If you’ve watched an American build video or read a US spec, you’ll have seen the word Sonotube. It’s a brand name, not a product type. In the UK, the same thing is usually called a concrete form tube, column former or cardboard piling tube.
They all do the same job. A strong cardboard tube is stood upright, filled with concrete, and leaves a clean round column or pile once the concrete has set.
This guide covers the sizes available in the UK, what form tubes are used for on site, and how a UK-made tube compares with Sonotube. It’s written for groundworkers, site managers, engineers and self-builders who need round concrete columns without a long wait for imported stock.
What is a concrete form tube?
A concrete form tube is a single-use mould for round concrete columns, piers and piles. It’s made by spiral winding layers of heavy fibreboard around a mandrel and glueing them into a rigid tube.
The spiral winding spreads the pressure of wet concrete evenly along the tube. That stops it bulging, splitting or losing its round shape during the pour. Thicker walls, made from more layers, handle taller pours and larger diameters.
Once the concrete has set, the tube is cut and peeled away. For below-ground piles and void forming, it’s often left in place. There’s no formwork to clean, store or send back.
At Essex Tubes, our cardboard piling tubes are wound in-house in Tilbury from 100% recycled fibreboard. Offcuts and used tubes can go straight into cardboard recycling.
What are concrete form tubes used for?
On UK sites, form tubes are mostly used for foundations and anything that needs a round, smooth concrete column.
- Foundation piles and piers. The tube goes into a bored hole and holds the shape while concrete is poured. It stops loose ground from falling in and keeps the pile a consistent diameter.
- Piles in heave-prone clay. Across the London Clay belt and other shrinkable clays, ground swells and shrinks with moisture. Our heavy-duty piling tubes have a slip coating that lets the clay move past the pile instead of gripping it.
- Round columns above ground. Car parks, canopies, porches, entrance columns and bridge piers. A smooth inner surface leaves a finish that needs little making good.
- Post and sign bases. Fence posts, lamp posts, signage, decking and garden structures.
- Void forming. Smaller tubes cast round holes through slabs and walls for services and drainage. We’ve supplied void formers from 50mm diameter up to 500mm for motorway support posts on the M4.
- Props and set builds. Large tubes are also used for film and theatre sets and shop displays, as columns that look like stone or concrete.
Concrete form tube sizes in the UK
UK form tubes are specified in millimetres by internal diameter, which is the diameter of the finished column. We wind more than 100 diameters from 34mm to 656mm, cut to any length.
Our stock piling tube sizes suit 200mm, 250mm and 300mm bores and go out the next working day to the UK mainland. Other diameters, lengths and wall thicknesses are made to order in 3–5 working days, with no minimum order.
Use the table below to estimate how much concrete each metre of column needs. Figures are the internal volume of the tube, before any allowance for waste or over-break in the bore.
| Internal diameter | Concrete per metre of column |
|---|---|
| 150mm | 0.018 m³ |
| 200mm | 0.031 m³ |
| 250mm | 0.049 m³ |
| 300mm | 0.071 m³ |
| 450mm | 0.159 m³ |
| 600mm | 0.283 m³ |
Internal volume of the tube only. Allow extra for waste and over-break in the bore.
For example, a 2.5m pile in a 300mm tube needs about 0.18 m³ of concrete. For typical prices by diameter, see our piling tube sizes, strength and cost guide.
How UK concrete form tubes compare to Sonotube
Sonotube is a brand of spiral-wound concrete form made by Sonoco, a US packaging company. It’s the best-known name in North America, which is why it turns up in so many guides and videos. The product works the same way as a UK form tube; the differences are mostly sizing, availability and lead time.
| Feature | Sonotube round forms | Essex Tubes concrete form tubes |
|---|---|---|
| Made by | Sonoco (USA) | Essex Tube Windings, Tilbury, Essex |
| Sizing | Imperial: 6" to 36" (about 152–914mm); larger via Sonotube Commercial | Metric: 34mm to 656mm internal diameter, 100+ sizes |
| Lengths | 12ft (about 3.66m) standard; custom on request | Any length, cut to order |
| Distribution | Dealers throughout North America | Made and delivered in the UK |
| Lead time | Depends on importer or stockist | Stock sizes next working day; bespoke in 3–5 working days |
| Minimum order | Set by stockist | No minimum order |
| Wet weather | RainGuard rain-resistant paper | Moisture-resistant coating available |
| Ground heave | Not covered in the round-form literature | Slip-coated heavy-duty piling tubes for shrinkable clay |
| Material | Paper fibre | 100% recycled fibreboard, 100% recyclable |
Sonotube details from Sonoco's Sonotube round concrete forms brochure (2016 edition).
- Metric drawings. UK engineers specify piles and columns in millimetres. A 300mm tube matches a 300mm drawing; a 12″ tube is 305mm, which changes concrete volumes and cover to reinforcement.
- Lead time. A US-made product has to be imported and stocked. A UK-wound tube can be on site the next working day.
- Exact lengths. Ordering to length means less cutting and waste on site than working from 12ft stock lengths.
- Larger diameters. If you need a column wider than 656mm, Sonotube’s range goes bigger. Talk to us first, but that’s where an imported product may be the better fit.
If you’re also weighing up plastic, our cardboard vs plastic piling tubes guide covers cost, strength and waste.
How to choose and order the right form tube
Start from the engineer’s drawing, then check these five things before you order.
- Internal diameter. Order the finished column size. Tell us if your drawing gives an outside diameter instead.
- Length. Allow for the full pour height plus any length that will sit below ground. We cut to length, so you don’t need to buy a long stock length and trim it.
- Wall thickness. Taller pours, larger diameters and faster pour rates push harder on the tube. Thicker walls resist bulging. If you’re not sure, send us the pour height and diameter, and we’ll recommend one.
- Ground and weather. For wet sites or tubes that will stand before the pour, ask for a moisture-resistant coating. For piles in shrinkable clay, ask for slip-coated heavy-duty piling tubes.
- Delivery. Stock sizes go out the next working day. Bespoke tubes take 3–5 working days, so build that into your programme.
On site, stand tubes upright and dry, brace them plumb before the pour, and pour steadily rather than all at once. Strip above-ground tubes once the concrete has set enough to hold its shape, following your engineer’s guidance.
Get UK-made concrete form tubes
We wind every tube in our Tilbury factory, so you deal directly with the people who make it. Send us your diameter, length and quantity, or just your drawing, and we aim to reply within 24 hours.
Browse our cardboard piling tubes or request a quote. You can also call +44 (0) 1375 851613.
In the UK, the same product is usually called a concrete form tube, column former, cardboard piling tube or cardboard concrete form. Sonotube is a US brand name.
Sonotube is made by Sonoco in the US and sold mainly through North American dealers. UK-made form tubes do the same job, in metric sizes, with next-day delivery on stock sizes.
For columns that will be seen, yes. Cut the tube and peel it away once the concrete has set. For below-ground piles and void formers, the tube is often left in place.
Yes, when the wall thickness suits the diameter, pour height and pour rate. Spiral-wound tubes hold their round shape under the pressure of wet concrete. Your engineer sets the structural design; we match the tube to it.
We make more than 100 diameters from 34mm to 656mm, in any length. Tubes for 200mm, 250mm and 300mm bores are held in stock.
Stock sizes are delivered the next working day to the UK mainland. Bespoke sizes take 3–5 working days. There’s no minimum order.