Posi-Joist prices
What Posi-Joists really cost
Quick answer: On our online shop, a 225mm Posi-Joist costs from £25.37 for a 2m length, and around £46–£48 for a 4m length, excluding VAT. That works out at roughly £11 to £19 per metre, depending on depth, length and joist centres. Longer, deeper joists cost more per metre, but a Posi-Joist floor often costs less overall once you count the time it saves your trades.
This page shows our current online prices, what affects them, a worked floor example, and the hidden savings that don’t show up in a price per metre.
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How pricing works
Why there’s no single price per metre
Every Posi-Joist is made to measure. The price depends on the depth (and the steel web it uses), the length, the joist centres and the loads your floor has to carry. So two joists of the same length can cost different amounts.
On our shop you choose the depth and centres, type in the length and see the price straight away. Each order comes with a design drawing and full structural calculations for building control.
For anything beyond a simple single span (trimmers, stairwells, beams, heavy loads or deeper joists), we design the whole floor for free and price it from your drawings.
Current prices
Posi-Joist prices by length
Prices per joist from shop.hets.uk, excluding VAT (checked 1 November 2026):
| Length | 225mm PS9, 400mm centres | 225mm PS9, 600mm centres | 253mm PS10, 400mm centres | 253mm PS10, 600mm centres |
|---|---|---|---|---|
| 2.0m | £26.24 | £25.37 | £27.82 | £27.82 |
| 3.0m | £39.79 | £38.47 | £42.29 | £42.29 |
| 4.0m | £47.31 | £45.73 | £50.07 | £50.07 |
| 5.0m | £72.36 | £86.23 | £63.46 | £71.00 |
| Longest online | £99.02 (5.7m) | £86.40 (5.1m) | £113.30 (6.1m) | £101.21 (5.4m) |
Prices are for standard square ends. 130mm trimmable ends add £2.00 per end. Prices can change; the shop always shows the current price.
Joists approaching their maximum span need heavier timber, so the price per metre rises at the top of each range. A deeper joist at the same length can sometimes cost less. Deeper joists (304mm, 373mm and 421mm) are priced by quote with a free design.
Worked example
What does a Posi-Joist floor cost?
Example: a 4.0m x 5.0m room (20m²), with 4.0m joists running across the 5.0m width. Number of joists = width ÷ centres, rounded up, plus one.
| 225mm PS9 at 400mm centres | 225mm PS9 at 600mm centres | |
|---|---|---|
| Joists needed | 14 | 10 |
| Joist cost (ex VAT) | £662.34 | £457.30 |
| Cost per m² of floor | about £33 | about £23 |
Add hangers, restraint straps and strongbacks, any trimmable ends, delivery and VAT. Local zone joist delivery is £350 plus 1% of the order (max £50 extra), or collect free from Swanmore. Whether 600mm centres work for your floor depends on the loads and floor deck, which we confirm in your design.
Cost factors
What affects the cost of Posi-Joists?
- Span: longer joists cost more, and the price per metre rises as a joist nears its maximum span.
- Depth: 225mm and 253mm joists are the most economical; deeper joists span further and suit bigger rooms.
- Joist centres: 600mm centres need fewer joists than 400mm, if the design allows.
- Loads: heavy tiles, screed, underfloor heating, partitions or a gym or office floor need a stronger design.
- Deflection: we design to the NHBC 12mm limit as standard, or tighter if you ask; a stiffer floor can cost more.
- End details: trimmable ends (up to 130mm each end) add a small cost but save time on site.
- Metalwork: hangers, straps and strongbacks are part of the floor and need budgeting for.
- Delivery and lead time: delivery depends on your zone; 5-day and 48-hour services cost extra.
Hidden savings
The savings you don’t see in the price per metre
Posi-Joists can cost more per metre than solid timber or I-joists. The real saving comes once the floor is down and your trades move in.
- First fix runs straight through: plumbers, electricians and ventilation installers pass pipes, cables and ducts through the open web. No notching, no drilling and no checking hole limits.
- Big services stay in the floor: 110mm soil pipes and 75–90mm MVHR ducts fit inside the floor zone, so there are no bulkheads, boxing-in or dropped ceilings to build and finish.
- Quicker second fix: flat ceilings and wide 72–147mm flanges give plasterers and floor fitters a bigger fixing surface.
- Less cutting and setting out: joists arrive made to length and labelled for top, left and right ends, so carpenters fit them rather than cut them.
- Fewer joists, walls and beams: longer spans can allow wider centres and remove internal load-bearing walls.
- Planned before it arrives: the free 3D model lets your trades agree service routes before installation, cutting clashes and return visits.
- No separate joist design fee: design and calcs for building control are free with every quote.
The full picture
Delivery, metalwork and lead times
- Joist delivery (Local zone, most of the south): £350 + 1% of the order (max £50 extra). Medium zone £400, Long zone £700.
- Fast Track (5 day) delivery: £500 / £600 / £1,000 by zone. Express (48 hour): £650 / £800 / £1,500.
- Metalwork and fixings: free standard delivery on orders over £200, next day £40.
- Collection: free from Hill Farm Yard, Swanmore, by arrangement.
- Lead time: 15–20 days from design approval as standard.
- Prices: online prices exclude VAT; every design quote includes the exact delivery cost for your site.
FAQs
Posi-Joist cost questions
How much does a Posi-Joist cost per metre?
On our online shop, 225mm and 253mm Posi-Joists cost roughly £11 to £19 per metre, excluding VAT. The rate depends on depth, length and joist centres, and rises as a joist nears its maximum span.
Are Posi-Joists more expensive than solid timber or I-joists?
They can cost more per metre. A whole Posi-Joist floor often works out cheaper because it needs fewer joists and internal walls, and services run through without notching, drilling or boxing-in.
How many Posi-Joists do I need?
Divide the width of the floor by the joist centres, round up and add one. A 5m wide room needs 14 joists at 400mm centres or 10 at 600mm centres. Your design confirms the exact layout.
Is the design included in the price?
Yes. Online orders include a design drawing and structural calculations. For full floors, our design and calcs are free with every quote.
Do the prices include VAT and delivery?
No. Online prices exclude VAT, and delivery is added at checkout. Local zone joist delivery is £350 plus 1% of the order, or you can collect free from Swanmore.
Can I buy Posi-Joists online?
Yes. 225mm and 253mm Posi-Joists at 400mm or 600mm centres are sold cut to length at shop.hets.uk. For deeper joists or full floors, send us your drawings for a free design and quote.