Attaching Plasterboard to Sheet Metal in Pre-Fab Studio Outbuilding Ask your questions and find answers on many subjects relating to plastering and dry lining

[Ian Dudley]

Hi there. I have an pre-fab sound proof studio as an outbuilding. The structure was purpose designed for this and I picked it up second hand from a music college.

It works fairly well, and massively reduces the noise, but some sound still leaks, I think from gaps in the structure and empty screw holes from where it's been disassembled and rebuilt.

To help counter this I want to line the inner walls with sound bloc plasterboard. This will also give a nicer finish as well.

My question is about fixing. The walls of the studio are made from purpose built metal panels, which are 10cm thick consisting of three sheets of metal with Rockwool in the voids in between. I’m looking to attach the plasterboard directly to the inside wall, as I already have a good level of isolation in the wall design and don’t want to lose the interior space from putting up battens. This is just to supplement the sound absorption and introduce another type of material (which helps with freq range), I'm not expecting it to be the major sound insulator. I've included a pic to help visualise it.

The inner walls are therefore sheet metal, I think powder coated, and the metal is about 2-3mm thick. It will take self tapping screws, but it takes quite a bit of effort with a powerdrill to get them to tap in, and I’m worried they will tear up the plasterboard in the process leading to a poor fix.

Would it be ok to use adhesive over the whole wall surface in order to attach the plasterboard? If so, can you recommend a suitable adhesive, and any particular preparation I should do? I tried contacting the British Gypsum people, but all they could tell me is that none of their adhesives will work on metal.

Thanks in advance.

[attachment=0]Studio2.jpg[/attachment]

[fenny666]

Hi. You should be able to mechanically fix the boards quite easily so there is no need to use adhesive in this application hence why BG couldn't recommend one.

You said you're using self tapping drywall screws but these are specifically designed for light gauge metal i.e c stud etc. What you need are jackpoint point screws which are used for I studs and heavier gauge metal. They have a tip like a drill bit that bores a hole into the metal.

One other suggestion you might want to consider is to fix res bar to the metal sheet first and then fix the boards to that. You'll lose an extra 15mm but it's used specifically to improve acoustic performance.

Let us know how you get on.

Cheers

[Ian Dudley]

[quote="fenny666"]Hi. You should be able to mechanically fix the boards quite easily so there is no need to use adhesive in this application hence why BG couldn't recommend one.

You said you're using self tapping drywall screws but these are specifically designed for light gauge metal i.e c stud etc. What you need are jackpoint point screws which are used for I studs and heavier gauge metal. They have a tip like a drill bit that bores a hole into the metal.

One other suggestion you might want to consider is to fix res bar to the metal sheet first and then fix the boards to that. You'll lose an extra 15mm but it's used specifically to improve acoustic performance.

Let us know how you get on.

Cheers[/quote]

Hi there, thanks for the response. When I talked about self tapping screws, I meant the kind you describe. I actually re-assembled this thing myself after moving it (all 4.5 tons of it!), and used many of those screws in putting it all back together and attaching stuff like the trunking, etc.

My concern with those is that they spin freely for quite a while as they drill the hole in the metal, and whether that would carve out too loose a hole in the plaster and lead to a weak attachment.

The other thing I've had suggested is Everbuild's Pink Grip Dry Fix for plasterboard, which apparently will adhere directly to sheet metal. Looks like it would be a relatively simple installation as well.

I'll have another look at the res bars though as well. I had planned to put 15mm sheet up, but perhaps if I drop to 12mm to minimise the impact of adding the bar it wouldn't be too bad. The air gap would probably more than make up with the thinner material in terms of acoustic performance. Bars and screws would also be less messy and easier to keep consistent than a curing adhesive like Pinkgrip.

[fenny666]

Hi.
In this instance where what you're fixing to is very hard and, as you've astutely perceived, unless you can keep the screw constantly perpendicular any deviation will widen the hole in the plasterboard resulting in, at best, a less than optimal fix.

This is a good example to demonstrate how a drywall screwgun comes into its own and how it's far superior to a cordless driver when fixing plasterboard and especially so in your application. But I won't bore you with that unless I'm asked to. My advice, if you dont want to shell out on a screwgun I'd look at an alternative. I'm not saying it's impossible with a driver but at the very least it would laborious if not tedious and as there's easier alternatives I don't see the point.

Screwgun aside I think your best bet is adhesive. I don't see any reason why this wouldn't work. The only negative I can see is if you ever needed to remove the board and make good. But if you don't foresee a reason to then this might be the way to go. I don't know a great deal about this but from my experience I've never had any problems with 'no nonsense' adhesives from screwfix. One thing I would suggest, although someone might suggest otherwise, is to use solvent free as the solvent based tends to form a skin quite quickly so would give you less working time. Obviously it's important to degrease the metal. I'd do a small test patch and suck it and see. One thing I should mention is this is akin to dot and dab. It's a good practice to cut and dry fit all the boards first. This gives you more time to tamp the boards back to where you want them (flush joints etc) before the adhesive sets. This might not be a concern for you in this application but thought I'd mentioning anyway.

I'm erring on ruling out the res bar, from an acoustics point of view what you'd gain from using it would be negated by using a thinner board so likely a waste of money.

I'd be interested to hear how you get on.

Cheers