Trade & Bulk Buyers

Bulk Packer Buying Guide: Which Sizes and Types Do Professionals Use Most?

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Why Trade Buyers Need a Bulk Packer Guide

For installation teams, glazing companies, and window/door fabricators, packers are not a small accessory — they are one of the most heavily used consumables across all jobs.

Trade buyers need to know:

  • Which packer sizes are used most often
  • How many to stock in bulk
  • Which types are essential for daily installs
  • Where mixed sets fit into procurement
  • How to reduce downtime and material waste

This guide reveals the sizes and types that real professionals use most, based on industry standard practice.

The Three Most-Used Packer Sizes (Core Bulk Stock)

Across every installation and fabrication environment, three packer sizes dominate usage:

3 mm Packers – The Workhorse Size

Used in roughly 40% of all installations.

Applications:

  • General spacing
  • Frame alignment
  • Side packing
  • Toe-and-heeling
  • Drainage gap support
  • Door and window glazing

This is the single most important size to stock in bulk.

4 mm Packers – Essential for Levelling

Used in around 25% of installations.

Applications:

  • Levelling uneven sills
  • Balancing out-of-square frames
  • Supporting heavier units
  • Creating consistent reveal gaps

Installers use these daily, so trade buyers should order them in larger quantities.

5 mm Packers – Critical for Toe-and-Heeling

Used in about 20% of installations.

Applications:

  • Toe-and-heel support in side-hung windows
  • Door sash support
  • Major height adjustments
  • Heavy glazing units

This size is especially important for door installers and large window frames.

Together, these three thicknesses account for 85% of all packers used.

Secondary Packer Sizes (Lower Volume but Still Necessary)

You should carry smaller quantities of the following:

1 mm Packers

Used for micro adjustments and fine tuning.

2 mm Packers

Used for small variations in aperture or reveal.

6 mm Packers

Common in door installation, heavy frames, and older properties.

8–10 mm Packers

Used for:

  • Oversized frames
  • Timber installations
  • Levelling larger gaps
  • Structural work
  • Commercial doors

These are purchased less frequently, but vital for certain job types.

Which Types of Packers Should Be Bought in Bulk?

The packer type is just as important as thickness.
Here’s what professionals typically buy in large quantities:

Flat Packers (Primary Bulk Stock)

Used in nearly every installation.

Buy in bulk:

  • 3 mm
  • 4 mm
  • 5 mm
  • 6 mm (for door-focused teams)

Flat packers should make up the majority of your stock.

Bridge Packers (Medium Bulk Stock)

Needed for:

  • Frames with reinforcement screws
  • Fixing points inside glazing chambers
  • Avoiding pressure on screw heads

Trade buyers should buy:

  • 5 mm bridge packers
  • 6 mm bridge packers

Bridge packers prevent glass stress — a major cause of callbacks.

Wedge Packers (Light Bulk Stock)

Used less than flat packers, but critical for:

  • Out-of-square openings
  • Older buildings
  • Precision alignment

Procurement managers should keep:

  • 1–2 boxes of wedge packers
  • Used mainly by installers working on renovations

Where Mixed Assortment Packs Fit Into Bulk Buying

Mixed packs are not a substitute for bulk boxes, but they are still essential.

Mixed sets are perfect for:

  • Unpredictable jobs
  • Properties with uneven cavities
  • Installers who encounter variable gaps
  • Fine adjustments that bulk boxes cannot cover alone

Most professional teams carry:

  • Bulk boxes of the 3 core sizes
  • 2–3 mixed sets for flexibility

This combination gives the best cost efficiency and versatility.

How Many Packers Should a Trade Buyer Stock Monthly?

For companies doing 20–40 windows per month, recommended monthly stock:

  • 3 mm: 1–2 boxes (1,000 each)
  • 4 mm: 1 box
  • 5 mm: 1 box
  • Mixed sets: 1–2 sets
  • Wedge packers: 1 box
  • Bridge packers: 1 box

For larger companies installing 100+ windows per month:

  • 3 mm: 3–5 boxes
  • 4 mm: 2–3 boxes
  • 5 mm: 2–3 boxes
  • Mixed sets: 3–5 sets
  • Wedge packers: 2 boxes
  • Bridge packers: 2–3 boxes

These levels minimise restocking interruptions and avoid downtime.

How Bulk Buying Reduces Material Costs

Buying packers in retail packs is expensive and inefficient.
Bulk purchasing offers:

  • Lower cost per packer
  • Less time spent reordering
  • Reduced trips to merchants
  • Long-term material savings
  • Better onsite organisation

Bulk boxes also ensure consistent thickness — essential for quality control across multiple installations.

Bulk Packers Improve Team Consistency

For companies with multiple installers:

  • Everyone uses the same thicknesses
  • Colour-coded sizes prevent errors
  • Training becomes easier
  • Fewer installation discrepancies
  • Quality control becomes standardised

This leads to fewer callbacks and smoother project delivery.

Final Thoughts

Trade buyers and procurement managers should focus on stocking the packer sizes and types used most by professionals.
The essential bulk sizes are:

  • 3 mm
  • 4 mm
  • 5 mm

Complement these with:

This ensures your installation teams have the correct materials for every job, improves efficiency, and reduces long-term costs.

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