How do you check roof truss assembly in Qardho?

Weak supervision during roof truss assembly in Qardho mostly shows up later as a roof that moves, dips or leaks. The trusses may still stand, so nobody stops the sheeting. The faults sit in the setting-out, the temporary bracing and the fixings, and each one is quick to check if somebody is on the roof while the work is open.

What does weak supervision miss at the truss layout stage?

It misses trusses set to the wrong spacing or out of square, because nobody marks the wall plate before the first truss goes up. General practice is to set out the truss positions on the wall plate, keep the spacing even, and check diagonals so the first few trusses sit square to the building. On a hot inland site, timber and steel both move with the day, so readings taken at midday can differ from those taken early morning. Ask the site supervisor which line or reference the setting-out came from and whether the wall plate was checked for level before assembly. If the answer is vague, ask the project manager for the truss layout drawing and walk the roof with a tape and a string line. The municipal engineer's office can be asked whether it holds any records for the plot, but the drawing and the setting-out check remain the practical test.

How do you catch unbraced or unstable roof frames?

You walk the roof while the trusses are still bare and look for the bracing that holds them until the sheeting is fixed. General practice is to install temporary bracing and diagonal ties as the trusses go up, not after the last one, and to keep them until the permanent restraint is complete. Weak supervision lets a crew stand trusses one by one and leave them unbraced overnight, so a gust or a nudge moves a whole run. Check the bracing pattern against the truss supplier's erection guidance, and confirm with the project engineer how long the temporary bracing is meant to stay. Ask why any truss lacks a tie, and record the answer. Unstable roof frames can also come from trusses fixed to a wall plate that is not itself restrained, so check that the plate is anchored before the trusses load it.

How do you check the fixing record before sheeting?

The fixing record is the list of nails, screws, straps or bolts used at each connection, and it is the part most often left to memory. General practice is to fix each truss to the wall plate and each connection with the number and type of fasteners named in the truss design, then record what was used. Ask for the fixing schedule from the truss supplier or the project engineer, then spot-check a few connections against it with the fasteners in hand. Photograph each connection before the sheeting covers it, and file the photographs with the inspection note. If a connection was already covered, ask the supervisor to open one and show the fixing. Confirm any fixing detail with the project engineer before accepting it, since the correct fastener depends on the truss material and the design.

What to do next

Pick one roof under construction and ask the site supervisor for the truss layout drawing, the fixing schedule and the bracing plan. Walk the roof with a tape, a string line and a level before sheeting begins, and photograph every connection. Write down what you found and send it to the project engineer for confirmation.