Can you use reflectix as a vapor barrier?

Author: Miss Cassandra Conroy MD  |  Last update: Wednesday, January 7, 2026

The product provides a vapor/moisture barrier, which is a strong contributor to the efficiency of the system. Reflectix® is available in convenient roll sizes which contributes to ease of handling and installation.

What can I use instead of vapor barrier?

Drywall works too, and is pretty much the standard for this sort of thing. You could also use plywood or anything else that can act as an air barrier while still being vapor permeable to allow for some inward drying.

Is Reflectix a thermal barrier?

Reflectix® is a safe, easy-to-use, thermal insulating material providing cost-effective, high-efficiency performance for a wide range of applications.

Do you need an air gap with Reflectix?

For either a reflective insulation or a radiant barrier, an air space is required on the reflective side of the product. (Most Reflectix® products are reflective (shiny) on both sides.)

Can you use foil insulation as a vapour barrier?

Aluminium foil can be used as a vapour barrier and also as a vapour retarder, for example when perforated aluminium foil is used.

Radiant Barrier Foil installation do’s and don’ts.

Which side of reflectix faces out?

An air space must exist on a minimum of one side of the product (always on the reflective side (residential attic – preferably oriented facing down)). Radiant barriers by definition do not require an enclosed air space to provide benefit. This application (radiant barrier) is typically installed in a ventilated attic.

What can be used as a vapour barrier?

There are a wide number of materials available to create effective vapour barriers, including:
  • Elastomeric coatings.
  • Aluminum foil.
  • Paper-backed aluminum.
  • Polyethylene plastic sheet.
  • Asphalt-coated Kraft paper.
  • Metallized film.
  • Vapour retarder paints.
  • Extruded polystyrene or foil-faced foam board insulation.

Is Reflectix a moisture barrier?

The product provides a vapor/moisture barrier, which is a strong contributor to the efficiency of the system. Reflectix® is available in convenient roll sizes which contributes to ease of handling and installation.

How much heat can Reflectix handle?

The following website states that Reflectix can withstand temps up to 180* F.

Can you use Reflectix as insulation?

Reflectix® will provide adequate insulating without extra wrapping. Begin at the end of the house by stapling the product to the top of the band board or subfloor. Insert the product half way up into the joist cavity and staple the product edge to the side of the joist.

What is the difference between a radiant barrier and a vapor barrier?

* vapor barrier or vapor retardant is a material which does not allow water vapor to pass through it. * non5perforated radiant barrier is a vapor retardant (vapor barrier) and if used, it will not allow water vapor to pass through.

Is Tyvek a thermal barrier?

No, Tyvek house wrap itself does not have an R-value, which is a measure of thermal resistance or insulation. The purpose of a Tyvek house wrap is not to provide insulation, but to act as an air and moisture barrier. It blocks drafts and moistures, helping your insulation to do its job more effectively.

Is fi foil a vapor barrier?

The product also can be used as an effective vapor retarder. The aluminum facing also reduces radiant heat transfer for added R-value or as a radiant barrier and is available in 1000 square foot rolls 54″ wide.

When should you not use a vapor barrier?

Because a vapor barrier is a low permeable barrier, it keeps moisture from passing through. This is beneficial to keep moisture away from a dry surface but will trap moisture behind it if installed on a water-damaged concrete wall, causing the wall to fail further.

What insulation does not need a vapor barrier?

In Most Cases, Attic Insulation Does Not Need To Provide A Vapor Barrier. The good news is that blown-in insulation should not need a vapor barrier. Blown-in is primarily used on the attic floor, and vapor barriers are not a concern for attics in our climate zone.

What is the best vapor barrier?

Here are the best vapor barriers for walls, handpicked by our team:
  • 6 Mil White Dura-Skrim® Reinforced Plastic Sheeting. ...
  • 6 Mil and 10 Mil Dura Skrim® Fire Retardant Reinforced Plastic Sheeting. ...
  • 6 Mil, 8 Mil, and 14 Mil Tuff-Scrim™ Reinforced Poly Sheeting.

What temperature does Reflectix melt?

2.5 Material Softening Point: In direct contact with the heat source the material shall withstand 180O F and with a 1 inch airspace 240O F.

Is Reflectix better than fiberglass?

1 With fiberglass insulation R-values ranging from R-15 to R-19 for two-by-four wall systems, Reflectix appears to be a better insulating material than fiberglass or other thick, dense materials.

Which side of reflective insulation faces out?

if it is hot outside, the reflective part of your foil insulation must face outside. if it is freezing outside, the best orientation of the reflective part is inside. if you press the foil side of the insulation tight up against the wall (foil facing outward), the radiant barrier will not work.

What is the difference between a moisture barrier and a vapor barrier?

Moisture barriers block both liquid water and water vapor, while vapor barriers focus on blocking water vapor only. Many products do both jobs, but you should know what your barrier is designed to do and pick the right one for your project.

What type of insulation is used for the vapor barrier?

Treated paper or foil used as a vapor retarder typically comes in the form of kraft or foil-faced batt insulation. It is useful in situations where the wall finish has been removed and new exterior wall insulation is being installed, as well as in new builds.

Can Tyvek be used as a moisture barrier?

Tyvek® weather barriers and related products, like sealants and flashing tape, are used to help create a building envelope system for homes and commercial buildings. Tyvek® can reduce air and water infiltration to help prevent drafts and water damage.

What can I use for a vapor barrier under my house?

Cover the crawlspace floor with a single layer of plastic moisture polyethylene vapor barrier. Overlap any seams and tape them with waterproof seam tape. “Make sure you overlap the plastic at least 12 inches,” Church says.

What can be used as a heat barrier?

Radiant barriers consist of a highly reflective material, usually aluminum foil, which is applied to one or both sides of a number of substrate materials such as kraft paper, plastic films, cardboard, oriented strand board, and air infiltration barrier material.

Do I really need a vapour barrier?

Depending on where you live, the vapour barrier will either go on the inner surface of the insulation (if you live in a cold climate) or the outer surface of the insulation (if you live in a hot climate). It's safe to say that a vapour barrier will be needed for almost all projects.

Previous article
How can I make my dryer ball more effective?
Next article
What happens if you turn your ice maker off?