, the need to underpin foundations could arise more often in the future, as soils dry out and offer less support than they have done in years gone by.
What is the Purpose of Underpinning Foundations?
Underpinning foundations are used when the depth of a building’s foundations need to be increased. Normally, small sections of the ground below the existing foundations of the building will be excavated before they are underpinned. This will usually be done with concrete but when the quality of the ground is so poor that using concrete isn’t possible, piling can be used instead.
This allows for some flexibility in difficult situations as there are different types of piling available that can be used for underpinning. Underpinning foundations can be used for a few different reasons. For instance, if another storey is being added on to the building, the existing foundations might not be able to take the increased load and so underpinning will be required. Also, if a house has suffered from subsidence and the current foundations have been damaged or have moved, underpinning foundations could be used to help rectify the problem.
It’s important that underpinning foundations are put into place in the correct manner, or else they could cause damage to the building. This is why it is so important to always use experienced, professional services when making any alterations to the foundations of a building.