Insulating your loft is one of the simplest ways to cut heat loss and lower your energy bills, and it's a job most confident DIYers can tackle in a weekend without specialist tools or experience.
This beginner-friendly guide from NWTT walks you through the whole process from start to finish, so you can whip your home into shape before the cooler months!
What you will need
Screenshot our shopping list below so you have everything you need before you get started.
Tools
- PPE, including a dust mask, protective gloves, and safety goggles
- Sharp utility knife
- Tape measure/a>
- Torch or portable work light
- Scaffold or kneeling board
- Staple gun/a>
Materials
- Loft roll insulation (enough for two layers, so 270mm total thickness)
- Insulation for the loft hatch
- Draught excluder strip
- Tank jacket (if you have a water tank in the loft)
- Pipe lagging
- Eaves vent baffles
- Timber battens or loft legs and OSB boards or loft boards (for adding extra storage)
Do you need a professional to insulate your loft?
In most cases, you can safely insulate your own loft with a little know-how and time. However, if any of the following apply, it would be safer to call in an expert:
- You have electrical cables or downlights in the ceiling below - Insulation applied over the top of electrics can be a fire risk.
- There is visible damp, mould, or water staining on the timber or ceiling - This requires investigation before you cover it.
- Your loft has signs of bats or a pest infestation - Bats are a protected species in the UK and disturbing their roost is against the law. If you do find bats, speak to the Bat Conservation Trust.
Check your current insulation
Most UK homes will have somewhere between 100mm and 120mm of insulation already in place. However, the government-recommended depth is 270mm, so this task will likely be a topping-up process rather than starting from scratch.
If your current loft has no insulation, or you’ve had to remove it after an infestation or roof leak, you’ll be handling a full first fit. There’s no real difference; you’ll just need to factor in needing more insulation.
Get the loft ready
Before you can lay any insulation, clear the loft of boxes, bags, and clutter so you can move freely. Trying to tuck insulation under or around things takes much longer, and you are likely to miss patches.
You should also ensure you have adequate light, as most lofts are pitch black, even during the day. This isn’t a step that can be ignored, as in homes with unboarded lofts, you will only be able to step on ceiling joists or kneeling/scaffold boards laid across them.
Safety first: If you do step into the gap between, you’ll likely break the plasterboard ceiling of the room below, and you could even trip if you can’t see what you are doing clearly.
Insulate the loft hatch
An uninsulated hatch is an easy route for heat loss, so ensure you start here!
Wearing your PPE, cut a piece of insulation or rigid foam board to fit on top of the hatch door and fix it in place.
Next, add a draught excluder strip around the frame.
Lay the first layer of insulation
Unroll your mineral wool insulation between the joists, cutting to length with a sharp knife as you go. If the insulation layer comes up to or very close to the joist height, you don’t need a second layer.
Top tip: Ensure you tuck it in snugly, but try not to fully compress it, as this will affect its performance.
Lay the second layer
This is the step that often catches people out - the second layer of insulation should be laid at a right angle to the first, running over the top of the joists, rather than between them.
Why it matters: If you don’t cover the joists, they can act as a ‘thermal bridge’, letting heat escape through the wood.
Keep the eaves clear
When you get to the edges of the loft, where the roof meets the walls, you will see vents or gaps in the eaves. These vents allow for air circulation, which prevents damp and condensation build-up.
You shouldn’t block these gaps with insulation — instead, use vent baffles to hold the insulation back without blocking airflow.
Insulate the water tank and pipes
If you have a water tank in the loft, you can now apply a purpose-made tank jacket and lag any exposed pipework to stop them from losing heat or freezing over in the winter.
Important: Don’t insulate directly underneath the tank, as the small amount of rising air from the room below will stop it from freezing in harsh winters.
Add loft boarding
This optional step is designed to give homeowners extra storage if they want it, without impacting the performance of the insulation itself.
If adding boards, use loft legs or timber battens to create a gap between the top of the insulation to prevent compression, and attach the loft or OSB boards. This step can be done throughout the loft or just around the loft hatch, and gives you somewhere stable to stand as well as a sturdy place to put Christmas decorations and out-of-season goods.
Create warmer winters with NWTT
As the colder months approach, you might be wondering just how cold it will get this winter, and just how high your energy bills might be.
Considered one of the quickest ways to reduce bills, increase comfort, and see a return on investment, insulating your loft is actually pretty simple and achievable.
For everything you need and support, NWTT is ideally placed to help. With North West branches and expert advice just a short drive away, or Click & Collect services for those a little more pressed for time, you can get the job done in no time at all.
Call 01942 720 777 or order online to get started, and we’ll help however we can.