Porcelain and Sintered Stone Countertops

Porcelain and sintered stone are the newest of the mainstream countertop materials and the least understood. On paper they beat quartz and granite on almost every measure. In practice they ask more of the fabricator than any other slab, and a few of their limits only show up at the edges. This page covers what they are, where they earn their place and what to ask before you commit.

What they are

Porcelain slabs are made the way porcelain tile is made: refined clays, feldspar and other minerals are pressed and fired in a kiln until the body fuses into a dense, glass-like mass. Under the American standard for ceramic tile, ANSI A137.1, porcelain is defined by performance: a water absorption of 0.5 percent or less when tested by ASTM C373. The large, thin pieces used for counters and walls are called gauged porcelain tile panels or slabs, and have their own standard, ANSI A137.3, which applies that term to pieces of one square meter or more.

Sintered stone is a trade term for slabs made by compacting mineral powders under very high pressure and firing them so the particles bond without melting fully. The recipe and process vary by maker, and so do the names: ultra-compact surface and sintered ceramic are the same family. The category has no single consumer definition, so compare the technical data sheet for a specific slab instead of relying on the label.

For a homeowner the two behave alike. Both contain no resin, which is the source of their main advantages over engineered quartz, and both are thinner and lighter than a stone slab.

How they compare with quartz and granite

The quartz and granite columns are explained in full in quartz versus granite.

Heat, sunlight and stains

These slabs come out of a kiln, so a pan from the oven does not trouble them. There is no binder to scorch or yellow. Sunlight does not shift the color either, which makes them a sound choice for a counter under a large south-facing or west-facing window, for a kitchen that opens to a patio through wide glass doors, and for outdoor kitchens.

Because the body absorbs almost no water, liquids stay on the surface. Wine, coffee, oil and turmeric wipe off, lemon juice and vinegar do not etch, and there is nothing to seal. Day-to-day cleaning is dish soap and water.

Edges: where the material is weakest

The face of the slab is extremely hard. The edge is where trouble happens, for two reasons. The slab is thin, and a very hard material is also a brittle one. A cast iron pan swung into the edge at the sink, or a heavy pot dropped on a corner, can take out a chip where granite would survive.

You can reduce the risk considerably:

• Choose an eased or slightly rounded edge, not a sharp square one.
• Ask for rounded outside corners on islands and peninsulas.
• Pay attention to the sink. An undermount cutout leaves an exposed inner edge that takes the most knocks; ask the fabricator how it finishes and protects that edge, or consider a sink with a rim that covers it.
• Make sure the slab is fully supported. Thin slabs depend on a flat, continuous substrate or full-perimeter support as the maker specifies, and on cabinets set dead level.

Mitered edges and thickness

A thin slab looks thin. To give the counter the visual weight people expect, fabricators cut the edge of the top and a narrow strip at 45 degrees and bond them into a mitered apron. Done well, the counter appears to be a thick block and the pattern turns the corner and runs down the face. The same technique makes a waterfall end on an island.

The miter is also the most delicate part of the job. The point of the miter is a sharp, thin edge of a brittle material, so it is normally finished with a small bevel or eased corner. Ask to see a mitered sample from the fabricator you intend to use, and look at how tight and how visible the glue line is. Edge options in general are covered in countertop finishes, edges and thickness.

Printed pattern or through-body

Most marble-look and stone-look porcelain carries its pattern as a print fused into the surface. The body underneath is a plain color. Three things follow:

• A profiled edge cut into the slab exposes the plain body, which is why mitered edges are standard on veined designs.
• A chip shows the body color.
• Drain grooves, recessed drainboards and other details ground into the surface cut through the print.

Some slabs are through-body, meaning the color, and in a few products the veining, continues through the thickness. Plain and fine-speckled colors are commonly through-body. If the edge detail matters to you, ask to see a cut edge of the exact product, not a photograph of the face.

On patterned slabs, also ask how many different faces the design comes in. A print repeats, and two identical slabs side by side on a long run or across a seam are noticeable.

Fabrication is the deciding factor

The slab is manufactured under tension and has to be cut in a particular order with blades and settings made for it. Cutouts need rounded inside corners. Handling and transport need frames and suction equipment, since a large thin slab can crack under its own weight if carried flat. A shop that cuts mostly granite and quartz may take porcelain on reluctantly, price it high or decline it.

That makes the fabricator a bigger part of this decision than the brand of slab. A good one will tell you where the seams must go, what edge it will warrant and which sink details it recommends. Expect the fabrication share of the cost to be larger than for quartz, and expect less room for changes after templating. The gap between template and installation is the same as for any slab counter, as described in the countertop overview.

What to check before you buy

• How many porcelain or sintered kitchens the fabricator has completed, and whether you can see one or see photographs of its seams and miters.
• Slab size and thickness, and whether your island can be done without a seam.
• Whether the pattern is printed or through-body, and what the cut edge looks like.
• How many pattern faces exist and whether book-matched pairs are available.
• The substrate or support the maker requires, and who provides it.
• The finish: polished, matte or textured. Matte and textured faces hide water spots and fingerprints better; some show metal marks.
• Who warrants what: the slab maker for the material, the fabricator for the cutting and installation.
• The sink and cooktop models, fixed before templating.

Who should choose porcelain or sintered stone

Good fit: you cook with heat and do not want to think about trivets; the counter sits in strong sun; you want a marble look with no etching (compare the other look-alikes on the marble page); you want counter, backsplash and perhaps an outdoor counter in one material; or you prefer a thin, modern edge.

Poor fit: you want an ornate edge profile; the household is hard on sink edges and corners; you want veining that runs visibly through the stone; or no fabricator near you works with it regularly.

A slab backsplash in the same material is a natural companion; see kitchen backsplashes and wall finishes. JDI Construction's published planning range for a slab backsplash add-on is $3,000-$8,000. To see how this material would work in your layout, start at our Vancouver kitchen remodeling page.