Tension Springs

Upholstery Tension Springs for Sofa Seats and Backs

Shop upholstery tension springs and replacement fixing plates for repairing sprung sofa seats, chair seats, furniture backs and suitable traditional furniture.

Livedale supplies two types of furniture extension spring:

• Lighter 18-gauge back tension springs
• Stronger plastic-covered 14-gauge seat tension springs

The range also includes a replacement nine-hole side fixing plate used to position and secure compatible springs.

These products are commonly known as:

• Upholstery tension springs
• Furniture extension springs
• Sofa seat springs
• Chair seat springs
• Sofa back springs
• Chair back springs
• Stretch springs
• Replacement furniture springs
• Parker Knoll-style tension springs

The correct spring depends on its intended position, wire gauge, unstretched length, fixing arrangement and the amount of tension required once installed.

Shop Furniture Seat and Back Tension Springs

18-Gauge Upholstery Back Tension Springs – 36cm to 46cm

The 18-Gauge Upholstery Back Tension Springs – 36cm to 46cm are lighter and softer than the plastic-covered 14-gauge seat springs.

They are commonly used in suitable sprung furniture backs, including some Parker Knoll furniture.

Available spring lengths include:

• 36cm
• 38cm
• 40cm
• 42cm
• 44cm
• 46cm

The stated measurement refers to the coiled spring section only. Each end also has a hook measuring approximately ½″.

These replacement upholstery back springs should normally be extended by approximately ½″–1″ when fitted between suitable fixing points.

Potential applications include:

• Sprung armchair backs
• Sofa backs
• Lounge-chair backs
• Traditional furniture repairs
• Replacement Parker Knoll-style back springs
• Furniture originally constructed with extension springs

The lighter 18-gauge wire allows the spring to respond more easily to pressure than the heavier 14-gauge seat spring.

A back spring should not be used as a replacement seat spring solely because the overall length matches.

14-Gauge Plastic-Covered Upholstery Seat Tension Springs – 34cm to 46cm

The 14-Gauge Plastic-Covered Upholstery Seat Tension Springs – 34cm to 46cm are designed for suitable sprung furniture seats.

Available spring lengths include:

• 34cm
• 36cm
• 38cm
• 40cm
• 42cm
• 44cm
• 46cm

The stated length refers to the coiled section of the spring and excludes the hooks. Each hook measures approximately ½″.

These springs should normally be extended by approximately ½″–1″ when installed.

The plastic sleeve helps separate the seat cushion and upholstery layers from the bare metal spring, reducing direct rubbing against the wire.

Potential applications include:

• Sprung armchair seats
• Sofa seats
• Lounge chairs
• Traditional furniture repairs
• Replacement Parker Knoll-style seat springs
• Furniture originally fitted with plastic-covered extension springs

The 14-gauge construction provides greater resistance than the lighter 18-gauge back spring and is more appropriate for seat applications carrying direct body weight.

17″ Nine-Hole Upholstery Tension Spring Fixing Plate

The 17″ Nine-Hole Upholstery Tension Spring Fixing Plate is a replacement side plate for compatible seat and back tension-spring systems.

The plate measures:

• 17″ long
• Nine spring-fixing holes

The multiple holes allow compatible tension springs to be positioned along the side of a suitable furniture frame.

This type of plate may be used when:

• An original fixing plate is damaged
• Existing spring holes are worn
• A complete furniture spring system is being restored
• Compatible seat or back springs need secure fixing points
• A traditional chair or sofa is being rebuilt using an existing tension-spring arrangement

Before ordering, compare the replacement plate with the original component and check:

• Overall length
• Number of holes
• Hole spacing
• Hole diameter
• Plate position
• Frame-fixing arrangement
• Number of springs required

The spring plate must be secured to sound furniture-frame timber before the springs are placed under tension.

Seat Tension Springs and Back Tension Springs

Seat and back tension springs may look similar, but they are designed for different levels of support.

Upholstery Seat Springs

Seat springs carry direct body weight and generally require stronger resistance.

The 14-gauge plastic-covered tension springs are intended for suitable furniture seats and provide firmer support than the lighter back-spring range.

The plastic covering also helps protect the cushion and surrounding upholstery from rubbing directly against the metal wire.

Upholstery Back Springs

Furniture backs normally require a softer response and less resistance than seat bases.

The 18-gauge tension springs flex more easily and are intended for suitable sprung chair and sofa backs.

Do not select a spring according to length alone. The wire gauge and intended furniture position must also match the original construction.

Choosing the Correct Replacement Furniture Spring

Before ordering replacement sofa or chair tension springs:

1. Identify whether the spring is fitted in the seat or back.
2. Measure the coiled section without stretching it.
3. Exclude the hooks from the spring-length measurement.
4. Check the wire gauge where possible.
5. Record the hook shape at both ends.
6. Measure the distance between the fixing points.
7. Count the number of springs.
8. Measure the spacing between neighbouring springs.
9. Inspect the fixing plates.
10. Compare an undamaged original spring where possible.

Matching the original spring type, gauge and length is normally the safest starting point.

Do not order a longer or shorter spring simply to compensate for damaged fixing plates or an altered furniture frame.

Measuring Upholstery Tension Springs

Measure the spring while it is relaxed and removed from tension wherever possible.

