# Forum Contacts & Links Timber, Tools & Hardware Suppliers  38mm timber - best way to buy?

## Cuppa

The flanges on my I joists are 38mm deep. Where the joists run parallel to internal walls I need to use some infill timber/battens to attach ceiling plaster to as in diagram.   
So the battens need to be 38mm thick, width not that important so long as its enough to screw the edge of the plaster sheet to. 
Trouble is ...... it seems that 38mm is not a standard timber size (although Im sure Ive bought it before - maybe many years ago in the UK?)  
So what is the cheapest means of getting some 38mm.  I can rip it on my Triton table if need be.  
thanks
Cuppa 
ps. Why would an Aussie company make i joists with a flange size not able to be matched with standard timer sizes? Grrrr

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## Snipper

I'd always run ceiling battens the opposite way over those I joists regardless if they're 450mm centres or not.  So I  would do it totally different.  Easiest way to get 38mm other than green ob hw which you can't/shouldn't use with seasoned framing is 35mm pine with a 3mm packer above bringing down to 38mm.

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## ringtail

Battens are normally screwed to the bottoms of the I joists. If not, simply run trimmers around walls where required.

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## Cuppa

I planned to attach plaster directly to the ijoists. Is that not the norm? I’ll run trimmers where I can, but it’s not possible everywhere. 3mm packers will do the job albeit with more stuffing around than I’d expected. Thanks for the suggestion..

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## Snipper

Having just looked at your shed thread it all makes sense now.  Best way is have a I joist either side of the wall which would work out cheaper for a tradie than stuffing around trimming walls.  Ceiling battens spread the deflection better from the upstairs weight/movement meaning no plaster cracks but yours being only a mezzanine, it might be ok.  Some of the cheaper builds use a direct fix to 600mm centre trusses with a different plasterboard. If you have not allowed for the ceiling battens in your frame height, you will be ripping down standard plaster sheets again meaning more time/money.  16mm metal furring channel ceiling batten would be alright for your build, leaving a 12mm minimum gap around all walls for the full plaster sheet to slip above. saving cutting plaster. Some chippies just nail these up with the framing gun but are better off screwed.

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## Cuppa

Is a furring channel just another name for a metal batten? 
Not sure that I’m following what you are saying, are you suggesting that I really _should_ use battens?  
I’m not clear how that would help me with trimming the top of the internal walls - how are the ends of the channel/battens secured when the joist is, say 400mm from the wall? And what if a joist runs along the top of a wall so the edge of the joist is flush with the wall (as in my diagram above)?    
Stud height is 2355 + bottom plate 35 + top plate 45 - Total wall height = 2435mm

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## SilentButDeadly

Furring channel = metal batten. Fix end of batten to the wall by splaying the batten with tin snips and screwing the flattened sides to the wall...it's rough but it works! 
Failing that...wing it really truly and use the plasterboard or whatever wall cladding you are using to support ceiling at the edges...seen that done more times than is 'right'.

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## joynz

Hi Cuppa 
The difference between metal batten and furring channel are a slightly different profile (and furring channel has a broader range of uses) : see page 32 for images in link below  http://www.boral.com.au/plasterboard...o_products.pdf

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## Cuppa

Thanks SBD, I get it now.   
However with a wall height of 2435, minus 16mm for batten, & 10mm  for ceiling gyprock  it only leaves 9mm for a gap at floor level even if the wall sheets were butted right up to the ceiling sheet. Pretty tight. 
Time is less of an issue for me than it is for a tradie so I reckon I might persist with the timber trimming  between joists - live & learn eh?    
The mezzanine floor will be used for storage & won’t get walked on too often & hopefully with the 300x63 i joists spanning 3900mm ( minus width of walls = 3720mm span)  @450mm centres it should be rigid enough not to move & crack the plaster.

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## phild01

Would overlaying another top-plate or 20mm pine help.

