Outdoor Concrete Worktops
Slightly off topic, I suppose for this time of year but still worth a blog post! AND of course many of you may still be creating an outdoor space even though it's winter. After all, what’s more fun than a crisp Winter’s evening BBQ! Wrapped up warm, roasting chestnuts and sipping Vin Chaud or Gluhwein. Yum
So outside, polished concrete can behave differently to its indoor counterpart. The between the outdoors and the inside of your cozy home is obvious - temperature and also moisture. Many of you will also have heard of freeze-thaw action. This is where moisture absorbs into a material such as stone or indeed concrete, then when the temperature drops, the moisture turns to ice, expands and opens up fissures in the material.
So what does that mean when it comes to your handcrafted polished concrete?
Well, the concrete you have made (or are planning to make) will behave pretty much the same. When it comes to moisture (rain) and then a drop in temperature, the H2O absorbed in your concrete will eventually show signs of expansion in the form of fissures and cracks.
So how do you guard against this? Well there are a number of ways. In the same way you cover your BBQ over during the Winter months or when it’s not in use, you could do the same for your concrete.
Of course if your concrete is under cover, for example beneath a canopy roof, then that should already be taken care of.
A second option is to ensure that your concrete has a water-repellent surface.
“But what about heat?”, I hear you say. Well if you’re talking about the scorching temperatures some parts of the UK experienced during the summer then that would definitely be a design consideration. Another consideration would be if you plan to build a concrete worktop and then put a BBQ, pizza oven or similar directly on top.
Just as your concrete tops will expand with freeze-thaw action, they will definitely expand when a 500degC appliance is sat on top of them.
If this is something you are planning then the thickness of the concrete is important. Anything too thin and the concrete will expand and literally “ping” a crack at the hottest point.
So a minimum thickness of 40mm is advised if not thicker. With greater thickness comes more weight so bear that in mind also. Your cabinets or structure on which the concrete is sat may require a bit of beefing up! 40mm thickness is by the way the minimum thickness for a hearth for a wood-burning stove.
Ultimately, there’s no reason that the concrete worktops you have installed in your outdoor kitchen or BBQ area won’t be as long-lasting as the ones in your kitchen. The “aftercare” that you give to your handmade concrete just may be a little different than that applied to any indoor polished concrete.
As ever if you do have any questions then fire them off to info@concretelab.co.uk.