Kitchen Worktops

20mm vs 30mm Granite and Quartz

By March 11, 2019 No Comments

We are often asked about the various thickness options available with granite and quartz worktops. Is it safe and suitable to use 20mm quartz or 20mm granite worktops? Is there a cost difference between 20mm and 30mm quartz or granite? We are always keen to ensure our clients have all the necessary information available to them regarding choice, suitability and cost of 20mm and 30mm granite or quartz worktops to help make an informed choice.

Standard thickness of stone worktops and how they compare to alternative laminate and wood options.

Typically wooden worktops and laminate worktops can be found in thicknesses of 38mm-40mm, the standard thickness for almost all stone worktops (granite and quartz) is 30mm, however thinner options have always been available. It is only very recently that the kitchen styles have leant well to the thinner 20mm stone worktops and as such demand has increased.

Traditionally the thicker/more chunkier worktops were suited to the ornate profiles of the kitchens of yesteryear, whether you fancied the look and feel of natural wood or stone, having a chunky work surface to complement the cabinets was the order of the day.

However in recent years modern kitchen styles have become minimalist, profiles are thinner with handleless kitchen designs from the Continent becoming ever more popular. Following this trend, the hunt for worktops which are thinner, offering the same level of durability whilst remaining cost effective is on the rise.

It is important to note that not all 20mm stone worktops are the same and therefore the suitability and price is not always consistent. Furthermore, there is demand to create contrasting looks with oversized edge profile that are 50mm plus with mitred apron joints, however in this post we will aim to discuss 20mm and 30mm granite and quartz.

Benefits and disadvantages of 20mm granite & 20mm quartz

20mm Granite


Although almost all granite slabs are available in the 20mm thickness so the options are vast, however the suitability of 20mm granite as a kitchen worktop needs to be evaluated on a slab by slab basis. Some 20mm granites are more suited to applications other than kitchen worktops.


Due to the natural veins and fissures found within the majority of natural granite slabs, the thinner slabs are often coated with a plastic mesh to the rear of the slabs to help prevent cracks and breakages. Using a thinner option such as 20mm granite compared to 30mm granite means you run the risk of cracks appearing at these weak points over time if the cabinets and worktops are not sufficiently reinforced and supported. Areas where there are cut outs for hobs and sinks further create opportunity for breakages during fabrication, transit and install.

Some natural granites are far better in terms of overall tensile strength, the weak points are mostly found within slabs that feature exotic veins and patterns. For example a plain black granite such as Absolute Black Granite features a dense rock formation with the natural minerals tightly bonded together. Not only is this type of granite very hard on the surface, its inner strength is far superior than that of something like Bianco Antico Granite or Cosmic Black Granite which feature exotic patterns, large veins and naturally occurring fissures.

Most exotic granite colours in 20mm are usually reserved for areas with less traffic such as wall cladding, upstands and window sills where the chance of cracking is minimal after install.

In conclusion, choosing a densely formed granite in 20mm thickness as a worktop is a far better choice when compared to those granites with patterns and fissures in 20mm. The additional material and labour required to create sufficient support for such granites can often outweigh the cost benefits of choosing the cheaper 20mm granite (see cost benefits below). If you have your eye on an exotic granite it may be advised to consider the 30mm option for complete peace of mind, the edge can still be profiled so as to create a thinner, more streamlined look (see final conclusion below).


The cost difference between 30mm and 20mm granite is usually between 8-10% (cheaper for the thinner option) and can be confirmed at the time of quotation. In some cases the difference in cost can help to bring the kitchen in on budget, however if additional support is required for the worktops then this may add some labour/material cost to your final quote.

Additional support can include batons and ensuring unsupported areas are no wider than 600mm apart. Your fabricator may also insert steel reinforcements around the areas with cut outs for hobs/sinks. 

20mm Quartz


Almost all quartz worktops on todays market will be available with a 20mm thickness. Even where a manufacturer offers different finishes (i.e polished & matt), most colour-ways will be available in the thinner 20mm quartz. Traditionally reserved for upstands, backsplash and window sills, 20mm quartz is becoming very popular as a worktop and as such 20mm jumbo sized quartz slabs have been made available to offer customers the same design options as the 30mm version.


As quartz slabs are an engineered stone, the colour, consistency and durability can be controlled on each and every slab. Although the 20mm quartz stone is thinner, the tensile strength is far superior when compared to some 20mm granites. This ultra compact surface ensures for no fissures or weak points and as such can be used in a multitude of scenarios with complete peace of mind that you have product that will stand the test of time.

The thinner 20mm quartz is more lightweight so can be ideal for transporting and installing in challenging areas (such as high rise buildings, lofts etc). 20mm quartz offers a similar level of protection and durability as its 30mm counterpart and is usually cheaper to buy too.

Additional support may be required but no more than we would request for the 30mm quartz worktops in any case.