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## Cuppa

> Hi Cuppa 
> The difference between metal batten and furring channel are a slightly different profile (and furring channel has a broader range of uses) : see page 32 for images in link below  http://www.boral.com.au/plasterboard...o_products.pdf

  Ta. So the furring channel is fixed up hanging from clips (& thus uses up a bit more height & gives it some adjustment) whereas the metal batten is nailed/screwed directly to the joists.  Wouldn’t screwing /nailing a metal batten on distort it (squash it) or is my assumtion that the open side faces upward incorrect?

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## Cuppa

> Would overlaying another top-plate or 20mm pine help.

  
Al the joists are now nailed to the top plates & you don’t get second goes with i joists.  There are some places where I can create a ‘trimmer ledge’ on top of a wall, which I’ll do, but on a couple of walls I’ll still need to run some timber between the joists as in my diagram above.

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## Snipper

> Is a furring channel just another name for a metal batten? 
> Not sure that I’m following what you are saying, are you suggesting that I really _should_ use battens?  
> I’m not clear how that would help me with trimming the top of the internal walls - how are the ends of the channel/battens secured when the joist is, say 400mm from the wall? And what if a joist runs along the top of a wall so the edge of the joist is flush with the wall (as in my diagram above)?    
> Stud height is 2355 + bottom plate 35 + top plate 45 - Total wall height = 2435mm

  Sorry, I mean I would personally batten it but many wouldn't which is perfectly alright.   
The joist flush on the wall would be easiest nailing a 45mm cleat straight into the side of the joist flush with the bottom. (top of wall plate)
The other side could be done just as simply by screwing a 90 x 35 straight onto the top plate overhanging by half (45mm)  careful selection of straight timber is important for this method.  Can use packers if required in various spots to maintain a flat, straight line being perfectly aligned with the I joists.  Just run a straight edge under the joist and pack the plate to this. 
 Whether you choose to batten over these trimmers is irrelevant but your margins using the 16mm batten, tight top sheet and around 10 mm gap on the bottom is the perfect wall height for square set ceilings. (no cornice, taped and filled as internal cnr) 
Alternatively a 10mm gap under (the norm as a plaster packer laying around to start the first sheet is common.) and 16mm above would be alright providing you don't use 55mm cornice as it wont cover the top rebate in the plaster sheet,  It can be filled obviously but a hassle.  
If using 55mm cornice, lift sheet off floor around 20mm and will be alright,  67mm skirting just covers the bottom rebate.  The only place the higher bottom sheet becomes an issue is in wet areas trying to waterproof but not impossible

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## Snipper

> Ta. So the furring channel is fixed up hanging from clips (& thus uses up a bit more height & gives it some adjustment) whereas the metal batten is nailed/screwed directly to the joists.  Wouldn’t screwing /nailing a metal batten on distort it (squash it) or is my assumtion that the open side faces upward incorrect?

  My first boss had a special adaptor bush on the old senco air framer that set the depth of nail drive to attach the furring channel as it can be nailed/screwed or hung by adjustable screw on clips
the 16mm (x 35mm) stuff can span 900mm centres but is too flimsy for my liking.   Your 450mm centres is better. Open side up.  Better to screw them as they do squash up but the 2 edges still keep the height pretty consistent. End fixing needs to be done as far back as possible as they will squash in on the sides flattening them.  Thety can be packed inside on the end if close end fixing is required. (20mm) 
If you need to trim between the I joists then I would cut noggins between I joists inner webs, checkout the bottom flange so the noggin is flush on the bottom. Skew nail in place,  space as required and nail noggins/trimmers in between these.

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## Spottiswoode

> I'd always run ceiling battens the opposite way over those I joists regardless if they're 450mm centres or not.  So I  would do it totally different.  Easiest way to get 38mm other than green ob hw which you can't/shouldn't use with seasoned framing is 35mm pine with a 3mm packer above bringing down to 38mm.

  I was thinking similar. Just grab some 3mm packer and cut it to size. Alternatively you could put the packer on the I joist flange and make it the size to suit whatever batten timber you have. Eg if you want to use 45mm battens, then use a 7mm packer.

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## Cuppa

This is an illuminating thread, thank you all for your input. In particular thanks to our ‘newbie’ Snipper. I can see you becoming a valued member in a very short space of time.  
Now I just need to learn what questions to ask_ before_ I make mistakes!   
Cuppa

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