Quartz countertops have become an increasingly popular choice for kitchen and bathroom remodeling projects in recent years. Often touted for their durability, low maintenance, and stylish appearance, quartz counters are favored by many homeowners and designers. However, one common question that arises is: are quartz countertops porous?
What is Quartz?
Quartz is a man-made engineered stone that is composed of ground natural quartz crystals combined with polymer resins and pigments. The quartz content typically ranges from 90-94%, while the rest consists of polymers and pigments.
Compared to natural stone like granite or marble, quartz has very low porosity. This is due to the resin binders that fill in the spaces between the quartz particles, making the material denser and less permeable. The polymer resins make quartz resistant to staining, etching, and absorbing liquids.
Are Quartz Countertops Porous?
The simple answer is no, quartz countertops are non-porous. The resin used in manufacturing quartz slabs fills the natural pits and cracks in the quartz, resulting in a dense, impermeable surface.
While quartz has microscopic pores, they are too small for liquids and bacteria to penetrate. Quartz density, low water absorption rate (less than 0.5%), and impermeable surface make it essentially non-porous for all practical purposes.
This non-porous nature is one of the key benefits of quartz counters. It makes quartz resistant to staining, etching, mold growth, and harboring bacteria. Liquids and spills sit on the surface rather than absorbing into the material.
Quartz Density Makes it Non-Porous
The typical density of quartz slabs ranges from 2,300 to 2,500 kg/m3. This high density is due to quartz particles being packed tightly together with resin fillers that eliminate air pockets.
Higher quartz density directly correlates with lower porosity. Dense quartz counters do not have enough pores for liquids to seep into or penetrate the surface.
Quartz counters with 93% quartz content or more are considered non-porous. Lower quartz content may increase porosity slightly but not enough for liquids to absorb into the countertop.
Low Water Absorption
Quartz has a water absorption rate of less than 0.5% according to ASTM standards. This means that very little water is absorbed by quartz slabs.
The low absorption rate also indicates low porosity. Porous materials like wood or concrete can have water absorption rates of over 5%.
When liquids spill on quartz, they remain on the surface rather than being absorbed by any pores. This allows for easy cleanup without any staining.
Impermeable Surface
While quartz has microscopic pores, they are not interconnected so liquids cannot travel through the material. The resin binds the quartz particles together to create an impermeable surface.
This impermeable surface prevents liquids, oils, and dirt from penetrating into the countertops. It also inhibits the growth of mold and mildew, as moisture has no way to seep into the quartz.
Quartz’s non-porous surface also resists permanent staining. Most spills can be wiped away without leaving a trace. Only prolonged exposure to strong chemicals may stain quartz.
Differences from Natural Stone
Unlike quartz, natural stones like marble, granite, and soapstone are more porous. This is because natural stone is 100% derived from the earth without any resins or binders added.
- Marble – Very porous and prone to etching and staining. Marble has a water absorption rate of 0.4-0.7%.
- Granite – Slightly porous depending on variety. Water absorption rate of 0.05-0.4%.
- Soapstone – Extremely porous due to high talc content. Water absorption over 5%.
While sealing can help protect natural stone counters, sealants wear off over time. Quartz’s non-porous quality is inherent and permanent without the need for sealing.
Is Quartz Completely Non-Porous?
There is some debate regarding whether quartz is completely non-porous or not. Here are the two schools of thought:
- Quartz has microscopic pores that make up less than 0.5% of its volume. These pores are not interconnected and are too small for liquids to penetrate. For all intents and purposes, quartz can be considered non-porous.
- Quartz does contain tiny pores under electron microscope examination. So it cannot be claimed to be 100% non-porous. However, the pores are minimal and have a negligible effect on quartz’s resistance to staining and etching.
In either case, the fact remains that quartz has extremely low porosity compared to other natural and engineered surfaces. The porosity is so minimal that it does not undermine any of quartz’s benefits in a practical setting.
How is Quartz Made Non-Porous?
Quartz obtains its non-porous quality from the manufacturing process. Here are the key steps:
- Mixing – Finely ground quartz is mixed with polyester resins, pigments, and other additives that bind the material together.
- Compacting – The mixture is compacted under vacuum conditions to remove air pockets and compress quartz particles densely together.
- Vibration – The slabs are vibrated to further eliminate air bubbles and pores. Vibration creates a uniform, dense slab.
- Polishing – Finally, the slabs are polished to form a smooth, impermeable surface. The polishing fills any remaining microscopic pores or pits.
The combination of pressure and vibration fuses the quartz grains and resin together into a solid, non-porous material.
Pros of Non-Porous Quartz
The non-porous nature of quartz provides several advantages that make it an appealing countertop choice:
- Resists staining and etching from spills and chemicals
- Does not harbor bacteria or enable mold/mildew growth
- Low maintenance without need for sealing or polishing
- Easy to clean and keep sanitary
- Prevents moisture damage to cabinets and substructures
- Durable and scratch-resistant surface
- Keeps appearance pristine over years of use
- Ideal for kitchens and bathrooms prone to spills
The impermeable surface makes quartz an excellent option for homes with kids and high traffic areas. Quartz requires very little maintenance while retaining its like-new appearance.
Cons of Non-Porous Quartz
There are a few potential drawbacks to the non-porous quality of quartz:
- Price – Quartz is more expensive than porous natural stone and laminate.
- Lack of patina – Unlike natural stone, quartz will not develop a patina or worn look over time. The surface remains uniform.
- Prone to cracks – While resistant to scratches, quartz can crack under extreme impact. Repairs are difficult on the non-porous surface.
