Boss Design Sia Task Chair

Sustainable ergonomic seating with a recycled mesh back — 70% recycled materials, five mesh styles, four nature-inspired frame colours.

Sia carries the torch for sustainability while softening the workplace with flowing, organic curves, a slim profile and an array of nature-inspired colours. Boss Design drove virgin materials down to just 30%, reduced the component count and assembled the chair without adhesives — so it comes apart as easily as it goes together. The knitted mesh back is woven from SEAQUAL® yarn made from 100% post-consumer recycled plastic recovered from land and sea. The result is a work chair with a lighter look, a lighter footprint, and full ergonomic adjustment developed with FIRA ergonomist Levent Caglar.

Price from

£373.00

£447.60 incl. VAT

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Care information

Fabric Care Instructions

Felt and upholstery should be cleaned with a cloth dampened with water and, if necessary, using mild cleaning agents. Dilute the cleaning agent with water according to the manufacturer’s recommendations and apply it to the soiled areas with a soft sponge or cloth. Do not use agents containing alcohol, acetone, bleach or other solvents. In case of heavy contamination, use mild soap or a special upholstery cleaning agent. Avoid scratching, pressing, or rubbing the cleaned surface to prevent damage to its structure.

Metal Components

Wipe exterior walls and other metal components with a cloth dampened with a mild all-purpose cleaning agent. Do not use agents containing alcohol, acetone or other solvents. After cleaning, wipe all surfaces dry.

Glass

Use a soft, damp cloth to clean the glass. Remove heavier contamination with liquid without ammonia.

System Furniture

Use a soft, dampened cloth for system furniture care. If soiling is heavy, soak the cloth in liquid or a mild furniture cleaning agent. Any whiteboard should be cleaned regularly with a special dry-erase cleaner, at least once a week or more often, depending on how often it is used.

Lighting
Hanging lamps and LED lighting should be wiped with a dry cloth, taking special care to avoid accidental damage or scratching.

Delivery and Shipping

Typically, the lead time for most standard products is 4 to 6 weeks.

If you need your order delivered sooner, please contact our team—we’re committed to doing everything we can to accommodate even the tightest deadlines.

Description

A chair built to leave less behind

Most task chairs are sold on what they add — layers of mechanism, panels of moulding, a component list that runs to three figures. Sia was designed around what could be taken away.

Boss Design started by cutting the component count, then removing the adhesives entirely. Nothing on the chair is glued, which means nothing has to be prised, shredded or landfilled when the chair reaches the end of its working life. Parts unbolt, separate cleanly and go back into their own material streams. Virgin material use across the chair is down to 30% — the other 70% is recycled.

That figure is the headline, but the details behind it matter more to a fit-out specifier. The knitted mesh back is woven from SEAQUAL® yarn, produced from 100% post-consumer recycled plastic waste collected from land and sea. It is available in 32 colour options of recycled yarn across the five mesh styles. The reduced component count lowers the sourcing footprint, where the overwhelming majority of a task chair’s cradle-to-gate carbon is generated.

Ergonomics developed with FIRA

Sia’s adjustment range was developed working closely with ergonomist Levent Caglar at FIRA, and the numbers are genuinely generous for a chair at this level:

Seat height: 120mm of travel (400–510mm) — covers 5th percentile female to 95th percentile male seated postures without a footrest for most users
Seat depth: 80mm of adjustment (400–480mm) — the single most-neglected adjustment on budget task seating, and the one that decides whether a shorter user gets any back support at all
Lumbar height: 100mm of adjustment — the lumbar pad moves to the user, not the other way round
Back lock: 3 positions, plus free recline
Weight-balance mechanism with additional tension adjustment — the chair self-adjusts to the user’s weight on sitting, so recline resistance is broadly right before anyone touches a dial, with a tension control for users at the extremes

That last point is the one worth labouring in a fit-out context. Weight-balance mechanisms exist because most people never adjust their chair. In a 200-desk office, a chair that is ergonomically correct out of the box is worth more than a chair with twelve levers nobody pulls.

Technical Specifications

Back: Recycled knitted mesh, SEAQUAL® yarn (100% post-consumer recycled plastic)
Mesh styles: Runner, Solid, Duo, Fizz, Cloud
Mesh colours: Up to 32 recycled yarn colours (26 in Gabriel Runner; 8 in Solid)
Frame & lumbar colours: Black, Copper Brown, Reed Green, Oyster White
Seat upholstery: Camira Era and other Camira / Kvadrat ranges to order
Base (standard): Black nylon five-star
Base (option): Polished aluminium five-star
Castors (standard): Black
Castors (options): Silver, eco
Arms (standard): Armless
Arms (options): Height-adjustable, 3D Multifunctional with arm pads

Dimensions

Dimensions in mm:

Seat height: 400-510
Seat Depth: 400-480
Back Height: 610
Back Width: 455
Lumbar Width: 255
Armrest Height: 195-295
Armrest Width (Overall): 500
Overall Height: 1010-1120
Overall Width: 705

Five mesh backs, one chair

Sia is a single chassis with five distinct back treatments. They share the same frame, mechanism and adjustment range — the difference is the character of the back and the colour palette open to you.

Runner (SIA/1/RUNNER) — Gabriel Runner mesh, with the widest colour library at 26 options. The choice when the chair has to match an existing fabric scheme or a brand palette exactly.

Solid (SIA/2/SOLID) — single-colour recycled mesh in eight colours. The straightest read of the design; the safest specification for large, uniform floors.

Duo (SIA/3/DUO) — two-tone recycled mesh, one colour front, another behind. Reads as a plain back from the front and a flash of colour from the aisle, which works well in open-plan layouts where the backs of chairs are what people actually see.

