# Forum Home Renovation Plastering  fibre cement sheeting for garage ceiling

## CuriousChris

Hi Guys and Gals 
I am lining the ceiling of my garage it is a 7.5M*6M all steel construction shed.  
I was advised not to use gyprock or other paneling as steam from hot cars will cause sagging. So I am going to use fibre cement sheeting. 3m*1.2M*4.5mm sheets 
I am going to use 0.42mm ceiling battens to hang the sheeting.  
I just wanted to confirm that I should run these at 450 centres with a gyprock needlepoint screw every 200mm. 
Does that sound reasonable or is it overkill. Should I run 600mm centres? 
Any advice would be greatly appreciated. 
Chris.

----------


## sol381

Never heard that one before.. Pretty much every new home that has a built in garage has plasterboard on the ceiling..superceil should be enough..Up to you but fibre cement doesnt normally go on a ceiling.. Hard to set as well.

----------


## pharmaboy2

Who advised you? 
anyway, 4.5mm needs lots of battens because it sags, ceiling gyprock however will span your trusses - you can't reliably set 4.5 so you have to have plastic joiners everywhere.  The above are the reasons you never see it on a garage ceiling (carport maybe, but not garage)

----------


## sol381

you're only 2 posts behind me pharma better just post for no reason to boost my tally.

----------


## pharmaboy2

> you're only 2 posts behind me pharma better just post for no reason to boost my tally.

  WHat do you mean? 
(don't encourage me to add to the useless post list on this site  :Wink: .  )

----------


## sol381

Out of consideration and to keep this thread on track I wont post for no reason.

----------


## ringtail

4.5 is rubbish on ceilings unless you batten the crap out of it. Go for villa so it can be set or plain 6 mm and use those horrible joiner strips. Better still scrap all that crap and use ply. FC sheet/screws/metal battens don't always play nice together either.

----------


## CuriousChris

Glad I didn't buy them then.  
I was going to use plastic joiners as a workshop come garage I want an "industrial look" I was even thinking of using pan head screws, but was aware unless they are lined up perfectly it could look stupid so the needle point gyprock screws were to give me options. Though flushing is an expensive option, although I have successfully tackled it myself, I don't have the time and gyprockers are not cheap. 
The walls are going to be sturdy 8mm compressed fibre cement to ensure it will stand up to the occasional car door and clumsy handyman.  
I was going to use the 8mm fibre cement on the roof but felt it was too heavy. I have quite a bit sitting there I got rather cheap.  
Chris

----------


## pharmaboy2

> 4.5 is rubbish on ceilings unless you batten the crap out of it. Go for villa so it can be set or plain 6 mm and use those horrible joiner strips. Better still scrap all that crap and use ply. FC sheet/screws/metal battens don't always play nice together either.

  Horrible joiner strips????? 
anyways they beat the crap out of cracked joints on set outdoor ceilings - anyway the 4.5mm revealed jointer strip but fitted to 6mm versilux is our choice

----------


## CuriousChris

@pharmaboy2 Nooice.  
@ringtail What thickness ply would you suggest? the ceiling joists are at around 1100 centres I imagine I would still need to batten them.

----------


## ringtail

PB, those pvc joiners that the sheet edges slide into. Agree with the cracked (and mouldy) joints. That looks good. Must have a look at those joiners.  
CC, probably 12 mm but one could use 9, 12, 15,16,17,18. You will still need to batten unless you went 18mm - which is heavy and expensive. 9 or 12 with 450 or 600 battens

----------


## ringtail

Got a link to those joiners PB ? I can't see them on the JH website

----------


## phild01

> PB, those pvc joiners that the sheet edges slide into. Agree with the cracked (and mouldy) joints. That looks good. Must have a look at those joiners.

  I have seen similar and was told they did it with some type of weathertex moulding. The sheet abutted the moulding rather than slide into it.

----------


## pharmaboy2

> Got a link to those joiners PB ? I can't see them on the JH website

  Accessories for HardieFlexâ¢ sheet in eaves lining sizes | James Hardie 
The ones second up from the bottom.  The ones third up from the bottom require a nail through sheet and through joiner whereas these ones are like the std profile in that you slide the sheet in and only need to nail every 30. 
when using 6mm you have to take the edge off the sheet with a grinder to bring its thickness down so it will slide in - only takes a couple of minutes per sheet.

