Is extending the basement a viable option?
Q. The previous owners of my unlisted Victorian home were serial but
incremental renovators. They added a conservatory to the rear of the
property and later converted the basement below the old part of the
house. As my family now needs more space, it seems logical to extend
the current basement to match the modern above-ground footprint. Will I
need planning permission to do this? If so, are planners likely to look
on my scheme favourably? What can I do to maximise my chances of a
successful application?
A. Planning law states that the construction of a basement is development
that requires planning permission. Nevertheless, the question here is
whether the basement extension can actually be considered permitted
development. If that sounds like a contradiction, the best way to
understand permitted development is that the General Permitted
Development Order effectively grants blanket planning permission for
all kinds of development that fall within its parameters.
As it happens, there's nothing in the new permitted development
rules to say that a basement isn't covered. So, here, regardless
of whether the conservatory was permitted development, a basement
could be built under it, extending some three metres into the back
garden, provided it was more than seven metres from the rear
boundary.
The three-metre length assumes the council would take the view that
the basement and conservatory together constitute effectively a
two-storey extension. If, as is possible, they view the basement as a
single storey extension (ie they ignore the conservatory) then four
metres would be allowed. If you wanted to enlarge the conservatory to
match that, then you'd have to apply for planning permission.
Your scheme shouldn't be contentious from a planning point of
view, but I'd recommend getting pre-application advice from the
council. Good, clear plans are a must too, but otherwise this should
be straightforward.
Mike Dade
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