Tarp Terminology Glossary: Mil, Denier, Scrim, GSM & More

Quick Answer

What do mil, denier, scrim and GSM mean on a tarp?

Mil tells you how thick the material is. GSM tells you how much one square meter of the finished material weighs. Denier describes the linear mass of the yarn used in a woven reinforcement. Scrim is that reinforcing woven grid or base fabric inside a laminated or coated tarp.

They describe different layers of the specification, so a professional comparison should not convert one into another as if they were equivalent quality grades. For a deeper technical specification workflow, see DERFLEX's tarp specifications guide.

Measurement Map

Four measurement systems describe four different things

A clear tariff, quotation or specification starts by separating thickness, area weight, yarn size and reinforcement density.

mil / mmPhysical thickness

GSM / ozFinished mass per unit area

Denier (D)Yarn linear mass

Weave / MeshReinforcement density

Term	What it measures	Direct conversion?	Useful buyer question
Mil	Thickness in thousandths of an inch.	Yes: 1 mil = 0.0254 mm.	How thick is the finished sheet or coated fabric?
GSM	Finished material mass in grams per square meter.	Yes, to oz/yd2.	How much material mass is present per square meter?
oz/yd2	Finished material mass in ounces per square yard.	Yes: 1 oz/yd2 ≈ 33.9057 GSM.	How does a North American ounce grade compare to a metric weight?
Denier	Linear mass of yarn or fiber.	Not to GSM or mil.	How substantial is the reinforcing yarn?
Weave count	How densely yarns are arranged in the reinforcement.	No universal conversion.	How dense is the load-carrying grid?

Do not force GSM into mil. A material's weight-to-thickness relationship changes with resin density, coating build, scrim structure, lamination, surface finishing and polymer formulation. Use DERFLEX's tarp mil thickness chart when thickness is the main selection question.

Specification Decoder

How to read a tarp specification line

The example below is a notation example, not a fixed DERFLEX product promise. It shows how the different fields work together.

Example notation

PVC coated polyester · 1000D × 1000D · 20 × 20 · 650 GSM · 0.55 mm · lacquered

One line can describe polymer system, reinforcement yarn, weave density, finished area weight, physical thickness and surface finish. Mechanical values and fabrication details should still be stated separately when they matter.

PVC coatedDescribes the polymer surface system applied over the reinforcing textile.

1000D × 1000DDescribes yarn linear mass in warp and weft directions.

20 × 20Describes a weave-density convention; confirm the supplier's unit and counting method.

650 GSMDescribes total finished material mass per square meter.

0.55 mmDescribes physical thickness, separate from GSM.

LacqueredDescribes a surface finishing step that can affect appearance, cleanability and handling.

Image Pack

See the terminology in real tarp materials

The written specification becomes easier to understand when buyers can see coating, fabric body, roll production and finished material examples.

DERFLEX tarp material samples showing different scrim, GSM and coating constructions — Material sample set: different tarp constructions can vary in yarn, weave, coating, GSM and thickness.

DERFLEX blue PVC coated polyester tarpaulin showing coated fabric structure — PVC coated polyester: finished performance comes from coating plus woven reinforcement.

DERFLEX PVC coated fabric production line for tarpaulin roll manufacturing — Coating production: process control affects coating build, surface and repeatability.

DERFLEX heavy duty blue tarp fabric close up showing woven texture — Close-up texture: visible fabric body does not replace tensile, tear or adhesion test data.

Buyer Reference

Tarp terminology glossary

Definitions are intentionally short enough to scan, but each term includes the procurement reason it matters.

Find a term

Measurements & Base Construction

Use these terms to understand what the tarp is physically made from before comparing claims such as “heavy duty.”

Mil

One thousandth of an inch. A 20 mil material is 0.020 inch thick, or 0.508 mm.

Buyer use: compare physical thickness within similar material families.

Millimeter (mm)

A metric thickness unit. One millimeter equals about 39.37 mil.

Buyer use: common on technical data sheets for coated fabrics and flexible sheets.

GSM

Grams per square meter: the mass of one square meter of finished material.

Buyer use: compare finished weight, estimate handling weight and control repeat orders.

oz/yd2

Ounces per square yard: another area-weight unit, common in North American vinyl and canvas tarp markets.

Buyer use: converts directly to GSM, not to mil.

Denier (D)

A yarn linear-mass unit. One denier means 9,000 meters of yarn weighs one gram.

Buyer use: understand the reinforcing yarn size; read it with weave density and strength data.

Scrim

The woven or grid-like reinforcing structure inside many laminated or coated tarps.

Buyer use: the scrim carries much of the tensile load and helps stop local damage from spreading.

Warp

The yarn direction running lengthwise in woven fabric, generally along the production direction.

