HDPE Shims: Packing and Levelling Plates for Equipment and Structures

30 October, 2026 | Admin

Short answer: Shims are thin plates placed under
equipment, plates or structural members to level them, fill small gaps
and adjust height. HDPE shims are made from high-density polyethylene,
so they do not rust, are light, resist moisture and many chemicals, and
are easy to cut to size. Choose the thickness and size for the load and
gap, and use steel shims where load is very high.

This guide covers HDPE shims. HDPE sheets and rods, UHMWPE pads and
UHMWPE fender are different products.

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Plastic weight calculator — Work out the weight of HDPE Shims sheets, rods and tubes in kg
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Table of Contents

What shims are for

Surfaces are never perfectly flat or level. When you install a pump
base, a machine, a bridge bearing or a steel member, small gaps remain.
Shims fill those gaps so load is carried evenly and the equipment sits
level and aligned. Without shims, bolts can pull parts out of true and
stress the structure.

Why HDPE shims

they do not corrode, so they are good in wet, humid or chemical
areas
they are light and easy to handle
they are non-conductive, which helps where isolation is needed
they are easy to cut or drill on site
they can also help with some vibration and noise

Limits

HDPE is a plastic, so it compresses and creeps under very high,
sustained loads. For heavily loaded machine bases, steel shims may be
required. Check the allowable compressive load for the material and the
project specification before using plastic shims on structural loads.
Heat also softens HDPE, so avoid hot locations.

Choosing thickness and size

Gap: measure the gap you need to fill.
Load: know the load on each shim and make sure the
shim area is large enough.
Size: cover the full bearing area where load
applies.
Stack height: keep the number of stacked shims
small. A single shim of the right thickness is more stable than many
thin ones.
Colour coding: some shims come in colours by
thickness to help site teams.

Installation tips

Clean the surfaces and remove rust, grit and burrs. Place shims flat
and fully under the load-bearing area. Tighten bolts gradually and
re-check level. If a shim is partially under a plate, it can tilt the
plate, so cover the full area. Do not use damaged or cracked shims.

Common mistakes to avoid

using plastic shims for loads beyond their capacity
stacking many thin shims instead of one correct shim
leaving the shim only partly under the baseplate
using shims in a hot location
confusing HDPE shims with HDPE sheets bought for another
purpose

Questions to ask your
supplier

What thicknesses and sizes are available? Can shims be cut to my
size? What load limit applies? Are colour-coded thicknesses available?
Is the grade suitable for outdoor use?

Diode Trading EST supplies HDPE products across Saudi Arabia, and
every order ships with a Material Test Certificate. request a quote

Shims and structural
approvals

On structural steelwork, shim material, thickness and the maximum
stack are often set by the engineer. Always follow the approved drawing.
If the drawing calls for steel shims, do not substitute plastic. Where
plastic is allowed, give the load and the bearing area so that the
supplier can confirm the size and thickness is suitable.

Cutting and drilling

HDPE can be cut with a fine-tooth saw, a knife for thin sheet or a
router. Drill with sharp bits and moderate speed so the plastic does not
melt. Remove burrs so the shim sits flat.

FAQ

What are shims used for? Levelling, packing gaps and
adjusting height under equipment or structures.

Are plastic shims strong enough? For many
applications yes, but check the load. Use steel where load is very
high.

Can HDPE shims be cut on site? Yes, with a saw or
knife.

Do HDPE shims rust? No. They are corrosion free.

Products related to this article

Diode Trading EST supplies these Engineering Plastics from stock in Dammam, with delivery across Saudi Arabia and the GCC.

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