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1. Is it necessary to remove old building paper before applying DuPont™ Tyvek®?
It is not critical to remove building paper prior to installing DuPont™ Tyvek®. However, it is necessary to carefully inspect for damaged areas that may not be clearly visible under building paper. Since building paper does not have the same breathability characteristics of DuPont™ Tyvek®, the wall may lose some of its ability to dissipate moisture to the outside if the paper is left on the wall.
2. How long can DuPont™ Tyvek® be exposed before siding?
DuPont™ Tyvek® HomeWrap® and DuPont™ Tyvek® StuccoWrap®, DuPont™ Tyvek® DrainWrap™, DuPont™ Tyvek® ThermaWrap™ and DuPont™ Tyvek® AtticWrap™ should be covered within 120 days (4 months). DuPont™ Tyvek® CommercialWrap® should be covered within 270 days (9 months).
3. Can you use DuPont™ Tyvek® in combination with a vapor barrier?
Using a vapor barrier depends on how the rest of the wall system is built and the climate the wall is in. If the majority of the year is spent heating the home where the inside temperature is greater than the outside, it is generally good to use a vapor retarder behind the interior drywall. In hot humid climates, vapor barriers should not be used.
4. Is DuPont™ Tyvek® a vapor barrier?
No, DuPont™ Tyvek® is not a vapor barrier. It is breathable, allowing moisture vapor to pass through it.
5. Should DuPont™ Tyvek® be placed over or under the sheathing?
DuPont™ Tyvek® can be used either over or under sheathing. When DuPont™ Tyvek® is used under sheathing, it functions only as an air barrier and does not protect the sheathing as a secondary water barrier. DuPont™ Tyvek® has been used directly over studs where there is no sheathing, although use of sheathing is a highly recommended building practice.
6. Does DuPont™ Tyvek® have an R-value?
In 2006 DuPont introduced Tyvek® ThermaWrap™, a weather resistive, insulating breathable membrane designed to manage radiant heat flow through the wall. This metalized product helps increase the R-value of insulation.
7. What is the difference between DuPont™ Tyvek® and black paper?
Black paper or building paper was not designed as an air retarder like DuPont™ Tyvek®. Unlike DuPont™ Tyvek®, building paper can absorb water. Building paper tears easier than DuPont™ Tyvek® and can degrade over time when under continual exposure to water. Building papers are less permeable to moisture vapor transfer than DuPont™ Tyvek® increasing the potential moisture vapor trapped inside the wall could cause mold, mildew and rot.
8. What is the difference between DuPont™ Tyvek® and other housewraps?
Many other wraps are perforated, which means in order for them to breathe, the manufacturer has punched holes in them, resulting in a reduction of air and water holdout effectiveness. DuPont™ Tyvek® is a non-perforated, nonwoven product with microscopic pores that are so small air and bulk water have a difficult time passing through but since DuPont™ Tyvek® is breathable, moisture vapor can easily escape from the wall.
9. Can you use DuPont™ Tyvek® under any primary facade?
Yes, DuPont™ Tyvek® can be used under any façade including brick, stucco, vinyl, cedar siding, and stone. Proper installation under each façade is essential to ensure DuPont™ Tyvek® provides the maximum level of air infiltration resistance and bulk water holdout.
10. Can DuPont™ Tyvek® be used in attics? On roofs? Under Floors? On the interior?
In 2006 DuPont introduced Tyvek® AtticWrap™, a unique, breathable membrane that helps create an airtight seal to reduce air leakage and energy loss through the roof. All other DuPont™ Tyvek® products in Canada and the US have been tested and approved as a product to be installed behind exterior walls.
11. Where can I buy DuPont™ Tyvek®?
DuPont™ Tyvek® is available at authorized dealers throughout the country.
12. How many feet on a roll of DuPont™ Tyvek® tape?
There are 165 feet on a roll which will be enough to tape a 9’ x 150’ roll.
13. Can DuPont™ Tyvek® be used as flashing?
DuPont™ Tyvek® weather resistive barriers have not been tested or approved as a flashing material. DuPont introduced the DuPont™ Flashing System that provides comprehensive protection from water leaks. It is designed to help direct water to the building exterior instead of trapping it inside the wall system and causing water damage.
14. Can DuPont™ Tyvek® be used with the lettering facing in?
DuPont™ Tyvek® HomeWrap®, DuPont™ Tyvek® StuccoWrap®, DuPont™ Tyvek® DrainWrap™ and DuPont™ Tyvek® CommercialWrap® are equally effective in both directions. However, DuPont™ Tyvek® StuccoWrap® and DuPont™ Tyvek® StuccoWrap® have a specially engineered surface that should be placed with the grooves in a vertical direction.
15. If I caulk seams, why should I use housewrap too?
Since most lumber typically has moisture content of 15 to 20%, when the house dries, the moisture content drops. The lumber will shrink slightly and pull away from the caulk, breaking the seal. Over time the caulk’s effectiveness is reduced. By using DuPont™ Tyvek® maximum air infiltration resistance and bulk water holdout is maintained since the entire wall assembly is covered in a protective envelope.
16. Can I tape sheathing board seams?
Taping sheathing board or fan-fold seams creates a continuous vapor barrier, so moisture vapor would have no where to escape. Adhesion of tape to foam and wood would also be temporary, due to thermal expansion and contraction of the wall assembly. A more effective and efficient means to provide air infiltration resistance and bulk water holdout is to properly install DuPont™ Tyvek® using our best practice guidelines. Since DuPont™ Tyvek® is flexible, it will continue to provide protection to the sheathing when undergoing thermal expansion and contraction.
17. Doesn’t housewrap make a house too tight?
With more energy efficient construction, "building tight; ventilating right" is the best practice. Mechanical ventilation is more important with today’s sophisticated energy saving home features. However, blower door testing on homes wrapped with DuPont™ Tyvek® show natural air exchange rates per hour that are well within acceptable guidelines per ASHRAE Standard 62.
18. Why should I tape seams in the DuPont™ Tyvek®?
Taping the seams with DuPont™ Tyvek® Tape gives you the best Tyvek® to Tyvek® adhesion, optimal protection against air and bulk water penetration, and extra durability protection during the building’s construction phase.
19. Is DuPont™ Tyvek® necessary over foam board?
DuPont™ Tyvek® adds considerable protection against leaky seams in foam board, similar to the protection provided over wood sheathing. Foam boards alone, even interlocking foam boards, do not adequately stop air leakage due to wall movement from settling and thermal expansion and contraction.
20. How many rolls of DuPont™ Tyvek® are required for a typical two-story house?
For a typical two story, 2500 square foot house, the general rule of thumb is two rolls of DuPont™ Tyvek® size 9’ x 150’ should be adequate to wrap the house. However, this estimate may vary slightly depending on the house elevation.
21. What type of fasteners is recommended when installing DuPont™ Tyvek®?
DuPont™ Tyvek® can be installed using a variety of fasteners depending on the application. To attach DuPont™ Tyvek® to wood, insulated sheathing board or exterior gypsum board, use nails with plastic washer heads, such as DuPont™ Tyvek® Wrap Caps. You may choose to use wide staples with a minimum 1” crown. For steel frame construction use DuPont™ Tyvek® Wrap Cap Screws.
See related documents, such as How to Install, Product Guide Specifications and Physical Property Data Sheets, in the Technical Information section of this web site.