Quick answer. An Andersen 100 Series casement or awning sash can use three different weatherstrip styles: a primary perimeter seal, two side-mounted leaf strips, and a top-rail bulb near the room side. These are positions and functions to identify, not three alternative names for the same item. 12
Which piece are you looking at?
| Where you find the damaged strip | Name to investigate | What to record before ordering |
|---|---|---|
| Around the full sash perimeter | Primary weatherstrip. Andersen describes one continuous piece around that perimeter. 2 | A wide photo of the sash and a close photo of the channel, plus any unit identification |
| Along the two outward-facing sash sides | Leaf weatherstrip. Andersen places two pieces at these side positions. 2 | Which side, an outside/inside orientation note, and whether one or both are affected |
| On the upper sash rail nearest the interior | Top-rail bulb. This is a separate upper position, not simply another section of the main perimeter strip. 2 | A photo of the top edge showing where the strip seats |
This map answers which component to investigate. It does not identify an exact compatible SKU by the appearance of rubber alone.
A four-check identification worksheet
- Record whether the unit is a 100 Series casement or awning, rather than deciding from the strip shape. Andersen's replacement guidance names both opening types. 1
- With the sash safely accessible, take an overall photo, then close-ups of the perimeter, outside-facing side positions, and interior-near top rail. Mark the same viewing direction in each image. 2
- On your worksheet write:
position / still attached? / torn, missing or flattened? / window type / identification evidence. Leave unknowns blank rather than estimating dimensions. - Match the location to the manufacturer's named component before opening a parts listing. The manufacturer's 100 Series casement category separates leaf, primary and top-rail bulb listings. 3
Why a matching-looking listing is not enough
Before ordering, confirm the exact installed window series, sash position and manufacturing details with Andersen. These are separate component locations, not interchangeable seals; a photograph or strip shape alone cannot establish a manufacturer-approved replacement part.
What result should you take away?
- Position identified: label the damaged region as primary, leaf or top rail and retain its image.
- Candidate product only: when you have a product number from a listing, cross-check its Works With field and the exact window/edition before buying.
- Not identifiable: if one photo could describe two different channels, stop. Do not pry, cut or glue anything just to make an assumed match.
Safe work boundary: Andersen's help page provides channel-removal and pressing guidance, but a diagnosis is not permission for unsafe access or nonmatching parts. Follow the specific official installation directions and use appropriate eye protection; have difficult or elevated sash work assessed rather than improvising. 1
Sources and references
All footnoted manufacturer facts were checked against the original publisher pages on 2026-10-11. A source describing a product family does not prove a specific unit or replacement fit.
Andersen Corporation, Andersen Help Center 000003325 ©2026, Details; Order Parts; Install Parts > Note; original issuer document (source consulted 2026-10-11).↩
Andersen Corporation, Andersen Help Center 000003325 ©2026, Details; Order Parts; Install Parts > Note; original issuer document (source consulted 2026-10-11).↩
Andersen Corporation, Andersen Parts Store live category snapshot 2026-10-11, Results 1-7 of 7; original issuer document (source consulted 2026-10-11).↩
Andersen Corporation, Andersen Parts Store live product snapshot 2026-10-11, Product Details; Specifications > Works With; original issuer document (source consulted 2026-10-11).
Andersen Corporation, Andersen Parts Store redirect to product leaf-sash-weatherstrip/01t2J000006XkZxQAK 2026-10-11, Product Details; Specifications > Works With; original issuer document (source consulted 2026-10-11).
Andersen Corporation, Andersen Parts Store live category snapshot 2026-10-11, Results 1-7 of 7; original issuer document (source consulted 2026-10-11).