How to install vapor barrier behind shower wall

While other manufacturers advise against it, such as DensShield, which has a built-in moisture barrier. For vapor barriers that are installed behind the tile substrate, the installation is quick and easy but there are some considerations to keep in mind.

First, whether you chose a plastic sheeting or lb felt paper, when installing onto the wood studs, it is suggested that you use a minimum amount of staples to minimize any entry points for moisture.

Ideally, the plastic sheeting should be one continuous piece, but where two pieces need to be seemed together, a water resistant tape can be used to adhere overlapping edges. If you choose to install lb felt paper, the horizontal pieces should be continous that start from the bottom up, then overlap each other a minimum of 2 to 4 inches, encouraging moisture to exit into the shower area. Where a seam connects two pieces, there must be a minimum of 6 inches of overlap.

A vapor barrier can be applied or installed over the tile substrate using a liquid or sheet membrane. There is a clear advantage of using a liquid membrane, it is relatively easy to apply over the tile substrate, along with the use of a fiber mesh tape, you can secure joints and changes of plane. A sheet membrane has just as much of an advantage for ease of installation, but you gain the further benefit of continuity of thickness.

The seams and joints still need to be covered with a fiber mesh tape but you will be left with a sturdy surface. The industry standard, as well as most local building codes, do not encourage the use of a vapor barrier behind and over the tile substrate.

If moisture reaches your vapor barrier behind the tile substrate it should have the opportunity to evaporate, this process is hindered when a second vapor barrier is applied or installed to the outside of the tile substrate. In this case, there is less breathability to encourage evaporation, which ultimately could cause mold growth.

A standard argument would be that moisture would never reach behind the tile substrate if a liquid membrane is applied or a sheet membrane is installed over the tile substrate. This specification covers minimum performances and specification criteria for an air barrier material or system for framed, opaque walls of low-rise buildings. The provisions are intended to allow the user to design the wall performance criteria and increase air barrier specifications for a particular climate location, function, or design.

Self-Adhered Sheet Air Barrier. This specification for self-adhered sheet air barriers is developed by a professional association, the Air Barrier Association of America, to provide guidance to the design professional. ABAA Fluid-Applied Air and Vapor Barrier. This specification for air barriers that are fluid-applied and also act as vapor barriers is developed by a professional association, the Air Barrier Association of America, to provide guidance to the design professional.

This specification for closed-cell, medium-density spray polyurethane foam air barriers is developed by a professional association, the Air Barrier Association of America, to provide guidance to the design professional.

This specification for fluid-applied vapor permeable air barriers is developed by a professional association, the Air Barrier Association of America, to provide guidance to the design professional. More Info. Access to some references may require purchase from the publisher. A whole-house draft barrier is a continuous layer of air-tight materials that block air leaks. This barrier can be integrated with other materials to also function as a water barrier, thermal barrier, and vapor barrier.

For example, rigid foam insulation can be used to block thermal flow as well as air flow when seams are sealed with tape, caulk, adhesives, or liquid-applied sealants. Some rigid foams have an integrated water control layer as well.

Additionally, drywall can serve as an interior air barrier when the seams are taped and spackled, and caulk, spray foam, or gaskets are used to seal around wiring, plumbing, and other penetrations. It also serves as the vapor barrier when finished with paint. Insulation should be in full contact with the air barrier layer. Whole-house draft barriers block air flow that can undermine the thermal protection with a complete high-performance insulation system.

What this means to you is less wasted energy along with enhanced comfort, quiet, and durability. The Building America Field Kit allows you to save items to your profile for review or use on-site. Sign Up or Log In. Walls Behind Showers and Tubs Print. Scope Images. Install an air barrier behind showers and tubs installed on exterior walls. Install insulation without misalignments, compressions, gaps, or voids in all exterior wall cavities behind tubs and showers.

Cover the wall cavities with a rigid air barrier or other supporting material to prevent cavity insulation from sagging and to create a continuous thermal barrier. Rigid air barrier materials for use behind showers and tubs include fiber-cement, fiber-reinforced gypsum, glass mat gypsum, or fiber mat-reinforced cementitious backer panels.

See the guide [WM. Fill the entire wall cavity with insulation to the R-value required by local code or higher. Install 2x4 blocking between the wall studs, if needed, to support the air barrier. Cut cement board, fiber cement board, paperless gypsum board, Thermo-Ply, or other thin barrier material to size to cover area behind tub see Figures 1 and 2.

Apply a thick bead of caulk to the surface of exposed studs, wood blocking, and bottom plate. Nail or screw the thin-profile air barrier material to the studs. Cement board is not waterproof; it must be coated with a fluid-applied waterproofing, or a water-resistive barrier must be applied behind it that allows drainage See the guide Cement Board Installed Behind Tile and Panel Tub and Shower Enclosures.

Use caulk or foam to seal seams and any holes made through the air barrier material. Install the new tub. Block holes around the tub drain with sheet goods and spray foam. Finish the walls by installing fiberglass wall panels or tiling the surface. The condition that will influence your decision most as to whether you should install a vapor barrier, besides your local building codes, is going to be the atmospheric conditions outside of your home and inside your shower area.

Vapor and condensation behavior is going to differ in different regions where temperature differences are greater during a season or much less during a single day, building materials are going to react differently due to these differences, and the immediate area in your shower upon being exposed to vapor will behave accordingly.

You will know the conditions in your shower area better than anyone else but you will need to have a firm understanding of the materials you intend to use in order to have a successful installation of your shower walls. Install Vapor Barrier. How To Install Vapor Barrier.

Shower Walls. Tile Substrate. Vapor Barrier Tips. Do not install a vapor barrier over an existing plastic sheeting, this will promote condensation Use a minimal amount of staples to secure the vapor barrier to the walls studs Run the height of the vapor barrier from the top, all the way down into the shower pan, make sure not cut too short before the water barrier Use appropriate tape to adhere two pieces of vapor barrier and edges to avoid moisture entry to the back walls.

Found These Also. How to install a vapor barrier Three types of moisture barriers Vapor Barriers: How they work and why they matter Vapor barrier and backer board using the Dix System Vapor barrier explained 5 reasons to use a vapor barrier How to install a vapor barrier in a shower wall Felt paper, plastic sheeting, or RedGard as a vapor barrier Vapor barrier behind hardiebacker RedGard as a vapor barrier. Pressure balance valve keeps water temperature within a safe 3 Degree F Faucet and finish lifetime limited warranty Trim kit only, must purchase rough-in RUNBX to complete the unit Meets standards set by Americans with Disabilities Act.

Remember This. Always consult a professional contractor in your area to ensure that your bathroom or kitchen remodel follows the state and local building codes.