• a posi-joist with a white background
  • posi joists installed and ready for a floor covering
  • close up of a posi-joist
  • a building without a roof taken from above
  • posi-joists stacked up in front of a loaded lorry
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Posi-Joist: 421mm Depth

Posi-Joist: 421mm Depth

£53.09
£53.09
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What's included?

All strongback bracing timber is included in the price. If you need restraint straps, please add these separately here.

Disclaimer

Please note, maximum span refers to the total length of the joist including bearings. Posi-Joists ordered here are intended for domestic floors only or flat roofs with a build up weight not exceeding 100kg per m2. They should be spaced at no more than the centres specified, and should not be used as beams or trimmers supporting other elements. For all other requirements, please contact us for a full design and quotation.

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  • Place your order

  • We'll contact you and produce your design

  • Then deliver on a day that suits you

Posi-Joists offer a practical solution for modern construction, blending the lightness of timber with the strength of steel. Their open-web design allows for longer spans, making them perfect for spaces where uninterrupted lengths are needed. The structure also makes it easy to route services like plumbing and electrics, eliminating the need for costly modifications.

How Far Will Posi-Joists Span?

FAQs

Does the span include bearings?

Yes, if your joists are sitting on your bearings, please include these in your span measurement.

How does ordering work?

After you've placed your order, we'll give you a ring to confirm your measurements, delivery location, delivery dates/times and any other essential pieces of information before we begin manufacturing your products. This gives you some time to let us know if anything needs changing before it's too late. Once you're fully happy and have given us the go-ahead, we'll begin manufacturing your joists ready to be delivered for your specified date.

Can I supply more measurements?

Yes—either use the 'order special instructions' box in the basket or send us an email with any specific requirements you may have along with your name and/or order number.

What are your delivery options?

- Fast Track (5 Working Days)
- Standard (2-3 Weeks)

Both are free if you spend over £2000, or £150 if under £2000.

Is bracing timber included?

Yes—all strongback bracing timber is included in the price above.

Do I need a structural engineer?

No, you don't need a structural engineer. We will design the roof truss and provide you with the necessary structural calculations for building control.

Are Posi-Joists treated?

99% of the time Posi-Joists are not treated. Treatment is only necessary if you live in the red marked areas on this map. If you do require treatment, please get in touch.