CUTTING IN A ROOF

[FORDER]

MY PROBLEM IS TRYING TO WORK OUT HOW TO GET THE ANGLES ON THE RIDGE BOARD PLUS THE MEASURMENT TO THE BIRDSMOUTH ON THE WALLPLATE. CAN ANYONE HELP.

 

[DAZB]

Roof framing is difficult to do and even harder to explain without showing you but the easiest way to do it is to do a dry run on the lawn or drive.The angles that meet the Ridge board are the same as the pitch of your roof. i.e: if your pitch is 30 degrees then the rafter cut is 30 degrees. Set your bevel to that angle and cut these two first.Then get a small offcut of the Ridge board , lay it stood on end and butt the rafter cuts up to it so they are sitting flush and creating the shape of the roof on the floor.From this position you should be able to relate this to the width of the building you are roofing and determine where you need to cut the birdsmouth in order for it to sit in place.Using the rise of your roof ( the height of the ridge from the wall plate )you can place a timber across the laid out rafters , measuring down from the ridge till it is in the correct position.You can then mark it and slide it across and draw round the corner of the timber to mark the birdsmouth ' NOTE' !! the birdsmouth should be no more than one third of the depth of the timber used !! Slide it the other way and repeat for the other side.If this sounds a little complicated then I will try to direct you to a site with a few diagrams but without understanding all the terminology it may be hard going.Try a dry run with roofing lat first and once you have got the first pair correct the rest should be the same on a straight run of roof.Let me know if you need more help.

 

[FORDER]

THANKS YEP UNDERSTAND THAT PART . NEXT BIT IS THE 2 SLOPING RIDGE BOARDS THAT GO OUT TO THE CORNERS OF THE BUILDING . CUTTING THE ANGLES THAT COME DOWN THAT SLOPE ?

 

[DAZB]

This is a far more complicated set up to explain and near impossible to relate over the Internet.Other than getting a Joiner in to cut in your hips you could find your angles by trial and error but it is very frustrating as you need to make Compound Mitre cuts ( cuts on two slants at the same time ) and you may have to do them by hand if you don't have access to a decent Chopsaw.Another method would be to get hold of a book on the subject but even then you will need some understanding of the angles and terms used ( definately not for a novice ).A book of Tables is available called the Roofing Ready Reckoner which will assist in working out length of rafters, angles, bevels and so on but it is not at all easy to get straight into.My advice would be to get a First Fix Joiner to do the job and for you to 'labour' for him and then you can see the process and pick his brains.Good luck with your roofing.