Description
What it is — and why it costs more than flashing tape
DuPont FlexWrap NF is not a wider version of DuPont Flashing Tape. It is a different material for a different problem: the corner.
A sill pan has two inside corners, and those corners are where water gets in. With flat flashing tape you cut, overlap and hope. FlexWrap NF stretches and conforms, so the corner is formed in one continuous piece with no seam — and it does it without mechanical fasteners, even in flexed areas.
It also bonds to substrates flat tape struggles with: foam board, fiberboard, and concrete masonry unit (CMU).
6″ or 9″?
- 6″ — standard residential window sills. Enough width to form the pan and turn up the jambs on typical openings. The size most houses need.
- 9″ — wider sills, doors, and details that need more lap up the jamb
If you are flashing standard windows, 6″ is the one. Step up to 9″ for sliders, doors, and deep sills.
FlexWrap NF vs. standard Flashing Tape
| FlexWrap NF | Flashing Tape | |
| Top sheet | Micro-creped DuPont™ Tyvek® | Polypropylene film |
| Stretches into corners | Yes — seamless | No — cut and lap |
| UV exposure | 270 days (9 months) | 120 days |
| Water intrusion | No leakage at 718 Pa | No leakage at 300 Pa |
| Non-nailable substrates | Yes — foam, fiberboard, CMU | Limited |
Specifications
| Construction | Micro-creped DuPont™ Tyvek® top sheet + 100% butyl adhesive + split-release liner |
| Adhesive | 100% butyl — no asphalt or bitumen |
| Size | 6 in × 75 ft (1 roll) |
| Application temperature | As low as 25°F (-4°C) on clean, frost-free surfaces. Performs best above 75°F (24°C) |
| UV exposure | Up to 270 days (9 months) |
| Primer | Not required on common building materials |
| Shipping weight | 9.5 lb |
| UPC | 083014102366 |
| Condition | New, factory sealed |
Standards and warranty
| AAMA 711 | Class A (no primer required), Level 3 thermal exposure (176°F for 7 days) |
| Air leakage | < 0.04 cfm/ft² |
| Water intrusion | No leakage at 718 Pa |
| Water vapor permeability | < 1 perm |
Backed by DuPont 10-Year Limited Warranties when installed as part of the Tyvek® WRB system.
Installation notes
You need:
- A clean, dry, frost-free surface
- Primer over concrete, masonry, glass-mat exterior gypsum sheathing, and in cold or adverse weather
- To install the sill first, then jambs, then head — shingle-lapped so water sheds outward
Do not use it for:
- Through-wall flashing applications
How many rolls you need
75 ft per roll. A standard 3 ft window sill pan with both corners turned up runs about 5 to 6 ft:
- Roughly 13 window sills per roll
- A house with 12 to 15 openings: one roll covers the sills
Common approach: FlexWrap NF on the sills where the corners are, and 6″ Flashing Tape on the jambs and head where the run is flat. You get the corner performance where it matters without paying for it everywhere.
Contractor and volume pricing
Ordering for a full job or a subdivision? Call (832) 463-7946 or email sales@85builders.com with your quantity and the job-site ZIP code and we will send pricing the same business day.
We accept Texas resale certificates for tax-exempt purchases.
Frequently asked questions
Why is this more expensive than flashing tape?
Different material and different job. FlexWrap NF has a Tyvek® top sheet and stretches to form corners in one piece, carries more than double the UV rating, and holds water at more than twice the pressure. On flat runs, standard flashing tape is the right call and costs less.
Is this genuine DuPont?
Yes. New, factory-sealed product in original DuPont packaging. Not generic, not repackaged.
Do I need fasteners in the corners?
No. DuPont states it does not require mechanical fasteners even in flexed corner areas.
Can I install it in cold weather?
Down to 25°F (-4°C) on a clean, frost-free surface. It performs best above 75°F, and cold or adverse conditions call for primer.
How long can it stay exposed?
Up to 270 days — nine months of UV exposure.
Can I use it for through-wall flashing?
No. DuPont specifically excludes that application.
How fast does it ship?
We ship next business day from Cypress, TX.






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