As for insulating below the joists an insulating laminate insulation bonded to plasterboard such as celotex pl4000 or a separate rigid pir insulation board finished with a separate sheet of plasterboard can be securely fixed to the joists to provide an internal finish to the roof.
Loft insulation between roof joists.
To increase the thickness of your roof insulation layer you can.
Consider using high density r 30 batts which are as thick as r 25 batts but fit into 2x10 framing.
If the loft is going to be used as living space then the insulation should be placed at rafter level to create a warm roof.
Cold deck or cold roof is where the insulation is below the roof deck and the associated joists.
Rolls of mineral wool can be used if the joists in your loft are regular.
You can also add rigid foam insulation under the rafters which adds r value and eliminates thermal bridging through wood rafters.
But if you simply fill the spaces between the joists with insulation and then board over the top you won t achieve an adequate depth of loft insulation.
What about storage space.
Lay mineral wool between the joists and then fit rigid insulation boards across the joists with floorboards on top.
Insulating between the joists of your loft will keep your house warmer but make the roof space above colder.
But if you plan to use your loft for storage only then a conventional cold roof option where the mineral wool insulation rolls are placed in between the ceiling joists above the top floor.
We would always recommend having a breathable membrane in place between the tiles and the rafters too to allow the roof to breathe.
Some old loft insulation installations can easily feature as little as a single layer of around 100mm insulation between the ceiling joists.
Flat roof insulation always requires professional insulation and damp roofs require professional assessment before work can be carried out.
The most common solution to top up existing loft insulation levels is to lay glass mineral wool insulation over the top of the existing insulation within the ceiling joists although if this is in.
Alternatively battens can be secured to the underside of the.
A vent baffle should be installed between the insulation and the roof decking to maintain the ventilation channel.
Pipes water tank and loft hatch.
Joists are the horizontal beams which make up the floor.