Dividing by 12 gives the ratio of inches in rise per distance.
Roof area formula.
Which is the same as saying a 45 degree slope a 12 in 12 slope or the roof will rise 12 for every 12 of horizontal run.
We used this detail to calibrate our folding carpenter s rule scale for reading roof slope from the ground.
Select the area measure.
Thus a moderate 6 in 12 roof pitch means that the roof rises 6 inches vertically for every 12 horizontal inches it runs.
Divide your roof pitch by 12.
Double click in the roof angle column of the area measurement type the roof angle and press enter.
The answer to this is the total number of squares on your roof for which you need to purchase shingles.
You may want to hide the display of the area value in the plan view to avoid confusion.
Area cos roof angle pi 180 area is the value of the area measurement.
Divide the area you calculated in step 4 by 100.
The roof area is calculated.
Clear the show caption check box.
Explanation of the formula.
6 calculate the total surface area of the roof using the following formula.
The roof area for a hip end is the same as for a gable end the intersection is equivalent to a hip slightly conservative so there is usually no need to consider triangles when measuring a roof.
For example 40 feet x 30 feet 1 200 square feet next multiply the area by your roof s pitch.
Details of that procedure are at roof measurements.
The roof area is simply 114x18x2 plus 30x18x2 giving 5184 square feet which is perfectly adequate for estimating materials.
Measure the length of the rafters from the peak to the lower edge.
Roof pitch is given as the number of inches in height change over the distance of one foot.
To accurately calculate the area of your roof you must first determine its slope or pitch.
A roof s pitch is determined by how much it rises vertically for every foot it runs horizontally.
Right click on the area measure then click properties.
Roof angle is the value in the user defined.
1 200 x 1 05 1 260 square feet to allow for hips ridges and waste add 10 of your final number for a gable roof and 17 of your final number for a cottage roof.
Multiply your house length by your house width to get the area.