3 Reference General Construction Knowledge Section 7 – Construct Ceiling Frames (from P278) The ceiling frame is the horizontal area between the top of walls and the roofConsists of ceiling joists,trimmers, hanging beams and counter beams
4 CEILING JOISTS – P279Joists carry the ceiling sheets and provide a lateral tie between base of opposing rafters
5 CEILING TRIMMERS – P279-80Sometimes called trimming joists, short lengths at right angles between ceiling joists. Give fixing to ends of ceiling sheets and can provide fixing for internal walls.
6 HANGING BEAMS – P280,81These provide support to the ceiling joists mid-span, must be blocked at ends and if large sections may need to be strapped
8 SUPPORT TO JOISTS – P280There are three common types of support between ceiling joists and hanging beams, joist straps, triple grips and ceiling dogs
9 Remember:Hanging beams go above the joists, so we have to block the ends. see page 281
10 CUTTING HANGING BEAMS P281 Where hanging beams run across ceiling joists with end protruding past the rafter line as in a hipped roof, they must be cut but also supported via a trimmer
11 COUNTER BEAMS – P282Counter beams run at 90deg. To the hanging beam and supports it when it’s length exceeds it’s allowable span, ends of counter beams are packed slightly to allow for deflection.
12 SET OUT & ERECTION OF FRAME – from P283 GABLE ROOFthe set out of the ceiling frame is based on the set out of the raftersFirst check top plates for straight & squareMark position of gable end raftersThen work from one end, set out position of common rafters, other side of line becomes joistsSee sketch
14 Next cut all ceiling joists to length and fix into position, double skew nail Cut and fix ceiling trimmers to endsCut and fix trimmers above internal walls where required
15 Lastly fit hanging beams to the centre of the ceiling joists length over each room as required Remember fixing and blocking for hangers
16 REVIEW ON WORKSHEET Review this part of your text book In your own words answer the questions on your worksheet
17 REVIEW ANSWERS TO WORK SHEET Purpose of frame….Designed to enclose the room, keep it freefrom dust and it also provides insulation andSecurityFunction of ceiling joists…The horizontal member that carries the load ofthe ceiling sheets and act as a tie between therafters at their base
18 Function & position of hanging beams…. Function of trimmers….To provide fixing for ends of ceiling sheets,also internal walls where they fall betweenjoists and help give lateral stability to frameFunction & position of hanging beams….To support ceiling joists mid-span, must be supported on load bearing walls & blocked at ends
19 Fixing to hanging beams by…. Joist strap, triple grip, or ceiling dog andshould be fixed alternate sides at every secondjoistHanging beams at external wall ….Trim hanging beam to pitch of rafterFunction of counter beams….Run 90 deg. to hanging beam and providessupport to them where they exceed their ownspan
20 Set out and erection…Check top plates are straight and squareMark gable end rafters at each endFrom one end set out common rafters marking each side of line for (r) rafter and (j) joistCut joists to length and fix into position, double skew nailFix trimmers to ends and where required for internal wallsFix hanging beams to the centre of joists length in rooms requiredProvide strapping where required