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Big job? roof bracing framework and gable wall restraint


I'm looking to buy a new house (first time buyer) and the survey has come up stating the following:

"There is insufficient bracing to the roof framework which could allow movement of the trusses. Also, the flank gable walls has not been properly restrained and is at risk of movement. Correct bracing and restraint should now be provided by a competent contractor in accordance with current Building Regulations. The main roof void does not appear to be sufficiently ventilated. Fixed air vents should now be installed to prevent moisture condensing on the timbers. In the long term, it is possible that timber decay could develop if correct ventilation is not installed. The vents should not be obstructed by insulation."

Now to me, this sounds like quite a big job but then again I'm not expert, hence the question here :)

Does anyone know if this is a large job? It's a 3 bed, detached house. Is it reasonable for me to ask a couple of builders to pop around to the house to take a look to assess the extent of the work?

Any advice would be appreciated. Thanks

1 Answer from a MyBuilder Roofer

Best Answer

When you are up the loft you need to fix 4"X1" (100mm x 25mm) treated timbers to the existing rafter load points.
Firstly look at the ridge point (top of trusses), there should be a solid timber running the length of the roof line. Making sure the timbers lap each other by 2xno trusses.
Secondly look at the ceiling and mid way rafters and repeat the above.
Then you need to fix diagonal bracings at 45 degrees to the wall plates, making sure they lap each other by two trusses again. (You might want to fit the diagonal bracings 1st if you are tight for space).
For fixings I would use 3" 10s screws and a combination drill on a slow setting, as nailing or using an impact driver could loosen or crack tiles.
If the roof span exceeds 10m (wall plate to wall plate) then you need to fit chevron bracing. This is achieved by fixing bracings over 3 trusses at 45 degrees to gable ends, but starting the next bracing in line on the last truss you finished on ! On the opposite side of the roof repeat, but in the other direction making an x formation.
Metal restraint straps at 1500mm should then be fixed (screwed and plugged), using 4" 10s to the gable ends on the previously fixed timber bracings. There should be 5 per gable and no more than 2m between steel restraint straps.
The tile vents should be placed around a third up the roof slope to allow correct ventilation. As mentioned not to be covered by insulation. Around 4 vents per roof pitch should do the trick.
Look out for pipes and cables as well !
Long winded but doable lol

Hope this helps,
Lee Jones


Answered 16th Sep 2017

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