Mitek Posi-Joists are now one of the most widely specified floor joist systems for new build residential projects in the UK — and it is easy to understand why. The open metal web design allows plumbers, electricians and heating engineers to run all their services through the floor without drilling or notching the structure, eliminating one of the most common causes of delay and conflict between trades on site.
At Dunscar Timber Engineering, we design and manufacture Mitek Posi-Joist packages from our Bolton workshop. We work from your drawings, design the joist layout and manufacture every joist to the exact lengths your project requires. We supply builders, contractors, developers, architects and structural engineers across Bolton, Greater Manchester, Lancashire and the wider North West.
What Are Posi-Joists?
A Posi-Joist is an engineered floor joist made up of two timber chords — a top and a bottom — connected by a metal web system pressed from galvanised steel. The result is a strong, lightweight floor joist with a series of open triangular spaces running the full length of the beam.
Those open spaces are what make Posi-Joists so useful on site. Unlike solid timber joists, which require drilling or notching to allow services to pass through, Posi-Joists allow pipes, cables, ducting and ductwork to run straight through the floor zone without touching the structural timber at all.
Posi-Joists are manufactured under the Mitek brand to consistent engineering tolerances, and each package is designed specifically for the project — not cut from standard stock lengths.
Where Are Posi-Joists Used?
Posi-Joists are used as the primary floor joist system in a wide range of new build and development projects across the North West, including:
- New build residential houses and bungalows
- Housing developments and multi-plot schemes
- Self-build projects in Greater Manchester and Lancashire
- First floor and intermediate floors in two and three storey properties
- Extensions where longer floor spans are required
- Any project where plumbing, electrics, MVHR or underfloor heating is being run through the floor zone
They are particularly well suited to modern new build construction where multiple trades need to work in the floor zone — exactly the situation where traditional solid timber joists create the most problems on site.
The Services Integration Advantage
The biggest practical benefit of Posi-Joists on a new build is how they handle building services — and it is the main reason builders and developers across Bolton, Greater Manchester and Lancashire specify them as standard.
On a traditional solid timber joist floor, every trade needs to drill or notch through the joists to route their pipes, cables and ductwork. Done within permitted limits this is manageable, but in practice joists are frequently over-drilled, drilled in the wrong location, or weakened by multiple trades working in the same area. This causes structural issues, on-site conflict and — in some cases — costly remedial work.
With Posi-Joists, none of this happens. The open metal web gives every trade a clear route through the floor without touching the structural timber. Drainage pipes, electrical cables, MVHR ductwork and plumbing run side by side through the floor zone without conflict.
The results on site:
- No drilling or notching of structural members
- No weakened joists or structural compromise
- Less conflict between trades working in the floor zone
- Faster installation for plumbers, electricians and heating engineers
- A cleaner, more organised build overall
On a single plot this is a useful time saving. On a multi-plot development , the cumulative saving across every unit is significant.
Posi-Joists vs Traditional Solid Timber Joists
Posi-Joists are not always the right choice for every application, but for new build floor construction in the North West they offer a number of clear advantages over solid timber:
Services routing: Solid timber joists require drilling or notching for all services. Posi-Joists provide an open web that allows free routing without touching the structural timber — eliminating the most common source of on-site conflict between trades.
Span capability: Posi-Joists achieve longer clear spans than solid timber of comparable depth, giving architects and structural engineers more flexibility in floor layout design.
Dimensional consistency: Posi-Joists are engineered products manufactured to consistent tolerances. They are more dimensionally stable than solid timber and less prone to warping, twisting or shrinkage over time.
Weight: Despite their structural performance, Posi-Joists are lightweight and straightforward to handle and install on site.
Design flexibility: Every Posi-Joist layout we produce is designed around your specific floor plan — bearing points, trimmer joists, stairwell openings and cantilevers are all accounted for in the design. You receive a full layout drawing alongside the manufactured joists.
Posi-Joist Designed and Manufactured in Bolton
Every Posi-Joist package we supply is designed and manufactured specifically for the project at our Bolton workshop. As a TRA member and ISO 9001 accredited manufacturer, every package meets the structural and quality standards your project requires.
