Home › Blog › Fenestration › Window & Door Systems › Window and door sealing material selection
Glazing Tape, Setting Blocks, Weatherstrip, and Weep Baffles: Choosing Window and Door Sealing Materials
An operating window or door is not one seal; it is up to nine die-cut sealing, cushioning, and positioning interfaces, and each one answers to a different material family. Choosing well means letting the interface and the NAFS performance target pick the material, not letting the nearest catalog line pick the interface. This guide walks the families H-O converts for window and door work, the decision each one wins, and the standards that govern them, so the part on the drawing matches the test the unit has to pass.
Request a quote for your project →
Which sealing family wins each interface?
The Window and Door Systems application page sorts a unit into five zones: the sash-to-IGU glazing interface, the sash-to-frame weatherstrip line, the hidden frame interior, the hardware and assembly positions, and the door perimeter.
The families below are organized the same way, each introduced by the decision it wins, with standards named by designation: NAFS-2022 for the performance class, ASTM E283 for air leakage, ASTM E331 and E547 for water penetration, ASTM C864 Option I for setting blocks, ASTM D1056 for cellular compression-deflection grades, and UL 94 for flammability classes.
Per-grade values are taken from the technical data sheet on file, not from headline numbers.
Glazing tape beds the insulating glass unit
The sash-to-IGU interface is the primary seal, and a pre-cut foam tape replaces wet glazing with a dry bond the line can handle immediately. BGT crosslinked polyethylene glazing tape in the 1032, 1016, and 1008 thickness classes is the drop-in default for shallow residential pockets: plasticizer-free, dimensionally stable, and the low-risk pairing against a silicone IGU edge seal because it has no mobile species to migrate.
Where the pocket is deeper, the frame heavier, or the IGU acoustic, PVC foam glazing tape in the 15# and 25# density classes brings higher compression-deflection bedding. Because plasticized PVC near a silicone sealant deserves a compatibility check, confirm that pairing under the ASTM C1087 framework before committing.
Setting blocks carry the glass dead load
Setting blocks hold the glass off the frame and transfer its weight to the sash, so they are dense and hard, not cellular. Glazing-grade solid silicone in the 80 to 90 Shore A band per ASTM C864 Option I is the conservative default, placed at the quarter points per the GANA Glazing Manual with length scaled to glass area at roughly 0.1 inch per square foot.
The softer commercial durometers in the same family (down to a 30 Shore A commercial grade) belong in cushioning and pad positions, never under the lite, where they creep and load the IGU edge seal.
Weatherstrip is EPDM by exposure, neoprene by wear
The weatherstrip compresses under sash closing force to form the secondary air-and-water seal, and the chemistry should follow the dominant aging mechanism.
EPDM owns exposure-driven faces because its saturated backbone resists UV and ozone: the RE-series premium EPDM blend (grades RE41E through RE45E, compression-deflection rising through the series per ASTM D1056) for commercial-class and high-exposure work, and the 553 and 563 solid EPDM sheet grades (553 at 50 Shore A and 563 at 60 Shore A, for joints built for a dense strip rather than a compressible gasket, ozone tested per ASTM D1149 and heat aging per D573).
Where contact is wear-driven, hinged patio doors, entry doors, operating commercial windows, the SCE neoprene blend (through SCE45B) tolerates abrasion and incidental oil better, carrying a UL 94 HF-1 line on its TDS.
The hidden frame interior decides the air and water tests
Three components nobody photographs decide the NAFS results. A balance cavity left open is a convective chimney from the weatherstrip line into the conditioned space; a die-cut ClipFoam crosslinked PE chimney block (the 2# density grade is the industry-standard chimney-block material, near-zero water absorption per ASTM D3575) closes it.
Weep holes need a reticulated polyurethane weep baffle (an uncoated 30 PPI grade indoors, a coated grade for UV-exposed sills) that drains water while excluding insects and wind-driven reverse flow.
Hollow frame cavities are convective thermal bridges, and polyether PU cavity insulation (for example the HyPUR-cel I-series, hydrolysis-resistant for damp interiors) supports a frame U-factor improvement that belongs to the whole-frame thermal model, not to the foam alone.
