# Forum Home Renovation Plastering  Flush jointing blue board like plasterboard ?

## steve bartolo

I've searched this forum but haven't quite found an answer. If I clad an external wall with blueboard (Hardie Tex or the like), can I flush joint where the recessed edges meet? ie: the same way as paper tape and base coat on plasterboard? James Hardie site says that their wet area base coat is not approved for external cladding. 
I preferably want to be able to sand the join so the whole area of sheeting can just be painted - no render or textured finish.

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## Bloss

If you RTFM at http://www.jameshardie.com.au/products/harditex.html you'll se that Hardie recommends flexible textured coatings for its 'blue board' products. They do not recommend any filler and paint as the result will always be visible joints if not cracks if anon-flexible filler is used (even if tape is underneath). 
So you either use the HardiTex not according to instructions by filling with some flexible filler or the better option - use the right product for the smooth look you want. If you want fibre sheet use Hardiflex http://www.jameshardie.com.au/products/hardiflex.html as that's what will allow you the smooth flat painted finish you are after (but IMO still hard to hide joins). The joins are supposed to be masked and sealed using Hardie's polyurethane sealant - in practice an adept DIYer can apply sealant and press in and level using a spatula/ scraper without masking although sometimes the overlap marks are visible under certain paints.

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## Gaza

you can get a flexible setting compund from dulux to use, i herd the other day that JH is going to have there own product this year some time. 
You will need to put movement joints in to break the wall up to ensure the cracking does not occur.

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## Bloss

But why use blueboard when it's not the manufacturer's recommended product to get a smooth flat painted surface. Just use the right product . . .  :2thumbsup:  If you already have blueboard that you want to fill and coat is one thing - but the questions was about starting from scratch to clad.

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## Blocker

Steve,
The products required to put a finish on blueboard are not usually sourced from JH as they are paint products.If you contact a Trade outlet for Dulux(Acratex),Wattyl (Granosite),Taubmans (Armawall) or Haymes (Rendertex) they can supply a sandable joint filler that can be painted with either smooth or texture coatings. 
Regards,
Blocker :2thumbsup:

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## Rod Dyson

I have used a product specified on a job at the Fitzroy swimming pool from Dulux for flush finishing blue board. I can't remember the name of it.  The finishing coat was a grey colour and an absolute b&%^%^##ED to sand!  Stung the eyes.  I have no idea how good it worked because I havent been back.  It was the change room ceiling. They needed to be able to hose it down. 
Cheers Rod

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## steve bartolo

Bloss, Gaza, Blocker, Rod 
Thanks a lot for your replies. Gives me something to think about and some avenues for investigation. 
Much appreciated, Steve

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## Bloss

> Steve,
> The products required to put a finish on blueboard are not usually sourced from JH as they are paint products.If you contact a Trade outlet for Dulux(Acratex),Wattyl (Granosite),Taubmans (Armawall) or Haymes (Rendertex) they can supply a sandable joint filler that can be painted with either smooth or texture coatings. 
> Regards,
> Blocker

  But the question was about filling the joints to then paint smooth so about whether blueboard was the right choice - not about finishing blueboard  :Confused:  In any case all good info so he should be able to make a choice.  :2thumbsup:

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