HEAT AND YOUR KITCHEN WORKTOPS

Are my kitchen worktops resistant to heat? Which is the most heat resistant worktop? What temperatures can my quartz worktops take? 

These are frequently asked questions which we have heard many times. And, to be honest, there is a lot of misinformation about. I have just had a quick trawl of granite and quartz worktop websites and seen a ton of contradictory and misleading info. Here at Affordable Granite we try hard to tell it like it is, with both the good and bad news of the different kinds of solid stone kitchen worktops all spelled out for you.

The problems with heat affecting stone come in various ways. We have written on it before – but this is an update which I hope clarifies things further. I want to look at:

1. Intense heat – absolute temperature limits
2. Localized or rapid – problems due to sudden heating
3. Prolonged or repeated – long-term issues at relatively low temperatures

Intense heat means high temperatures. For every material, there are temperatures that you simply must never reach, for however long or however general/localised. 

Natural Stones

For igneous rocks, like Steel Grey or Black Pearl, that temperature would be very high indeed – higher than you can achieve in a home setting.

For other natural stones, somewhat lower limits would apply, but heat resistance would still be very good – into the hundreds of degrees.

Those absolute limits aren’t the whole story, though! It is perfectly possible to damage a natural stone surface at far lower temperatures than the absolute maximum – please read on, below!

Quartz – Engineered stone

Quartz is considerably more prone to damage from high temperatures. Silestone recommend no exposure to anything higher than 160°C. This is down to the plastic resin which binds the mineral content together.

This means that you must definitely avoid contact with oven-hot pans and utensils.

Ceramic and Porcelain

Ceramic worktops such as Laminam, Sapienstone or Dekton are formed under heat and pressure, in processes in many ways akin to the natural processes which create real stones. As such, they are highly heat resistant – and will hold up well in an extreme temperature test against the likes of Steel Grey Granite. In other words, at temperatures achievable in a domestic kitchen, there is no issue with generalised heating. But see below on sudden and localised heating.

Relatively low temperatures if applied consistently to one small area can cause damage.

Electric kettles and air-fryers tend to stay in one place in your kitchen. Even where the heat that they produce on the surface beneath them is no where near the maximum recommended for the product, we have seen issues, especially in quartz worktops. Check what your appliance is supposed to do – and check what it is actually doing in terms of heat output. We recommend the use of a mat or some kind of trivet under electric kettles. Watch also for some coffee makers, toasters and even some microwave ovens.

The same advice holds true above dishwashers and any other under-counter appliance that may leak heat upwards.

Damage of this kind tends to take two forms:

1. Gradual discoloration of resin-based engineered stones – quartz. This is a bit like the fading of curtains under harsh sun.
2. Hairline cracks in stone due to repeated expansion and contraction. This may occur especially in large areas with poor support – perhaps over an L-shape corner unit, which is exactly the case where you tend to put a kettle. Cracks generally run from the zone of regular heating to the nearest join or corner.