Can you board a loft over insulation?

Author: Scotty Ortiz  |  Last update: Wednesday, July 8, 2026

When you're ready to install your loft boards, you should position them above your insulation using Loft Leg supports designed for this purpose. This will avoid compressing the insulation and ensure it is working to its maximum potential.

Can I lay loft boards over insulation?

The insulation will not be effective if placed over boards. Again you must not board over insulation as this will compact it and causes condensation and more problems.

Do you need a gap between insulation and loft boards?

You don't need a gap between the boards and insulation, just make sure you don't compress the insulation, but you do need a gap in the corner where the roof comes down to allow airflow from the soffits into the loft.

How high should loft boards be above insulation?

According to regulations, loft insulation depth must be at least 270mm, which is usually higher than most loft floor joists. So when you try and board directly onto these joists, you're going to end up squashing the insulation down, which in turn means your insulation won't pass a building control inspection.

Does boarding over loft insulation cause damp?

No! Putting boards directly onto your joists will squash your insulation and restrict airflow in your loft. Not only is this against building regulations but it can also cause damp and mould to form in your loft from restricting the airflow.

Loft Boarding | Two very different style lofts back to back

What are the rules for loft boarding?

The Do's of Loft Boarding
  • Obtain the Right Tools for Your Loft Boarding Project.
  • Evaluate Your Current Insulation.
  • Measure the Loft Area.
  • Create a Raised Board Area.
  • Stagger Your Boards.
  • Don't Overload the Joists or Trusses.
  • Don't Install a Loft Board Directly to a Joist or Truss.
  • Don't Remove or Cut Holes In Your Insulation.

Is it a good idea to board a loft?

Great idea! Loft boarding is a savvy way to make the most of your attic space, offering a sturdy platform for storage while protecting your insulation.

Can I fix loft boards directly onto joists?

When you place loft boards directly on joists, you risk compressing or even having to remove some of the insulation. This can drastically reduce the thermal efficiency of your insulation. In fact, studies show that compressing 270mm of insulation down to just 100mm can reduce its effectiveness by over 50%.

Can a loft have too much insulation?

While loft insulation is an effective way to improve energy efficiency and reduce heating costs, over-insulating can lead to several potential issues. Firstly, over-insulation can lead to poor ventilation in the attic, which can cause moisture buildup and increase the risk of mould growth.

Can you walk on a boarded loft?

Yes, as long as the installation is carried out correctly. A solid raised loft boarding system will distribute weight evenly, meaning you can store items and walk on the boards with confidence.

Where not to put loft insulation?

One important thing to remember is that insulation should never be pushed right into the eaves because it will interfere with airflow. If you're going for a warm loft then you'll need much more insulation to be able to cover the underside of the roof along with the gable and party walls.

Can you use a boarded loft as a bedroom?

But if you want to make your loft a habitable space and more than just simple storage, then you'll need to go one step further than simply boarding out a loft. You'll need a complete loft conversion to ensure it's safe and comfortable to use as a habitable room, such as a bedroom or home office, for example.

Can you put 2 layers of insulation in attic?

You should install two layers of insulation in your attic; wood joists must be covered to allow the air to move. The first layer will sit between the joists, and the second layer will run perpendicular over the joists. The first layer should have the facing against the drywall to act as a vapor barrier.

Can I put boards over attic insulation?

Boarding over your loft insulation can be a great upgrade for your home when done correctly, so your insulation is not compromised. It can provide you with usable storage, or even extra living space, which will only enhance the value of your property.

How much gap do you leave between insulation and loft boards?

If using rigid insulation boards to insulate your loft there must be a gap between the roof covering and the insulation to allow air to circulate. This prevents any build-up of warm air that could lead to condensation. For this reason, a minimum gap of 50 mm must be left between the two to prevent it occurring.

Can you store things in an unboarded loft?

Storing things in an unboarded loft is generally not recommended. This can lead to various problems and can threaten the structural integrity of your house, depending on how much you're trying to store in the loft. Always make sure to get the floor of the area properly covered before attempting to use it for storage.

How thick should a loft insulation board be?

Since 2003, current building regulations recommend a depth of at least 270mm (mineral or glass wool) in the loft – use this as a starting point rather than a finishing line to see larger savings.

Can too much loft insulation cause mold?

Many of us know what causes mould; when moisture is trapped in the rooms of you home. Sometimes, there is insufficient insulation in the walls, so mould grows. However, not many people realise that additional insulation isn't always the answer. In fact, too much insulation can be the secret cause of mould.

Is it worth adding extra loft insulation?

Absolutely! By reducing the amount of energy needed to heat your home, loft insulation also reduces carbon emissions.

How to board over loft insulation?

Avoid attaching loft boards directly to the joists or trusses. This can compress the insulation and create stress on the plasterboard below. Raised Boards Are Best: Installing loft boards on raised supports or Loft Legs ensures that the insulation is left undisturbed, allowing it to work at its optimal level.

Should you nail or screw loft boards?

Once you're confident that you have placed your loft boards in a way that provides a safe area to stand on and store your things, it's time to screw them into place. Drill 2 or 3 pilot holes along the edge of each board, lining up with the centre of the joist below and fix them into place with screws.

How much weight can loft boards take?

According to British Standards, roof trusses (BS5268) can take a static load of up to 25kg per square metre – plus the weight of one person accessing the loft (a dynamic load of up to 180kg). Also, the lattice-beam structure of our raised loft flooring actually strengthens the joists.

What is the cheapest way to board a loft?

The cheapest way to board a loft would be off course to use a chipboard.

How much value does a boarded loft add?

Add Value To Your Property

As well as helping to improve your home's energy efficiency, boarding out your loft adds value to your property. A recent study found that by adding a boarded floor to empty loft space, you can add up to 8% to the value of your home due to the extra space created and the added room.

Do I need permission to board my loft?

Permissions and Adding Value with Loft Boarding

You do not need planning permission to board a loft, as long as the room will only be used as storage. Projects such as loft boarding are allowed under what is known as permitted development (PD) rights.

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