18/6/12

So this morning,We all lined up for class with Mark.We went back over the session we had last week in regards to the Roofing.Rafters and Trusses.We went over various terms for each section of a rafter set up.

After smoko we were split in 2 groups and one half of the class were to proceed with the Purlins while my half were put on the roof making task,we went back over SOH CAH TOA,We were given an angle for our roof,ours was 40 degrees.The width of our building was 2000mm,and the length was 2400mm,we halved the width,so 1000mm,We needed to find the length of our rafters.So,The method we used was,CAH as we needed to find the longest side.So Cos40 x 1000,That gives us the lengt of the Longest side,(The rafter).We used a sliding Bevel to transfer the angles to other rafters.A hand saw was used to cut them down to the correct lengths.We then had to cut out a piece known as the birds mouth.Matt showed us how to do this,For our roof,I measured out 1288 and marked a line,Then from the line I transfered it with a sliding bevel with 40 degrees.Then moved the bevel to the end with the builders square and adjusted it then moved it back forming the piece(Birds mouth) which is to be cut out,Once it was cut out,the rafter can frimly sit flush onto the top plate of the building.

Outriggers being nailed off.

Working out how to cut out or birds mouths.

Once all the rafters are cut,They are evenly spaced then attached to the ridge board at the top.We then skewed the rafters down.Tomorrow we will finish the building exercise,The Purlins should be attached and the raking top plate will be finished.Then we will be ready for marking.