Thread: Blueboard - What do I do

greenhorse, you are on the right track the compound is is just for the joints same as plaster board, then just paint the whole lot with one of the miriad of finishes available

G'day Greenhorse, I too have never worked on it but it is a complicated process. Each comany eg Dulux acratex, rockcote, CSR Cemintel etc has a system with their own patch compound, mesh tape, base coat, texture coat and top coat. Most are trowelled on with a steel trowel and finished with a plastic one. They have graded aggregate which is meant to make coating easier. Here is a pdf from Dulux Acratex.

I'd also look at Dulux Full cover texture. It is a DIY product, most others are only available from the trade outlets and applicators do courses to become accredited so that the warranty stands. Good luck, let us know how you get on.

Cheers
Pulse

I have worked with blue board over the last few years and have tried different methods for finishing the product. Yes you do have to tape the joins. Blue board is designed so anything will stick to it including polymer renders and paints.
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You can paint straight over the top of blue board but you will see all the nail heads and the joins if they are not finished well. If this does not bother you this is the easiest and cheapest method
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I have also used Du lux render effect paint which dries three time thicker then normal paint. It does give a better finish and is reasonably priced but nail holes are still visible but not as much as normal paint.
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I have use the Du lux product Acratex, which is a roll on sponge out product. I was not impressed for it is harder to apply then they would have you believe. It is also expensive with a 15litre drum being $110 trade and it only covers 4 Sq Metres.
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Render is the other option but you have to know what you are doing but it clearly is the best finish.

Originally Posted by greenhorse

Im hoping that some one can give me a few clues. I am currently building myself a work shed (for retirment) In my wisdom I decided to cover the outside with blue board. At the time I had the belief that you just painted it, now Im not sure.

A local store sold me some Wattle products for the jointing which seem to have a mix of 20% cement added to it and then placed on the joint with a mesh tape. This is then covered over with a finishing compound, much like you do with Plaseter board.

Will some one tell me if this is correct. my other questions are
Is the purpose of this board to render the whole thing or do you just do the joints and then paint it?

I have tapped & covered some of the joint but stopped because im not sure if Im doing the correct thing.

Ive asked plenty of people mostly I get the answer : "I know the board but never seen it worked on"

:confused:

hi you are doing it the correct way the purpose of this product is to render the whole wall but u can also paint as well .

another way is to cover each join with timber strips paint them contrasting colour to the board looks good

I have seen examples of blueboard where cracks appear in the finish where the boards join. Upon closer examination the joints had been taped so their must be a "technique" to tape the joints properly. I have seen cracks in plasterboard where it joins and plasterboard tends to be in a fairly benign environment. I would imagine that being exposed to the external environment would make any non-ideal joint a problem.

Originally Posted by grunto

I have seen examples of blueboard where cracks appear in the finish where the boards join. Upon closer examination the joints had been taped so their must be a "technique" to tape the joints properly. I have seen cracks in plasterboard where it joins and plasterboard tends to be in a fairly benign environment. I would imagine that being exposed to the external environment would make any non-ideal joint a problem.

hi grunto yes cracks will sometimes appear if boards a to close to each other for best results leave a 3 to 4 mm gap between joints when installing the blueboard if they are already on run a grinder in between the joints befor patching and only use 5% cement

Originally Posted by board&paint

hi grunto yes cracks will sometimes appear if boards a to close to each other for best results leave a 3 to 4 mm gap between joints when installing the blueboard if they are already on run a grinder in between the joints befor patching and only use 5% cement

Thanks for the tip. I have an opportunity to try this in a few week so I will see how it goes.

couldn't help but notice your conversation.
paint&board is correct when saying that there needs to be a gap of 3 to 4mm between sheets.
however grunto, there are a number of other reasons for blueboard joints to crack.
1. wrong product used: eg products designed for internal use only, yes i have seen, also not putting the specified amount of cement in the jointing compound, if the one you are using specifies cement. note: you are better of using a jointing compound that doesn't require cement (then you know that it is using a higher quality resin in the product.
2. not using the correct mesh tape: eg mesh tape designed for plasterboard
you need to use mesh tape that has a rating of 150 gsm or greater.
3 not enough expansion joints in the blueboard. eg: greater lengths than 6 meters without an expansion joint. i prefer to put them closer than that if possible, as blueboard is cement and especially north facing walls will heat up a lot, when cement heats up it expands thats why you need the gap in the board to allow expansion. i have seen walls where the joints actually bulge when in direct sunlight in summer, where there is not enough expansion joints.
4. excessive movement will also crack joints: the joints can only hold so much movement back. if there is foundation movement you won't stop the cracking, you will have to stop the foundations moving first.
Joe