# Forum Home Renovation Structural Renovation  Yellow Tongue Platform Floor

## OBBob

Hi All 
Am I correct in thinking that no expansion allowances are required for yellow tongue flooring (platform construction)? The installation guidlines don't mention it but I know it is an issue with normal timber floors.

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## Purse

> Hi All 
> Am I correct in thinking that no expansion allowances are required for yellow tongue flooring (platform construction)? The installation guidlines don't mention it but I know it is an issue with normal timber floors.

  
I know the BCA mentions that a cut-in floor requires a 10mm gap around the edges for expansion 
here is the quote directly from the building code:   
5.3 FITTED FLOORS (CUT-IN FLOORS)
Fitted floors (cut-in floors) are installed after walls have been erected, and after roofing,
wall cladding, doors and windows have been installed. Where boards are laid parallel with
walls, a minimum 10 mm gap shall be provided between the board adjacent to the bottom
plate and the bottom plate (see Figure 5.1).  
Hope this helps
Cheers
Purse

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## echnidna

No gaps are necessary for a YT platform floor.
(Theoretically this also applies to a strip flooring platform base but you can lose the whole lot if it gets wet.)
Drill some holes in the YT adjoining where the wall plates will go to let water drain if it rains before you get the roof on

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## thebuildingsurv

> Fitted floors (cut-in floors) are installed after walls have been erected, and after roofing.

  I imagine you are not fitting yellow tounge after you erect your walls.

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## OBBob

No ... platform floor prior to walls going on top. Later ... much later ... there will be a timber floor secret nailed over the yellow tongue, which I know I will need expansion gaps around the perimeter as a minimum ... but one thing at a time.  
Thanks guys.

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## Chandler

I believe particle board flooring (yellow tongue) can be used in wet areas, because of the need to ensure a water proof membrane, but I would still like to use FC sheeting under tiles in the bathroom and laundry.   
Can I mix and match Yellow tongue and Hardies Scyon (both tongue and groove flooring)?  
I see a website reference to Stuctaflor available in: 19mm (Yellow Tongue  spans 450mm  sheets 3600mm X 900mm),22mm (Red Tongue  spans 600mm  sheets 3600mm X 900mm) and25mm (Blue Tongue  spans 600mm  sheets 3600mm X 600mm).  
I see also that James Hardie Scyon FC wet area flooring are 19 mm (900mm X 1800mm)  
In other words, do the tongue and grooves match sufficiently, or should I just use standard (say 19mm) FC?

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## DvdHntr

If they don't match just pull the tongues out at the junctions and butt them together. You should have a timber member at the edge of the wet area.

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