Buyer use: tensile and tear values can differ between warp and weft.

Weft

The yarn direction running across the width of a woven fabric, at right angles to the warp.

Buyer use: check both directions when load or tear behavior is critical.

Weave Count / Mesh Count

A count describing how densely reinforcing yarns or strands are arranged. Conventions and units can vary, so supplier notation should be confirmed.

Buyer use: compare reinforcement density, but never use it without denier and test values.

Base Fabric / Substrate

The textile foundation that receives coating or lamination, often polyester in industrial PVC tarpaulin.

Buyer use: affects dimensional stability, tensile behavior, tear propagation and fabrication.

Materials & Surface Systems

These terms describe the polymer, textile family and finishing route that create the tarp's surface behavior.

PVC Coated Polyester

A woven polyester base fabric covered with PVC coating to create a durable, cleanable and weldable flexible sheet.

Buyer use: common for truck tarps, industrial covers, tents and reusable outdoor fabrications.

Vinyl Tarp

A market term commonly used for PVC-based tarp material or finished tarpaulin, frequently reinforced with woven polyester.

Buyer use: ask whether “vinyl” means reinforced coated fabric or unsupported sheet.

PE / Poly Tarp

A tarp commonly made from woven polyethylene tapes with laminated polyethylene surfaces.

Buyer use: compare mil, weave, UV treatment, hems and grommet reinforcement.

Canvas Tarp

A woven textile tarp made from cotton, polyester or blends, sometimes treated for water resistance.

Buyer use: useful where breathability or textile abrasion behavior matters.

Mesh Tarp

An open woven or knitted tarp designed to allow airflow while providing shade, screening or debris control.

Buyer use: openness or shade factor can matter more than thickness.

Clear Vinyl

Transparent flexible PVC sheet, available as unsupported film or reinforced clear fabric depending on the product.

Buyer use: specify clarity, thickness, flexibility and reinforcement separately.

Coating

A polymer layer applied to a textile surface to add properties such as water blocking, cleanability, color, abrasion resistance or weldability.

Buyer use: coating type and build should be matched to the end use.

Lamination

A process that bonds a separate film or layer to a woven base rather than building the surface only by coating.

Buyer use: coated and laminated constructions can have different feel, adhesion and performance.

Lacquer / Topcoat

A surface finishing layer applied over a coated material to adjust appearance, cleanability, printability, blocking or surface protection.

Buyer use: ask what the finish is intended to do instead of assuming every lacquer is the same.

Coating Adhesion

The bond between the surface polymer layer and the textile reinforcement.

Buyer use: important for folding, welding, abrasion and repeated handling.

Performance & Testing Terms

Marketing labels are less useful than defined performance terms measured with a stated method.

Tensile Strength

The resistance of the fabric to being pulled apart under a steadily applied load, usually measured separately in warp and weft.

Buyer use: critical for tensioned covers, curtains and transport tarps.

Tear Strength

The resistance to an existing cut, puncture or notch growing into a larger tear.

Buyer use: especially relevant around sharp cargo edges and attachment points.

Abrasion Resistance

The ability of a material surface and reinforcement to resist damage from repeated rubbing or scraping.

Buyer use: important for truck cargo contact, machinery covers and dragged tarps.

Puncture Resistance

The material's resistance to penetration by a concentrated point or sharp object.

Buyer use: do not infer puncture resistance from mil alone.

Waterproof vs Water-Resistant

Waterproofing describes a system intended to block water penetration; water resistance indicates limited resistance under defined exposure. The seam and finished-cover design matter as much as the sheet.

Buyer use: ask how seams, holes and interfaces are sealed.

Hydrostatic Head

A test concept that measures the water pressure a material can resist before leakage under the specified method.

Buyer use: useful only when the test method and acceptance value are stated.

UV Stabilized / UV Resistance

Indicates that the material formulation or finish is designed to resist degradation from ultraviolet exposure.

Buyer use: request the applicable test route or project requirement rather than relying on the phrase alone.

Flame Retardant (FR)

A material property describing reduced ignition or flame-spread behavior under a specific test method.

Buyer use: always specify the exact standard required by the market or project.

Cold Crack / Low-Temperature Flexibility

Terms used to describe how a coated material behaves when bent or stressed at low temperature.

Buyer use: important for winter transport, folding and repeated handling in cold climates.

Dimensional Stability

The ability of material to maintain size and shape under temperature, tension and processing.

Buyer use: important for large panels, repeated-fit covers and OEM programs.

Fabrication, Edge & Hardware Terms

A strong fabric can still fail early if load is concentrated into a weak seam, hem or attachment point.

Seam

The joint between two tarp panels, created by welding, sewing or another fabrication method.

