Timber floor systems are a key structural component in both residential and commercial construction. Choosing the right system affects not only performance and longevity, but also cost, construction speed, and even energy efficiency. Whether you’re working on a new build or an extension, understanding the various types of timber floor systems and where engineered timber like Metsä’s Finnjoist fits in, can make a significant difference to your project.
What Is a Timber Floor System?
A timber floor system is a structural framework that supports the flooring surface above it. It consists of components such as joists, bearers, and flooring sheets or boards. Timber floor systems are common in houses built on stumps, sloping blocks, or where subfloor ventilation is needed. They’re also used in multi-storey builds and mezzanine levels within warehouses and commercial spaces.
There are a few different types of timber floor systems:
- Conventional solid timber joist systems (e.g. hardwood or softwood)
- I-joists (engineered wood with top and bottom flanges and a web in between)
- Laminated Veneer Lumber (LVL) joists
- Open web floor trusses (e.g. POSI struts)
Each has its advantages depending on the site, span, design needs, and budget.
Why Builders Are Switching to Metsa Finnjoists
At ATS Building Products, we supply Metsä Finnjoist, a modern engineered timber joist that offers superior performance, reliability, and sustainability compared to traditional options.
Key advantages:
- Quieter floors: The design reduces floor creak and bounce
- Cost-effective: Offers lower installed costs due to reduced labour and fewer support points
- Lightweight: Easier and safer to handle on-site
- Slim profiles: Offers more design flexibility in tight builds
- Faster installs: Comes in longer lengths and with consistent quality
A newly available size – 300x63mm, further expands design flexibility for builders. Read more about the new size.
For specs and span tables, refer to the Finnjoist Brochure (PDF).
Key Considerations When Choosing a Timber Floor System
Before selecting a system, consider:
- Span requirements: How far the floor needs to span without intermediate supports.
- Acoustic performance: Is noise transfer an issue (e.g. in multi-storey homes)?
- Speed of installation: Some systems are pre-cut or prefabricated.
- Access to services: Some joists allow for plumbing and electrical to pass through.
- Site conditions: Uneven terrain or moisture-prone areas may limit options.
Finnjoist: Advanced Engineered Timber Flooring
What is Finnjoist?
Finnjoist (FJI) is an advanced engineered timber floor joist, manufactured in King’s Lynn, UK, combining the strength of Kerto® LVL flanges with durable, high-quality OSB webs. This innovative construction provides superior strength-to-weight ratios, allowing for impressive spans up to 12 metres while significantly reducing overall build times.
Key Benefits:
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Lightweight & Strong: Easy handling and quick installation, ideal for speeding up construction schedules.
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High Performance: Certified by third-party accreditations including BM Trada Q-Mark, European Technical Approval (ETA), and CE marking.
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Durability & Treatment: LVL flanges treated with TPAA preservatives (Brands 770 73 H2G or 768 73 H2G), suitable for Hazard Class H2 conditions.
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Reliable Bonding: Structural OSB webs bonded with Type 1 structural glue (EN 301), perfect for service Class 1 and 2 environments.
Finnjoist Sizes:
Finnjoists come in multiple configurations, ensuring versatile solutions for various project needs.
For additional technical details and specifications, visit Metsä Wood’s official Finnjoist page.
Frequently Asked Questions
Key factors include strength, span capacity, moisture resistance, sound insulation, and ease of installation.
Absolutely. With long span capability and high load ratings, Finnjoists are ideal for upper floors in modern homes.
Yes. Pine or LVL is often used for solid timber floor joists in residential settings, though span limits and stability need to be considered.
Engineered timber such as I-joists or LVL products like the Finnjoist are increasingly seen as the best all-round option due to their strength, straightness, and cost-efficiency.
A well-chosen timber floor system makes construction faster, more efficient, and more durable. While traditional options like solid pine still have their place, engineered systems like the Metsa Finnjoist offer compelling advantages. Whether you’re designing for tight spaces or looking for long-term performance, engineered joists deserve a serious look.
Want to explore more? Contact ATS Building Products to discuss options or request specifications.