Choosing the right seating isn’t just about filling a classroom — it’s about ergonomics, durability, and finding a solution that can survive decades of use. The Postura Plus Chair is one of the most widely used classroom chairs in the UK, engineered specifically to enhance student concentration and wellbeing.
1. Why Postura+? The Science of Sitting
Postura chairs were the first one-piece polypropylene chairs designed specifically for educational environments, and the design has continued to evolve since. Here’s what makes them stand out:
- Ergonomic Support: A “waterfall” seat edge reduces pressure on the thighs, while a flexible backrest provides dynamic comfort throughout the school day.
- Anti-Rocking Stability: The chair’s geometry — specifically its wide legs — prevents tipping, an important safety feature in busy classrooms with younger pupils.
- Anti-Static Design: Reduces static charge build-up, important in IT suites and science labs where electronic equipment is in use.
- Ventilation: Extra-large lower back ventilation panels help keep students comfortable during extended seated periods.
- Extreme Durability: Polypropylene shells are backed by a 20-year warranty, making this a long-term investment for any school estate.
2. Getting the Size Right — The “Perfect Fit”
Using the correct chair height is essential to reduce back pain and repetitive strain injury (RSI). Each Postura+ chair features a colour-coded sticker on the backrest, allowing staff to identify the correct size at a glance without consulting a spec sheet.
The table below covers all six sizes across the full age range, from nursery through to adult use:
| Size Mark | Age Range | Seat Height | Table Height | Max User Weight |
|---|---|---|---|---|
| Size 1 | 3–4 Years | 260mm | 460mm | 130kg |
| Size 2 | 4–6 Years | 310mm | 530mm | 160kg |
| Size 3 | 7–9 Years | 350mm | 590mm | 160kg |
| Size 4 | 9–11 Years | 380mm | 640mm | 204kg |
| Size 5 | 11–14 Years | 430mm | 710mm | 204kg |
| Size 6 | 14+ / Adult | 460mm | 760mm | 204kg |
Also, check that your existing desk heights align with the recommended table heights in the table above. Mismatched chair and desk heights are a common and easily avoided source of poor posture.
3. NEW to the Range — The One-Piece Stool
The Postura+ range has expanded to include the Postura+ One-Piece Stool, designed for specialist teaching environments such as science labs, art studios, and workshop spaces where standard desk chairs are impractical.
- Stackable: Sled-base design allows stacking up to 6 high for efficient storage when rooms need to be cleared.
- Lumbar Support: Features an integrated wide foot rail and a curved backrest — unusual at this price point for a lab stool — providing meaningful support during extended practical sessions.
- Two Versions: Available in low-back and high-back configurations to suit different bench heights and user preferences.
The stool is available in three seat heights:
| Version | Available Seat Heights | Seat Height | Table Height | Max User Weight |
|---|---|---|---|---|
| Low-back | 560mm · 610mm · 685mm | 260mm | 460mm | 130kg |
| High-back | 560mm · 610mm · 685mm | 310mm | 530mm | 160kg |
| Size 3 | 7–9 Years | 350mm | 590mm | 160kg |
| Size 4 | 9–11 Years | 380mm | 640mm | 204kg |
| Size 5 | 11–14 Years | 430mm | 710mm | 204kg |
| Size 6 | 14+ / Adult | 460mm | 760mm | 204kg |
4. Sustainability — Leading the Way
Postura+ is designed to help schools reduce their environmental impact without compromising on quality or longevity:
- Recycled Content: Standard one-piece chairs contain at least 30% recycled polypropylene.
- 100% Recycled Models: Jet Black chairs are manufactured entirely from recycled polypropylene — a strong choice for schools with sustainability reporting commitments.
- Circular Economy: All shells, steel frames, and glides are 100% recyclable at end of life.
- Healthy Indoor Air: Certified for low VOC emissions (Indoor Advantage Gold™), supporting good air quality in enclosed classroom environments.
5. Final Checklist for Buyers
Before placing your order with OSI School Furniture, work through this checklist to make sure everything is in order:
- Confirm Table Heights — Check that your existing desks align with the EN chair size marks using the table in Section 2. Ordering chairs without checking desk compatibility is one of the most common purchasing mistakes.
- Choose Your Colours — Select from 20+ standard colours. Custom Pantone/RAL colour matching is available for orders over 300 units.
- Consider Your Wider Range — For IT suites and flexible learning spaces, Postura+ is also available on 4-leg castors and as a Task Chair variant. These are worth considering alongside standard classroom chairs when equipping different types of rooms.
- Plan for Lead Times — If you’re fitting out ahead of a new academic year, factor in summer delivery windows. Getting your order in early significantly reduces the risk of delays.
- Check Upholstery Options — Seat pads are available across the range, with the exception of Size 1 and Size 2 chairs. A minimum order of four pads applies.
Ready to Upgrade Your Classrooms?
Finding the right chair for every learner starts with the right conversation. The team at OSI School Furniture works with schools of all sizes — from single-classroom upgrades to full-estate refits — to ensure every seat is the right fit. Get in touch today for a free consultation and sizing recommendation.
Postura+ Chairs FAQs
Pricing varies by model and configuration. As a guide, standard Postura+ one-piece chairs start from £26.50 ex. VAT, with most sizes falling in the £26.50–£34.80 range. Specialist variants are priced accordingly — castored and swivel options sit in the £65–£82 range ex. VAT, and the new One-Piece Stools start from around £56 ex. VAT.
A full breakdown of current prices by model (correct as of 20 February 2026):
Model | Price (ex. VAT) |
Postura+ One-Piece Chair | £26.50 – £34.80 |
Postura+ One-Piece Low Back Stool | £57.20 – £59.60 |
Postura+ One-Piece High Back Stool | £55.90 – £59.60 |
Postura+ Stool | £61.40 – £63.40 |
Postura+ High Chair | £74.90 – £80.40 |
Postura+ 4-Leg on Castors | £65.00 |
Postura+ Poly Swivel Chair | £78.90 |
Postura+ Low Task Chair | £81.90 |
Yes. Most schools order across multiple sizes — particularly when supplying a range of year groups. There is no requirement to order a single size, and OSI can help you calculate the right split based on your pupil age ranges.
There is no minimum order quantity* for standard chairs. Custom Pantone/RAL colour matching requires a minimum of 300 units. Seat pad orders require a minimum of four. *carriage charges may apply for small quantities.
Standard colours typically ship within 7–10 working days. Custom colour orders require additional lead time — speak to your account manager for a confirmed timeline. If you're planning for a September start, we recommend placing orders before the end of June to avoid the summer backlog.
Postura+ Task Chair variants and castored options offer additional flexibility for pupils who benefit from movement or adjustable seating. For pupils with more specific physical or sensory needs, we recommend consulting an occupational therapist before ordering. OSI can advise on which products are most commonly specified in SEND environments.
Polypropylene shells can be wiped down with most standard school cleaning products. Avoid abrasive cleaners or solvents, which can degrade the surface over time. Glides & castors are replaceable — contact OSI if you need replacement parts.
The warranty covers manufacturing defects in the polypropylene shell. If a chair fails under normal use within the warranty period, OSI will arrange a replacement. Claims are handled directly through your OSI account manager, so there's no need to contact the manufacturer yourself
Yes. OSI supplies through a number of public sector procurement frameworks, which can simplify the purchasing process for schools and academies that are required to procure through approved routes. Contact us to confirm which frameworks are currently active.
Source: KI Europe, Postura+ Collection Brochure 2026 v4, February 2025.
