ProSoft PUL Construction Types: Films, Fibers and Fabric Types

The Decision You're Making

You've chosen your ProSoft PUL type — ECO-PUL, CORE PUL, FoodSAFE PUL, or MediPUL — and now you need to select the specific construction that fits your project. This guide walks you through three construction variables that determine how your PUL fabric looks, feels, and performs beyond its waterproof barrier: film thickness (how robust the barrier is), base fiber (what material touches your product), and fabric type (the knit or weave structure that defines drape, stretch, and dual-function capability).

If you haven't selected your PUL type yet, start with ProSoft PUL Types: ECO-PUL vs CORE PUL vs FoodSAFE PUL vs MediPUL (DF-005). If you're not sure ProSoft PUL is the right brand, see What is ProSoft? The Complete Guide to Waterproof PUL Fabrics.

Film Thickness: 1 Mil vs 2 Mil vs 5 Mil

Film thickness controls the trade-off between barrier robustness and fabric flexibility. All ProSoft PUL maintains full waterproof protection regardless of film thickness — choosing between 1 mil and 2 mil is about durability requirements and handling characteristics, not waterproof quality.

Key Concept: Film thickness does not determine whether a fabric is waterproof. Both 1 mil and 2 mil ProSoft PUL hold at pressures more than 100× any normal use scenario — the difference between film thicknesses is physical toughness of the film layer itself (resistance to puncture, abrasion, and mechanical stress), not waterproof quality. The difference is physical toughness of the film layer itself — resistance to puncture, abrasion, and mechanical stress.

1 Mil (Standard)

The default film thickness for the majority of ProSoft PUL products. 1 mil film creates a softer, more flexible fabric that drapes naturally and sews easily on standard domestic machines. Rated at 225 psi hydrostatic pressure.

Choose 1 mil for cloth diapers, wet bags, menstrual products, mattress protectors, baby accessories, and any application where soft hand-feel and ease of sewing matter. This covers approximately 80% of consumer waterproof fabric applications.

2 Mil (Heavy Duty)

Thicker film for applications requiring extra higher puncture resistance and mechanical durability. 2 mil film creates a slightly stiffer fabric with 240 psi hydrostatic pressure rating.

Choose 2 mil for heavy-duty wet bags facing repeated stuffing and unstuffing, pet products where claws and teeth create abrasion risk, outdoor covers exposed to environmental stress, and any application where the barrier faces direct physical contact.

5 Mil (Ultra Heavy Duty)

The thickest film we have manufactured; especially for ultra heavy duty or large body applications where it requires mechanical longevity. 5 mil creates a thick fabric with a high hydrostatic pressure rating.

Choose this exclusively for structured products requiring maximum barrier strength — furniture cushion covers and industrial diaper bags.

Sewing Note: 5 mil is noticeably stiffer than 2 mil film, which is stiffer than 1 mil. If your project requires gathering, elastic casings, or tight curves, test a swatch before committing to yardage. Most domestic sewing machines handle 2 mil or 5 mil without difficulty, but the reduced drape changes how the fabric behaves in fitted constructions.

Base Fiber: What Touches Your Product

Base fiber determines the tactile qualities of the non-film side — what users feel, what absorbs, and what certifications the fabric carries. ProSoft PUL is available on four base fiber families.

Polyester

The most versatile and economical base fiber. Polyester does not absorb liquid — it provides a smooth, durable surface for waterproof-only applications where the PUL serves purely as a barrier. Polyester-base PUL dries fastest, costs least, and offers the widest selection of weights, prints, and specialty variants.

Choose polyester when the PUL layer serves exclusively as a waterproof barrier and you don't need the fabric surface itself to absorb.

Available across standard interlock, jersey, fleece, foam, mesh, and specialty constructions from 100 GSM lightweight to 315 GSM heavy duty. Polyester base is the foundation for most ECO-PUL, all standard CORE PUL, and most FoodSAFE PUL products.

Organic Cotton

Natural fiber providing softness, breathability, and absorbency at the fabric surface. Organic cotton base creates dual-function PUL when combined with fleece, sherpa, or loop terry fabric types — absorbing liquid on the cotton face while blocking it on the PUL reverse. Certified American-grown organic cotton meets US Trust Protocol standards.

