James Francis, product manager at Rockwool, shares advice on how to choose loft insulation that’s good for the customer and you.
Enquiries for loft insulation jobs are on the up and it’s no surprise given that a fitting 270mm of insulation in an uninsulated loft could save up to 1,310kg of CO2 per year in a detached home. The loft insulation market is vast, with a wide range of material types, but not all are created equal when it comes to long term thermal performance.
In fact, a reason you might be seeing an influx in enquiries is homeowners realising their loft insulation has sagged over time. For insulation to be effective – and remain so – dimensional stability is key as the air pockets within it help prevent heat transfer. Squashed and sagging insulation can affect these energy-saving capabilities.
To prevent this, it’s important to recommend a product that’s going to keep its strength and, in turn, its thermal performance. Stone wool loft insulation is ideal for this as it maintains its shape and density over time. In tests, it is proven to provide consistent performance – even up to 55 years – without a drop in its thermal properties.
Easy installation
Dimensional stability, density and flexibility also help when it comes to installation as you don’t have to precisely cut around rafters for a tight finish. Simply trim with a serrated knife or insulation saw and friction fit.
To maximise thermal performance and minimise heat loss through the timbers, loft insulation should be cross-layered between and over the ceiling joists. The first layer (generally of 100 mm thickness) is rolled between the ceiling joists, which are normally spaced at 400mm or 600mm centres and two layers of 100mm thickness are then cross layered over the ceiling joists for a total thickness of 300mm.
Products such as Rockwool Thermal Insulation Roll are designed to make this installation process more straightforward as it is supplied as a pre-split twin roll, with two 100mm layers for coverage in between and over the rafters. This means upgrading a customer’s loft can be as quick as a morning’s work but with energy savings that are shown to last for over half a century.
To make sure loft insulation performs as well as possible, it’s important to have accurate measurements so there are no gaps where heat can escape and likewise make sure there’s no open joints before rolls. Before fitting, inspect all joists, structural elements and electrical cabling too and any rot, damp or moisture should be looked at by a specialist prior to installation.
More than thermal
Thermal performance will likely be the main reason for installing loft insulation but isn’t the only benefit. Stone wool loft insulation is fire resilient, with products such as Rockwool Thermal Roll certified Euroclass A1 non-combustible. This means it does not contribute to fire growth and is capable of withstanding temperatures in excess of 1,000°C. Stone wool insulation also absorbs vibrations and traps unwanted sounds to reduce nuisance noise both to and from the home and has been proven to reduce up to 40% of incoming noise near airports.
A further benefit is its breathability, with stone wool allowing air vapour to pass through its structure and escape, reducing the risk of damp and mould which are common in lofts, and the remedial works they bring.
Bringing further environmental benefits, stone wool insulation is also reusable and recyclable, and Rockwool products are net carbon negative, saving over 100 times more CO2 during their lifetime than was emitted during their production.
Learn more about Rockwool loft insulation at Loft Insulation | ROCKWOOL UK.
