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