Choose organic cotton when skin contact comfort matters, when your product line markets natural fiber content, or when you need a single fabric that both absorbs and waterproofs.

Bamboo Viscose

The softest base fiber in the ProSoft line. Bamboo viscose (typically 60–70% bamboo with organic cotton blend in base fabric) provides exceptionally gentle skin contact with natural moisture absorption. Bamboo fleece and loop terry constructions create dual-function PUL with the softest hand-feel available.

Choose bamboo when tactile softness is the top priority — baby products, nursing pads, and premium skin-contact applications where hand-feel drives purchasing decisions.

REPREVE Recycled Polyester

Post-consumer recycled polyester made from plastic bottles (8–12 bottles per yard depending on weight). REPREVE provides the same performance characteristics as virgin polyester with verified recycled content for sustainability-focused product lines.

Choose REPREVE when your customers value environmental responsibility and recycled content claims.

Fabric Type: The Most Important Construction Decision

Fabric type is the single most impactful construction variable because it determines whether your PUL provides waterproofing only or waterproofing plus absorption in a single layer. Interlock, jersey, twill, and mesh constructions create waterproof-only barriers. Fleece, sherpa, and loop terry constructions create dual-function fabrics that absorb on one side and waterproof on the reverse.

Waterproof-Only Fabric Types

These constructions provide a smooth, non-absorbent surface on the non-film side. The fabric serves exclusively as a liquid barrier.

Waterproof-Only Constructions

Interlock: Stable double-knit with no curl at cut edges — the most popular PUL base for clean cutting and predictable sewing. Available in polyester and organic cotton. Choose interlock as the default for most waterproof barrier applications: diaper covers, wet bags, mattress protectors, and protective linings
Jersey: Single-knit with more drape and stretch than interlock. Edges curl when cut. Available in polyester and organic cotton. Choose jersey when you need softer drape or stretch in fitted applications — diaper covers with gussets, incontinence underwear, period underwear
Twill: Woven construction with minimal stretch and structured hand-feel. Available in organic cotton only. Choose twill for bags and structured products where dimensional stability matters more than drape — the stiffest ProSoft option, closest to canvas
Foam: Polyester foam base with cushioning and anti-slip grip (1.9 friction coefficient). Choose foam for padded waterproof surfaces — changing pad covers, examination table tops, wheelchair seat protectors
EZ Peel Loop: Hook-and-loop compatible surface on polyester base. Choose this exclusively for products requiring hook-fastener attachment without separate loop tape — adjustable diaper covers with hook closures

Dual-Function Fabric Types (Absorb + Waterproof)

These constructions absorb liquid on the textured face while the PUL reverse blocks it — replacing two separate fabric layers with one. This is ProSoft PUL's most distinctive capability: a single fabric that handles both moisture management functions.

Dual-Function Constructions

Fleece: Brushed pile surface that absorbs liquid while providing non-slip grip. The most popular dual-function construction. Available in organic cotton, bamboo, polyester, and CORE PUL variants. Choose fleece when you need absorbency plus waterproofing in one layer — bibs, burp cloths, changing pads, menstrual pads. The non-slip texture also prevents shifting during wear, which is why professional menstrual pad makers prefer fleece-backed PUL
Sherpa: Raised plush pile providing higher absorption capacity and cushioning than standard fleece. Available in organic cotton. Choose sherpa for maximum softness and absorption density — pet bed covers, castor oil packs, overnight protection products where the plush texture adds comfort and capacity
Loop Terry: Looped surface construction providing absorbent texture with quick wicking. Available in bamboo and microfiber. Choose loop terry when you need rapid liquid capture on the fabric surface — bamboo loop terry is validated for baby bibs where the terry instantly captures drool and spills while PUL protects clothing beneath

Dual-Function vs. Layered Construction: Dual-function PUL (fleece, sherpa, loop terry) replaces two separate fabrics — an absorbent layer plus a waterproof layer — with a single cut. This simplifies construction and reduces bulk. However, the absorption capacity of a dual-function PUL is lower than using a dedicated Zorb absorbent layer paired with standard PUL. For heavy absorption needs (overnight diapers, severe incontinence), use Zorb + ProSoft PUL as separate layers instead.

How Construction Variables Interact

The three construction variables — film thickness, base fiber, and fabric type — combine to create the specific performance profile of each ProSoft PUL product. Understanding how they interact helps you prioritize which variable matters most for your project.

