Attic usable and unused.
Division of pitched roofs with regard to their functions:
• Sloping roofs with an unused attic, acting as an attic, In the arrangement of insulation layers, they resemble a two-part ventilated flat roof. Thermal insulation is distributed over the ceiling. There is only a roof covering and a layer of initial covering on the roof slope, acting as the second plane of the roof drainage. Ventilation is conducted through openings in the gable walls and under the ridge. Air movement is caused by the action of the wind (pushing and sucking) and the temperature difference inside and outside the building. Ventilation should not cool the attic excessively. The air flow speed should be low and amount to approx 0,2 m/s.
• Pitched roofs with an attic should have a structure designed in this way, to truss elements – collarflies in a collar collar or ticks in a purlin-tick suspension device, made it possible to suspend the ceiling to them at a height of at least 2,5 m. In the attic, knee walls should be provided, which limit the roof slants to a height of approx 90 cm. The function of partition walls can be elevated external walls or walls recessed into the interior (which reduces the usable area).
The correct solution of the attic requires careful design of the thermal insulation solution, because the roof surface is a barrier that protects the interior against external factors.
The insulated roof slopes consist of a number of layers, each of which plays a specific role:
– outer layer, that is, roof covering, drains rainwater from the slope,
– a ventilated air gap allows air to flow under the roofing, from the inlet slot at the eaves to the outlet under the ridge,
– the initial covering layer is the second level of the roof drainage, which prevents moisture insulation, e.g.. as a result of water droplets or snow dust being blown by the leaks between the elements of the roof covering,
– thermal insulation layer with ventilated air gap, which provides insulation that fills the space between the rafters,
– vapor barrier insulation made of aluminum or polyethylene foil prevents condensation in the insulation layer,
– plasterboards or wooden paneling, being the internal sheathing.