The process is straightforward:
- Send us your drawings — we work from architectural drawings or floor plans at any stage of the project
- We design the layout — our team produces a full joist layout showing every joist position, length and bearing detail
- We manufacture to length — every joist is cut and manufactured exactly to the dimensions the layout requires
- We deliver to site — packages are delivered direct to site across Bolton, Greater Manchester, Lancashire and the wider North West, clearly marked and ready to install
Because every Posi-Joist package is designed from your specific drawings, there are no standard lengths to work around and no cutting waste on site. Everything arrives ready to go.
Our standard lead time for Posi-Joist packages is 10–15 working days from drawing approval — contact us early on any project where programme is tight.
Need a Posi-Joist quote in Bolton or the North West? Send us your drawings and we’ll come back to you with a free quotation.
Get Involved at Design Stage
One of the most common issues we see on new build projects across Greater Manchester and Lancashire is Posi-Joists being specified late — after the floor layout has already been drawn up, or after the structural engineer has produced calculations based on solid timber.
Getting your joist supplier involved early costs nothing and prevents a significant number of problems:
- The joist layout is designed around your actual floor plan from the start, not adapted afterwards
- Bearing points, trimmer positions and stairwell openings are all resolved before manufacture begins
- Services routes can be planned through the open web spaces before the build starts, avoiding costly clashes on site
- Lead times are managed without last-minute pressure on your programme
If you are at the design stage of a project in Bolton, Bury, Wigan, Preston, Chorley, Blackburn or anywhere across the North West and are considering Posi-Joists, get in touch early. We can work from early-stage drawings and refine the design as the project develops — at no cost until you are ready to proceed.
Supply and Lead Times
We manufacture Posi-Joist packages to order at our Bolton workshop. Our standard lead time is 10–15 working days from drawing approval, with delivery direct to site across Bolton, Bury, Wigan, Preston, Chorley, Blackburn, Manchester, Lancashire and the wider North West. If you are pricing a project and need to understand lead times before committing, contact us early and we can advise.
You Might Also Be Interested In
- Roof Trusses — designed and manufactured in Bolton, delivered across the North West
- Feature Trusses — bespoke oak and glulam trusses for exposed structural applications
- Glulam Beams — bespoke and curved glulam beams supplied from our Bolton workshop
Frequently Asked Questions
What is a Posi-Joist and how does it work?
A Posi-Joist is an engineered floor joist made from two timber chords connected by an open galvanised steel web. The open spaces in the web allow building services — pipes, cables, MVHR ductwork — to pass through the floor without drilling or notching the structural timber. This eliminates the most common source of conflict between trades on new build sites.
What are the advantages of Posi-Joists over solid timber joists?
Posi-Joists allow all building services to run through the floor zone without touching the structure, removing the need for drilling or notching. They also achieve longer spans than solid timber of the same depth, are more dimensionally stable, and come with a full engineered layout designed around your specific floor plan.
How long do Posi-Joists take to manufacture and deliver?
Our standard lead time is 10–15 working days from drawing approval. We manufacture at our Bolton workshop and deliver direct to site across Greater Manchester, Lancashire and the wider North West. Contact us as early as possible on any project where programme is tight.
Do you design the Posi-Joist layout as well as manufacture?
Yes. We design every package from your drawings and produce a full joist layout showing positions, lengths and bearing details before manufacture begins. The joists are then manufactured to exactly those dimensions at our Bolton workshop and delivered ready to install.
Get a Free Quote for Posi-Joists
Working on a new build or development in the North West? Send us your drawings and we’ll provide a free Posi-Joist quotation. We’ll design the layout, confirm sizes and come back to you with everything you need to proceed.
Call us on 01204 301671 Email sales@dunscartimber.co.uk Or use our enquiry form at dunscartimber.co.uk
Dunscar Timber Engineering — Unit 14 Dunscar Business Park, Blackburn Road, Bolton, BL7 9PQ