Hardware cushioning and assembly positioning
Behind locks, strikes, operators, and hinge reinforcements, a die-cut cushion pad absorbs vibration and keeps the screws from working loose over the service life. H-O Mount double-coated crosslinked PE tape in the 1008, 1016, and 1032 classes handles SDL grilles, trim, and hardware pads; where long-term compression-set resistance governs, PORON microcellular urethane (industrial 4701 grades such as the 4701-50 firm) holds its recovery, tested per ASTM D3574.
For door accessory gaskets and threshold cushions where the SCE classes are more than the joint needs, the broader neoprene foam family covers the duty.
Window and Door Sealing Families Side by Side
| Family | Form | Signature strength | Interface it wins |
|---|---|---|---|
| BGT crosslinked PE tape | Closed-cell XLPE tape | Plasticizer-free bedding | Sash-to-IGU shallow pockets |
| PVC foam glazing tape | Closed-cell PVC tape | Higher CFD, deep pockets | Deep pockets, acoustic IGUs |
| Glazing-grade solid silicone | Dense solid sheet/strip | Dead-load support, set resistance | Setting blocks at quarter points |
| RE-series EPDM blend | Closed-cell foam | UV and ozone headroom | Exterior weatherstrip |
| SCE neoprene blend | Closed-cell foam | Abrasion and oil tolerance | Door perimeter, operating sash |
| ClipFoam crosslinked PE | Closed-cell XLPE block | Compression fit, zero absorption | Balance chimney cavity |
| Reticulated PU baffle | Open-cell reticulated | Drains water, excludes insects | Sill weep holes |
| PORON microcellular urethane | Microcellular pad | Low compression set | Hardware cushion pads |
Illustrative and relative only; confirm each grade on its current technical data sheet. The NAFS performance class belongs to the whole unit design; each component supports the rating and does not create it alone.
Compression is the mechanism; set is the enemy
Every weatherstrip and perimeter gasket on a window seals by being compressed and pushing back, and the property that erodes that push-back is compression set, the fraction of deflection the foam never recovers. It is why a unit that passed ASTM E283 at certification can leak air at year five with no visible change on the line.
The ASTM D1056 compression-deflection class on each foam TDS is the controlling call-out: pick the firmness so the gasket works in the middle of its range against the real closing force, with allowance for door tolerance and hinge sag, and qualify one grade per program rather than substituting a neighboring grade that scatters the air-leakage results.
How H-O Products helps
H-O Products die-cuts and converts; we do not extrude or mold rubber profiles in-house.
We take roll, sheet, and bun stock from the foam and tape manufacturers and die-cut, kiss-cut on liner, slit, and laminate it to your drawing: glazing tape cut to length with mitered ends, corner-matched weatherstrip gasket sets, compression-fit chimney blocks, reticulated weep baffles, and laminated hardware pads, all made to order with material traceability and lot-code TDS records under our ISO 9001:2015 certified quality management system in Winsted, Connecticut.
Where a design needs an extruded bulb or leaf profile alongside the converted parts, we coordinate it through a partner network and convert the die-cut set around it.
Frequently asked questions
What materials are used for window and door sealing components?
A residential or light-commercial unit has up to nine sealing, cushioning, and positioning interfaces, each mapping to a family.
The sash-to-IGU primary seal uses crosslinked PE glazing tape or PVC foam glazing tape; setting blocks are dense solid silicone in the 80 to 90 Shore A band per ASTM C864 Option I; weatherstrip and corner gaskets are closed-cell EPDM foam (RE-series) or solid EPDM sheet (553/563) or SCE neoprene; balance cavities take crosslinked PE chimney blocks; weep holes take reticulated PU baffles; hollow frames take open-cell PU cavity insulation; and SDL grilles and hardware use double-coated XLPE tape.
All are die-cut to drawing, with properties per the TDS on file.
Should I use EPDM or neoprene for weatherstripping?
