James Hardie HardieDeck Questions & Answers

I can tell you a standard jig saw blade is useless, tungsten carbide and slow reciprocating speed might do it. Cement drill bit hole to make the pilot hole.

G'day David, The difference between 304 v 316 is easily researchable, whilst you're researching you may wish to learn why stainless and aluminium create a galvanic reaction and what the children of that unholy relationship look like. Given your lack of basic of knowledge on this matter I can see why you might want to use complete aluminium for a deck, it matches well with your comment about heat being an important consideration hence why lobbying for an aluminium deck surface. If my hearsay knowledge of body corporates is correct you probably stand a good chance of convincing them on the merit of your suggestion. If successful you will likely forever have a demonstration on why Australians don't manufacture much. I think that just about covers an aluminium deck.

The cost is a big factor , it is getting builders to accept that Aluminium has all the nessessary qualities needed , because we are in a FZ , there can be no combustable material , they all talk about Galvanised Subframe , Hardie Plank Decking , we have moisture most of the time in the soil under the present timber deck , that and Gal Subframe , white rust , normal rust , if the subframe is not sealed as manufactors installation guide , warranty is voided ,moisture permeating up though the hardie plank from the bottom is a concern ..

G'day Wayne, I used the recommended blade that JH called for on my makita circular saw. They generally call for a fibre cement blade which only has 6 or so teeth on each blade as I recall. The theory being less teeth =less dust as they sort of chip their way through, the result was still a good cut though. You could use a std wood blade but it would need quality hard facing on the teeth, JH are a bit paranoid about dust from their products. Grab a VAX wet/dry vacuum cleaner or any of the same style with the large 20L metal tub and connect that to your circular saw, it makes a difference.

Blow out your circular saw with the compressor each day if you can, cement dust is fine and stuffs electrical tools.

I asked JH techs about butt joint clearance and the tech said just shove the ends together, no need for an expansion gap. I wasn't game so I still left a couple of mm gap. When butt ends have a close gap any off perpendicular will show up so make sure you get nice square cuts on the ends.

Heat absorption is a factor of colour, white will only be a few degrees above ambient and black can more than double ambient. I used a light grey from the Avista colour range, (spotted gum if I recall) and it is pretty good, however my deck is under a verandah so only angled sun and only for a few hours before back in the shade.

String line your first run and be sub mm accurate, obviously there is no width ways flex in these planks so get the first run perfect. Having said that you can chase out any discrepancy plank to plank if you have to. But if you are going to install the top cap discrepancies will likely show.

Regards Mick

G'day Wayne, Good questions, whilst the fire safe version of the snap in capping is not designed as waterproof, it will (I would think) seriously impede water from draining away, I would think evaporation will be the prime means of removing puddled water. It will also restrict airflow over the deck.

Yes the SS steel screws are a bit of an issue, long term corrosion might be fine, but generally SS and aluminium are not the best bed fellows. I cannot recall if the drill holes through the jointer is anodised or drilled post anodization and hence raw and in contact with the SS screw, this could make a difference. The issue of backing screws appears to relate to where there is a slight unevenness in the supporting joists underneath or a bit of flex in the joists. This puts a tension on the screw that sits over a slightly below profile joist and with the slight flexing of foot traffic it can and does result in the screw backing out just enough to release the tension. The reality is likely not a significant issue except you will here a slight "tink" sound of the loose jointer when you walk over it. If you have a high OCD threshold then no issue really. But once that cap is in I cannot see an easy way to remove it. But talk to JH techs about it.

I used liquid nails instead of the JH proprietary adhesive under the boards due substantial price difference and it appears to be effective. However there may be a good reason to use the more expensive proprietary product. Liquid nails is pretty strong initially but time may break it down.

Do put a good anti slip treatment to the boards as they can be very slippery when wet, pretty good with an anti slip coating on them though, but all decking is a bit slippery when wet.

I am still very happy with my deck and the Avista top coat has held up well over the year or so it's been down.

Happy to answer any other questions

Regards Mick

PS I did leave the caps out on my install, and happy I did,