Loft Insulation Between Roof Joists

Alternatively battens can be secured to the underside of the.

Loft insulation between roof joists.

Insulating between the joists of your loft will keep your house warmer but make the roof space above colder. Pipes water tank and loft hatch. Cold deck or cold roof is where the insulation is below the roof deck and the associated joists. Joists are the horizontal beams which make up the floor.

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. Rolls of mineral wool can be used if the joists in your loft are regular. Lay mineral wool between the joists and then fit rigid insulation boards across the joists with floorboards on top. Consider using high density r 30 batts which are as thick as r 25 batts but fit into 2x10 framing.

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. To increase the thickness of your roof insulation layer you can. You can also add rigid foam insulation under the rafters which adds r value and eliminates thermal bridging through wood rafters. 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. 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. Typically a gap will have to be left for ventilation because this is a cold area. Flat roof insulation always requires professional insulation and damp roofs require professional assessment before work can be carried out.

What about storage space. 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. 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.