In brief
- A certificate of attendance records time spent in a room, not whether a roofer can turn a flashing upstand at a parapet or lap a sheet the right way.
- Water finds the weak junction, so the way to test flashing competence is to walk a roof the crew finished recently and look at the upstands, laps and fixings.
- Ask for the supervisor's own record of a flashing detail and a photograph of it before you accept the crew on your site.
Contents
It does not say who can form a lap, set an upstand or fix a sheet so that rain running down a wall turns out over the roof edge instead of into the wall. The work that stops leaks at junctions is hand skill, checked on a roof, not a sheet of paper.
How do roof flashing training gaps show up as leaks at junctions?
A classroom module on flashing usually covers the sequence of a detail: primer, membrane or sheet, lap, fixing, seal. The trainee watches the sequence and can describe it. On a roof the same person faces a parapet that is out of square, a wall that is not plumb and a sheet that has to be cut on site, and the description does not carry the hand.
The gap opens in the parts that are never practised. Forming a corner without a crease that holds water, dressing a sheet over a rough substrate, choosing a fixing that will not tear the sheet when the wind lifts it, and keeping the lap direction running down the slope. Test the junction during the project's specified water test or at the first rain, with the timing confirmed against the project programme, so a leak shows at the lap or upstand rather than in the middle of the sheet.
Training providers can close part of the gap by assessing on a mock-up, not on a form. Ask a provider whether its flashing module ends with a graded practical, and ask to see the marking sheet. If the answer is a written test only, the certificate records attendance at a course, not competence in the trade.
Does an attendance certificate prove a roofer can do the work?
No. A certificate records that the person attended a course. It does not record that the person formed a corner, set a lap or fixed a sheet to a stated pattern under observation.
Walk a roof the crew finished in the last few months and look at the junctions, not the field of the roof. Start at the parapet upstand. The sheet or membrane should turn up the wall and finish under a cover flashing or a reglet, with the top edge fixed and sealed so water cannot run behind it. A lap should run with the slope, and the overlap should be enough for the material and the exposure, confirmed against the project specification or the manufacturer's written instruction.
Then check the details that rain reaches first. Valley gutters, pipe penetrations, the joint between two roof slopes and the junction where the roof meets a higher wall or a tank base. Look for sealant used as the only line of defence. Sealant at a junction can hide a lap that was never formed, and it can fail within a season under sun and heat. Ask the supervisor to show the fixing pattern and the length of the fixings used at the edge zone. Photograph the junctions, note the date and keep the images with the handover file.
Where is the required lap and fixing spacing stated?
The required lap and fixing spacing is stated in the project specification or in the manufacturer's written instruction for the sheet or membrane. General practice fixes sheets more closely near edges and corners, where wind uplift is highest, but the spacing and fixing type belong to the project specification, so confirm them there rather than from a rule of thumb.
On site, a supervisor can build the habit with a first-off check. Before a roofer starts the full roof, one junction is completed and inspected against the specification. Only when that junction passes does the rest of the roof proceed. The check costs an hour and catches the lap direction, the fixing line and the seal before they are repeated across the whole area.
Contractors should also record who did which junction. A simple sheet with the roofer's name, the date and the detail inspected gives the client something to test later. Where the contract allows, make the first-off check and the junction record part of the scope before work starts, and check what your contract says about inspection and sign-off.
What to do next
Pick one roof the crew finished in the last six months and inspect the parapet upstand, one valley and one penetration. Photograph each junction, note who formed it and ask the supervisor to explain the lap and fixing against the specification. If the answers do not match what is on the roof, put the crew on a first-off check at the next junction before they cover any more area.
Frequently asked questions
Does a roof flashing certificate prove a roofer can do the work?
No. A certificate records that the person attended a course. Ask the provider whether the module ended with a graded practical on a mock-up, and ask to see the marking sheet. The stronger check is a finished junction on a recent roof.
What should a supervisor check first at a roof junction?
The parapet upstand. The sheet or membrane should turn up the wall, lap with the slope and finish under a cover flashing or reglet with the top edge fixed. Then check valleys, penetrations and the junction with a higher wall.
Where do I find the required lap and fixing spacing for a roof?
In the project specification or the manufacturer's written instruction for the sheet or membrane. General practice fixes sheets more closely at edges and corners, but confirm the spacing and fixing type against the specification or the engineer.
Local reporting: this article is written for building work in Gabiley and Somaliland. Ground conditions, prices and rules differ between places; confirm the details for your own site.