Loose-fill Loft Insulation Materials
Introduction
Loose-fill loft insulation is sold in bags and can be poured between the joists to the required depth. Due to the flexible loose nature of the product it is generally easier to install than rolled or matting insulation, especially if there are awkward corners or obstructions in the loft space.
Unlike rolled or matting insulation, loose-fill can also be applied where the joists are irregularly spaced, or the spacing is not suitable for the fixed width roll materials.
Loose-fill insulation materials generally have the same insulation value as rolls or matting, and thus should be applied to a similar depth. In the UK the total thickness of the insulation when laid should be at least 200mm (8in) and ideally up to 270mm (11in).
Loose-fill insulation is not generally suitable for draughty loft spaces as the air movement can shift the material around and reduce the insulating effect. If a floor is laid in the loft, as in a loft conversion, then this will prevent movement of the material.
Measuring the amount of material required
Calculate the floor area of the loft by measuring the length and width of the loft.
If your loft is not square or rectangular (an ‘L shape’ is two rectangles remember!) then measure the longest length and width to give a slight over-estimate.
On average, 200 litres of material is required to cover 1 square metre (1 M2) to a depth of 200mm (8in).
The bag sizes of loose-fill product vary by manufacturer, however once you have decided on the product you wish to purchase, simply multiply your total loft area by 200, then divide by the volume of the bag, to give an idea of how many bags you will need.
- It helps to round this figure up to ensure that you don’t run out of material before the job is finished.
Safety
- Mineral wool insulation can irritate the skin and throat.
When working in the loft space always;
- Wear a suitable dust mask to avoid throat irritation, and protective gloves to prevent irritation to hands.
- Wear long sleeve clothing and trousers to protect your skin. This should be the case even on warm days when the loft space can become very hot!
- Close the loft hatch when laying the material.
- Open the loft insulation packaging in the loft.
- Unroll or pour the material carefully to avoid creating dust clouds.
- Place any off-cuts and other waste into bin liners in the loft before removing.
- Wash any clothing used separately to regular washing to avoid contamination of non-work clothes.
How to install loose-fill loft insulation
Further information and useful links
- Making structural changes to your property
- Successfully damp proofing your home
- More walls and ceilings topics
- Building works topics
- Find an Insulation Installer near you
- National Insulation Association
- Energy Savings Trust (est.org.uk)
- Cavity Insulation Guarantee Agency (ciga.co.uk)
- Party Wall Guidance (rics.org)
- Impact of the Party Wall Act 1996 (communities.gov.uk)
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