How to build a concrete barbecue bench using fibre cement sheets?

Question

Hi There,

so im about embark on a BBQ build in our courtyard. im pretty confident with what im going to build but I did have a question about the cut out area where Iwill be placing the BBQ itself. ill be making a concrete bench top with form ply etc… and using fibre cement sheet in the cut out section. my question is, as my area is open/exposed to weather and not undercover, do I need to seal or waterproof the fibre cement sheets? is it ok for it to get wet? do I seal it so nothing gets in but then thats probably not great for allowing heat and moisture to get out. or lean it so water drains out?

Any advice would be greatly appreciated.

Cheers,

Tony.

Dave-1 · Answer

Good Afternoon @Tony_A

I am not sure what you mean by Micro cement? having a bench of 60-70mm thick is potentially go to be hard to do, especially if you havnt concreted before. Is the whole bench going to keep the form ply or are you removing it? If you are removing it how far apart are the supports for the bench going to be? I ask this as those diagonal braces you have really need to be fixed to the base as even 60-60mm of concrete is going to be heavy and I cant see any bracing to stop the legs drifting apart?

Dave

JacobZ · Answer

Hi @Tony_A,

Where exactly was the 60-70mm thick edge you are referring to? Is that edge going to be concrete?

If so, I can't really see why you'd need to alter the substrate to accommodate it. Is there a particular concern here?

A 400mm radius is going to be very tight, and I think you are going to struggle bending any fibre cement to that radius without snapping it. For example, the Villaboard Lining Installation Guide recommends a minimum bending radius of 1200mm, with extra care taken, for 6mm thick Villaboard. Using a thinner material like 4.5mm Hardiflex would likely help, but it still sounds very tight considering. Unfortunately, this might have to be a bit of a test and see scenario.

You might also like to have a read through this Jame Hardie Curved Walls Technical Supplement which details the process for installing curved fibre cement walls.

If it didn't make the radius, could you alter the design at all? Would a larger radius bend be possible? Or could you simply have a 90-degree corner instead?

Let me know what you think.

Jacob

Tony_A · Answer

Appreciate the response @EricL and @Dave-1. I did have another question. I was thinking about doing microcement for the bench top as we want to render our block bench the same colour. wanted to have a thick edge something like 60-70mm wondered what kind of substrate I need for that, was going to use some form ply (as I already have some) and then FCS over that and on the edges. I do though have a 400mm radius curve at the end though which I think is going to be problematic. was think hardiflex or something but fought it will bend that tight? any thoughts?

Thanks.