It's one of the most common questions we're asked — and the answer is: it depends on how it's done. Laying boards directly onto your loft insulation is a problem, but that doesn't mean you can't have a boarded loft. Here's what you need to know.
Why You Can't Just Lay Boards Straight Onto Insulation
Loft insulation works by trapping air within its fibres. When you compress it — by laying boards directly on top — that trapped air is squeezed out and the insulation loses much of its effectiveness. You end up with a boarded loft that's actually less energy efficient than before you started.
There's a regulatory angle here too. Current building regulations require a minimum insulation depth of 270mm. Many older homes have insulation installed to the previous standard of 100mm or less, which is already well below what's needed. Compressing what little insulation is there makes the problem worse.
So if you've seen DIY videos suggesting you can simply board over your existing insulation, it's worth understanding what that's actually doing to your home's heat retention.
The Right Way to Board Over Insulation
The solution is raised loft boarding — where the boards are lifted above the insulation rather than laid directly on top of it, leaving the insulation free to do its job at full depth.
We use two methods depending on your property. For most homes, we use raised structural timbers — either 4" (100mm) or 6" (150mm) — to strengthen and raise the floor above the top layer of insulation. For new build properties, we use Loft Legs, which are purpose-made raised support legs available in two heights: 175mm and 300mm.
Both approaches mean your insulation stays uncompressed beneath the boarding, and the finished floor is solid, safe, and properly supported. Electrical cables are made safe and pipes are boxed in where required as standard.
It's also worth knowing that boarding doesn't have to mean the whole loft. Boarding the full loft or just the central section are both practical options, and pricing is per square metre either way, so you only pay for what you need.
What If My Insulation Is Already Below 270mm?
If your insulation is thin, compressed, or patchy, a loft boarding project is actually a good opportunity to address both issues at the same time. Topping up insulation to the current standard before boarding is raised over it means you end up with a loft that's both properly usable and properly insulated.
Signs that your insulation may need attention include cold spots in upstairs rooms and heating bills that feel higher than they should be. According to the Energy Saving Trust, over 25% of heat is lost through an uninsulated roof — making it one of the most cost-effective improvements you can make to your home.
What About Electrical Cables and Pipes?
This is another reason to use a professional rather than attempt loft boarding yourself. When laying boarding, electrical cables need to be made safe and any pipes boxed in where required. Getting this wrong can create hazards that aren't immediately obvious — and aren't covered by a DIY job.
Does Loft Boarding Add Value?
A properly boarded loft — with safe access and usable storage space — is consistently seen as a practical selling point by estate agents. Done correctly, with insulation preserved rather than compressed, it's an upgrade that works for your home in the short and long term.
Does Loft Boarding Need Planning Permission?
No planning permission is needed for loft boarding in most cases. However, all materials and methods should comply with current building regulations — which is something we ensure as standard on every job.
Getting It Done in Berkshire
At The Loft Access Company, we carry out loft boarding across Maidenhead, Windsor, Slough, Marlow, Henley, and the surrounding areas. Every job includes making cables safe and boxing in pipes as standard, and we'll always flag if your insulation needs attention before we board over it.
Get in touch for a free, no-obligation survey and quote.
The Loft Access Company is a VELUX Certified Installer, TrustMark registered, FENSA registered, and a proud member of the Guild of Master Craftsmen.
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