I have a contractor installing external wall insulation at the back of my house. As part of the job, the roof of the gable end wall needed to be extended by 125 mm (half a slate width). I offered to source and buy the slates. After meeting with the contractors I suggested "There are 19 courses in total. Along the edge there are full width and half width slates so it seems logical to extend the roof-line by 125 mm. Marley make 500 mm x 500 mm slates for cutting so the probable solution could be pulling out all the tiles at the edge and cutting wide tiles to 375 mm for the 250 mm wide ones removed. This should allow them to be fixed on the existing battens which go virtually to the exterior edge of the brick. It would make sense to me to buy all the 250 mm wide slates as well as I can use the originals left over for other roof repairs".
They agreed to the slates and the subcontractor fitted them. The first picture shows the result - new slates are obvious.
The instructions for the slates say copper rivets must be fitted on all slates, here many are missing and it isn't possible to fit some of them because double width slates in the body of the roof - see detail:
He extended the battens even though I hadn't expected this. At the edge of the roof hit put some thin flexible board on the underside then tried to fill the space with mortar. I thought it was hardboard but he showed me a small bit and it is called Superflex:
The main contractor tells me it is undercloak and a "requirement". I haven't worked on roofs for decades but I would never put mortar onto a flexible board and expect it to stay.
The contractor has offered to do some remedial work. Screws with watertight grommets to hold down the tiles and a better mortar for the gap.
Advice please. Should I reject the work or am I being unnecessarily critical? Can it be made good without major work? Can I cut back the undercloak and battens to wall level and render up to slates?
They agreed to the slates and the subcontractor fitted them. The first picture shows the result - new slates are obvious.
The instructions for the slates say copper rivets must be fitted on all slates, here many are missing and it isn't possible to fit some of them because double width slates in the body of the roof - see detail:
He extended the battens even though I hadn't expected this. At the edge of the roof hit put some thin flexible board on the underside then tried to fill the space with mortar. I thought it was hardboard but he showed me a small bit and it is called Superflex:
The main contractor tells me it is undercloak and a "requirement". I haven't worked on roofs for decades but I would never put mortar onto a flexible board and expect it to stay.
The contractor has offered to do some remedial work. Screws with watertight grommets to hold down the tiles and a better mortar for the gap.
Advice please. Should I reject the work or am I being unnecessarily critical? Can it be made good without major work? Can I cut back the undercloak and battens to wall level and render up to slates?
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