It’s a question that sounds completely reasonable: if you insulate your home with something made from wood, won’t insects or rodents be drawn to it? After all, animals like warm, natural materials just as much as we do.
But the good news is that—despite the name—wood fibre insulation isn’t something pests tend to go for. In this article, we explain why that is, how the insulation is made, and what really matters when it comes to keeping critters out of your home.
If you’d prefer to listen to Chris and Andy talk about this very topic then just click play on the video below, where they discuss this question about pests in episode 18 of Can I Just Ask?
What Even Is Wood Fibre Insulation?
Let’s start with the basics. Wood fibre insulation is made from waste wood that’s been broken down and reformed into boards or batts. Depending on how it’s processed, the material has most of its natural sugars removed – especially in the case of wet-processed boards.
And why does that matter? Because it’s the sugars in natural wood that wood-boring insects like beetles and woodworm are usually after. Without those, and without the solid structure of timber, the insulation just isn’t an appealing home or food source for them.
So, even though it’s made from wood, it’s not the kind of material insects can tunnel through or feed on.
What About Rodents?
Rodents; mice, rats, and so on, aren’t especially fussy. If they find a way into a building and discover somewhere warm and protected, they’ll often move in. But here’s the key point: they don’t care whether that space is filled with wood fibre, mineral wool, or foam boards.
In other words, it’s not about the insulation – it’s about whether they can get into it in the first place. If your insulation is properly enclosed, sealed, and detailed, rodents won’t be able to access it.
Do Insects Nest in It?
We also occasionally hear questions about flying insects – things like wasps or ants. But in over 20 years of working with wood fibre insulation, we’ve never seen an infestation. Even ants, which are known to burrow into some materials, don’t seem interested in wood fibre.
Again, if bugs are getting into a wall or roof build-up, it usually points to poor detailing. Gaps, cracks, or unsealed service penetrations can all provide entry points. But these issues apply to any kind of insulation – not just natural ones.
The Bottom Line: Detail Is Everything
If there’s one thing to remember, it’s this: pests are more interested in opportunity than in material. They’ll exploit gaps, voids, and open cassettes if they can—but they’re not specifically drawn to wood fibre.
Good construction detailing – things like sealing gaps, protecting vulnerable edges, and designing tight junctions – is your best defence. Get that right, and your insulation will stay warm, breathable… and pest-free.