# Forum Home Renovation Flooring  Ceramic tile underlay over particleboard - what's wallboard adhesive??

## Vanda

Hi all, 
2 questions i'm hoping someone can answer!: 
1. Both Prima and BGC say to use 'wallboard adhesive' with a 3mm notch trowel when laying ceramic underlay to yellow tounge (particleboard), but I can't see anywhere where to buy this... is this just stud adhesive?? 
From BGC install manual:
For softwood floorboards, plywood and particleboard
flooring, it is recommended that the underlay be glued
to the floor with *wallboard adhesive* in addition to nailing. 
The wall board adhesive should be applied evenly over
the back of the underlay sheet with a 3mm notched trowel,
paying particular attention to the edges. Position and
nail down the sheet. Two or three temporary nails placed
towards outer sheet ends will prevent movement as sheets
are nailed down.  
2. I know when installing ceramic underlay over floor boards they go the opossite direction to how the floorboards are laid, but what about if it's over particlebaord... do you lay the board in the opposite direction or just lay them in the same direction but not over the same joints?  
From BGC install manual: 
When installing over panel flooring such as plywood or
particleboard, position the underlay joints so that they
do not coincide with joints in the underlying floor.  
Thanks in advance!
Cheers,
Vanda

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## Oldsaltoz

> Hi all, 
> 2 questions i'm hoping someone can answer!: 
> 1. Both Prima and BGC say to use 'wallboard adhesive' with a 3mm notch trowel when laying ceramic underlay to yellow tongue (particleboard), but I can't see anywhere where to buy this... is this just stud adhesive??  I have seen stud adhesive used on chipboard, but as a full coat, just dabs applied with a 50 mm scraper on a 200 mm grid pattern. 
> From BGC install manual:
> For softwood floorboards, plywood and particleboard
> flooring, it is recommended that the underlay be glued
> to the floor with *wallboard adhesive* in addition to nailing. 
> The wall board adhesive should be applied evenly over
> the back of the underlay sheet with a 3mm notched trowel,
> ...

  Good luck.   :Smilie:

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## phild01

I'm wondering what purpose ceramic underlay serves when tiling over particle board flooring.  I tiled directly to the particle board floor 20 years ago without a problem.  I am now about to change this floor and need to remove these tiles (laid with a rubberised adhesive) for a section they cover.  Only downside is I can't separate them from the floor. So would a glued down underlay have made the separation any easier!  Otherwise the tiles are still absolutely perfect like the day they were laid.

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## Vanda

> Good luck.

  Thanks OldsaltOz. 
So when you say 'lay the sheet across the existing sheet', do you mean in the same direction as the yellow tounge boards were laid or opposite? so_-_-_-_ as opposed to |-|-|-| (small lines are the Ceramic Underlay, bigger ones particleboard).
... Sorry, think I'm directionally challenged. 
Cheers

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## Vanda

> I'm wondering what purpose ceramic underlay serves when tiling over particle board flooring.  I tiled directly to the particle board floor 20 years ago without a problem.  I am now about to change this floor and need to remove these tiles (laid with a rubberised adhesive) for a section they cover.  Only downside is I can't separate them from the floor. So would a glued down underlay have made the separation any easier!  Otherwise the tiles are still absolutely perfect like the day they were laid.

  Fair point. I certainly know STA about what purpose it serves, but it's the manufacturers recommendation so that's why i'm running with it for now.
Cheers

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## phild01

> Fair point. I certainly know STA about what purpose it serves, but it's the manufacturers recommendation so that's why i'm running with it for now.
> Cheers

  Sometimes I think manufacturers make their recommendations in a way to sell more of their products...not always, just sometimes!

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## Oldsaltoz

> Thanks OldsaltOz. 
> So when you say 'lay the sheet across the existing sheet', do you mean in the same direction as the yellow tounge boards were laid or opposite? so_-_-_-_ as opposed to |-|-|-| (small lines are the Ceramic Underlay, bigger ones particleboard).
> ... Sorry, think I'm directionally challenged. 
> Cheers

  Original sheets run lengthwise left to right, so new sheets run fore and aft in a brick patten. 
You can lengthen of shorted the (bricks) to bridge joints in the floor sheets. 
Good luck.   :Smilie:

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## Oldsaltoz

> Sometimes I think manufacturers make their recommendations in a way to sell more of their products...not always, just sometimes!

  Timber and timber composite floors expand and contract depending on moisture, humidity. 
AC sheeting is not effected by small changes in humidity so move less. 
Thus avoiding movement problems, and the consequences of such movement. 
Stable timber floors with little or no change in moisture content and a rubberised glue can last many years, but for the sake a laying a few sheets you have a much better chance of surviving the dramas. 
This not a case of manufacturers selling more product, it a case of following good practice based on historic failures. 
Given the choice I would remove the timber floor and replace it 19 mm compressed fibre AC sheeting and never have to worry about it again in my life. 
Good luck.   :Smilie:

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## Vanda

Thanks all for the tips and advise. Even the few builders I've asked at work I know said they hadn't heard of the manufacturer recommendations regarding adhesive requirements for ceramic underlay to particleboard ("just nail it like I do, she'll be right"...) 
Anyway, going to use the below acrylic stud adhesive which says it can be used for fibre cement to timber. Gyprock 5.5kg Acrylic Stud Adhesive I/N 0731172 | Bunnings Warehouse 
Cheers,
Vanda

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## phild01

> Thanks all for the tips and advise. Even the few builders I've asked at work I know said they hadn't heard of the manufacturer recommendations regarding adhesive requirements for ceramic underlay to particleboard ("just nail it like I do, she'll be right"...) 
> Anyway, going to use the below acrylic stud adhesive which says it can be used for fibre cement to timber. Gyprock 5.5kg Acrylic Stud Adhesive I/N 0731172 | Bunnings Warehouse 
> Cheers,
> Vanda

  Just be mindful that stud adhesive shrinks - the reason for never putting a fixing through the dabs of stud adhesive on plasterboard.  Not sure nailing on its own is good enough either.  Still don't understand the need for the underlay for ceramic tiles.

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## Vanda

> Just be mindful that stud adhesive shrinks - the reason for never putting a fixing through the dabs of stud adhesive on plasterboard.  Not sure nailing on its own is good enough either.  Still don't understand the need for the underlay for ceramic tiles.

  Didn't know that about the stud adhesive shrinking. The details for the attached product mentioned: "Will not skin in the heat or thicken in the cold", but guess that doesn't rule out shrinkage.
Cheers

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## goldie1

Bostic make wall board adhesive

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