Hip Type 3 Installation Manual
Type 3 Hips are the most similar to the construction method used by timber trusses in hip ends. A type 3 hip end entirely uses roof trusses except creeper rafters may be used at the corner of the roof.
A summary of the installation process for the Type 3 Hip Construction is as follows:-
Install the Truncated Girder truss. Connect the 2 plies of the Truncated Girder truss together, fold the horns on the truss 45 degrees to face away from the hip end, connect the tiedown brackets using the pre-punched holes in the bottom chord as a reference (if used), and lift onto the roof, temporarily bracing if required;
Install the Half Trusses with Extended top chords. Fold the tabs at the top end of the Half trusses with extended top chords towards the center of the roof. If a bent tab is used for the bottom chord fold the tab so it doesn’t clash with any chord-web screws in the Truncated Girder Truss. If a bracket is to be used, install the nominated bracket on the half truss bottom chord. Attach the wall tiedown brackets using the pre-punched holes in the bottom chord as a reference (if used), and lift onto the roof. Align the locating hole in the top chord of the half truss with the locating holes in the Truncated Girder truss and fix with an M6.5-12x42 hex head screw. Follow instructions to fix the bottom chord tiedown to the Truncated Girder Truss.
Install the Hip Girder Trusses. Fold the tab at the top of the hip girder truss 45 degrees away from the hip end if a crown truss is used, or 90 degrees towards the hip end if there is no crown truss. Fold the tab at the bottom chord 45 degrees towards the hip end. Fix the Hip Girder Truss to the folded tabs in the Truncated Girder Truss and Half Truss with extended top chords with the nominated screws. Fix the tab in the bottom chord to the Truncated Girder Truss with the nominated screws. Tie down the Hip Girder truss to the wall frames with a 32 x 1mm strap brace with the nominated fixings.
Install the Half Trusses in the corner of the roof. Fold the tabs in the top and bottom chords and attach the nominated wall tiedown brackets using the pre-punched holes in the bottom chord as a reference (if used). Fix the Half Trusses to the Hip Girder truss and wall with the nominated fixings.
Install the remaining truncated trusses above the hip girder truss. Fold the horns away from the hip end and fasten the hip girder truss to the truss horns using the nominated fixings.
Install the first full truss. Install the first full truss and, if used, fold the tab in the crown tie and connect to the apex of the first full truss.
All fixings are described in detail in the detailed instructions below.
Fixing Details for folded tabs in Hip Type 3
It is very important that any tabs are folded using an appropriate folding tool that can provide a sharp fold at the flanges. A hammer shall not be used.
At least 2 #12-14x20 hex head fasteners should be installed no further than 35mm from the fold line of an inclined tab and no more than 20mm from a square tab to reach full capacity. Square tabs are commonly used for fixing bottom chords while inclined tabs are used for fixing top chords. Refer to the diagram below for fixing instructions.
If bent tabs are folded more than twice, they should be replaced with either an ENDUROHANGER bracket or, if at 45 degrees, an appropriate timber bracket. Contact Enduroframe for further instructions.
The Hip Type 3 consists of 4 types of trusses which are explained below:-
Truncated Girder Truss: This is a flush truncated truss, usually with 2 plies. It supports hip girder trusses. The horns are removed when the roof pitch is less than 8 degrees.
Hip Girder Truss: This is a truss with the top chord centered on the hip line. It is a single, flush truss with boxed top and bottom chords to form connection points for incoming half trusses. The boxed top chord extends to the ridge of the roof. This is similar to a hip truss option except it is engineered and the top chord extends to the ridge line. The corners of the top flange of the top chord will be a few millimeters outside the roof plane.
Half trusses with extended top chord: These run perpendicular to, and the top chord sits on top of, the Truncated Girder Truss.
Half Trusses: These are flush trusses with tabs on the end of both the top and bottom chord which fold to connect to the hip girder truss. They have a tab formed on the top and bottom chords. The half trusses in the corner of the roof shall be a minimum 350mm from the corner of the wall (not end of hip) to ensure that they are wide enough to be triangulated by a truss web in the event the heel height is raised.
The names of trusses are explained below:
The construction of the hip type 3 is shown in Figure 7.XX Hip Type 3 Overview.
Constructing a Type 3 Hip roof
To construct a Type 3 Hip roof:
Step 1: Study the entire set of architectural and fabrication drawings.
Step 2: Connect the 2 plies of the Truncated Girder Truss together. Use a 12 -14x20 hex head fastener through the service hole to connect the bottom chords of the Truncated Girder Truss together. Refer to Figure 7.23 for further information. Connect the 2 plies of the top chords together using a 200mm long pieces of U section with 2 x #12-14x20 hex head screws into each truss, spaced at a maximum of 2000mm apart.
Step 3: Set out and mark the Truncated Girder Truss positions as per Section 7.2. The top chords of the half trusses line up with the pre-punched holes in the girder truss top chord.