The cost difference between the 20mm quartz and the 30mm quartz is typically between 8-10% cheaper for the thinner option. The percentage difference in price can vary between various quartz brands/colours and can be confirmed at the time of quotation. Unlike 20mm granite worktops, generally the support provided by standard sized cabinets is sufficient and as such the thinner worktops can be installed without fear of additional labour and material costs associated with creating extra support.

As most upstands, window sills and cooker backsplash areas are offered in a 20mm thickness you may find such items offered at additional discount if you opt for the 20mm worktops too. Typically your fabricator would need to purchase in an additional 20mm slab to complete the order which further adds to material wastage, another somewhat cheaper option is for the fabricator to cut the upstands/window sills/backsplash from the 30mm slab and then mill down the rear to the 20mm thickness. In either option additional material and labour costs will be taken in to account should you wish to opt for the 30mm worktops and 20mm upstands for example. Opting for 20mm worktops and 20mm upstands will likely mean your fabricator will not need to buy in additional material nor mill down any material to fulfil the order.

Benefits and disadvantages of 30mm granite & 30mm quartz

30mm Granite


Granite slabs in 30mm thickness are the most common, quarries world wide will generally cut the majority of slabs for the retail market in 30mm thickness so there are plenty of exciting colours and patterns to choose from.  30mm granite is most popular firstly due to the additional tensile strength offered by the thicker material and secondly because the majority of fabricators are geared up to facilitate 30mm slabs. Slabs thicker than 30mm are heavier, in some cases require specialised tooling and the demand is very low which makes 30mm slabs the sweet spot in terms of price and availability for granite worktops.


Although some exotic granites should be avoided in 20mm (for a kitchen worktop) almost all exotic granites in 30mm slabs are available for you to buy with complete peace of mind. Although natural fissures are still present and cracking is still an issue with some granites, the chances of this happening are massively reduced with the 30mm option when compared to the 20mm granite kitchen worktops. Most of the issues are likely to happen whilst in fabrication or in transit, once the 30mm granite has been professionally installed the end user can stay rest assured their new granite kitchen worktops will stand the test of time.


Although 30mm granite slabs are slightly more expensive when compared to 20mm granite, the popularity of engineered quartz surfaces in recent years has meant granite prices have been dropping. In some cases the most popular granites such as absolute black granite or steel grey granite are now cheaper than the entry level engineered quartz worktops.

30mm Quartz


Almost all quartz slabs are offered in a 30mm thickness as standard, with the 20mm options offered as an alternative. 30mm quartz can usually be found in jumbo slab sizes giving end users the opportunities for seamless worktops and large kitchen islands. If your chosen slab is not available in 20mm the 30mm worktops can be milled down, or a shark nose edge profile (see image below) can be added to create a more streamlined look.


Quartz stone is specifically engineered for use in the kitchen both in terms of strength and performance. As with the 20mm quartz above, you can use 30mm quartz as a kitchen worktop with complete peace of mind. The engineered quartz is a compact surface that is both tough and durable, ideal for busy households.


Although 30mm quartz is slightly more expensive when compared to the 20mm quartz, the price difference isn’t always consistent and can fluctuate between 8-10% on average. With the rise in popularity of quartz within the UK homeowner market, supply levels have been steadily increasing with new brands coming in to the market every year. More competition for the bigger brands have meant wholesale prices have started to drop for the most popular selling colours. A combination of premium brands, trending colours and patented technologies can drive up prices for particular products, however cheaper alternatives can always be found within the huge amount of options now on offer.

So, should I go for 30mm Granite or 20mm Quartz?

Our Final Conclusion

If you wish for a thinner more streamlined look to suit your kitchen then it would be safe to say 20mm engineered quartz would be the best option. Although we can safely say 20mm quartz and 30mm quartz are both suitable as kitchen worktops, there is no definitive answer to the 20mm granite debate. The 20mm granite options need to be evaluated on a case by case basis for the suitability of its intended purpose.

If you cannot find a colour or pattern within the quartz or you simply prefer the look of natural granite then you may consider a 20mm granite which does not feature large exotic patterns and veins.

There are also some alternative options to make your 30mm granite or quartz look thinner. Although an unfinished 30mm granite edge can still look to appear “chunky”, once it has been polished and the edges have been worked the result is a more refined looking edge which still works harmoniously with the slender proportions of a contemporary kitchen.

Furthermore, 30mm granites and quartz are ideal for routing modern edge profiles such as our “Sharknose edge” to create a more streamlined look. Using the latest Computer Numeric Controlled (CNC) technology, we can reshape your chosen slabs using a range of the latest edge profiling tools.

Shark Nose Edge Profile

Shark nose Edge Profile example
Shark Nose Edge Profile underside

At Stone Culture we aim to provide our clients with all the necessary information to ensure for a high quality end product that will stand the test of time. If you have any questions regarding the suitability of 20mm granite worktops or 20mm quartz for your home or workplace please do not hesitate to call our friendly team on 0121 630 2251 or request a call back here:

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