A trench has been dug round a brick built building showing settlement cracks and I noted that the concrete foundations are laying on top of a band of natural gravel. I last worked on such a problem in the 1950s when serving my time as a Bricklayer and we undercut the foundations, laid concrete with sufficient gap to insert large jacks, lifted the house and then built support pillars. Does that make sense and if not what would be done nowadays?
Underpinning on a gravel base.
- Thread starter BML
- Start date
Modern remedial s are a wee bit different
Check out Shire Piling, they have several videos selling their "systems" it is a system based around bored "piles" which are mechanically fixed to the foundations, but will only work effectively in some types of soil. This system "locks" to building in its "deformed" state and stops any further movement
or
Look at Uretek this system, can [it is claimed] actually lift a building, its systems can certainly "lift" slabs, there are several promo videos by this company.
The above pair are [probably] the most long standing exponents in their different way of attacking Subsidence.
Over the past 5/7 /10 years many, many more "systems" have jumped on this band wagon, which is fueled by the Insurance Companies repair methodology in Subsidence repairs
Simple form a hole, undermine a small area of the underside of the foundations, insert a jack has to a greater extent run out of "fashion" yes if hit / miss mass underpinning [which has also run out of "fashion" ] did have a jack involved, but that was a "Sacrificial" prop used as a completely temporary measure to stabilise the building until the concrete mass fill had taken a set.
Ken
Check out Shire Piling, they have several videos selling their "systems" it is a system based around bored "piles" which are mechanically fixed to the foundations, but will only work effectively in some types of soil. This system "locks" to building in its "deformed" state and stops any further movement
or
Look at Uretek this system, can [it is claimed] actually lift a building, its systems can certainly "lift" slabs, there are several promo videos by this company.
The above pair are [probably] the most long standing exponents in their different way of attacking Subsidence.
Over the past 5/7 /10 years many, many more "systems" have jumped on this band wagon, which is fueled by the Insurance Companies repair methodology in Subsidence repairs
Simple form a hole, undermine a small area of the underside of the foundations, insert a jack has to a greater extent run out of "fashion" yes if hit / miss mass underpinning [which has also run out of "fashion" ] did have a jack involved, but that was a "Sacrificial" prop used as a completely temporary measure to stabilise the building until the concrete mass fill had taken a set.
Ken
Many thanks for the advice. I'm having nothing to do with remedial work having wrapped my trowel up many years ago. The square where the house is have a number of houses showing settlement cracks. They were built along with a considerable number of other sites for employees of the UKAEA and had a good reputation but the house I referred to has foundations that rest on gravel of an indeterminate depth. IF it is deep it looks like an ongoing problem. The Building Regulations officer was due today and I wait with interest to see what he set out as requirements.