Upholstered Sofa Frames Built to Your Pattern

Bare or sprung frames for sofas, loveseats, sectionals and lounge chairs in kiln-dried hardwood, hardwood plywood or both, built to your pattern and ready to pad and cover.

Send an RFQ What to send

Sofa frames: a loveseat with an exposed wooden frame and arms

Sofa framesAt a glance

Frame types: Solid hardwood, plywood, mixed, knock-down and sectional
Common materials: Poplar, hardwood plywood, rubberwood, beech, radiata pine
Joints: Dowels, glue and staples, corner blocks, bolts
Moisture: 8 to 12 percent at assembly, typical
Supplied as: Bare frames, frames with springs or webbing, KD frame kits

A sofa frame is hidden under foam and fabric, so buyers often judge it last. It still decides how long the sofa lasts. The rails carry the springs, the corner blocks keep the frame square when someone drops onto the seat and the arms take side loads every day. Sofa frame factories cut, join and staple these parts to your pattern. Many also fit sinuous springs or webbing so the frame arrives ready for padding.

Three choices drive the price more than the size of the sofa: solid hardwood versus plywood, glued and stapled versus knock-down construction and whether springs are fitted at the frame plant. Two frames for the same three seat sofa can differ in cost by a wide margin because of these choices, even when the outline is identical.

Species and panels

PoplarLight, straight and holds staples well. The most common hardwood in upholstery frames sold in the US.
PlywoodHardwood plywood for shaped arms, backs and panels. Ask for the grade and the glue type.
RubberwoodStable plantation hardwood. Common for frames with exposed wood parts that also get a finish.
BeechHard and strong. A classic frame wood in Europe, often doweled rather than stapled.
Radiata pinePlantation softwood, low cost and easy to machine. Used for back frames and parts with light loads.
AshStrong and tough. Used where the frame shows, such as exposed arms and legs.

Types of sofa frames

Name the type on the RFQ. Factories that make one type well do not always make the others.

Type	What it is	Fits
Solid hardwood frames	Rails, posts and arm parts cut from kiln-dried lumber, joined with dowels or glue and staples and braced with corner blocks.	Mid and upper price sofas and lounge chairs where buyers ask what the frame is made of.
Plywood frames	Side panels, arm shapes and back profiles CNC routed from hardwood plywood sheets, then stapled and glued to rails.	Shaped arms and curved backs that are hard to cut from lumber. Repeatable in high volume.
Mixed hardwood and plywood frames	Hardwood for the seat rails and spring rails, plywood for arm panels, back shapes and cross members.	Most volume upholstery today. Strength where the load is, lower cost elsewhere.
Knock-down frames	The frame splits into seat, back and arm sections that bolt together with metal brackets or bolts and cross dowels.	Sofas shipped in a box to e-commerce buyers, and sofas that must fit through narrow doors.
Sectional and modular frames	Corner, armless and chaise units with matching rail heights and connector hardware between units.	Sectionals where units are mixed by the buyer. Rail heights must match across every unit.

Typical specifications

Starting points used across the trade. Your drawing sets the real values, and each factory confirms what it can hold on the quote.

Spec	Typical value	Note
Rail stock	About 3/4 to 1 1/4 in (19 to 32 mm) thick hardwood, typical	Front and back seat rails carry the springs. Give their section on the drawing.
Plywood thickness	About 5/8 to 3/4 in (15 to 18 mm) for arm and back panels, typical	State the number of plies and the face species if it matters to you.
Sinuous spring spacing	About 4 to 5 in (100 to 130 mm) on center, typical	Set by the seat comfort you want. Mark clip positions on the rail drawing.
Overall tolerance	About ±2 to ±3 mm on width, depth and height, typical	Tighter on sectional units that must line up side by side.
Moisture content	8 to 12 percent at assembly, typical	Wet lumber shrinks after stapling and loosens joints. Ask for a moisture check at the frame line.
Seat height	About 17 to 19 in (430 to 480 mm) for the finished sofa, typical	The frame height plus spring and cushion. Put the finished target on the drawing.

Typical values, not a guarantee. Confirm every value that matters to you on the quote and the approved sample.

How it is built

Glued and stapledParts are glued and fixed with pneumatic staples, then braced with corner blocks. Fast and stiff when the staples go into solid wood, weaker when they go into plywood edges.
Doweled jointsRails are doweled and glued into the posts, often with corner blocks glued and screwed in each corner. Common on hardwood frames sold with a longer frame warranty.
Corner blocksTriangular or square blocks glued and screwed or stapled inside each seat corner. They stop the frame from racking when the seat takes a sudden load.
Knock-down fittingsMetal brackets, bolts and T-nuts or cross dowels join the sections. Hole positions must match across every frame so any back fits any seat.

Finish options

Bare frameRaw wood, ready for webbing, springs and padding. Most frames ship this way.
Frame with springs or webbingSinuous springs clipped to the seat and back rails, or elastic webbing stapled across the frame. Say which spring gauge and webbing type you use now.
Show-wood finishedExposed arm caps, legs or base rails sanded and finished to a color sample before upholstery. Ask how the finished parts are protected in transit.

