Loft Insulation Between Roof Joists

Some old loft insulation installations can easily feature as little as a single layer of around 100mm insulation between the ceiling joists.

Loft insulation between roof joists.

Cold deck or cold roof is where the insulation is below the roof deck and the associated joists. What about storage space. When you use solid insulation board to create a warm loft the key thing to remember is ventilation you must keep a 50mm gap between the roof and the rigid insulation board. To increase the thickness of your roof insulation layer you can.

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. The first layer of wool is placed between the joists and then a second layer is placed at right angles which covers the joists and also makes the insulation up to the correct depth of 270mm. 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. Joists are the horizontal beams which make up the floor.

Alternatively battens can be secured to the underside of the. Flat roof insulation always requires professional insulation and damp roofs require professional assessment before work can be carried out. 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. We would always recommend having a breathable membrane in place between the tiles and the rafters too to allow the roof to breathe.

Typically a gap will have to be left for ventilation because this is a cold area. 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. Lay mineral wool between the joists and then fit rigid insulation boards across the joists with floorboards on top. Pipes water tank and loft hatch.

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. You can also add rigid foam insulation under the rafters which adds r value and eliminates thermal bridging through wood rafters. Consider using high density r 30 batts which are as thick as r 25 batts but fit into 2x10 framing.