Record:

• Length of the coiled section
• Length of each hook
• Coil diameter
• Wire diameter or gauge
• Hook direction
• Distance between fixing points
• Amount of extension when fitted

The product lengths on this page refer to the spring section and do not include the approximate ½″ hook at either end.

The installed spring should normally be stretched by approximately ½″–1″ beyond its relaxed spring length.

A spring fitted with too little extension may not provide adequate support. Excessive extension may overload the spring, fixing plate or furniture frame.

Choosing Between 14-Gauge and 18-Gauge Springs

A lower gauge number indicates thicker wire.

The 14-gauge seat spring is therefore thicker and firmer than the 18-gauge back spring.

Choose a 14-gauge plastic-covered spring where:

• The original spring was fitted beneath a seat
• Firmer resistance is required
• The existing spring has a protective plastic sleeve
• The furniture uses compatible seat fixing plates

Choose an 18-gauge spring where:

• The original spring was fitted in a furniture back
• A softer and more flexible response is required
• The existing back construction uses lighter extension springs

The two ranges should not be treated as interchangeable.

Replacement Parker Knoll-Style Springs

Tension springs are commonly associated with suitable Parker Knoll chairs and other furniture constructed with extension-spring seat and back systems.

Before ordering springs for Parker Knoll furniture, check the actual spring measurements and construction rather than relying only on the furniture brand or model description.

Different items may use:

• Different spring lengths
• Different wire gauges
• Seat and back springs within the same chair
• Different fixing plates
• Different numbers of springs
• Replacement components fitted during earlier repairs

Use an intact original spring and plate as the main reference wherever possible.

Installing Upholstery Extension Springs

A tension spring works by extending between two secure fixing points.

A typical installation may involve:

1. Removing the cushion and upholstery layers.
2. Photographing the original spring arrangement.
3. Checking the furniture frame.
4. Inspecting the side fixing plates.
5. Removing the damaged spring safely.
6. Matching the replacement length and gauge.
7. Connecting one hook to the fixing point.
8. Extending the spring carefully.
9. Securing the opposite hook.
10. Checking alignment and tension.

The spring should sit in the same orientation as the original and should not rub against sharp timber, loose metalwork or unsuitable fixings.

Inspecting the Fixing Plates

The fixing plate carries the load transferred by the tension springs.

Before fitting replacement springs, inspect it for:

• Distortion
• Cracks
• Enlarged holes
• Corrosion
• Loose frame fixings
• Sharp edges
• Previous modifications

Also inspect the furniture timber behind the plate.

A new spring should not be placed under tension if the fixing plate or supporting frame is loose or damaged.

Where the plate requires replacement, the 17″ Nine-Hole Upholstery Tension Spring Fixing Plate provides a compatible-style option for suitable furniture systems.

Upholstery Layers Around Seat Tension Springs

Plastic-covered seat springs are designed to help protect the cushion from rubbing directly against bare spring wire.

The complete furniture construction may also include:

• Hessian
• Felt
• Platform cloth
• Polyester wadding
• Foam cushions
• Fibre cushions
• Upholstery fabric

Browse:

• Upholstery Hessian
• Upholstery Felts
• Platform & Base Cloth
• Polyester Wadding
• Foam & Fillings

Replace damaged protective layers before returning the cushion to the frame.

Tension Springs or Zigzag Springs?

Tension springs extend between fixing points and generally have hooks at both ends.

Zigzag, sinuous or serpentine springs use a continuous curved-wire shape and are normally retained by frame clips.

Choose upholstery tension springs where:

• The original furniture used hooked extension springs
• The springs connect to side fixing plates
• A Parker Knoll-style seat or back system is being repaired
• The replacement matches the original gauge and length

Choose Zigzag, Sinuous & Serpentine Upholstery Springs where:

• The original furniture used curved-wire springs
• The springs are retained by frame clips
• There are no hooked ends
• The furniture uses bracewire or connecting clips

The two spring systems should not normally be interchanged without redesigning the furniture support structure.

Return to Upholstery Springs to compare the available furniture spring systems.

Safe Removal and Installation

Tension springs store energy while stretched and can move suddenly when released.

Wear suitable eye and hand protection and keep the furniture frame stable.

Take care when:

• Unhooking old springs
• Stretching replacement springs
• Working near damaged hooks
• Removing fixing plates
• Handling corroded wire
• Working around old staples and nails
• Fitting springs under tension

Keep hands and face away from the expected path of a released spring.

Do not install a spring with:

• Damaged hooks
• Severe corrosion
• Distorted coils
• Cracked plastic covering
• An incorrect gauge
• An unsuitable length

For suitable gripping and stretching tools, browse Upholstery Pliers, Stretchers & Pincers.

Trade Upholstery Tension Springs

Livedale supplies furniture tension springs, replacement sofa and chair springs and compatible fixing plates to professional upholsterers, furniture repairers, manufacturers and training workshops throughout the UK.

The range includes lighter 18-gauge back springs, stronger plastic-covered 14-gauge seat springs and replacement nine-hole fixing plates.

Approved trade customers can access preferential pricing across eligible products after registering for a trade account.

Measure the relaxed spring section, identify the correct gauge and inspect the complete fixing system before ordering.