Buyer use: seam width, direction and process can control leakage and load transfer.

Hot-Air Welding

A process that uses heated air and pressure to fuse compatible thermoplastic-coated materials.

Buyer use: common for large PVC coated tarp panels and field or factory fabrication.

HF / RF Welding

High-frequency or radio-frequency welding uses electromagnetic energy to heat compatible materials at the joint.

Buyer use: suitable for many PVC fabrications where repeatable welded seams are required.

Sewn Seam

A mechanical seam created with thread and stitching.

Buyer use: can be effective for some textiles, but water sealing and stitch-hole stress may need separate consideration.

Hem

A folded or reinforced perimeter edge that increases stiffness, protects the cut edge and supports hardware.

Buyer use: specify hem construction when the edge carries tie-down force.

Webbing Reinforcement

A strong woven tape added to edges, seams or load paths to distribute forces.

Buyer use: often more important than simply adding material thickness around attachment points.

Grommet / Eyelet

A reinforced ring installed through the tarp to create a tie-down or attachment hole.

Buyer use: spacing, material and surrounding reinforcement should match the applied load.

D-Ring

A D-shaped metal or polymer attachment ring fixed to reinforced webbing or patches.

Buyer use: useful where straps or hooks need stronger, directional attachment points.

Rope-Reinforced Hem

A perimeter hem containing rope or cord to add body and help distribute edge loads.

Buyer use: common in some poly and industrial tarp constructions.

Reinforced Corner / Wear Patch

An extra layer of fabric, webbing or compatible material placed at high-stress or high-abrasion zones.

Buyer use: targeted reinforcement can be more efficient than making the entire tarp heavier.

Size, Production & Purchasing Terms

These terms reduce the commercial misunderstandings that cause fit, repeat-order and quotation problems.

Cut Size

The material dimensions before hemming, seaming or other fabrication reductions.

Buyer use: a cut-size tarp may finish slightly smaller after edge construction.

Finished Size

The usable dimensions of the completed tarp after seams, hems and reinforcement are made.

Buyer use: state finished coverage dimensions for fitted or repeat OEM programs.

Roll Width

The manufactured width of the fabric roll before panel joining.

Buyer use: wider material can reduce seam count for large covers, depending on equipment and product construction.

Tolerance

The permitted variation around a nominal dimension, weight, thickness or other specification.

Buyer use: essential for fair inspection and repeat-order consistency.

Sample / Approval Sample

A representative material or finished item reviewed before bulk production.

Buyer use: approve color, hand feel, surface, construction and test route before scaling.

OEM

A supply arrangement in which material or finished tarps are produced to a buyer's specification or brand program.

Buyer use: define repeatable specs, labels, packing and approval controls.

Private Label

A program in which products are supplied under the buyer's brand, packaging or market identity.

Buyer use: clarify logo, label, barcode, carton and artwork requirements before quotation.

MOQ

Minimum order quantity for a specific material, color, construction or finished product program.

Buyer use: MOQ can vary with standard versus custom requirements; confirm for the exact specification.

Lead Time

The time required for sampling, production, packing or delivery, depending on how the supplier defines it.

Buyer use: ask what event starts the clock and whether transport time is included.

RFQ

Request for quotation: the buyer's structured inquiry describing the application, specification, quantity and commercial requirements.

Buyer use: a clearer RFQ produces more comparable quotations.

RFQ Translation Guide

Turn vague tarp language into a specification a factory can quote

Common buying phrases sound clear but often hide multiple technical decisions. Translate them into measurable or verifiable fields before comparing suppliers.

“Heavy duty tarp”

Define material family, GSM or oz, mil/mm where relevant, denier, weave, tensile/tear target, abrasion exposure, reinforcement and handling cycle.

“Waterproof tarp”

Define coating or film system, seam method, penetrations, installation slope, expected rain exposure and any applicable water-resistance test method.

“UV resistant”

Define climate, outdoor duration, color requirement and the project or customer test route if one is required.

“Strong scrim”

Request fiber type, warp × weft denier, weave density and measured tensile / tear values.

“Custom tarp”

Provide finished dimensions, shape, seam map, hems, webbing, grommet / D-ring positions, wear zones, logo and packaging.

“Same as my current tarp”

Send a physical sample or complete datasheet and identify which characteristics must match: weight, thickness, color, flexibility, strength, surface and fabrication.

Procurement Risk

Common terminology mistakes that create bad tarp comparisons

Most specification problems begin before production—when two suppliers are quoting different constructions under the same simple label.

Converting GSM directly to mil

Weight and thickness are different properties. Ask for both when both matter.

Assuming 1000D means a 1000 GSM tarp

Denier describes yarn linear mass; GSM describes finished material mass per area.

