The code calls for a minimum of 1 in.
Pitched roof insulation ventilation.
Warm pitched roof to create a warm pitched roof insulation such as kingspan kooltherm k7 pitched roof board should be fitted between and over the rafters.
Insulating a pitched roof in a pitched roof insulation is usually introduced in one of three areas.
To provide ventilation opening points can usually be provided on the following areas of a pitched roof.
Fabrications with 3mm 10mm openings are acceptable.
As this requires fitting insulation above the rafters the roof covering will have to be removed in order to fit the insulation.
Above the rafters so the whole roof structure is warm below and between the rafters so the roof space itself is warm or between and above the ceiling joists the cold roof option.
If you choose to vent the roof deck then be serious about it and really vent it.
If the roof covering or roof membrane is a material of high moisture resistance or impermeable then the building regulations require a 50mm wide ventilation gap beneath the roofing felt and tiles.
A cold roof is the most common type of roof construction often taking the form of an uninhabited storage space.
Slating and tiling for pitched roofs and vertical cladding code of practice recommends that roof ventilation be provided in accordance with bs 5250.
To provide adequate ventilation and to avoid condensation in roof voids pitched roofs that have insulation at ceiling level should be ventilated to the outside air.
Roofs with a pitch of.
A roof void above an insulated ceiling.
For example in the average house with a cold loft there should be a minimum of a 7mm continuous ventilation gap at eaves when using a vapour permeable underlay with a normal unsealed ceiling.
Eaves soffits and fascias.
Ventilation openings should prevent the entry of birds etc.
Bs 5250 sets out the minimum requirements for roof space ventilation.
The ventilation requirements of a pitched roof depends on the type of roof membrane used under the tiles or slates and battens to keep moisture or rainwater coming in from outside.
Regulation ventilation and insulation of pitched roofs.
Of airspace between the top of the insulation and the back of the roof sheathing.