Mass Concrete Underpinning
Mass Concrete traditional underpinning is the most established underpinning technique, most commonly used to strengthen an existing foundation and rectify issues such as subsidence and ground heave – in recent times there has been an uptick in demand for mass concrete underpinning in order to retrofit basement areas.
Construction Sequence
Underpins are excavated in a hit and miss sequence, most commonly each of these underpins will be 1.0m – 1.5m in width, an access pit is excavated & excavations in excess of 1.2m are shored with timber.
Once access has been gained to the correct designed depth the underside of the footing is cleaned, any loose material removed and shutters installed.
Concrete is then poured 75mm shy of the underside of existing foundation, once cured the residual is dry packed with a sand/cement mix to ensure load transfer into the underpin.
Applications
Domestic/commercial subsidence & heave foundation failures, basement retrofits.