----------


## sol381

They actually look really good in the pic you posted.. never used them before.. Prob wouldnt use them on soffit.. The flat straight jointer are still best.

----------


## CuriousChris

@ringtail. I'd be better off sticking to the 8mm fibre cement sheets I already have. The ply would be far too expensive. I decided to drop from the 8 to 4.5 because I didn't have enough 8's to do the whole job and was concerned they were too heavy for the ceiling. With 4.5's at 450 centres I figured I wouldn't get sag and the sheets are a reasonably priced. I can leave them raw. 
I really should not have taken his word for it when he said that gyprock would absorb too much moisture. Hell my bathroom ceiling is doing just fine after 30 years  :Smilie:  
I think gyprock is probably the best solution for me. its cheap I'll just have to make time to do the flushing myself.

----------


## ringtail

> They actually look really good in the pic you posted.. never used them before.. Prob wouldnt use them on soffit.. The flat straight jointer are still best.

  They do look good eh. Must remember them for next time. Have you painted the recess black PB or is that just a shadow effect ?

----------


## pharmaboy2

> They do look good eh. Must remember them for next time. Have you painted the recess black PB or is that just a shadow effect ?

  No, those are painted all one colour.   The ones specific for 6mm are already painted black and give a 10mm expressed joint which I thought was a bit over the top. 
heres a picture of the eaves with the same joints but std 4mm versilux (actually, might be hardieflex, I can't remember on availability)   
Depends on what you are trying to achieve sol - this is Modern architecture, so not much is standard - flat joiners were definitely out

----------


## ringtail

> @ringtail. I'd be better off sticking to the 8mm fibre cement sheets I already have. The ply would be far too expensive. I decided to drop from the 8 to 4.5 because I didn't have enough 8's to do the whole job and was concerned they were too heavy for the ceiling. With 4.5's at 450 centres I figured I wouldn't get sag and the sheets are a reasonably priced. I can leave them raw. 
> I really should not have taken his word for it when he said that gyprock would absorb too much moisture. Hell my bathroom ceiling is doing just fine after 30 years  
> I think gyprock is probably the best solution for me. its cheap I'll just have to make time to do the flushing myself.

  8 is way too heavy for ceiling IMO. Ply can be as cheap or expensive as you like depending on the grade.

----------


## ringtail

> No, those are painted all one colour.   The ones specific for 6mm are already painted black and give a 10mm expressed joint which I thought was a bit over the top. 
> heres a picture of the eaves with the same joints but std 4mm versilux (actually, might be hardieflex, I can't remember on availability)

  
Hmmm. 10 mm joint could look cool I reckon but either way, yours came out tops.

----------


## sol381

does look good.. As was stated. depends on the style of house. i think i need to look at jh website more often, all these new design materials im missing out on.

----------


## ringtail

Yep me too. I really hate those standard joiners on ceiling sheets. Fine on the eaves but I don't rate them on ceilings. This may change the game.

----------


## CuriousChris

Checkout all the love for plastic joiners. 
@ringtail Unless you know something I don't, 9mm structural (crap finish, knot holes etc.) ply is more expensive than the cost of fibre cement (4.5mm) per sqm and close to twice the cost of plasterboard. If I wanted a nicer finish (marine grade) the cost would be much much higher again.

----------


## pharmaboy2

> Checkout all the love for plastic joiners. 
> @ringtail Unless you know something I don't, 9mm structural (crap finish, knot holes etc.) ply is more expensive than the cost of fibre cement (4.5mm) per sqm and close to twice the cost of plasterboard. If I wanted a nicer finish (marine grade) the cost would be much much higher again.

  Ply is easier to finish with screws into steel.  Screw fixing hardieflex always sits proud or then suddenly goes all the way through.  With ply you can probably get self imbedding trim heads for steel, either express the joint with a 5mm spacer or you can use 25/12mm battens as cover strips which has a kind of coastal look. 
your main difficulty is dealing with fixings that determines product.

----------


## CuriousChris

> Ply is easier to finish with screws into steel.  Screw fixing hardieflex always sits proud or then suddenly goes all the way through.

  Isn't that the same with gyprock? Certainly was for me until I got a drywall driver bit. That was also why I was originally going to go with a pan head screw. The screw sits loud and proud and doesn't drive through the fibre cement. The look of an uneven line of screw heads was what I was mostly worried about.  
I was thinking of making up a template to make sure all the screw positions where straight and positioned at exactly the same centres.

