underfelt tiled roof

[netty]

The builders have torn holes in the roofing felt under the tiles. Their solution is to staple a flimsy cloth looking piece of material to the underside of the roofing rafter tucked in above the window lintel and into the cavity. I feel this is makeshift and potentially problematical solution. Could any one with roofing experience offer their opinion. The builders plan to put the ceiling in tomorrow, any answers would be greatly appreciated