Fizz (SIA/4/FIZZ) — the patterned recycled mesh, with a fine speckled texture across the back. The most-specified variant in the UK market and the one most competitors lead with.

Cloud (SIA/5/CLOUD) — textured recycled mesh with a softer, more diffuse surface. The gentlest option visually, suited to quieter task areas and touchdown spaces.

Across all five, the frame and lumbar are available in Black, Copper Brown, Reed Green and Oyster White. The three non-black finishes are what distinguish a Sia floor from a sea of generic mesh seating — Reed Green against a Cloud mesh in a neutral tone is a very different room from black-on-black.

Where Sia works

Sia is a task chair, not an executive chair, and it is specified accordingly:

Open-plan desk banks — the slim profile and low visual mass stop a large floorplate reading as a sea of black plastic
Touchdown and hot-desk areas — the weight-balance mechanism means the chair suits whoever sits in it next
Agile and destination workspaces — the nature-inspired palette is the point; Sia is one of the few task chairs that improves a room rather than disappearing into it
ESG-led fit-outs — where recycled content and end-of-life disassembly have to be evidenced, not just claimed
Meeting and project rooms — armless Sia specified alongside a table works where a boardroom chair would be over-specified

Where it is less suited: 24/7 control rooms and shift environments, where a heavy-duty synchro mechanism and a higher weight rating are the right call. Talk to us about the Boss Design Trinetic or a Sedus alternative for those.

Specifying Sia for a fit-out

For orders of ten or more, a few decisions are worth making before you order:

Arms or no arms. Sia is offered armless, with height-adjustable arms, or with 3D multifunctional arms with pads. For desk-based staff working at fixed-height desks, multifunctional arms earn their cost. For touchdown and meeting positions, armless is usually the better specification and lets chairs tuck fully under the table.

Base finish. The black nylon five-star base is standard. The polished aluminium base is a visual upgrade that reads well in client-facing areas and is worth restricting to those areas rather than applying floor-wide.

Castors. Black castors are standard; silver castors and eco castors are options. Specify hard-floor castors for polished concrete, resin and timber — the standard castor is intended for carpet, and getting this wrong is the most common post-installation complaint on any chair.

Colour strategy. Rather than one colour across the floor, Sia’s four-frame finishes and 32 recycled yarn colours support zoning — Reed Green in collaboration areas, Oyster White in quiet zones, Black at core desking. It costs the same and reads as a considered scheme rather than a bulk purchase.

Furnify has been specifying and supplying commercial office furniture since 2016, across more than 500 installations. If you are building a schedule, send it over and we will price the whole thing — chairs, desks and storage — as one.

FAQs

Is the Boss Design Sia chair actually sustainable, or is it greenwashing?

The claims are specific and measurable, which is the test. Virgin material content is down to 30%, meaning 70% of the chair is recycled material. The mesh back is woven from SEAQUAL® yarn, made from 100% post-consumer recycled plastic recovered from land and sea. The chair contains no adhesives, which is what makes end-of-life separation possible rather than theoretical, and the component count is lower than conventional task seating. Boss Design publishes cradle-to-gate carbon data per configuration.

What is the difference between the five Sia mesh options?

All five share the same frame, mechanism and adjustment range. Runner uses Gabriel Runner mesh with 26 colour options and is the choice for matching an existing scheme. Solid is single-colour recycled mesh in eight colours. Duo is two-tone, with a different colour front and back. Fizz has a fine speckled pattern and is the most widely specified. Cloud has a softer, more diffuse texture. The difference is entirely aesthetic.

How adjustable is the Sia chair?

Sia offers 120mm of seat height adjustment, 80mm of seat depth adjustment and 100mm of lumbar height adjustment, plus a three-position back lock and free recline. The weight-balance mechanism sets recline resistance automatically to the user’s weight, with a tension control for fine adjustment. The adjustment range was developed with ergonomist Levent Caglar at FIRA.

Does the Sia chair come with arms?

Sia is supplied armless as standard. Height-adjustable arms and 3D multifunctional arms with pads are available as options. For fixed-height desking, multifunctional arms are usually worth specifying; for touchdown and meeting positions, armless allows the chair to tuck fully under the table.

What is the lead time on the Boss Design Sia?

Sia is made to order, with a typical lead time of four to five weeks from order confirmation. Larger fit-out orders are scheduled with you so delivery lands against your programme rather than in advance of it.

Is the Sia suitable for 24-hour or shift use?

Sia is designed for standard commercial task use. For 24/7 control room or multi-shift environments, a chair with a heavy-duty synchro mechanism and a higher weight rating is the correct specification — talk to us about the alternatives.

Can I get the Sia in colours other than black?

Yes. The frame and lumbar are available in Black, Copper Brown, Reed Green and Oyster White, and the mesh is available in up to 32 recycled yarn colours, depending on the mesh style. Seat upholstery is specified from the Camira and Kvadrat ranges.

Do you install the Sia chairs?

Yes. Installation, delivery and placement are handled through our installation arm, Installify, across London and the UK. For fit-out volumes this includes unpacking, placement to a floor plan and removal of all packaging for recycling.

Contact Furnify

At Furnify, we specialise in essential office furniture, including acoustic pods, task chairs, desks, storage, and even ping pong tables and other office games for creating a fun space for employees to unwind during breaks.

See how our office furniture solutions can help you make the most of your space and give your team the environment they need to do their best work. Contact us online or call 020 7632 7573 for an informal chat about how our expert team can help.

Boss Design Sia Task Chair

Care information

Delivery and Shipping