# Ceilings & Basic Roofing

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Ceilings & Basic Roofing
Revision Created by Michael Martin March 2004 / revised April 2007

General Revision Textbook questions & answers Review A4 sheets
Components sketches All calculation exercises ceilings and roofs

Ceiling Frames Basic set-out of ceiling frame Members & their function

Ceilings continued What is the function of a hanging beam ?
To support the ceiling joists mid-span, must be blocked at ends and a counter beam? What is the function of the ceiling joists themselves ? To support the lining material and also act as a tie between opposing rafters

Ceilings continued Also support to members
Review your worksheets from this section

Flat roofs Generally less than 10º pitch
More often ceiling joists and rafters all in one

Skillion roofs Walls at either end at different heights
Two ceiling types, raked and level

Lean to roofs Constructed against an other wall or roof Extensions
Carports Verandas awnings

Simplest method of marking skillion roofs
Scribe the birdsmouth

Gable roofs Members and their function Finish’s Calculations
Revise your worksheets for this section

Quick Questions What is the function of a purlin?
To give support to the rafters mid span Where can a strut gain support from? It either has to transfer it’s load to a load bearing wall or a strutting beam What is the function of collar ties? To stop rafters from sagging acting as a tie between opposing rafters above the purlin

Set out of common rafters
Can be done with steel square or By calculation

Plumb & level bevel Remember where they are in relation to the roof
P28 of text handout

Transfer onto steel square

Gable definitions – Review handout
Span – horizontal distance overall the wall plates Rise – vertical height from the x-y line to where the upper edge of rafters would intersect ½ span or run – plan length of rafter Centre line length or set out length – the hypotenuse in the triangle, formed by the ½ span and the rise Roof pitch – expressed in different ways, degrees, pitch ratio etc. see P56 of your handout notes

Other roof members – left to right
ridge Wind bracing purlin Collar tie strut

Other struts (this one is a half scissor)
Scissor struts

Gable end finishes Flush gable Verge overhang ? Boxed gable ?

Extra members for boxed gables ?
With boxed gable ends you have A bottom chord or tie piece Also gable studs for fixing of linings Or for ties to veneer skin

Calculations Review you worksheets
Review calculation sheets recently done in class

Now you can build this Test next week 5:30 to 7:00
Then class continues after dinner break.

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