How sofa frames are made

The usual process chain, from dried lumber or panels to packed goods. Ask which steps happen in-house and which go out to another plant.

01Kiln dryingFinal moisture content, internal stress and how much the part moves after delivery.
02Rough millingHow much clear wood you pay for, which defects reach your parts and how evenly the color runs.
03Finger jointing and edge gluingJoint strength, water resistance, how visible the joints are and whether panels stay flat.
04Planing and mouldingFinal thickness and width, how square and straight the part is and how much sanding the surface needs.
05CNC routingShape accuracy, hole positions for hardware and how well parts from different batches fit together.
09Joinery and assemblyHow strong and rigid the product is, how square it stands and how it ships.
11Inspection and packingWhether the goods that leave the factory match the order, and whether they arrive in the same condition.

Who orders sofa frames

New models usually start with one or two sample frames that the brand upholsters and tests, then a pilot run of a few dozen frames. Repeat orders run by model and size, and many plants quote per frame with a minimum per model rather than per order.

Upholstered furniture brands

Buy frames for their own models and pad, cover and pack in their own plant. They care about repeat accuracy and frame strength.

Sofa in a box sellers

Need knock-down frames that fit a parcel size carton and assemble with a few bolts. Hole accuracy and carton size decide the margin.

Contract and hospitality suppliers

Need frames for lobby and lounge seating that take heavy daily use, often with a durability test named in the tender.

Rules that may apply

TSCA Title VI applies to hardwood plywood, MDF and particleboard in frames sold in the US
Flammability rules such as California TB 117-2013 or the UK Furniture and Furnishings (Fire) (Safety) Regulations 1988 apply to the finished upholstered product, mainly its covers and fillings, so state the market and who handles them
Lounge and public seating may need a durability test such as ANSI/BIFMA X5.4, so state the standard if you need it
EUDR due diligence for wood placed on the EU market

What to send for a quote

With these points stated, every matched factory quotes the same product.

The frame pattern or drawing with outer size, rail heights and seat depth
A section for each rail and the arm and back shapes
Materials (hardwood, plywood or both) and where each one goes
Joint type (glued and stapled, doweled or knock-down) and where corner blocks go
Springs or webbing: none, sinuous springs or webbing, with gauge and spacing
Quantity per model and size for the first order and the yearly volume

Send an RFQ for sofa frames

What to check on samples

Approve one sample in writing and keep it as the reference for every shipment.

Build and upholster one frame from production parts before the run continues
Square and size of each frame against a jig or template
Moisture content on rails and posts at the frame line
Staple depth and glue on joints, with no staples into plywood edges at load points
Hole positions on knock-down frames with a test assembly from random parts

Where orders go wrong

The problems that cost buyers of sofa frames the most time and money, and how to head them off in the RFQ.

Staples into plywood edges at load pointsStaples pull out of plywood edges under repeated load. Ask for solid wood or corner blocks wherever the seat or arm load enters a joint.
Spring rails without clip positionsIf the drawing does not show where the spring clips go, each plant spaces them differently and the seat feels different between lots. Mark them on the rail drawing.
Knock-down holes drilled by handHand drilled bolt holes make frames that do not swap between units. Ask for holes drilled in a jig or by CNC, and test fit random parts.

Questions about sofa frames

Related guides:

Upholstered Furniture Frames: Wood Species, Joints and Specs to Request
Furniture Joinery Types for Production: Dowel, Mortise and Knock-Down
MDF vs Plywood vs Particleboard: Choosing a Panel for Wood Products

Reference: Wikipedia: Upholstery

Hardwood or plywood sofa frames: which should I order?

Most volume sofas use a mix: hardwood seat and spring rails where the load is, plywood for arms and back shapes. All hardwood frames cost more and are easier to sell on frame strength. Tell us the price point and we match factories that build that type.

Can a factory fit the springs or webbing?

Many frame plants clip sinuous springs or staple webbing before shipping. Send the spring gauge, spacing and webbing type you use now. If you have none, ask for a proposal.

Who gives the frame warranty?

The brand that sells the sofa sets the frame warranty to its customers. Ask the frame plant what it tests, such as a seat drop or racking test, and set your warranty on what the frames pass.

Do sofa frames need a flammability test?

Rules such as California TB 117-2013 and the UK fire safety regulations test the finished upholstered sofa, mainly covers and fillings, not the bare frame. State the market so the full product is planned for it.

Can I get knock-down frames for sofa in a box?

Yes. Say the carton size limit and the tools the end buyer will use. Frames are split into seat, back and arm sections with bolts or brackets. The plant then test fits random parts.

Need sofa frames made to your spec?

Send the drawing, species and quantity. We match you with up to 3 wood manufacturers that make sofa frames and reply within 24 business hours.

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