Ceiling problem - what boards should I use?

[neutryno]

I have converted about three quarters of the garage to a gym (~3.5m x 4m), it all seemed to be going well…. but for the ceiling I just fitted pvc planks (2700mm x 250mm x 5mm) which were screwed to the joist (600mm centres). I’d accept I wasn’t going to insulate the gym and it seemed an attractive and easy solution. However, 2 months later and the vented portable AC unit has pulled off a section of the tiles. When the AC unit is running opening the outward against the air pressure difference is quite a task so in retrospect it wasn’t such a good idea to leave it like that!

So believe I need board out the ceiling and then screw and glue the tiles back on this time, to avoid issues. And probably fit an air vent to equalise the pressure a bit to avoid anything similar to happening again.

I have already fitted LED light strips just 40mm below the ceiling and they are as low as they can go. So want to board out using the thinnest strongest option, I’ll need some space to actually fit the pvc planks back. With 600mm centres I am concerned about sagging and having the boards fixed solidly to the ceiling to avoid a similar situation. Adding some noggins would be a solution? But if they aren’t required it would be easier.

So does anyone have any thoughts on the best boarding to use and any words of caution or alternatives?

 

[Wayners]

Tile backer board is thin and strong

 

[neutryno]

Tile backer board is thin and strong

Thanks for the imput. I did think that might be an answer when I was searching but I saw on one site it should be fitted on 300mm or less centres, also that it was susceptible to movement due to temperature fluctuation, is there a version strong enough for 600mm centres? I've seen temps as high as 35C this summer which wasn't warm and as low as 14C so far this winter. I had a thermometer in the house loft and it got down to 10C. So whatever I use would probably need to be reasonably stable in a range from 5C-45C. I know the PVC panels that will fit to it will suffer from expansion and contraction so ideally the ceiling would be fairly low expansion and contraction if possible.

 

[cdbe]

OSB sheets.

 

[Koolpc]

Isnt 600 centres a bit wide for a ceiling? I would def think about strengthening that more if putting sheets up.

 

[neutryno]

Isnt 600 centres a bit wide for a ceiling? I would def think about strengthening that more if putting sheets up.

It is a new build garage and I believe is the standard as it probably saves them £5 a garage! The joists are braced above as we added an attic area. Hence, why I wanted something thin but I meant lightweight as thin and lightweight as they usually go together. I am thinking I will need to add extra noggins just in case

 

[neutryno]

OSB sheets.

Definitely an option but was hoping there might be something thinner.

 

[Deluks]

I'm confused, what are the tiles doing, are they on the ceiling?

I'd second the tile backer cement board idea. You could add additional timbers between the joists to give enough fixing points.

 

[cdbe]

Definitely an option but was hoping there might be something thinner.

Comes in as thin as 9mm, and you can screw or staple your cladding straight into it.

 

[neutryno]

I'm confused, what are the tiles doing, are they on the ceiling?

I'd second the tile backer cement board idea. You could add additional timbers between the joists to give enough fixing points.

There are no tiles they are pvc planks, this is where the pvc planks came down from

 

[Deluks]

You could glue a plywood backer onto the pvc boards to make them stiffer.

Doesn't like you have adequate support, nothing much will span a distance like that without sagging under it's own weight.

 

[neutryno]

You could glue a plywood backer onto the pvc boards to make them stiffer.

Doesn't like you have adequate support, nothing much will span a distance like that without sagging under it's own weight.

It is partially the stiffness but I believe the issue was the suction from the AC unit. You can see on the joists the little bits of plastic where the boards were ripped away under the pressure difference. Once it started coming away the weight of the boards that had come away started pulling the rest with them. This was the section directly under the AC unit the rest of boards are still attached without any problem. I assume because once the seal was broken there wouldn't be the same pressure differential.