Can we get samples before placing a bulk order?

Yes. Sample rolls ship by courier so your team can handle the product, check the print and run it on a test deck before you commit. Tell us which series and grammage you want to evaluate and we will arrange the shipment.

Can you print our own brand on the roll?

Yes — private-label printing is a standard part of the programme. Your logo, lap and nailing guides, contact line and safety wording can all be printed in line during production. Print plates and minimum quantities are confirmed per item.

What is the minimum order quantity?

Minimum order is one pallet (56 rolls), on any specification, for both factory-direct and US warehouse shipments. Send us your target roll spec — width, length, grammage and print — and we will confirm the MOQ for that item.

Do you supply test reports with each shipment?

Yes. Test reports are issued per order and travel with the shipping documents. If your market requires third-party testing or a specific standard, raise it at quotation stage so the test plan is agreed before production begins.

Can we audit the factory or send a third-party inspector?

Both are welcome by appointment. Let us know the scope — checklist, standard or customer requirement — and we will have the relevant batch records and production staff available on the day. Remote video walk-throughs can also be arranged.

Which markets do you export to?

We supply distributors, contractors and private-label partners across North America, Europe and Asia-Pacific, with selected lines held in US and EU warehouse stock. Contact the sales desk to confirm current availability for your destination.

Home › Resources › Ice & Water Shield vs Synthetic Underlayment

Comparison

Ice & Water Shield vs Synthetic Underlayment

These two products sit next to each other on the shelf and are often specified in the same sentence, which leads buyers to treat them as substitutes. They are not. One is a localised waterproofing membrane, the other is a full-roof weather-resistant barrier. Here is the practical difference.

At a glance

The core difference

	Synthetic underlayment	Ice & water shield
Standards	ASTM D8257	ASTM D1970
Attachment	Mechanically fastened with cap nails or staples	Self-adhered to the deck
Vapour behaviour	Vapour permeable — the deck can dry through it	Near-zero permeance — it is a barrier
Nail sealing	No; each fastener leaves a penetration	Yes; the membrane reseals around the fastener
Typical use	Full roof field	Eaves, valleys, penetrations, low slopes
Cost tier	Mid	Premium
Coverage weight	Very light per square	Heavy per square

Decision

Choosing by location on the roof

The single most useful way to think about it: use synthetic across the field, and ice & water shield where water sits. Water sits at the eave when ice dams form, in valleys where runoff concentrates, around any penetration, and across any section shallow enough to slow drainage.

Steep, unobstructed field — synthetic underlayment. It is lighter, faster to install, lets the deck dry, and costs far less per square.
Eaves in a cold climate — ice & water shield, typically from the edge to inside the exterior wall line.
Valleys — ice & water shield, because concentrated runoff is the highest-risk location on a shingle roof.
Chimneys, skylights, vent pipes — ice & water shield, since flashing details are where leaks actually start.
Low-slope sections (2:12 to 4:12) — either the double-layer felt/synthetic pattern or a single layer of self-adhered membrane across the whole section.

Caution

The mistake to avoid

Do not use ice & water shield as a full-roof covering on a vented attic assembly simply because it is the higher-grade product. Its near-zero vapour permeance means a deck that gets wet has no drying path. On the right assembly it is excellent; on the wrong one it traps moisture.

The corollary also holds: a vapour-permeable synthetic sheet is the wrong choice at an eave in a freeze-thaw climate, because wind-driven water backed up behind an ice dam will find every cap nail.

FAQ

Common questions

Can I use synthetic underlayment at the eave instead?

Only where the code does not require an ice barrier. In cold-climate jurisdictions the eave ice barrier is a code requirement, not an upgrade option, and a mechanically fastened sheet does not satisfy it because it does not seal around fasteners.

Which one lasts longer?

Published service expectations generally run longer for self-adhered modified bitumen than for felt, and synthetics fall in between depending on product and exposure. Longevity on a real roof depends far more on whether the sheet was correctly specified for its location than on any single product's rating.

Can they be used together?

Yes — that is the normal assembly. Ice and water shield goes down first at the eaves, valleys and penetrations, and the synthetic sheet covers the remaining field, lapping onto the self-adhered membrane.

Keep reading

Related resources

StandardsASTM D1970: Self-Adhered Ice & Water ShieldThe standard behind self-adhered ice barrier membranes, and the properties that matter in cold climates.StandardsASTM D8257: The Synthetic Underlayment Standard, ExplainedWhy D226 and D4869 do not really test synthetic underlayment, and what D8257 adds.Code & PracticeRoof Slope and Underlayment Layers: Single vs Double CoverageHow the 2:12 and 4:12 thresholds decide whether you need one layer or two, and what that does to material quantity.ClimateUnderlayment for Cold Climates and Ice Dam ProtectionIce dams back water up under the shingle course. The only underlayment that survives it is one that seals around its own fasteners.

All resources

Products

Where this applies

ProductIce & Water ShieldSelf-adhered membrane for eaves, valleys and penetrations.ProductSynthetic Roofing UnderlaymentLightweight permeable sheet for the roof field.

From the blog

Longer reads

From the blogSynthetic vs Felt: What Builders Actually BuyWeight, tensile strength and UV ratings compared — and what that means for how a distributor should stock the line.From the blogIce & Water Shield: Before You Stock Another RollThickness, cold-weather adhesive and UV tolerance — what to ask a factory before committing to container volume.

Need the spec sheet behind the claim?

Tell us the product, roll spec and destination. We will send the current data sheet, test reports and a quotation against your actual requirement.

Request a Quote

Chat with us on WhatsApp