How to Successfully Raise Your Loft Floor With Timber

If you need to raise your loft floor with timber but don’t know where to start, our timber experts have compiled this comprehensive guide with step-by-step instructions and commonly asked questions to help you tackle this DIY project. 

Why Raise a Loft Floor?

Raising your loft floor is a fantastic way to create extra storage space. By lifting the floor, you can install proper boarding across the entire loft, giving you a sturdy, safe surface to store all those items that need a home. Plus, raising the floor allows you to add more insulation, which is great for boosting your home's energy efficiency. With better insulation, you'll stay warmer in the winter and lower your energy bills.

Is Raising a Loft Floor Beginner Friendly?

Raising a loft floor is a bit more complex than your average DIY task. We recommend it for intermediate DIYers who have some experience and confidence under their belts. This ensures that the job is done safely and correctly, especially since it involves working with structural elements and insulation. If you're comfortable with measuring and securing timber, as well as working with insulation, then this could be a great project for you.

Consider Insulation Regulations

When raising your loft floor, it's crucial to consider the depth of your insulation. Laying hardboards directly on top of your existing joists can compress the insulation, reducing airflow and diminishing your home's energy efficiency. To avoid this, you'll need to install new joists above the existing ones, creating the necessary space for both insulation and proper ventilation.

This is especially important if your current insulation is older and has shrunk over time.

The UK government recommends a loft insulation depth of at least 27cm to effectively reduce heat loss in your home. When adding in new joists, you need to ensure you have enough space to meet this guideline and still allow for extra breathing space to promote airflow and minimise condensation.

Check Your Existing Joists 

Before you begin raising your loft floor, the first crucial step is to inspect your existing timber joists. You need to ensure they are structurally sound with no signs of dampness, rot, or damage. Any compromised joists should be repaired or replaced before proceeding. 

The Materials You’ll Need

Raising a loft floor with timber does not require complex materials or professional tools, making it a good DIY project. However, getting the measurements correct will be very important and it’s essential to consider what you can fit through your loft hatch. 

• Carcassing Timber 
• Hardboard Sheets 
• Loft Insulation 
• Nails or Screws 
• Joist Hangers 

What Timber Should You Use? 

When raising a loft floor, it's crucial to choose the right timber to ensure the structure is safe and durable. You’ll need strength-graded timber, either C16 or C24, as these grades are specifically rated for load-bearing purposes. The timber boards should be long enough to span your loft from wall to wall, with enough depth to provide solid structural support. Additionally, using treated timber is important, as it helps protect against dampness and insect infestation, ensuring your loft floor remains sturdy and secure over time. 

Selecting the right size timber is essential. Make sure to accurately measure your loft to figure out the timber sizing you need. At Covers Builders Merchants, we stock a wide range of top-quality, strength-graded Structural Timber and our depots offer a timber-cutting service so you can get the exact dimensions you need. We also have incredible offers like this Sawn Treated Carcassing Timber C24 100 x 100mm in our Smart Deals. 

Remember: Safety First 

When working in a loft, safety is key. Wear gloves, a dust mask, and goggles to protect against insulation fibres and dust. Be careful where you step – stick to the joists, as the plasterboard won’t support your weight. Good lighting and ventilation are also important to keep your workspace as safe as possible. 

Our Step-By-Step Guide 

1. As we mentioned before, first you need to make sure your existing joists are in good condition. 
2. Then you need to start creating the new timber subframe by cross-battening new joists above the existing ones. It’s important not to put the new timber joists directly on top of the old ones as this will be too much weight for them to bear, taking into consideration deflection (the amount a structural beam bends when bearing the weight of a load), and could lead to cracking in the ceiling below. 
3. Place the new timber joists so they are running in the opposite direction to the existing ones. Secure them from one load-bearing wall to another with bolted-down joist hangers, leaving a gap (ideally 25mm but it depends on the dimensions of your timber) to allow for deflection without damaging the existing joists. 
4. The new joists must be evenly spaced out, the distance you need between each joist depends on the size and strength of the timber you’re using. If you need more structural support, you’ll need to either move the joists closer together or increase the strength or depth of your timber. The even spacing is very important here, make sure you measure accurately from either the centre of each joist to the next, or from the outer edge to the next outer edge. 
5. Once you have securely attached the new joists, you can lay your additional loft insulation. Remember the recommended depth is 27cm and you need to leave extra breathing space. 
6. With the insulation in, you can lay the hardboard sheets. You will need each end of the sheet to match up with the middle of a joist, so the longer the sheet the better as this increases the strength of the board and reduces cut-off wastage (but consider what size board will fit through your loft hatch). Place the boards in a staggered, brickbond pattern and nail or screw them down so they are securely fastened to the joists below. 
7. Finally, enjoy the extra space provided by your new, insulated loft floor. 

Find Top-Quality Timber For Your Project 

We have an extensive collection of top-quality timber and other building materials, so you can find everything you need for your next DIY project in one place. We also have a team of friendly experts who are always happy to help you with advice and find exactly what you need. 

When you shop at Covers Builders Merchants, you’ll experience the difference of shopping at a family-run business with over 175 years of industry experience. Find your nearest Covers depot now!