Repairs: roofs and rainwater goods

A surprising number of building owners seem unable to resist the urge to move into the roof space for storage or other purposes.

The first things to go are the ‘excessively inconvenient’ struts, spars and chords, which are sawn away at a whim. What did the householder think the timbers were there for?

These 'improvements' (usually) quickly become apparent from the outside. There may be clearly visible sagging of the external surface of the roof. The edges of interlocking tiles often become unlocked in the process because the slight curvature of the roof causes the roofing battens to bend and the tiles to kick up out of line. Ceiling joists may also start to sag, causing joints between plasterboard sheets to open and the plaster over the nail heads to pop off in the ceiling, if the ceiling bends under the now-unrestrained loads of the new floor or the pre-existing water tank.

If the roof is over a block of timber-framed flats, the situation can only get worse because of the various owners and interests involved in the resolution. Nevertheless, you should seriously consider a new roof frame. For example, if considerable repairs are required (which is likely) it may be very difficult to establish load-bearing walls on which to temporarily support the structure, in addition to the disruption to the other residents that may result if temporary support needs to be taken up through each floor of the building.

Solution

If distortions prove minimal, it is possible to reinstate the framework by inserting new struts with oversized plywebs to plate over the new connecting points. Such a repair is suitable for all dwelling types, but a few extra investigations are needed before proceeding (particularly for flats, given all the various interests involved):

• Carefully consider legal as well as structural issues. Do other residents need temporary relocation and so on?
• Is an insurance backed claim from other residents against the defaulting flat owner likely?
• Will it hinder the repairs process? Will this property (and the others) be mortgage-worthy if the works are done in a particular way?
• Should the works be supervised by a chartered building surveyor or a chartered structural engineer? (Some mortgage lenders are surprisingly choosy about using one or the other.)