Slab building is one of the oldest and most approachable ways to make pottery by hand. Instead of throwing on a wheel, you roll clay into flat sheets, cut them to shape and join them together. Mugs, plates, platters, vases and soap dishes can all be made this way, and the method leaves room for the soft, slightly wobbly character that makes handmade ceramics feel alive.
Here's a walk through the basics, from a lump of clay to a finished, fired piece.
choosing your clay
For functional ware, a stoneware clay is a good place to start. It fires to a dense, durable body that's suitable for everyday use once glazed. A clay with some grog (fine particles of already-fired clay) is more forgiving for slab work: it helps the clay hold its shape, dry evenly and resist cracking at the joins.
Before you start, wedge the clay to even out its moisture and push out air pockets. Trapped air can cause bubbles and weak spots later on.
rolling an even slab
The most important thing in slab building is an even thickness. If one part of a piece is thicker than another, it dries and shrinks at a different rate, and that's when warping and cracks appear.
- Use guide sticks. Place two strips of wood of equal thickness either side of the clay and let your rolling pin run along them. Around 5 to 6 mm is a good thickness for mugs and small plates.
- Roll in different directions. Roll, lift and turn the slab, and flip it over every few passes so it doesn't stick and the clay is stretched evenly.
- Work on canvas or cloth. A fabric surface stops the clay sticking and lets you lift the slab without distorting it.
compressing the slab
Once rolled, run a flexible rubber or metal rib firmly across both sides of the slab. This compresses the surface, aligns the clay particles and smooths away the cloth texture. It's a small step that makes a big difference: compressed slabs are much less likely to warp or crack as they dry, especially across flat bases.
adding texture
A freshly rolled slab is the perfect moment to add surface texture, while the clay is still soft enough to take a clear impression. Shells, leaves, lace, wooden stamps and carved blocks all leave beautiful marks. Press firmly and evenly, then lift straight up so the impression stays crisp. Every piece in our shop starts this way, with impressions from shells collected on Cornish beaches.
Remember that glaze will pool in deep marks and break thin over raised edges, which is what makes textured surfaces come alive after firing.
soft slab or leather hard?
You can build with slabs at two quite different stages:
- Soft slab: freshly rolled and flexible. Ideal for curved forms like mugs and cylinders wrapped around a former, or plates draped into or over a mould. Pieces made this way have a relaxed, organic feel.
- Leather hard: firm enough to hold its own shape but still damp. Better for crisp, angular forms such as boxes and straight-sided dishes, where the walls need to stand up on their own.
templates and formers
Cut card templates for each part of your piece, lay them on the slab and cut around them with a sharp knife held upright. For a mug, a rectangle for the wall and a circle for the base is all you need. A cardboard tube or rolling pin wrapped in newspaper makes a simple former: wrap the soft slab around it, join the seam, then slide the former out once the clay can hold itself.
scoring and slipping: making joins that last
Every join needs to be scored and slipped. It's the step beginners most often skip, and the most common reason pieces come apart in the kiln.
- Score both surfaces to be joined with a needle tool or serrated rib, making a crosshatch of shallow marks.
- Brush on slip, which is clay mixed with water to a thick cream.
- Press the edges firmly together and wiggle slightly so the scored surfaces interlock.
- Reinforce the inside of the join by blending in a thin coil of soft clay with a finger or wooden tool.
Joining pieces at the same moisture level matters too. Soft clay joined to dry clay will shrink at different rates and pull apart.
handles
Handles can be pulled by hand, rolled as a coil or cut as a strip from a slab. Attach them once the body is firm enough to support them, scoring and slipping both ends, and smooth the joins so the handle looks as though it grew from the mug. A thick, rounded handle is comfortable to hold, which is why our seastone cup has such a generous curve.
drying slowly
Slab-built pieces need patience while they dry. Cover them loosely with plastic for the first day or two so the whole piece dries at the same rate, paying particular attention to handles and rims, which dry fastest. Flip plates and platters over once they're firm so the base can dry too. Rushing this stage is the main cause of S-shaped cracks in bases and splits at seams.
firing
Once bone dry, pieces go through a first, lower bisque firing, which turns clay into ceramic while keeping it porous enough to take glaze. After glazing, a second, higher glaze firing matures the clay and melts the glaze into a glassy, food-safe surface. Stoneware is typically glaze fired somewhere around 1220 to 1280°C, depending on the clay body.
try it yourself
Slab building is a lovely way to begin with clay because it doesn't need a wheel, just a rolling pin, a few simple tools and some patience. If you'd like to try it with guidance, our mug handbuilding workshop in our studio near Lostwithiel, Cornwall, takes you through the whole process, from rolling your first slab to adding texture and a handle.