How to build a planter with blueboard cladding?

[PeterEllis49]

I am designing a planter box for my daughter's small garden.  I have used Adam Woodham's DIY Raised Planter Box design and video as the design basis.  My planter will be "L" shaped with 2.4 meter long sides and four 200mm sleepers high.  My daughter wants the planter to have a rendered look similar to her town house and hence it will be clad with blue board.

Two questions:

Q1          On the Bunning’s site I found two blue boards which appear suitable.  Hardie Tex (non-textured and requiring textured paint but less expensive), and Hardie Fine Texture (only requires painting but is more expensive).  The first is cheaper but requires a more complicated finish.  Are there any other options? And are there other factors I need to take into account?

Q2          MitchellMC recommended in a post re a blue board clad planter that the cladding not be fixed directly to the sleepers but rather fixed to battens to ensure no moisture transfer from the sleepers to the board.  Mitchell’s drawing showed relatively heavy treated pine battens (70 x 35 ?).  I was wanting to minimise the thickness of the planter walls and keep cost down by using a lighter treated pine material (maybe 19 x 40).  I cannot find this size on Bunning’s site.  Any suggestions re an alternative?

[EricL]

Hello @PeterEllis49, 

Using the HardieTex is the cheaper alternative. If you need a textured finish, you'll need to use textured paint or render the surface of the HardieTex (but it depends on the type of finish you are after).

The James Hardie 2440 x 1200 x 8.5mm Hardie Fine Texture Cladding on the other hand has a fine rendered look already which is why it is more expensive.

In regards to the battens, I suggest looking at the 150 x 25mm Plinth H4 Treated Pine Sawn Wet 3.6m. It is possible to use H3 treated timber, but you'll need to make sure that the frame does not touch the soils surface as it is not treated for direct soil contact. Just keep in mind the lighter the frame the more you'll need to support the cladding.

Let me call on our experienced members @Dave-1 and @Nailbag for their recommendations.

If you need further assistance, please let me know.

Eric

[Nailbag]

Hi @PeterEllis49 

@MitchellMc could confirm if there were any issues with this idea, being to clad the external side of the sleepers with builders plastic and taping any joins with duct tape. Then fix the blue board. The plastic should be enough of a barrier for this small project not to be an issue with moisture leeching.

Regards, Nailbag

[Dave-1]

Morning @PeterEllis49 

Sadly I havnt rendered anything yet I have plans to redo my retaining wall and one of teh things I have in mind is moisture moving through the material. I get why @MitchellMc has that air gap. A smaller one as @EricL has suggested would work. Moisture is always around and I figure if we are going to the effort to build something then to factor that in is a wise option.

The top of the garden bed (the header piece) would cover it and really give it a look of a true rendard surface due to the thicker style.

Dave

[MitchellMc]

@PeterEllis49,

I think you'll be fine using thinner batons. My preference would be to go with the pre-textured cladding and just paint it. @Nailbags' suggestion of using plastic as a barrier sounds like it would work too.

Mitchell