Here’s Everything You Need to Know About Insulating Your Attic

Caeva O'Callaghan | November 20th, 2023

It’s one of the most important energy-saving tips you can do around the home. But updating your attic insulation is a project that’s often misunderstood, treated as an afterthought, or worse – never done at all.

Read on for a complete lowdown on the surprisingly simple world of attic insulation, and along the way we’ll answer these questions:

  • What’s the best type of attic insulation?
  • How to install attic insulation?
  • Is insulating your attic expensive?

Insulating your attic isn’t too expensive, there are grants available and it is always important to make sure you use a certified professional.

What is attic insulation?

It’s kind of like putting a hat on when it’s chilly outside. Heat rises, so if your roof is a weak spot you’ll end up turning on the radiators to compensate, wasting money and energy. Good, cosy insulation traps heat inside your home.

Does your attic need new insulation? You can tell by going outside. If yours is the roof all the seagulls and pigeons sit on because it’s toasty warm, you need new insulation. Likewise, if there’s snow on everyone else’s roof but yours, it means heat is escaping – and you could be losing money.

Do I need to insulate my attic?

Yes, unless you love a freezing cold house and wasting money on heat escaping from your roof.  By insulating your attic you can lower your heating bills, keep your house warmer, improve your BER rating and reduce your energy emissions.

There are also grants available in Ireland through the SEAI (Sustainable Energy Authority of Ireland). For attic insulation, there is up to €400 available. Do make sure you comply with regulations to ensure you can avail of any grants available. Beyond your attic, there are also other insulation grants available so check these out as it may make sense to insulate other parts of the home whilst doing the work.

If your attic insulation is under 100mm, it’s a good idea to thicken it to the recommended 270mm to improve your home’s BER rating.

Types of attic insulation

There’s a range of insulation materials available, which do different jobs and are suitable for different houses and budgets. Here’s the most common ones:

Batt or blanket loft insulation

The most common type of insulation, batts are available in rolls of foil-backed felt, rock, glass or mineral fibre. Batts are easy to install yourself, but some materials can irritate the skin, so watch out and wear gloves and goggles. You can buy recycled sheep’s wool batts, which are a little more expensive, but non-irritant and good for the environment.

Batts can be bulky, so you need an open attic space you can access. If you plan on flooring your attic, there’s unlikely to be enough space between the joists for the recommended 270mm thickness. This means you may have to raise the floor, or buy insulation-backed flooring.

Loose-fill loft insulation

If you have irregular joists or a small, inaccessible space to insulate, loose-fill is a great option. It’s made from a variety of granular or lightweight materials such as cork granules, mineral wool, cellulose fibre or even polystyrene. It involves getting a pro to blast the fill up into your attic space.

Loose fill is great for oddly-shaped attics, or if you have obstructions. It’s great for topping up existing insulation, and installation only takes a couple of hours. But it can come loose in draughty lofts – which means either you need to spend more money sealing your roof, or splash out on an environmentally friendly fill such as recycled newspaper or cork. You don’t want to find polystyrene balls all over your lawn after a storm!

Sheet insulation

Designed for insulating the sloping sides of a roof, this insulation comes bonded to firm boards. Available with fire-resistant, moisture-resistant or even decorative covering, you can order it precut to the exact size you need for an extra cost.

Greener sheet insulation options include cork, straw and wood, and it can be covered with plasterboard for loft conversions. It’s one of the most effective forms of loft insulation but also more costly, and synthetic sheet insulation materials use a lot of energy to produce.

How you use your attic after insulation

What happens in your attic can greatly affect how you insulate it. Don’t go up there, and never plan to? Great, you can add as much insulation as you like and not worry. Plan on storing your Christmas decorations or suitcases? You’ll need to board your attic, which means laying a plywood floor over the joists as a platform. However you probably won’t be able to fit 270mm of insulation underneath – so you’ll need to raise the floor, or use insulation backed boards.

Plan on converting your attic into a bedroom or study? Don’t put insulation in the floor, or the heat won’t rise through it and you’ll be freezing. Instead, use sheet insulation on the sloping walls, stopping the heat from escaping and creating a surface you can wallpaper or paint.

Final tips and tricks

Don’t forget about your hatch! Make sure it fits snugly, and apply draught-stripping between the hatch and frame. Seal up any other holes going up into the roof – above pipes, for example – before you insulate your attic.

Insulating your attic floor (versus putting sheet insulation in the slope of the roof) will make it colder. If you have pipes or a cold water tank up there, you’ll need to install lagging to make sure they don’t freeze in winter.

Got damp? Effective insulation will make it worse, as it cuts off ventilation. If you have damp in your attic you need to sort that out first with the help of a professional.

Installing attic insulation is easy when you know how, and with a little planning ahead you can keep your home cosy for years to come.

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If you have any queries about insulating your home and the impact that it may have on your insurance, call us today.  You can call us directly on 0818 224433 or 042 9359051.

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All Information in this post is accurate as of the date of publishing.