How do you correctly insulate a loft? Do you lose your storage space if you insulate correctly? Do you put loft boarding over insulation? This guide outlines the various do’s and don’ts of insulating a loft.
Heat rises, and at least 25% of it is lost through the roof in an uninsulated home (Source: Energy Saving Trust). This loss can lead to higher energy bills and an uncomfortable living environment.
Loft insulation can help combat this problem, but it’s essential to install it correctly to ensure you’re maximizing its efficiency without sacrificing your storage space.
A report from the DECC found that only 65% of English homes have sufficient levels of loft insulation. This leaves many homes vulnerable to unnecessary energy consumption, where heat escapes through the poorly insulated roofs, making heating costs skyrocket.
The Importance of Loft Insulation
Current government guidelines require a 270mm depth of quilt insulation to achieve a U-value of 0.16W/m²K, ensuring the heat in a home is retained in the habitable rooms below.
In some newer builds, this insulation depth can be even deeper to meet stricter thermal performance targets.
This increased depth of insulation results in the insulation being significantly deeper than the joists or trusses. As a result, lofts become difficult to navigate, and boarding over the insulation for storage can become a challenge. However, with the right products, it’s possible to add storage while maintaining the insulating benefits of the loft.
How to Install Loft Boarding Over Insulation?
If your insulation is already in place and quite deep, you may wonder how to install boarding over it. Do you squash the insulation down and screw the boards to the joists or trusses? Or should you remove the insulation? Is there a better way to approach this? Let’s break down the best practices for installing loft boarding over insulation to make sure your loft remains functional, insulated, and safe.
Do’s
1. Raised Loft Boards on Loft Legs
The best method to install loft boarding over insulation is by raising the boards above the insulation. This will ensure the insulation is not compressed and continues to perform at its optimal level.
Use Products Like Loft Leg: A product such as the Loft Leg is ideal for this task. Loft Legs are designed to create a raised boarded area, which allows you to lay boards above the insulation without affecting its performance. These products are cost-effective, easy to install, and provide a safe, accessible area for storage.
Create a Safe Raised Area: By using Loft Legs, you’ll create a raised platform above the insulation, which keeps the insulation in place and untouched. This ensures no compression, which could otherwise cause a reduction in thermal performance. Plus, it gives you that much-needed storage space without compromising on insulation.
Plan Ahead: It’s essential to plan ahead before starting the installation process. Understand the size of the loft, the amount of insulation, and the weight capacity of the loft structure. Installing raised boards might sound simple, but without proper planning, you could run into challenges later.
2. Check the Loft’s Load Capacity
Before installing any loft boarding, always check that your loft structure is capable of handling the weight. Most new build homes are designed to handle the storage weight of 25Kg per square meter, plus the weight of a person moving around in the loft (BS 6399-1:1996 / EN1991-1-1). However, older properties may not be designed with this load in mind.
Structural Analysis: If you’re unsure of your loft’s capacity, it’s worth getting a structural analysis or consulting with a professional to ensure the added weight won’t cause any problems.
3. Use Recommended Fixings
When fixing Loft Legs to trusses or joists, or fixing loft boards onto Loft Legs, use the manufacturers recommended screws. The screws are 4.0mm x 30mm general purpose screws and have been extensively tested to ensure they drive easily through the Loft Legs and loft boards, while at the same time creating a very secure fixing.
4. Use Tongue and Groove Loft Boards
When selecting loft boards, use 18-22mm chipboard or OSB board and ensure that the boards have tongue and groove edges. The tongue and groove edges will provide additional strength to the finish raised platform. Consider staggering the joints on the loft boards too, while not essential this will add further strength to the completed raised loft boards.
5. Leave Space for Ventilation
Inadequate ventilation in your loft can result in moisture build-up, leading to issues like mould and mildew. As you install loft boards over insulation, make sure to leave room for proper airflow.
Ventilation Gaps: Make sure that vents, soffits, and any other required air pathways are not blocked by insulation or the loft boarding. Blocking these vents can lead to condensation issues, which may damage the loft structure and insulation over time.
6. Install Downlight Covers
If your loft contains recessed downlight fittings, it’s important to protect them when installing insulation. Cover downlights with a product like a Loft Lid or a similar downlight cover before rolling insulation over the top.
Don’t Place Insulation Directly Over Downlights: Insulation placed directly over downlights can overheat and become a fire hazard. By using downlight covers, you ensure that the insulation remains safe, and the downlights function properly. Modern LED downlights run a lot cooler and are not as susceptible to heat build-up. The Loft Lid in this case will help to create an air tight seal around the fitting to help maintain the ceilings airtightness and ensuring heat is not escaping into the loft space.
Check here for more tips on how to insulate a loft correctly.
Don’ts
1. Never Squash the Insulation
One of the most significant mistakes homeowners make when installing loft boarding over insulation is compressing the insulation. This may seem like a simple way to create more space, but squashing the insulation drastically reduces its effectiveness.
Squashing Reduces Thermal Performance: Compressing insulation can decrease its ability to trap air and prevent heat from escaping. Studies have shown that squashing insulation from 270mm down to 100mm will reduce its performance by over 50% significantly affecting your home’s energy efficiency.
Avoiding Compression: Always make sure that the insulation remains undisturbed and is continuous. By using raised loft boards, you ensure that the insulation stays in place, without any risk of compression.
2. Don’t Block Vents
Ventilation is crucial in any loft space. Blocking ventilation pathways, such as soffit vents, with insulation can lead to issues with moisture build-up, which can cause mould growth and even structural damage.
Leave Vents Open: As you lay insulation, make sure it doesn’t block any vents or airflow systems. This allows air to circulate properly and prevents moisture accumulation.
3. Don’t Remove the Insulation
It might be tempting to remove some of the insulation to create more room for storage or make the boarding process easier. However, removing insulation defeats its purpose of retaining heat.
Removing Insulation Reduces Thermal Efficiency: If you remove insulation, the loft will lose its heat-retaining properties, leading to a colder home and higher heating bills.
4. Don’t Install Loft Boards Directly on Joists
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.
5. Don’t Overload Your Loft
Even if your loft is designed to carry storage weight, overloading it with heavy items can put unnecessary stress on the structure. Always consider the weight of stored items when planning your loft storage.
Stay Within Weight Limits: Ensure that you store only lightweight items and avoid placing excessive weight on the loft structure.
Check here for more loft boarding mistakes to avoid.
Where to Get Help With Loft Insulation
Installing loft boarding over insulation is an easy process and is essential if you want both storage and for your quilt insulation to work at its optimum performance. With the correct products, such as Loft Legs, this is easy and cost effective too.
Loft Legs have been designed to be a quick, cost effective DIY solution, so you don't need a professional installer to install them. If however, you would like someone to price up the full job and carry out the work, Loft Leg have a list of recommended installers covering most of the United Kingdom. The recommended installer list can be found here.
Whether you’re a seasoned DIYer or a first-timer, we’re here to guide you through the process. If you need any assistance, our office number (01282 861001) is manned from 9 am until 4 pm every weekday. Our team is available to provide expert advice and answer any questions you may have about your loft insulation project.
By following the do’s and don’ts outlined in this blog, you can create a well-insulated loft with plenty of storage space. Ensure you’re following all the necessary steps to keep your home energy-efficient and your loft safe for storing your items.
Browse our range of loft products and contact us today for more information.