The most common reasons for having to strengthen an existing roof is either that the roof has deteriorated because of woodworm infestation or rot, or that it now has to support a new and heavier roof covering.

Often older slate roofs were recovered with heavier concrete tiles without any consideration being given to the supporting roof structure. The result of this is that the roof starts to deflect excessively. In extreme cases the roof may even collapse. Sometimes this is picked up by the homeowner, sometimes it is picked up when alterations are being carried out, but more often than not it is picked up by a Surveyor when the property is being sold. It is normally possible to design an economic strengthening scheme which can be fitted in a day or two with minimal disruption to the building.

We need the following information to design the necessary roof strengthening work:

the distance between the front and rear walls

the approximate height of the roof above eaves level

the span of the purlins

the size of the existing purlins (assuming they are in good condition and are being retained), keeping the existing purlins will reduce the size of the new purlins which will be required

the type of roof covering.

the approximate location of the building

Design information

All design work is carried out in accordance with BS5268 (The structural use of timber).

The calculations provided will be suitable for Building Regulation approval.