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Posi-Joist: 373mm Depth

Posi-Joist: 373mm Depth

Regular price £39.22
Regular price Sale price £39.22
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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.


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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Posi-Joists combine the lightness of timber with the strength of steel to produce a floor and roof truss system that allows you to span far greater distances than would be possible with alternative timber products. Thanks to their open-web design, services such as plumbing and electrics can be routed through without the need for modification.

Need restraint straps? Add these here!

How does ordering online work?

1. Place your order on our website
2. We'll contact you to confirm your order before manufacturing
3. We'll deliver your products at a time and day that suits you

Can't find what you're looking for? Contact us for a custom design

What is a Posi-Joist?

Put simply, a Posi-Joist is a system of timber and steel webbing that can be used for both floor and roof structures. Each design is unique to suit a chosen project and can be manufactured to a range of different widths, depths and lengths. We’ve drawn this fairly standard house type to demonstrate some of the benefits over traditional timber floors.

Posi-Joists are available in a range of depths to suit your requirements and can achieve greater clear spans than traditional joists, often reducing the need the need for internal load bearing walls. The options include:

PS8: 202mm
PS9: 225mm
PS10: 253mm
PS12: 304mm
PS14: 373mm
PS16: 421mm

Click here to view our Posi-Joist span table.

Posi-Joists are manufactured to suit the size of your building, saving time on site. The standard end detail is suitable for building into walls or can be used with joist hangers where required. The trimmable end detail allows for 130mm of trimming to either end of joists, useful for those projects where the building dimensions may have some variance.

An additional benefit is stairwells and other openings are easily formed. This stairwell opening uses just two joist hangers. The Posi-Joists connecting to the trimmer timber make use a top chord support detail, removing the requirement for joist hangers.

Traditional floor noggins are replaced with a single length of timber, known as strongback bracing, and is threaded through the joists and nailed to each timber post within the Posi-Joist.

When we design your floor, we will take care of all of these details and provide you with fully detailed easy to understand drawings to work from, as well as a fully interactive 3D model—this can be viewed below. Our designs are supplied free of charge with all quotations provided. For simple projects you can also try online ordering.


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 your products treated?

As standard, our products 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.