Metal Web Joists
The Ultimate Engineered Flooring & Roofing Solution
Upgrade your build with Calldene Metal Web Joists—the superior hybrid structural system that combines the lightness of timber with the strength of steel webs. Also known as Posi-Joists, these engineered components are designed to outperform traditional solid timber by offering longer spans, simpler service integration, and rock-solid stability.
Whether for a residential extension, a new build housing development, or a commercial flat roof, our metal web joists deliver speed, safety, and cost-efficiency to your project.
Why Choose Metal Web Joists?
The “Posi-Joist” system effectively eliminates the most common headaches associated with floor and roof construction.
- Unmatched Service Integration (Open-Web Design): The defining feature of the metal web joist is its open steel web structure. This provides complete freedom for routing services without the need for drilling, notching, or structural modification.
- Easy Routing: Run electrical wiring, plumbing, and HVAC ducting freely through the void.
- MVHR Ready: Ideal for modern mechanical ventilation and heat recovery systems (MVHR) which require large diameter 100mm+ ducting.
- Zero Mistakes: eliminates the risk of tradesmen drilling in the wrong place and weakening the joist.
- Superior Spans & Design Flexibility: Metal web joists can span significantly longer distances than solid timber or I-joists of the same depth.
- Open Plan Living: Achieve large open-plan rooms without the need for intermediate load-bearing walls or expensive heavy steel beams.
- Design Freedom: versatile sizes allow for creative architectural layouts in both floors and roofs.
- Lightweight & Safe Handling: Weighing up to 40% less than equivalent solid timber joists, these units are easier to maneuver on-site.
- Reduced Crane Use: Often light enough to be man-handled, saving on plant hire costs.
- Health & Safety: lighter loads reduce the risk of lifting injuries for site personnel.
- Dimensional Stability (No Squeaks): Unlike solid timber, which creates “bounce” and shrinks over time causing creaky floors, metal web joists are precision-engineered to be dimensionally stable.
- No Shrinkage: The minimal timber content and metal web design virtually eliminate shrinkage (typically less than 1mm).
- Silent Floors: A rigid, stable platform means no more call-backs for squeaking floorboards.
- Easy Fixing: A wide top and bottom chord (min 72mm) gives carpenters a generous area for fixing flooring and plasterboard.
The Calldene Advantage
We don’t just supply products; we provide structural solutions. As a specialist manufacturer, we oversee every stage of the process.
- Precision Engineering: Every joist is designed using advanced software to ensure it meets exact load and span requirements.
- Fast Lead Times: Our efficient manufacturing process ensures your joists arrive when you need them, preventing site delays.
- Full Design Support: Our in-house technical team provides full layout drawings and calculations.
- Installation Services: We offer a complete supply-and-fit service if required, handled by our experienced installation teams.
Frequently Asked Questions:
Q: Can I cut metal web joists on site?
A: Generally, no. The span and web positions are engineered specifically for your project. However, we can design “trimmable ends” into the joist (allowing up to 130mm of trimming) to accommodate inconsistent site measurements.
Q: Are they suitable for flat roofs?
A: Yes, they are excellent for flat roofs. We can even design them with a built-in “fall” to ensure proper water drainage without the need for firring strips.
Q: How do they compare in cost to standard timber joists?
A: While the unit cost per joist may be slightly higher, the installed cost is often lower. You use fewer joists (due to wider spacing), save hours on electrical/plumbing labor, and eliminate the cost of hiring heavy lifting equipment.
Ready to get your project moving?
Get a fast, competitive quote for your Posi-Joists today. Contact us here.
0207 046 0971
Building 1063 Cornforth Drive, Kent Science Park, Sittingbourne, Kent, United Kingdom, ME9 8PX
Dover Trussed Roof Company and Triad Timber Components are Calldene companies.