What is Jesmonite? The Material Behind ALT Hackney's Homeware

People ask me this fairly regularly, usually after handling something I've made. They'll turn a bowl over, or run a finger along the edge of a dish, and say some version of "so... what actually is this?" It's a fair question. Jesmonite doesn't have the immediate cultural recognition of ceramics or concrete, even though it's been around for decades and is used everywhere from film sets to high-end interiors.

So here's the proper answer. The one I'd give you if you came to the studio and asked over a cup of tea.

Right then — what actually is it?

Jesmonite is a water-based composite material. It has two main parts: an acrylic liquid base and a mineral powder (gypsum-based), which you mix together to create a workable slurry that can be cast, moulded, sculpted, and pigmented in all sorts of ways.

It was developed in the UK in the 1980s by a company called Jesmonite Ltd — so yes, it's actually British, which I've always liked. It was originally created as a more versatile and safer alternative to fibreglass for use in architectural and theatrical applications. Over time, makers and designers cottoned on to its potential for smaller-scale work too, and now you'll find it in everything from jewellery to furniture.

What does it feel like?

This is the bit that's hard to describe without physically putting something in your hand. The closest I can get is: imagine if concrete and resin had a baby, and that baby had better manners. It has real weight to it — it feels substantial in a way that instantly signals quality — but it's also smooth. Not cold like metal or ceramic, but not plasticky either. It sits somewhere in its own category.

"It has real weight to it — it feels substantial in a way that instantly signals quality — but it's also smooth. It sits somewhere in its own category."

The surface can be left quite raw and matte, or sanded back to a smoother, more refined finish. I tend to go for something in between — enough texture to show that it's handmade, smooth enough to feel genuinely lovely to use.

Why do I use it?

Honestly, a lot of it comes down to what it lets me do. I make everything in small batches, by hand, on my own — and Jesmonite suits that way of working really well. Here's why I keep coming back to it:

It's made without nasty chemicals

Unlike resin (which requires solvents and produces fumes), Jesmonite is water-based. I work in a studio, not an industrial facility, so being able to use something that doesn't require heavy-duty ventilation or special disposal is genuinely important to me. It's also significantly lower in VOCs (volatile organic compounds) than most alternatives.

Every batch is genuinely different

When I mix a colour, it's never perfectly identical to the last time. The pigments interact slightly differently depending on the temperature, the ratios, the amount of mixing time — all sorts of small variables. That means every piece has its own character. There are no two pieces exactly alike, which feels right for something handmade. It's a feature, not a flaw.

It takes finishing beautifully

Once cast and cured, Jesmonite can be sanded, sealed, painted, or left as it is. The finishing process is where a lot of my time goes — and it's where the material really rewards patience. A well-finished Jesmonite piece looks and feels genuinely refined, not like something knocked together.

It's durable

People sometimes worry about whether decorative homeware will survive actual life — things being knocked, dust being wiped away, the general chaos of a home. Jesmonite, when properly made and sealed, is robust. It's not indestructible (nothing is), but it's not precious either. You can live with it.

Is it safe to use at home?

Yes. Once cured, Jesmonite is completely inert — there are no ongoing emissions or anything to worry about. It's used in all sorts of settings, including food-adjacent ones (though I'd always recommend checking the specific sealer used if you're planning to use a piece as a food vessel).

All of my pieces are sealed before they leave the studio, which protects the surface and makes them easy to care for. A wipe with a slightly damp cloth is all they need — no special cleaning products, no faff.

Is it sustainable?

This is a question I take seriously, and I'll give you an honest answer rather than a marketing one. Jesmonite is better than many alternatives — it's water-based, lower in harmful emissions, and the finished material is quite long-lasting (which matters, because a thing that lasts is more sustainable than a cheap thing you replace every two years). It's also produced in the UK, which keeps the supply chain shorter.

It's not perfect — no manufactured material is. But it sits in a reasonable place on the spectrum, especially compared to resin-based alternatives, and I feel comfortable using it knowing I've weighed that up.

So — why does any of this matter to you?

When you buy something handmade, I think it's reasonable to want to know what it is and how it was made. Not just because it's interesting (though I think it is), but because it helps you understand what you're actually getting. A Jesmonite piece from ALT Hackney isn't a mass-produced object with a handmade-adjacent story stuck to it. It's something I mixed, poured, finished, and considered — made from a material I've spent real time getting to know.

That's the version I want to be able to give you when you ask "so what actually is this?" A proper answer, not a shrug and a flourish.

If you've got more questions — about the material, the process, or anything else — feel free to get in touch. I'm always happy to talk about how things are made. It's kind of my favourite topic.