Most lofts in the UK have somewhere between £30 and £150 worth of insulation up there, plus a couple of grand of stuff in cardboard boxes that no one's looked at since 2019.
Whether you should board over the lot depends on a question almost no one asks: how thick is your insulation now?
Because if it's the modern standard — 270mm of mineral wool — you cannot lay floor boards directly on the joists without doing something about it first.
The joists in most UK houses are 100mm deep. Insulation should be 270mm. That's 170mm of insulation that has to sit above the joists, not crammed down between them. If you board straight onto the joists you're squashing 170mm of fluff into a 0mm gap. The thermal value is destroyed. The boards also bow over time as the wool tries to expand back.
This is the single most common loft mistake we see — and we see it every week.
The fix: raised loft legs
Loft legs are little plastic stilts. They sit on the joists and lift the floor 100–200mm clear of the insulation. The boards screw onto the tops of the legs. The insulation stays loft, the floor stays flat, the house stays warm, and you've got proper usable storage.
Brand-wise we usually use LoftZone StoreFloor or similar systems. Materials cost about £15/m² for the legs. Combined with boarding, a typical 20m² walkable loft works out around £900–£1,400 fitted, including the boards. A full-loft board (40–50m²) is closer to £1,800–£2,800.
What about just leaving it un-boarded?
That's a fine choice. If you don't store much in your loft, don't bother boarding it. Top up the insulation to 270mm, fit a decent ladder, put a couple of small free-standing storage shelves in the boarded centre walkway only, and you're done.
The mistake is partial boarding without raised legs — laying a few boards down "just enough to walk on" and crushing the insulation under them. That happens at almost every house we visit.
Old houses and odd lofts
Period properties around Bath, Wells and Frome sometimes have lofts with weird joist spacing, sloping ceilings or tons of structural timber across the floor. These don't always take standard boarding — sometimes you need bespoke flooring cut to fit awkward shapes, or in really old properties, lifting the existing 1970s loft floor first to find what's underneath.
Worth a quick survey in those cases before committing. We'll come up and have a look — it's not always a quick "yes, board the lot" answer.
What about a loft conversion instead?
Different question entirely. If you're considering a loft conversion at some point — a habitable room with rooflights or a dormer — don't board the loft now in a way that has to come up later. We can lay boards in a "removable" pattern that lets a future conversion happen without fighting your previous DIY.
Either way, if you're not sure whether boarding is right for you, give us a ring on 07516 555 377 and we'll have a look. Free quote, no commitment, honest answer.