Buying by “heavy duty” label alone

There is no single universal heavy-duty grade across PE, PVC, canvas and mesh.

Ignoring warp and weft direction

Strength values and yarn construction can differ by direction.

Comparing fabric while ignoring finished tarp details

Seams, hems, webbing, grommets and wear patches often control real service failures.

Requesting FR without naming a standard

“Flame retardant” should be tied to the required market, project and test method.

Application Translation

Which terminology matters most for different tarp jobs?

The same spec sheet should not be weighted equally for every application. Prioritize the terms that describe the domi, nant failure mode.

Application	Terms to prioritize	Why they matter	Do not rely on
Truck / trailer cover	Denier, weave, GSM/oz, tensile, tear, abrasion, cold flex, seam, webbing, D-rings/grommets.	Repeated folding, highway airflow and cargo contact load both fabric and attachments.	Mil alone.
Construction cover	Material family, tear, UV, waterproofing, seam, grommet reinforcement, finished size.	Wind, rough handling, sharp edges and temporary installation dominate.	“Heavy duty” label.
Outdoor equipment cover	GSM, coating, UV, abrasion, size, ventilation/condensation design, hem.	Long exposure and repeated fitting create weathering and contact wear.	Color as a quality proxy.
Mesh/privacy tarp	Yarn, weave/knit, GSM, openness/shade factor, edge reinforcement.	Airflow and wind load are intentional design variables.	Thickness as the main selector.
Clear enclosure	Actual mil/mm, clarity, formulation, cold flexibility, reinforcement if present, seam method.	Optical and flexible-sheet properties may matter more than woven-textile metrics.	Denier if the sheet is unsupported.

Related DERFLEX Guides

Continue from definitions into selection

This glossary is the terminology hub. Use the dedicated guides below when you need deeper selection rules for a specific number or buying decision.

Tarp Specifications GuideBuild a complete fabric + finished-cover specification. Tarp Mil Thickness ChartCompare mil, mm and duty ranges without confusing thickness with weight. GSM, Mil, Thickness & Weight GuideMove from units into application-based material selection. Tarp Buying GuideCompare materials, sizes, construction details and procurement questions. PVC Vinyl Tarp MaterialSee how coating, polyester reinforcement and fabrication work together. Heavy Duty TarpaulinTranslate “heavy duty” into material, reinforcement and application requirements.

Questions buyers ask about tarp terminology

Direct answers to the specification terms most often confused in supplier quotations.

Is GSM the same as tarp thickness?

No. GSM measures mass per square meter, while mil or millimeter measures physical thickness. Two materials can share the same GSM and still have different thickness because the base fabric, coating build and polymer density differ.

Is higher denier always stronger?

Not automatically. Higher denier means greater yarn linear mass when comparing similar fibers, but finished fabric strength also depends on yarn quality, weave density, coating, tensile and tear values, and finished-cover construction.

What is scrim in a tarp?

Scrim is the woven reinforcing grid or base structure inside many coated or laminated tarps. It helps carry tensile load and control tear propagation, while the surface layer provides properties such as water blocking, color and cleanability.

What does 12×12 weave mean on a tarp?

It is a weave-density notation describing how many reinforcing yarns or strands are arranged in each direction within the supplier's stated measuring unit, commonly an inch. Confirm the counting convention because terminology can vary.

Can I convert ounces per square yard to GSM?

Yes. Both are area-weight units. One ounce per square yard is approximately 33.9057 GSM. That conversion does not tell you the tarp's mil thickness or denier.

What does 1000D × 1000D mean?

It usually indicates 1000-denier yarn in both the warp and weft directions of the reinforcing textile. It does not by itself specify weave count, finished GSM, thickness, tensile strength or waterproofing.

Which tarp term best predicts durability?

No single term does. Durability depends on the failure mode. Compare the relevant combination of yarn, weave, finished weight, thickness, coating adhesion, tensile/tear performance, UV exposure, seams, edge reinforcement and attachment design.

What information should I send for a tarp quotation?

Send the end use, material direction, finished dimensions, target GSM/oz and thickness if known, base fabric or denier, exposure conditions, required tests, seam and reinforcement details, hardware layout, quantity, branding, packing and destination. If you have an existing sample, include it as a reference.

Have a tarp spec that is difficult to compare?

Send DERFLEX the application, existing datasheet or sample, finished size, target material weight or thickness, reinforcement requirements, fabrication details, quantity and destination. The team can help translate the terminology into a clearer quotation specification.

Request a Specification Review Explore Tarp Solutions

Technical note: terminology and notation can vary by material family, market and test method. Use the supplier's documented test standard, approved sample and written tolerance when a value is contract-critical.