----------


## sstyln

@pharmaboy2 you won't get cracks in the plaster ceiling if you install following the 3 step process using papertape. Refer to page 76 of the Gyprock Residential Installation Guide 
If you are worried about moisture use Gyrock Aquachek. This can span 600 centers. You can also use Ultra Base 60 for the taping and second coat as this product is mould resistant. 
For the walls if you are worried about knocks you can use Gyprock Impactchek

----------


## pharmaboy2

> @pharmaboy2 you won't get cracks in the plaster ceiling if you install following the 3 step process using papertape. Refer to page 76 of the Gyprock Residential Installation Guide 
> If you are worried about moisture use Gyrock Aquachek. This can span 600 centers. You can also use Ultra Base 60 for the taping and second coat as this product is mould resistant. 
> For the walls if you are worried about knocks you can use Gyprock Impactchek

  
No way, been there, done that, it cracked.  On a 10 year time frame, about 50% crack or bubble when done properly - it's just a function of moisture and lots of temperature variation.  That's the feedback I got from a number of builders.  CSR or boral won't pay the 10k to fix it so the warranty is worthless

----------


## ringtail

> Ply is easier to finish with screws into steel.  Screw fixing hardieflex always sits proud or then suddenly goes all the way through.  With ply you can probably get self imbedding trim heads for steel, either express the joint with a 5mm spacer or you can use 25/12mm battens as cover strips which has a kind of coastal look. 
> your main difficulty is dealing with fixings that determines product.

  Was pretty much going to be my reply. Screws and fc just don't mix. I've never used screws that actually work as advertised in FC. If they do actually embed properly there is bugger all sheet below the head so the fixing capability is nil. Something to consider with a ceiling  :Biggrin: . Another option well worth considering is zincalume custom orb. Cheap enough, no setting, no painting, lighter, stronger, long spans.

----------


## phild01

> I've never used screws that actually work as advertised in FC. If they do actually embed properly there is bugger all sheet below the head so the fixing capability is nil.

  Yep, though practically nil :Smilie:

----------


## phild01

> I've never used screws that actually work as advertised in FC. If they do actually embed properly there is bugger all sheet below the head

  Yep.

----------


## CuriousChris

@ringtail I had considered custom orb. the problem is that I will have  to provide a heat break. metal on metal will only make the garage  overheat in Summer and be frigid in winter. so I would have to go a few  extra yards in the insulation and some form of thermal break using timber  battens or specialised thermal break material.  
Of course the upside is it will easily span the 1200 between joists, is lightweight and can be cut to measure. So I guess its not as bad a choice as I had thought. 
Food for thought.

----------


## ringtail

Got a roof blanket under the shed roof ?

----------


## CuriousChris

Unfortunately no. After they built the shed the guy who put it up said "I guess we should have put some sarking up. I could take the roof off and do it But I'll only do that if I am forced to.

----------


## joynz

> Unfortunately no. After they built the shed the guy who put it up said "I guess we should have put some sarking up. I could take the roof off and do it But I'll only do that if I am forced to.

  Fibre cement is not known for its insulation properties. 
Why not just retrofit sarking or roof blanket as part of adding the ceiling?

----------


## CuriousChris

> Fibre cement is not known for its insulation properties. 
> Why not just retrofit sarking or roof blanket as part of adding the ceiling?

  I will be insulating between the ceiling and the roof.  
I was  not saying fibre cement has any insulating qualities, but compared to metal it is brilliant. When  considering custom orb or any other metal ceiling no matter how much  insulation you put in the ceiling its not worth a damn without a good  thermal break between the metal frame and the ceiling. Putting  insulation in such a roof is almost as good as relieving yourself in a  strong westerly.  
Putting up a thermal blanket would have been  ideal, whether the cost is too excessive to retrofit it I am not sure.  In fact I was surprised that the material is relatively cheap, so it  comes down to labour, dismantling the skin of the shed and refitting it.

----------


## Rod Dyson

> @pharmaboy2 you won't get cracks in the plaster ceiling if you install following the 3 step process using papertape. Refer to page 76 of the Gyprock Residential Installation Guide 
> If you are worried about moisture use Gyrock Aquachek. This can span 600 centers. You can also use Ultra Base 60 for the taping and second coat as this product is mould resistant. 
> For the walls if you are worried about knocks you can use Gyprock Impactchek

  No it can't it needs to be 450 centers unless its 13mm

----------

