Firrings on a pitched roof - Please help :)

[rebecca1971]

Please can someone advise?

im currently having an extension, and our roofer measured up for our new trusses and did it wrong (hes just great, we love him)

His little measuring device calculated at 20 degress, but its actually 17. Anyway we were thrilled at this, especially when our bricklayers offered one of the trusses up for fit and told us. ohh the memories of that day, lovely...

Anyway, I was just going to scrap the whole roof, buy a log burner and burn the roof (money) but the roof rafter maker company suggested we use firrings to make the wrong pitch (20) match the old pitch (17) is this a doable thing?

we are taking all the roof tiles off the old roof anyway and just wondered your thoughts?

its not such a great problem to get new rafters made, costs about £500, my problem is im unable to find anyone who can actually give me a precise measurement, im worried im going to buy a new roof and be back at this point with 2 piles of rafters to burn! but of course I dont want a bodged job!

Info it gratefully received

Thankyou

 

[datarebal]

some truss makers will measure for you... having said that firings will probably work, We have worked on roofs where the pitches were wrong the other way round and used firings.
Or get a carpenter to do you a cut roof

can you tell?

 

[^woody^]

I've had this happen a few times where dimensions and angles were slightly out for one reason or another, so new trusses don't align with the existing roof.

If a shorter span or lower pitch, then it's easy to just determine the required sizes and fix the furrings on top of the trusses. Not a problem.

But in your case, you would do as suggested and put the furrings on the existing rafters/ trusses.

 

[noseall]

Yes, we have had the truss company (their surveyors mistake) do it for us. What the truss companies tend do is always err on the lower pitch side so that the mistakes can be easily rectified with a filler.
I now measure the pitch myself using levels and trig' (don't trust devices) and corroborate with the truss company, irrespective of what the surveyors says.