created by michael martin may 04 / reviewed & updated april 2010
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HIPPED ROOFS - TWO
Created by Michael Martin May 04 / Reviewed & updated April 2010
Roof Geometry
Drawing Exercise – Hip End
Gives a good understanding of the different triangles found in a hipped roof
Which we use to create the different bevels
Roof Geometry
Lets have a look, one by one at these shapes in the roof
Ref: P38 text 1) Plumb bevel
common rafter 2) level bevel
common rafter
Roof Geometry
3) Edge bevel for the creeper
Ref: P39 text
Roof Geometry
4) Edge Bevel Purlin
Ref: P 40 text
Roof Geometry
5,6,7) Plumb, level and edge bevel for the hip
Ref: P 41 text
Roof Geometry
8) Face bevel purlin
Can be looked at two ways
Ref: P 42 text
Development of bevels – steel square One way to
develop these bevels is on a steel square
Follow these on from page 43 in your text
These are a matter of remembering (a) what creates them (b) calculations
Remember for these the three constants
Rise The Run from
rise per m. run, so 1.0m
The Plan length of hip per m. run of common rafter, so 1.414
Steel square
Plumb and level bevel common rafter
P 43
Steel square
Edge bevels for creeper and purlin
Ref: P44
Steel square
Plumb and level bevel for the hip
Ref: P 44
Steel square
Edge bevel hip
Ref: P45
Steel square
Face bevel purlin
Ref: P 45
Steel square summary
All bevels on one page
Same as example from last week
Ref: P 46
Direct Method
There is reference in your text on page 47
This is a practical project
For this method it is easier to show you on a drop saw
A lot of people use this method
Combining Triangles
This method also requires you to remember the three constants, rise, run, plan length hip
It is a very simple method
More people are adopting it to use
We’ll draw one on paper now, then again on plywood in workshop
Roof Bevels
You must be able to develop these bevels to pitch any roof we do from now on
What method you choose is up to you Some of you will choose different to
others, it doesn’t matter
Review hipped roof
What we’ve done so far Identify and cut our new members,
centering rafters, hips, crown end and creepers
Set out our pattern rafter, which we use to calculate the length of our creepers
Calculate the length of our hips or measure them in situ
Develop our eight bevels for the roof
Purlins in the hipped roof
Also known as underpurlins Parallel to ridge & plates Normally spaced at 2100mm
centres Placed in a continuous line
around the four sides of the roof
Joined at corners, under the hips
Joins are a compound cut made up of face and edge bevel purlin
Purlins continued
Look at page 29, 30 in your text book to gain an understanding of the position of the purlin in a hipped roof
Strutting is still via inclined struts, or fan struts or alternative cable struts, as for gable
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