Glazing Packers – Size & Colour Guide

A quick, trade-first reference for glazing packer thicknesses (mm), colour coding, typical uses and compatibility. Colours follow common UK trade convention—always check the product page for any exceptions.

Quick legend

1 mm = Green 2 mm = Black 3 mm = White 4 mm = Grey 5 mm = Blue 6 mm = Red

Thickness (mm)	Colour	Typical use	Common pack type	Notes
1	Green	Fine levelling, anti-racking adjustments, tight tolerances.	Flat Frame	General levelling; very common in window installs. Use to take up minimal gaps without lifting sightlines.
2	Black	General levelling; very common in window installs. General levelling; very common in window installs.	Flat Frame Wedge	Good “everyday” thickness for most sets and sills.
5	Blue	Support under heavier members; spanning small voids.	Flat Bridge	Popular with bridge packers to maintain drainage paths.
6	Red	Larger corrections; sill and transom setting.	Flat Bridge	Avoid over-packing transoms; keep frame true and plumb.
3	Varies — see product page	Intermediate shimming where 2 mm is light and 5 mm is high.	Flat Bridge	Check colour mapping on the specific product listing.
4	Varies — see product page	Intermediate shimming; frame alignment and anti-rattle.	Flat Bridge	Bridge versions available for weep/slot spanning.

Which pack for which job?

Flat Packers

General levelling and support under frames and units.

Bridge Packers

Span drainage/weep slots so water paths stay clear.

Wedge Packers

Fine adjustment and anti-rattle support for secure, accurate fitting in tight areas.

Compatibility & notes

Suitable for uPVC and aluminium frames.
Typical sizing tolerance: ±0.2 mm (size-dependent).
Colour usually = thickness (see table/legend); mixed boxes available.

Recommended mixes

Window install (uPVC): 1 / 2 / 5 / 6 mm assortment.
Service van stock: mixed box + extra 2 mm blacks.
Commercial glazing: include bridge 5–6 mm for drainage spans.

Reading colours on site

Check the face: use clean, natural light to confirm colour.
Avoid dirt misreads: wipe surfaces; colour should be even.
When in doubt: confirm with a thickness gauge or caliper.

FAQs

Do colours always equal the same thickness?

In most UK trade ranges, yes (e.g., 1 mm Green, 2 mm Black, 5 mm Blue, 6 mm Red). Always check the product page for any exceptions.

Are packers re-usable?

They’re durable and can often be reused if undamaged. For critical installs, we recommend new stock for consistency.

Which sizes are best for aluminium?

Aluminium frames commonly use 1–2 mm for fine set-out and 5–6 mm for bearing under sills and transoms.

What if I need 3 mm or 4 mm?

We stock intermediate sizes in selected ranges. Colour may vary—see the specific product listing.

How many boxes for a 10-window job?

It depends on frame style and openings, but a common mix is 1× mixed box + 1× extra 2 mm and 1× 5 mm. Add bridge packers if spanning drainage.

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