Match the chemistry to the dominant aging mechanism. EPDM has the better UV and ozone resistance, so it owns exposure-driven positions: exterior weatherstrip and perimeter gaskets, with the RE-series blend for commercial-class and coastal exposure and solid 553/563 EPDM sheet where the joint is designed for a dense strip, ozone tested per ASTM D1149.
Neoprene (the SCE series) tolerates abrasion and incidental oil better, so it owns wear-driven positions: hinged patio doors, entry doors, and operating commercial windows. Both families step through ASTM D1056 firmness grades; pick the family for the failure mode first, then the grade against the closing force.
What durometer is a window setting block, and how big should it be?
ASTM C864 Option I covers dense elastomeric setting blocks in the 80 to 90 Shore A hardness band, and the GANA Glazing Manual places two blocks at the glass quarter points with length scaled to glass area at roughly 0.1 inch per square foot and width matched to the IGU thickness with clearance. Dense solid silicone in that band is the most commonly specified block. Substituting a softer 60 or 70 Shore A material lets the glass settle, loads the IGU edge seal, and shortens sealed-unit life, so specify the band and the sizing rule on the drawing.
Does H-O extrude weatherstrip profiles, or convert them?
H-O die-cuts and converts. We take roll, sheet, and bun stock from the foam and tape manufacturers and die-cut, kiss-cut on liner, slit, and laminate it to your drawing; we do not extrude or mold rubber profiles in-house. If a design needs an extruded bulb or leaf profile alongside die-cut corner gaskets and pads, we coordinate the extrusion through a partner network and convert the rest. What we do in Winsted, Connecticut is precision conversion under an ISO 9001:2015 certified quality management system, with lot-code material traceability.
Get a window and door component recommendation
Tell us the NAFS class and Design Pressure target, the frame substrate and finish, the exposure and climate zone, the closure hardware, and any flammability class, and we will recommend a family and grade direction and quote die-cut components to your drawing.
Samples typically ship in 3 to 5 business days for common die-cut configurations on materials we keep on hand; standard production runs about two weeks after drawing approval; expedited service is available. MOQ varies by material and part.
Family-owned in Winsted, Connecticut since 1971 · ISO 9001:2015 certified · OEMs worldwide send us a drawing — and get back their part.
Related reading
Request a quote for your window & door sealing part
Send H-O your drawing or describe the part—engineering reviews every RFQ and converts samples on your geometry.
Last updated · Reviewed by H-O Products engineering (ISO 9001:2015 certified converter, Winsted, CT).
References
- NAFS-2022 / AAMA/WDMA/CSA 101/I.S.2/A440-22 (North American Fenestration Standard, performance classes); ASTM E283 (air leakage); ASTM E330 (structural performance); ASTM E331 / E547 (water penetration); ASTM E2190 (insulating glass unit performance).
- ASTM C864 Option I (dense elastomeric setting blocks); GANA Glazing Manual (setting-block placement); FGIA/AAMA 813 (muntin attachment).
- ASTM D1056 (flexible cellular rubber, compression-deflection grades); ASTM D2240 (durometer); ASTM D3574 (flexible polyurethane foam); ASTM D3575 (crosslinked polyethylene foam); ASTM D1667 (vinyl chloride foam); ASTM D1149 (ozone resistance); ASTM D573 (heat aging); ASTM D2979 (probe tack); UL 94 (flammability classes, per grade).
- Manufacturer technical data sheets for the BGT, PVC glazing tape, glazing-grade silicone, RE-series and 553/563 EPDM, SCE neoprene, ClipFoam, reticulated polyurethane, HyPUR-cel, H-O Mount, and PORON families named on the parent application page.
This article summarizes window and door sealing material-selection principles using the families and published methods cited on the parent application page. Comparisons are qualitative; per-grade values are TDS figures and must be confirmed on the manufacturer's current technical data sheet. NAFS performance classes belong to the complete unit design under the AAMA/WDMA/CSA 101/I.S.2/A440 evaluations; no component alone certifies a unit.
All parts are custom manufactured to order; minimum production run quantities vary by material and part. H-O is a die-cut converter, not a raw-material producer, and does not extrude or mold elastomers in-house.