The existing roof structure may be altered or upgraded as part of the conversion.

Type of Structure:
Two key structures are used for roof construction, the traditional framed type and truss section type. The traditional framed
type is normally found in pre-1960s houses where the rafters and ceiling joists, together with supporting timbers, are cut to size and assembled. This style of structure has more structural input so is frequently the most appropriate type for conversion. The area can be simply opened up by strengthening the rafters and adding supports, all at a reasonable cost. Since the 1960s the most common form of construction was factory made truss roof sections. These utilise thinner, cheaper timbers but have structural reliability with the additional braced diagonal timbers. These allow a house roof to be erected and felted in a day, which is a huge benefit. Nevertheless, this type of truss suggests that there are no load bearing structures below and opening up the area demands greater added structural input. This generally involves the insertion of steel beams between load bearing walls for the new floor joists to hang on and to support the rafter section, together with a steel beam at the ridge. This additional structural input requires skill, knowledge and equipment which can all be provided by Harris Loft and Extensions Ltd.