Fixing To... Insulated Plasterboard


So you want to hang something on the wall, and your wall happens to be made of insulated plasterboard! Basically what this means is plasterboard backed with a sheet of insulation attached to it – these come in different thicknesses from about 20mm to over 100mm, and help increase energy efficiency, lowering your bills and carbon footprint. Some also have a foil vapour barrier between the plasterboard and the insulation. 

Insulated plasterboard is widely used in new builds, but also in older ones which have been retrofitted. It’s usually used to improve the insulation of external walls and can be added to e.g. brick walls without taking up a lot of extra space. 

A side view of a corner of a sheet of plastervoard with insulation backing

How do I know if I’m dealing with insulated plasterboard?

You’ll obviously know if you added it or built the house yourself – but how can you work out what kind of wall you have if you’ve moved in and have no information to go by?  

Generally, an uninsulated wall will sound more hollow if you knock on it compared to insulated, but this isn’t always reliable, especially if you’re inexperienced.  

You’re more likely to encounter insulated plasterboard if you’re fixing to an external wall – it can be used on internal walls as well, but isn’t usually the most cost-effective option for their insulation. If you’re hanging something from the ceiling, bear in mind that insulated plasterboard can also be used for overboarding ceilings!  

You won’t necessarily have to cut holes in your walls to find out what’s there if you have pre-existing holes in it, like an electrical socket or switch! Removing the cover of an outlet or switch and looking into the space around it may help you see if the plasterboard is insulated (obviously turn the circuit off first and check the outlet for power with a circuit tester!) Another option would be to drill a hole or remove a small part of the plasterboard (somewhere out of the way) and use a torch to see in. 

I’ve definitely got insulated plasterboard, what do I do now?

You’ll need to consider if you’re fixing to the plasterboard itself or the masonry behind it, how the insulated plasterboard has been installed, and the thickness of the insulation.  

If the insulated board is attached directly to the masonry using dot and dab or drywall adhesive, you’ll need to either fix to the masonry through the insulation (recommended for heavier items like TVs) or fix to the plasterboard itself with a bit of extra help – more on that below. 

If your insulated plasterboard is attached to timber studwork, you can simply fix to the timber studs with wood screws as long as they are long enough to reach through the insulation and the timber stud is in a convenient position. Alternatively, you can fix directly to the rear of the plasterboard making a hole within the insulation.  

OK, I need to fix to the masonry, what do I do?

If you’re fixing to the masonry through the plasterboard and insulation, you’ve got a couple of options. With thinner insulation you can use regular dot & dab or masonry wall fixings, like Corefix, which secure the load to the masonry behind the plasterboard with a reinforcing steel core, as long as the distance from the front face of the plasterboard to the masonry is no more than 45mm.  

With thicker insulation, you may need to resort to different ‘work arounds’. You should still go with a masonry fixing, but having some kind of sleeve going through the insulation will protect it from being damaged by the screw. For example, you could use a masonry fixing together with a long screw and a space plug through the insulation, as shown in this video by Ultimate Handyman.

What if I’m fixing to the plasterboard itself?

For light loads like lamps, small mirrors or pictures, just use regular small plasterboard fixings or hooks like Cobra Walldriller. For slightly heavier items, fixings which are designed to open or spread out behind the plasterboard, like Gripit or Bullfix, allow you to fix heavier loads directly to the plasterboard by spreading the weight.

However, you may need to clear a space in the insulation (behind the plasterboard) to make sure the fixing can open properly and work its magic – Gripit actually has specific undercutting tools available for this. These mount onto a regular power drill – just make sure you pick one that’s the same size as your fixing and you’re sorted.  


I’m hanging a heavy radiator/cabinet/life size elephant sculpture, how strong is insulated plasterboard?

If you’re securing the load to the masonry or timber studs, you’re unlikely to have an issue as long as you use enough fixings. But what if you have very thick insulation, or no masonry or timber studs to fix to? On one hand, a plasterboard wall is stronger than you think, as the force of any weight is pushing down through it, and fixings like Gripit Blue or Geefix spread the load effectively. However, we’d still recommend using as many fixings as you can to spread the weight, with ideally no more than 30kg per fixing (but take note of the safe working load stated on the packaging for each fixing!)  

What about fixing to the ceiling?

If you’re fixing something heavy to an insulated plasterboard ceiling, we recommend securing the load to the timber ceiling joists with long wood screws if you can.  

Fixing heavy loads to ceiling plasterboard alone isn’t a good idea, as the force will be pulling OUT of the plasterboard rather than along it, which makes it much weaker. For lighter loads like small hanging plant pots, you can still fix straight to the plasterboard, but we recommend using a ceiling fixing like Cobra Versahook.

Have you got questions about fixings? Get in touch with us through email, call 01248 295022, live chat or the contact form