Fabric type is the primary decision because it determines single-function (waterproof only) versus dual-function (absorb + waterproof). Once you know whether you need a barrier-only or dual-function fabric, the field narrows significantly.

Base fiber is the secondary decision because it controls skin-contact feel, natural-versus-synthetic content, and whether organic certification is available. Within the same fabric type, switching from polyester to organic cotton changes how the product feels and what you can claim about it, but the waterproof performance remains identical.

Film thickness is the tertiary decision — relevant mainly for polyester-base waterproof-only products where 1 mil vs 2 mil creates a meaningful difference in handling and durability. Most organic cotton, bamboo, and dual-function products are available in 1 mil only, making this decision automatic.

Which Construction Fits Your Project?

By Product Type

Cloth diapers (covers) → Polyester interlock 1 mil PUL (W-375) as the standard starting point. Add Stretch-FIT for fitted covers with elastic . Upgrade to CORE PUL for institutional or daycare durability. Organic cotton interlock (W-389) if natural fiber marketing matters to your customers.

Cloth diapers (all-in-one) → Bamboo loop terry PUL (W-384) for single-fabric absorption + waterproofing. Zorb 4D CORE PUL (requires pairing with a Stay Dry Layer) for maximum all-in-one absorption capacity. Pair Zorb 3D + standard PUL for maximum absorption with independent component control.

Menstrual pads and period underwear → Organic cotton fleece PUL (W-391) for absorbent non-slip backing in one fabric. Add Stretch-FIT PUL (W-381) for flexible fitted construction. Stretch-FIT Organic Cotton Jersey LITE PUL for period underwear gussets requiring thinnest profile with stretch. Add Silver for odor control.

Wet bags → Polyester interlock 1 mil PUL (W-375) for standard wet bags. 2 mil PUL (W-273) for heavy-duty daycare use. REPREVE PUL (W-675) if your customers value recycled content. Printed PUL options (W-510, W-511) for retail appeal.

Mattress protectors → 2 mil PUL (W-273) for durable protection on flat surfaces. CORE PUL for institutional settings with commercial laundering. Foam PUL (W-367) for padded waterproof covers.

Baby bibs and burp cloths → Bamboo fleece PUL (W-404) for softest skin contact. Organic cotton fleece PUL (W-391) for organic certification. FoodSAFE organic cotton fleece PUL (W-683) or FoodSAFE bamboo loop terry PUL (W-686) when the bib contacts food directly.

Food storage → FoodSAFE PUL (W-396) as the standard option. FoodSAFE Stretch-FIT PUL for bowl covers needing elastic stretch. FoodSAFE Organic Cotton PUL for natural fiber food contact. FoodSAFE REPREVE PUL for eco-conscious food storage lines.

Pet products → 2 mil PUL (W-273) for scratch and puncture resistance. Organic cotton sherpa PUL (W-388) for pet bed covers with absorbent comfort. Premium Fleece PUL (W-386) for waterproof pet coat lining with non-slip surface.

Medical and healthcare → MediPUL Level 4 (W-561) for surgical gowns. MediCORE PUL (W-662) for institutional laundering durability. MediCORE Absorbent (W-665) for underpads requiring integrated absorption with pathogen barrier.

Incontinence products → Organic cotton fleece PUL Silver (W-209) for dual-function with odor control. Stretch-FIT Organic Cotton Fleece Silver PUL (W-661) for fitted garment-style construction. CORE PUL for institutional products with maximum wash durability.

Stretch Options: Standard vs Stretch-FIT

Most ProSoft PUL products have minimal or no stretch. Products designated Stretch-FIT incorporate Lycra for 4-way stretch (typically 10% width, 5% length) with elastic recovery. Stretch-FIT variants are essential for:

Fitted diaper covers with elastic leg and waist casings
Period underwear and incontinence underwear construction
Body-contour applications like fitted garment patterns
Bowl covers and elastic-edge food storage wraps

Standard (non-stretch) PUL is preferable for flat construction: wet bags, mattress protectors, changing pads, food storage bags, and any application where dimensional stability matters.

All fabric specifications may vary ±10% due to textile industry manufacturing standards. Order swatches before committing to yardage — thickness, drape, and hand-feel vary across constructions, and hands-on testing with your specific pattern will confirm the right choice.