- Heat damage – Direct high heat can damage quartz and compromise its non-porous property. Using trivets is highly recommended.
However, these disadvantages are minor when compared to the staining, etching, and maintenance issues associated with natural stone counters.
Is Quartz More Sanitary Than Other Countertops?
The non-porous quality of quartz does make it more sanitary and hygienic than other countertop materials.
Quartz resists the growth of bacteria, molds, and fungi because liquids cannot penetrate the surface. Porous materials like marble and granite are more prone to harboring germs within their pores.
Quartz also does not require sealing which can break down over time. So it retains its non-porousness and does not need periodic maintenance. This perpetual hygienic quality gives quartz an advantage over natural stone and concrete countertops.
However, quartz is not antimicrobial. It can still get contaminated by food residue, spills, and other dirt on its surface. Proper cleaning is required to keep quartz counters sanitary. But its non-porous property certainly makes cleaning and disinfection easier.
Does Quartz Need to be Sealed?
Unlike natural stone, quartz does NOT need to be sealed. Sealing is required for porous stones like slate, marble, granite, etc. to prevent staining and damage.
But sealing is completely unnecessary for quartz since it is already non-porous and impervious to liquids. In fact, sealing a quartz counter provides no benefits and manufacturers explicitly advise against it.
Sealants cannot penetrate the dense non-porous quartz surface. And sealants often contain chemicals like acrylics, epoxies, and polyurethanes that may actually damage the quartz and reduce its shine and clarity over time.
Is Quartz Heat Resistant?
While quartz countertops are very durable, their non-porous resin binders are susceptible to damage from excessive direct heat. Constant exposure to high heat can potentially cause:
- Discoloration
- Burns or cracks
- Loss of shine/smoothness
Placing hot pots, pans, and bakeware directly on quartz can reach temperatures beyond its heat tolerance. The sudden extreme heat impacts the structural integrity of the solid quartz surface.
The general rule is to avoid exposing quartz counters to sustained temperatures beyond 150°F (65°C). Higher temperatures – especially over 300°F (150°C) – risk thermal shock and damage.
To maintain its non-porous property and appearance, always use trivets or hot pads when placing hot objects on quartz. Avoid subjecting quartz to direct high heat outside of its thermal limits. Take care when using appliances like crockpots, portable grills, etc. to prevent heat damage.
Can You Cut on Quartz Countertops?
While quartz is exceptionally hard and scratch resistant, cutting directly on the surface should be avoided. Sharp knife blades can potentially scratch, pit, or dull the surface over time with heavy use.
To retain its flawless non-porous finish, always use a cutting board for food preparation. Never cut meats, hard vegetables, etc. directly on the counter. Avoid abrasive scouring pads too.
With proper cutting board usage, quartz counters will retain their factory-smooth surface without any knife marks or cuts compromising the non-porous quality. The integrity of the quartz will remain intact for years.
Are There Pore-Filled Quartz Options?
Most major quartz manufacturers utilize pure polyester resins to fill spaces between quartz particles. This creates a non-porous, impermeable surface.
However, some cheaper quartz varieties use a porous filler instead of resin to reduce costs. Common fillers include polyurethane, acrylic, and cement.
Pore-filled quartz tends to have lower density and is slightly more porous. Liquids have a greater chance of penetrating the surface.
For most water-resistant and durable non-porous performance, opt for 100% polyester resin filled quartz. Popular premium brands like Caesarstone, Cambria, Silestone, and Vicostone all use pure polyester resins.
How to Clean and Maintain Non-Porous Quartz
Caring for quartz counters essentially involves keeping the non-porous surface clear of grime buildup:
- For everyday cleaning, use a mild soap/detergent and warm water. Avoid abrasive cleaners or pads.
- Disinfect surfaces periodically with diluted bleach or hydrogen peroxide solutions.
- Rinse thoroughly after cleaning to remove any residue.
- Immediately wipe up spills – especially oils, wines, and acidic liquids.
- Avoid exposing quartz to strong chemicals like paint removers, oven cleaners, etc.
- Use trivets and cutting boards to protect from heat/knife damage.
With regular cleaning, quartz will retain its like-new non-porous state for decades. It’s a low maintenance countertop that does not require resealing or polishing.
FAQs
Can liquids penetrate quartz?
No, liquids remain on the surface of quartz and cannot penetrate the dense non-porous material. Only prolonged exposure to some strong chemicals may stain quartz.
Does quartz need resealing over time?
No, quartz never needs sealing since it is already non-porous. Sealants cannot penetrate quartz and may do more harm than good.
Is quartz healthier than granite?
Yes, quartz is generally regarded as more hygienic than granite due to its non-porous quality that resists bacteria growth. But both need to be kept clean.
Can you use bleach on quartz?
Yes, diluted bleach can safely be used to disinfect and clean quartz counters. But avoid prolonged exposure to harsh undiluted bleach.
Can quartz crack or chip?
Quartz is very hard and resistant to scratches. But excessive force, impact or sudden temperature changes can cause cracks in the slabs.
Conclusion
Quartz offers a high-end non-porous surface that combines the beauty of stone with excellent durability and low maintenance. Its impermeable polished finish repels liquids, resists staining, inhibits germ growth, and simplifies upkeep. While no material is 100% immune to damage, quartz comes as close as possible to a lifelong non-porous countertop. With some care and precautions against impacts and heat exposure, quartz counters will retain their like-new condition for decades. For homeowners seeking stylish worry-free countertops, quartz ticks all the boxes.