This blog is not an authoritative interpretation of the law; it is intended as a general guide.
In this blog, Icon Surveyor’s will consider what ‘Eccentric Foundations’ are, when they are used and why.
What is an Eccentric Foundation?
In the simplest of terms, an ‘Eccentric Foundation’ is a foundation that enables the proposed structure/building to remain within the boundaries of the building owners land. That is to say, the wall of the building and/or structure sits on the outer edge of the foundation and thus remains on the building owners land.
When are ‘Eccentric Foundations’ used?
This type of foundation is commonly used when building owners propose to build either an extension that is adjacent to or at the back of the property. The advantages of using this type of foundation draws, often determines whether a building owner’s architect/design team will use it in their design, this is particularly so, when space is limited. Primarily, this type of foundation is used up to the boundary line in order to prevent the tilting of floors in multi-story buildings. It must connect with another footing, often a strap beam or combine foundation is used. A strap beam is used to connect independent footings of two columns.
An eccentric footing might also be used when there is no possibility to adopt spread footings, or, the tolerable soil pressure is fairly high and there is a significant distance between the columns. In both of these examples it would be far cheaper for the building owner to use an eccentric foundation than it would to use a combined footing. Combined footings are used when two columns are so close that they overlap
Why are Eccentric Foundations used?
It has many advantages, the foremost being that the building owner maintains 100% of the ownership of the wall, which of itself, attracts further advantages. For example, this type of foundation is often used by a building owner whose, adjoining owner has expressed their intent to build an extension in the future and are therefore reluctant to want any projections on their land, or, when it is not possible when an adjoining owner has a foundation that projects onto the building owners land, or their own extension which prohibits a simple foundation to be built, the likelihood of a future Party Wall dispute is vastly reduced.
Icon Surveyors are happy to provide a free consultation to any building or adjoining owners who may be affected by the subject matter raised in this blog.