Short answer. In Therma-Tru's 2017 SITE 5, jamb compression weatherstrip and basic fixed-sill vinyl threshold service are separate repair categories. source Before buying what a seller calls a “vinyl insert,” first ask: is the worn piece along the stationary bottom threshold, or is it running up the door jamb?
A location test before a parts search
| Part-location clue | Manual section to consult | Why it matters |
|---|---|---|
| Flexible strip runs along a vertical jamb | 2017 p.5.21, Weatherstrip Replacement | It documents both press-in and nail-in jamb weatherstrip. source |
| Shaped vinyl piece spans the bottom fixed sill | 2017 pp.5.24–5.26, Basic Fixed Sill Vinyl Threshold Replacement | This is a different illustrated component/procedure. source |
| A small pad appears at the sill/jamb endpoint | Corner pad detail in fixed-sill sequence | The repair pages show pads at the two sill corners, separate from the threshold vinyl. source |
The edition and size trap
Even within the 2017 fixed-sill diagrams, Therma-Tru distinguishes replacement-vinyl illustrations for Book and U1 sizes from U1REV sizes. source Those labels are not permission to choose by door width alone. Preserve the old system designation and compare the precise profile/fit documentation for that series; this guide does not convert a diagram label into a currently purchasable or interchangeable SKU.
Practical identification workflow
- Photograph the full threshold with the door open, then the lower jamb with the door closed normally. Mark each photo bottom threshold, vertical jamb or corner pad.
- Determine whether the bottom is the basic fixed-sill style addressed by SITE 5 or a different adjustable assembly. Do not borrow instructions from the other style.
- If the issue is along the jamb, document whether the existing fixing appears press-in or nail-in without removing it. Both types are separately shown in the 2017 weatherstrip section. source
- If the issue is bottom vinyl, search the documented threshold-vinyl drawings for the correct size family, not for a generic jamb strip. source
- If moisture or light is the symptom but no missing part is confirmed, return to the 2017 troubleshooting matrix: strip, corner and bottom conditions occupy different entries. source
Record the outcome
Confirmed location + confirmed 2017 system family: seek the exact manufacturer item documentation. Confirmed location but unconfirmed family: stop before ordering. Both parts appear intact: record the symptom and request an inspection rather than trial replacements. No modern compatibility claim or repair-performance promise follows from these illustrations.
Primary sources and claim locator register
- — Therma-Tru original, 2017 Site Manual — SITE 5, US; p.5.21 (jamb strip) vs p.5.24 (fixed vinyl threshold). Publisher document.
- — Therma-Tru original, 2017 Site Manual — SITE 5, US; p.5.21, nail-in and press-in options. Publisher document.
- — Therma-Tru original, 2017 Site Manual — SITE 5, US; pp.5.24–5.26, separate fixed sill repair sequence. Publisher document.
- — Therma-Tru original, 2017 Site Manual — SITE 5, US; p.5.25, Book/U1 versus U1REV vinyl labels. Publisher document.
- — Therma-Tru original, 2017 Site Manual — SITE 5, US; pp.5.24 and 5.26, corner pad at sill ends. Publisher document.
- — Therma-Tru original, 2017 Site Manual — SITE 4, US; pp.4.3–4.5, separate leak rows. Publisher document.
Evidence and safety boundary
Therma-Tru’s 2017 SITE 5 (printed pp. 5.24–5.26) shows different fixed-vinyl sill configurations, including Book, U1 and U1REV details. Determine the exact sill configuration and whether the observed feature belongs to the sill insert or an adjacent jamb seal. Compare an undisturbed receiver and its location to the manufacturer drawing before requesting parts; a similar profile shape does not prove a fit.