In the wooden roof, the trusses are covered with a wooden substrate (stone), which is nailed onto the trusses. A membrane is welded or nailed onto the stone sheet to serve as a vapour barrier. A barrel is formed by means of wooden cylinders, in the gaps between which the insulating material is placed. The waterproofing membrane is placed on top and nailed with flat-headed nails to the wooden canes. A washer of synthetic rubber or other elastic material is inserted in place of each nail to prevent water from penetrating through the holes in the membrane. Alternatively, a second wooden substrate may be formed over the thermal insulation layer and the waterproofing membrane may be nailed or glued to it.

Above the membrane at regular intervals, horizontal bars are fixed for anchoring the tiles between which a second layer of thermal insulation material is placed to reduce the thermal bridges created by the wooden frames of the first layer. If another layer of wooden battens is inserted before the horizontal battens are laid, the roof becomes ventilated by using appropriate ventilation holes to allow air to enter from the edge of the tiles and the hot air to exit from the roof ridge. In this case, if a second layer of thermal insulation is used to leave a ventilation gap, the thickness of the thermal insulation should be less than the thickness of the purlins.

For the first thermal insulation layer it is recommended to use the graphite expanded polystyrene NEOCOAT TX EPS 100, ISOPOR EPS 150 and ISOCOAT TX EPS 80 and for the second NEOCOAT TT EPS 100 or ISOPLAK TX-TT EPS 120 and ISOCOAT TT EPS 80 in total thickness according to the KENAK.

In the wooden roof, the trusses are covered with a wooden substrate (stone), which is nailed onto the trusses. A membrane is welded or nailed to the stone. In the case of the inverted type, however, this membrane acts both as a vapour barrier and as a waterproofing layer. A barrel is formed with wooden cages, in the gaps between which the insulating material is placed. Alternatively, it can be covered with a wooden substrate or left free. Above the insulating layer, horizontal bars are fixed at regular intervals to anchor the tiles, between which a second layer of insulating material is placed to reduce the thermal bridges created by the wooden canes of the first layer. If another layer of wooden battens is inserted before the horizontal battens are laid, the roof becomes ventilated by using appropriate ventilation holes to allow air to enter from the edge of the tiles and the hot air to exit from the roof ridge. In this case, if a second layer of thermal insulation is used to leave a ventilation gap, the thickness of the thermal insulation should be less than the thickness of the purlins.

For the first thermal insulation layer it is recommended to use the graphite expanded polystyrene NEOCOAT TX EPS 100, ISOPOR EPS 150 and ISOCOAT TX EPS 80 and for the second NEOCOAT TT EPS 100 or ISOPLAK TX-TT EPS 120 and ISOCOAT TT EPS 80 in total thickness according to the KENAK.

Alternatively, instead of the above thermal insulation materials, the ISOLTETTO and NEOTETTO tile roof insulation system can be used, which are pressed expanded polystyrene moulded in a mould and have ventilation channels and channels/guides for the installation of the horizontal bars at the pitch that fits the Roman and Dutch (cement) tile with pitch 35,7cm and eliminates thermal bridges by preventing second thermal insulation layer and ventilation layer. It is laid in the appropriate thickness according to the KENAK. ISOLTETTO as well as NEOTETTO offers great ease and speed in construction by concentrating all the other layers in one layer.

Roof ventilation in countries like Greece with high sunshine is absolutely necessary because temperatures above 60°C develop on the tiles in summer because the sun's rays hit the roof almost vertically for the longest period of sunshine of the day and lead to overheating of the roof, making the work of the thermal insulation layer more difficult, especially in the case of thermal bridges and without them. The layer of properly calculated ventilation layer with properly calculated holes at the base and top of the tile layer dissipates on a continuous basis part of the heat absorbed by the tiles and dissipates it into the atmosphere, since the still air between the tiles and the thermal insulation layer is heated, its density decreases and rises upwards, leaving the holes in the roof top and giving way to fresh cool air, creating a ventilation current that helps the roof and its thermal insulation layer to function.

If it is a wooden roof, then on the inner side of the slab a wooden or metal barrel of thin bars is developed, which is fixed to it with strong plugs or pre-positioned hooks. The insulation boards are fixed in the gaps between the canvas with plugs or glued with an adhesive that does not affect the foamed materials (e.g. cement paste). Depending on the desired aesthetic effect, the whole structure is clad with plasterboard, particle board, fibreboard, glued wood panels or other types of mouldings, which are fixed to the casing of the canvas. For the thermal insulation layer it is recommended to use graphite expanded polystyrene NEOCOAT TX EPS 100, ISOPOR EPS 80 and ISOCOAT TX EPS 80 in the appropriate thickness according to the KENAK.