I have seen on numerous occasions Subsidence occurring because of a band of Peat, the depth of the Peat is irrelevant, a structure is standing for 20 / 30 Years, then one Summer the property over a short period of time starts to show indications of Subsidence.
The Kicker is that the property has stood on the Peat for a considerable time and for some reason, ground water rising, falling, torrential rain, a leaky drain, or water pipe the peat fails to support the load imposed and Subsidence occurs.
I have used Peat as an example, there are other Strata that will produce similar outcomes.
Likewise I have seen dozens of Subsidence occurrences in "Extensions" either Conservatories or brick, Timber frame extensions, the foundations of which are taken down to the same level as that of the Original property to which the "new extension" is being constructed, the new extension then begins after a period of time begins to Subside.
What generally happens is that the Builders of the original property have had to excavate out some poor ground bearing strata, the Extension Specialist bolls up and takes his new Extension excavation to the underside of the Original Property, after a wee while, the Extension begins to Subside.
Hence the need for a Ground investigation generally called an SI to a depth of 5.M.
As for the life expectancy of the jacking Mechanism? if the jacks are made of steel, they will corrode and fail at worst, Or if you need to Adjust the level but screwing the jack, will prove problematic, why because in the highly aggressive environment of where the jack is sited the Corrosion will Seize up the Screw itself? Even Stainless will be struggling? As an aside, how do you get at the screw to adjust it, also what is the maximum length of travel? I may have missed that on the promo clip?
The tiny excavation and dropping in a Block? Concrete of a known strength that totally fills the Excavation is the generally accepted method of forming a Foundation, Concrete will completely fill and get into contact with the base and sides of the Foundation excavation thus enhancing the Foundations ability to spread the imposed loading. As an aside, the imposed load on the Foundations dissipates at an angle of 45 Degrees uniformly, if the dimensions of the blocks used fail this criteria then the load being imposed will not be adequately be distributed.
Ken
The Kicker is that the property has stood on the Peat for a considerable time and for some reason, ground water rising, falling, torrential rain, a leaky drain, or water pipe the peat fails to support the load imposed and Subsidence occurs.
I have used Peat as an example, there are other Strata that will produce similar outcomes.
Likewise I have seen dozens of Subsidence occurrences in "Extensions" either Conservatories or brick, Timber frame extensions, the foundations of which are taken down to the same level as that of the Original property to which the "new extension" is being constructed, the new extension then begins after a period of time begins to Subside.
What generally happens is that the Builders of the original property have had to excavate out some poor ground bearing strata, the Extension Specialist bolls up and takes his new Extension excavation to the underside of the Original Property, after a wee while, the Extension begins to Subside.
Hence the need for a Ground investigation generally called an SI to a depth of 5.M.
As for the life expectancy of the jacking Mechanism? if the jacks are made of steel, they will corrode and fail at worst, Or if you need to Adjust the level but screwing the jack, will prove problematic, why because in the highly aggressive environment of where the jack is sited the Corrosion will Seize up the Screw itself? Even Stainless will be struggling? As an aside, how do you get at the screw to adjust it, also what is the maximum length of travel? I may have missed that on the promo clip?
The tiny excavation and dropping in a Block? Concrete of a known strength that totally fills the Excavation is the generally accepted method of forming a Foundation, Concrete will completely fill and get into contact with the base and sides of the Foundation excavation thus enhancing the Foundations ability to spread the imposed loading. As an aside, the imposed load on the Foundations dissipates at an angle of 45 Degrees uniformly, if the dimensions of the blocks used fail this criteria then the load being imposed will not be adequately be distributed.
Ken