Step 4: Install tiedown brackets to the wall top plates to fix the Truncated Girder Truss and half trusses with extended top chords.
Step 5: Lift the Truncated Girder Truss into position noting that the girder truss ply with the longest horn faces towards the hip end.
Step 6: Stand the Truncated Girder Truss in its set-out position and fix four #12-14x20 hex head self drilling screws through the nominated tiedown bracket at each heel connection into the truss chord. If the tiedown clashes with the pre-installed #12-14x20 hex head self drilling screws in the heel, remove the screws and replace with screws fastened through the tiedown bracket. Ensure that the at least the same number of screws that are removed are re-inserted and a minimum of 4 screws are inserted between the tiedown bracket and the Truncated Girder Truss. Repeat this process with the tiedown on the opposite side of the girder truss, and at the other end of the truss.
Step 7: Temporarily brace the Truncated Girder Truss and ensure that they are plumb and straight. This can be done using roof battens or roof bracing material fixed to the end wall and to the Horizontal top chord of the truss. Installing the half trusses with extended top chords to the Truncated Girder Truss will also help to plum the Truncated Girder Truss.
Step 8: Position the half trusses with extended top chords on the Truncated Girder Truss and end wall.
If a bent tab is being used to fix the bottom chord of the half truss with extended top chord to the bottom chord of the girder truss, carefully fold the tab away from the truss using a pair of sheet metal locking pliers or other appropriate folding tool.
Ensure that the tab is only bent once using either a pair of sheet metal locking pliers or an appropriate folding tool.
DO NOT USE A HAMMER AS THIS WILL NOT PROVIDE A CLEAN FOLD AND ALLOW PROPER FIXING THROUGH THE FOLDED TAB TO THE TRUSS AND MAY COMPROMISE THE CONNECTION STRENGTH.
If the tab is folded multiple times it should be removed and replaced with an ENDUROHANGER or TBJ-45 bracket.
Fix the tab in the bottom chord to the girder truss with 3 x #12-14x20 hex head fasteners.
Alternatives to fixing the half truss bottom chord to the Truncated Girder Truss bottom chord include ENDUROHANGER brackets and TBJ-45 brackets.
Fix the top chord of the half truss with extended top chord to the Truncated Girder Truss top chord with an M6.5-12x42 hex head fastener through the pre-punched holes in the respective trusses.
Step 9 - repeat this process for all half trusses with extended top chords.
Step 10 - Fold the tab at the top end of the half truss extended top chord 45 degrees towards the center of the roof. The fold should be made at the beginning of the notch in the top and bottom flanges to get the appropriate angle. This provides a fixing point for the hip girder truss.
Step 11 - Fold the tabs on the front face of the Truncated Girder Truss 45 degrees to face away from the hip end.
Step 12 - Install the hip girder truss spanning between the corner of the wall and the Truncated Girder Truss. The hip girder truss may be fixed to the tab in the Truncated Girder Truss using 3 x #12-14x20 hex head fasteners. Place a 32 x 1mm strap brace over the top of the hip girder truss and fix with 1 x #12-14x20 hex head fasteners and fold down over the Truncated Girder Truss. Fix the strap to both faces of the Truncated Girder Truss with 3 x #12-14x20 hex head fasteners on both faces.
Tie down the hip girder truss at the wall with a 32 x 1mm strap with 1 x #12-14x20 hex head fastener into the top flange of hip girder truss, and 3 x #12-14x20 hex head fasteners OR 3 x M6X1PX18 GX TEK screws on each side of the strap.
Step 13 - Fasten the folded tabs from the half truss with the extended top chords to the hip girder truss top chord with 3 x #12-14x20 hex head fasteners.
Step 14 - Repeat the process with the opposite hip girder truss.
Step 15 - Fold the tabs on the half truss top and bottom chords and connect to the hip girder truss. Connect the top chords with 3 #12-14x20 hex head fasteners with 2 of the fasteners installed within 35mm of the fold, and the bottom chords with 3 #12-14x20 hex head fasteners within 20mm of the fold in the bottom chord. If there is no tab in the bottom chord, use the nominated bracket to tie the half truss to the wall frame.
Step 16 - If there is no crown truss being used, fold the tab at the end of the hip girder truss 90 degrees towards the hip end so that it can connect to the opposite hip girder truss (note: only one of the hip girder trusses will have the tab.
If there is a crown truss being used, fold the tabs at the end of the hip girder truss 45 degrees away from the hip end so they can be fixed onto the crown truss with 2 #12-14x20 hex head fasteners.
Step 17 - Install any additional truncated trusses that that are beyond the girder truss, folding the tabs and connecting to the hip girder truss following the instructions at Step 13.
Step 18 - Install the first full truss. If a crown rafter is used and it has a crown tie, fold the tab in crown tie 90 degrees and fix to the top chord of the first full truss.