19/6/12

So this morning we went up stairs to learn more about Trigonometry.We were given a few mathematical equations that we had to solve.We used SOH CAH TOA,Sine,Cosine and Tangent.We were given an angle to work with along with a side to a triangle.For example,16 degrees with an adjacent of 300 and we are to find the Hypotenuse,The longest side.So we use CAH.300 divide by cos16 = 312.08, This is how you get the H side in this equation.

Sides of a triangle.

To find an angle,It is a little bit different.If we have two sides,Lets say,For our opposite,we have 1080 and for our adjacent,we have 7200,We go 1080/7200 =0.15  Then 0.15tan-1 which will give us the and of 8.53.





After the session in Class we resorted back to the E-Shed.My assigned group was to continue with the Gable Roof exercise.I started with making the Raking frames for the build,Then moved onto making the Outriggers,There are 3 out riggers on each side of the Gable roof,They are evenly spaced out and nailed into the rafters on the inside of the roof so that the fly rafters can be attached at the end of the roof on the outside.They also have plumb cuts at the top so that they can evenly join up to the Ridge board.With the Raking frame,We have studs that run from the bottom plate to the top of the raking plate with the top being on a 40 degree angle.For the center stud,we have 2 40 degree cuts on the top so that it sits flush within the top of the raking plates.Once all fit nicely we skew the nails through to sercure it all into place,I used 3 inch nails as this is only a small exercise.

Tomorrow we should have the task complete,All we have left to do is the purlins down the far end along with the fly rafters.Then we can get back to the house build.Mostly all the purlins have been installed to the house trusses,Attached with 2 4 inch nails top and bottom and a purlin screw in the middle,The nails are hit in on angles to prevent uplift of the roof in ruff weather conditions.

12/6/12

This morning we went back over Trigonometry and Pythagoras in regards to the Roofing and trusses.We went up stairs and started with the session.SOH CAH TOA was shown to us,this is used to find angles,and sides in a triangle,and a2+b2=c2 is used for finding a missing side.These formulaes are highly accurate and useful on a building site.A lot of time is saved using these methods.They are Plain and simple,easy to remember.SOH CAH TOA are drawn up into 3 triangles to make it super easy to find out which one to use for what ever problem that may occur.

Purlins being nailed off and checked for straightness.

Once we had gone over the mathematical side of things we then moved on with the build down stairs.We had to then calculate the amount of rows of purlins needed for the roof.We set up the first row down the end of the trusses,at the top end we measured 150mm down,then got the inside to inside measurement of the length of the trusses and divided it by 815mm,the overall measurement was 3605mm in length.We lended up with 6 rows of purlins,We also cut the hip purlins to the right angle and since they were short,we cut them over a trusse so they can be joined over something sturdy.Most of them have been installed to place.Two 4 inche nails were used to nail them down at the top and bottom.A purlin screw is to be put in the middle.

Purlins.

Soffits will then be installed once we have everything else sorted.