This guidance note provides advice on the methods, materials
and risks involved with insulating solid ground floors. The
energy saving resulting from insulating solid ground floors can
in many cases be of marginal benefit when the cost and
disruption to the building fabric are considered. Insulating other
building elements is likely to produce greater benefits in energy
efficiency for significantly less cost. This is partly because a
typical solid floor already provides a degree of insulation, but
mainly because the ground beneath maintains a stable
temperature of around 10 degrees C. However, where an
existing floor is being taken up, replaced or repaired, then it
can be worth making use of the opportunity to improve thermal
performance.
Solid ground floors can be a significant part of the history and
character of a building, so taking up floors and excavating
below to install insulation can be extremely damaging to
valuable historic fabric. Even where the floor finish is of no
particular historic value, any alterations to the floor structure
beneath need to take account of potential buried historic
features and archaeology. This can, for instance, be
particularly significant in churches. All such work will require
consent if the property is listed.