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Photos of trusses we have made for barn restorations


farmerjohn
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Nice sturdy frame that farmerjohn. Green timber, or dry graded?

and what did you make the pegs from?

cheers .

 

its green oak, thats why we put some oak pegs through, think they were about 25mm diamiter, just in case it dires back, didnt want the possibility of the tie beam shrinking back quicker than the principle rafters and potentially 'dropping out' we also put some adhesive in the half lap which will never be seen as well if i am being honist

dry graded would have been too expensive, as there was not building regs we did not need to use graded timber, but the guys i get the beams off are pretty good, i asked for not big shakes, knots or flaws that may affect the strucutre of the truss.

thanks, john

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dry graded would have been too expensive, as there was not building regs we did not need to use graded timber, but the guys i get the beams off are pretty good, i asked for not big shakes, knots or flaws that may affect the strucutre of the truss.

thanks, john

 

Hardwood is currently visual grading only for building regs. Effectively what you asked for is in fact the best grading there is. Very handy rule if you want to fell and mill your own timber. Softwood is much more tricky as you have to get it tested.

 

Alec

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Hardwood is currently visual grading only for building regs. Effectively what you asked for is in fact the best grading there is. Very handy rule if you want to fell and mill your own timber. Softwood is much more tricky as you have to get it tested.

 

Alec

 

yeh its odd that, does anyone know the reason for this? i asked for good oak but not HT graded (i think thatswhat they call it) so i dont get any paperwork with it, but it should be pretty good and only get charged green oak cost.

i had a structural engineer work out sections for truesses, purlings and ridges. only so i know that if we made it to a calculated spec it will not have any problems in the future.

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Here's a newish green oak truss roof that didn’t go so well!

I’m posting it because the cause of failure was down to the grading of the timber; specifically slope of grain. Oh and yes, the inevitable fissuring that occurs as green oak dries.

The raised tie beam result in really rather high bending moment at the connection to the rafter. The very artfully crafted dovetail jointed trusses at the start of this thread have a similarly high tie beam and relatively high moment. However the span of the trusses is very different.

Note the pegs haven’t failed in my example. The timber failing along its weakest axis. The eaves distortion resulted at both sides of the building pretty much equally. Oh and the ridge had a nice dip of about 300mm too. The first photo is not a 'before'. its a neighbouring truss at the other end of the roof.

edits.jpg.eba21067e638b73b4f098833d0b3f7b4.jpg

5976625630dae_DSC04735photopages.jpg.3f0bad298b736442015bce333b86f3d0.jpg

597662562ee8c_DSC04734photopages.jpg.d0e203d273c96a1ec5b1f460dec4cac5.jpg

597662562cb83_DSC04733photopages.jpg.d7c4bf88b0b67b050cd181e845a456a8.jpg

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