Hello All,
In the survey for a house I hope to buy, the surveyor has recommended I fit diagonal bracing / metal gable ties to the roof trusses as a precautionary measure.
Does anyone know what this involves and if it if possible to do it yourself?
Thanks for any info,
Tony
precautionary
Surveyors don't consider the roof battens to be adequate bracing. These trusses would have been laid flat at eaves level initially. They are then raised one at a time and nailed into the wall plates ( timber bedded on top of the last course of bricks - typically 100x47mm sawn treated) Some bracing is normally fitted diagonally to the inside faces of the trusses (what would be the inside face of a rafter on a traditional cut roof - typically 100x25) A further brace is installed just under the point of the ridge (apex) running the full length of the building. The bricklayer then builds the gables using the end truss as a guide for cutting his bricks. After this the lateral restraints are fitted ( galvanised bar approx 6mm thick and 30mm wide fabricated in an L shape. The small part of the L sits against the brickwork/blockwork, and the long length of the L is fixed to 2/3 trusses which are commonly at 600mm centres.
Possibly, but probably a job for a contractor. HTH. Not easy to explain using text.
-- Keith.
If you get exactly whats needed written down by someone suitably qualified it should not be particularly hard to do.
Regards, NT
Feeding it through the rafters when the roof is covered is a job and an half I imagine. You will never get them up through the loft hatch that is an inspection hole not a utility doorway.
The braces are rough sawn treated 4 x 1 and go under the top pieces of a built up rafter (roof trusses) they were not used as much in the 1970's as they are now when the trusses first started to be used. Just boards to hold the trusses apart. The idea of the diagonals is to stop wind movement and other shaking.
The bar -perforated zinc, rests on its own 4 x 1 at the gables (a pair equidistant)and along the wall plate (where the trusses run parallel to the wall. Something like 1.8 metres apart(??) -or is that for the wall plates I forget.) The hook fits inside the cavity.
Look up a site that shows trusses and google for what the surveyor specified to see diagrammes. Since the survey only suggested you do it you can work aroud it by using longer bar and bending it in the middle and just plug and screw it to the wall. Likewise you might just use more boarding in more accessible places if you want to do as he suggests. You don't have to use 4x1 for example and you might just run it flat on the top of the ceiling with something on the other spars. Screw or nail it makes no difference.
I would be surprised if it were not possible and practical to design something that could be carried in pieces up through the loft hatch. Its not like any parts of the structure are getting replaced.
Regards, NT
Possible yes, practical though?
Any bracing aught to span two rafters where they meet. If the house is a concrete or clay tiled roof dating from the 60's or 70's it will be ready for a re-tile soon so why not wait until then?
If the tiling is sound, there is no need to bother. I think it is a matter of diminishing returns. IMO the surveyor was just pointing out a difference in regs the buyer might not have expected or understood.
If you can stand up in the loft above the hatch then that's, say, 6'. Quite easy to get even longer lengths through most loft hatches.
MBQ
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