Any thatch is secured to the thatch below or to the roof timbers by using thatch fixings; generally either screw fixings, thatching spikes, string or hazel spars.
If the thatch is spiked or screwed to the roof timbers, galvanized steel bars are used which run across the surface of each course and the fixings secure these bars down. As the thatching progresses, the bars become covered by the next course of thatch.
This is a skilled process because if the bars are set too low they will become exposed before they should do as the thatch wears back, and if the bars are set too high the thatch will be too loose and may slip or blow off in strong winds.
The first photograph shows the old steel bars which, as the thatch wears back, have come to the surface and which is a sign the roof needs re-thatching.
The second photograph shows the positioning of the new bars within the new thatch with plenty of thatch over them but which have been positioned neither too high (near to the tops of the reed) or too low (near to the surface).