Concrete Question

[charliegolf]

I've been looking at concrete worktops for my grill area outside. I'm going for the pour in situ method and I'm posting to ask what mix to use. US seems to be the home of concrete worktops, and try as I might I can't seem to find a comparable mix to the ones they show in the vids. It appears to have no aggregate in it; rather a thick, soupy cement mix.

Does anybody have any idea of a UK product or can anyone suggest a menu for casting nice smooth white concrete?

Thanks.

CG

 

[IT Minion]

I did something like that. I used a mix of 2:1 sand to cement (snowcrete), reinforced with approx. 5% glass fibre. That turned it from a sloppy mortar mix into a weird unappetising spaghetti dish.

The sand was a vibrant yellow so the effect is creamy rather than white, you'd need dye (or white sand?) to get a good white shade.

Mine was a sub-scale demonstrator before I got round to doing a full sized table. It made an excellent child's picnic bench though.

IMG_20200517_152901

• IT Minion
• 21 May 2020

The odd patina on the top is due to an attempt to seal the concrete, which I don't think I got right.

 

[charliegolf]

IT Minion, thanks for that- the result is better than I was hoping for...

Couple of questions...

Is yours a make-in-the-mould version, where you turn it out afterwards and the 'best' side was on the bottom;
or, is it a trowelled finish on show, after chucking the mix in a tray and smoothing it off?

My plan is the latter, with a tile surface as a fall back if it's carp! Either way, may I pm you about the process?

Cheers

CG

 

[IT Minion]

IT Minion, thanks for that- the result is better than I was hoping for...

Couple of questions...

Is yours a make-in-the-mould version, where you turn it out afterwards and the 'best' side was on the bottom;
or, is it a trowelled finish on show, after chucking the mix in a tray and smoothing it off?

My plan is the latter, with a tile surface as a fall back if it's carp! Either way, may I pm you about the process?

Cheers

CG

Made in the mould. Melanie cast with silicone around the corners to give a rounded corner edge finish. I applied 'face' coat applied by hand then the fibre reinforced mix layered in afterwards. Despite my efforts one or two fibres did poke out the top which let the look down a bit, but plucking them out sorted it.

The underside is very rough, you'd struggle to get a nice finish with the fibres, although if you're tiling the top it's irrelevant. Happy to share additional details but I don't think I can claim it's the right way to do it yet. It'll need more time to prove that.

PM away, but I'm happy to dump and details on this thread for posterity.

 

[^woody^]

Use grano not ballast. 3:1 will do, 2:1 if you are nervous. You'll need something to vibrate the mould to toughen the slab up, hammer drill or sander.

Trowel the top or rub with polythene, when the water has evaporated and the mix begun to set.

 

[charliegolf]

PM away, but I'm happy to dump and details on this thread for posterity.

Please do, any details you can add....

CG

Woody, so no sand, just grano?

 

[^woody^]

No sand with grano. It has its own dust.