Loft Insulation DIY
Installing loft installation is a straightforward job for someone who is fit and competent, but there are potential hazards that you should be aware of. Lofts can be dark, dusty places full of junk, as well as routes for electric cables and piping, so it’s important that you survey your loft and take proper precautions to prevent an accident or injury.
Preparation and planning
- Work out how much insulation you’re going to need. Measure the dimensions of the loft (and the depth of the current insulation if any, to decide how much thickness you’re going to need to bring it up to 270mm)
- If you’re going to be filling the gaps between the joists, measure the gap between the joists so you know what width of insulation you need. If you’re laying over the top of existing insulation, the choice of width is less important
- Check that the loft is properly ventilated with either spaces at the eaves where the roof meets the floor, or from ventilators in the roof. If you cannot find these then you will need to address this to prevent condensation building up in the roof space and causing the timbers to rot
- Measure the size of your loft hatch so you know you’ll be able to get the insulation packs into the loft
- Check for any pipes as these will also need to be lagged to prevent them freezing as your loft will be a lot cooler once you have installed the insulation. You can buy different pre-formed pipe insulation in different lengths
- If there is a water tank in your loft you may also need to buy a tank jacket. These come in various sizes so measure the size of your tank.
Before you start
- Identify any potential hazards such as electrical cables and loose boards, and remove any boxes and other items so the space is completely clear
Wear suitable clothing including gloves and a dust proof breathing mask as glasswool fibres can irritate the skin. Space Blanket is a good choice if you’re concerned about this because it’s an encapsulated roll and you’ll find it’s virtually itch free
- You may need a knife to cut the insulation. Always take care when cutting as there are often electric wires running through the loft
- Get some wide planks or boards to walk on. These should be a minimum of one metre long so they span at least three joists. Only stand on the joists if you have to, but never in-between them, or you are likely to put your foot through the ceiling or even fall through it. That money-saving choice of doing-it-yourself could become very expensive in ceiling repairs!
Laying your insulation
- Start at the corner furthest away from the loft hatch. Tuck the end of the roll into the eaves but don’t completely block them – leave an air gap of at least 5cm to ensure there is sufficient airflow to prevent condensation
- If there is no existing insulation between the joists, start by laying 100mm between the joists
- Lay a further 170mm across this first layer at right angles to the joists. At this stage take extra care, working across the loft in a line. You will be covering the joists as you go, so be sure not to lose your footing when moving about
- You may need to cut the insulation to fit round pipes or route cables. Butt the ends together around the obstruction. This will avoid the risk of overheating and possible fires in the loft. Do not bend or pull wiring out of the way
- As you lay the insulation, lag any pipes as you come across them so you don’t have to walk across the loft once you’ve finished laying the insulation
- If you have a cold water tank, don’t put insulation under it. Instead fold the insulation up around the sides of the tank at the bottom and then wrap the tank jacket round the tank and over the top of the ends of the insulation to form a draught proof seal
- If there are hoses for extractor fans or recessed light fittings protruding into the loft space, trim the insulation around them, leaving a gap of 15cm all the way round
- Finally, don’t forget the loft hatch. Just nail or staple some insulation onto the back
- Now sit back, make yourself a cup of tea and enjoy a warmer house and lower heating bills for the rest of your life.