As can be seen from the location of these aggregates, the construction technique of the thatched roof was practiced everywhere in Val Vermenagna. This was because there were no shale rock quarries on the territory, that is, easily breakable for the creation of slates, while rye straw was easily found as a secondary product of the cultivation of food-use cereals. None of the rye was wasted: the kernels were used for the flour, and the stems for the frame of the roofs.
During the last century, the method used for threshing grass culms changed several times; if flails were used before, the second post-war period had switched to using motorized threshing machines.
The preparation of sheaves for use as a roof covering often took several years, but the coverings made with this technique were quite durable, lasting over 25 years, and well insulating. Moreover, the easy flammability of the material made it necessary to use various stratagems for the construction of chimneys and flues.
A typical roof frame is composed entirely of wood (main, secondary, ridge beams, chords and frontispieces or, in the absence of the latter, of the archaic type), on whose slats the straw is tied, superimposed on successive rows according to the ” vertical “or “horizontal”, method, the latter being more widespread.
The ridge line is the most delicate area of coverage, both for the discontinuity of the line and for exposure to the elements: for this reason there is a thicker straw layer and it is blocked by two strong bars that press it.
The pitches of the roof need to be more sloping than slate roofing, to better let the weight of the snow slide, which it would not have held up for a long time.
For good coverage 25kg of rye straw is required, a paltry weight for an underlying structure in dry masonry or completely in wood if for rural use.