Scope
Air seal around all plumbing and piping installed through walls, ceilings, and flooring to keep conditioned air from leaking into unconditioned space.
- Using a saw or drill, cleanly cut all holes no more than 1 inch larger in diameter than the diameter of the pipe.
- Seal all gaps and holes to unconditioned space with caulk or canned spray foam. For larger gaps, rigid blocking material can be cut to fit over the gap and sealed in place with caulk or spray foam.
See the Compliance Tab for related codes and standards requirements, and criteria to meet national programs such as DOE’s Zero Energy Ready Home program, ENERGY STAR Single-Family New Homes, and Indoor airPLUS.
Description
Generous holes are often cut through subflooring, walls, bottom plates, and top plates for plumbing pipes and vent stacks. These gaps are often hidden from view in under-sink cabinets, beneath tubs, behind shower enclosures, behind washing machines and dishwashers, or within wall cavities. If not properly closed up, large amounts of air can pass through these gaps, encouraged by pressure and temperature differences between conditioned and unconditioned spaces. These air leaks represent energy losses; they could also potentially allow warm, moisture-laden air into wall cavities or attics where it can condense on cold surfaces, creating moisture problems. Conversely, air leaking into the house from unconditioned sources such as the garage or crawlspace can affect indoor air quality and cause drafts. Air barriers need to be continuous to be effective; this means sealing all penetrations in exterior walls and in walls and floors adjoining unconditioned spaces.
Be sure to schedule sealing of plumbing holes after the pipes and plumbing have been installed and before the drywall is completed. Responsibility for sealing air leaks around plumbing should be included in the contract for the appropriate trade, depending on the workflow at a specific job site.
How to Air Seal Holes around Plumbing
- Use caulk or canned spray foam to seal piping holes through the top plates, bottom plates, and subfloor. Avoid running water pipes along exterior walls. Run piping next to floor joists in floors if insulating with batts to minimize disruption of cavity insulation. Water pipes should be insulated to R-3 (IECC 2012) even when they are installed in interior walls, to conserve the heat in hot water and to minimize the potential for condensation.
Figure 1. Foam holes for plumbing in the top plate, sill plate, or subfloor (Source: Courtesy of PNNL). - For larger holes in the top or bottom plate, use a rubber gasket. Use of a flexible gasket allows some movement of the vent stack without loosening the air seal (Lstiburek 2009).
- Cut a hole in the gasket to just fit the width of the pipe.
- Apply caulk to the top plate.
- Fit the gasket over the pipe and press down to adhere the gasket to the caulk.
- Staple the gasket in place.
- Apply more caulk around the pipe.
- Use caulk or canned spray foam to seal the holes made in rim joists for plumbing pipes. Keep the pipe runs close to the floor joists to avoid compressing the insulation.
Figure 2. Seal plumbing holes in rim joist with caulk (Source: Building America Best Practices Series Volume 12: 40% Whole-House Energy Savings in the Cold and Very Cold Climates 2011). Figure 3. Seal plumbing holes in rim joist with caulk (Source: Building America Best Practices Series Volume 12: 40% Whole-House Energy Savings in the Cold and Very Cold Climates 2011). - Use caulk or pre-fabricated gaskets to seal around the plumbing pipe penetrations in exterior walls. Make sure the gasket is properly integrated with the house wrap and that cuts in the house wrap around the gasket are taped or caulked.
Figure 4. Seal plumbing penetrations in exterior walls with caulk or a gasket (Source: Building America Best Practices Series Volume 12: 40% Whole-House Energy Savings in the Cold and Very Cold Climates 2011). - For bath tubs on outside walls, avoid running the water pipes along the exterior walls, if possible. Install piping, then air seal any holes in the exterior wall framing or subfloor.
- If the tub or shower is installed on an exterior wall, insulate and air seal the exterior wall behind the tub with sheet goods before the tub is installed. [See Walls behind Showers and Tubs for insulating and air sealing exterior walls behind showers and tubs.]
- After the drain is installed, seal the hole around the tub drain pipe with canned spray foam. For larger holes, seal the hole with pieces of water-resistant sheet goods such as rigid foam or cement backer board that is cut to fit around the pipe and caulked or foamed in place.
Figure 5. Use sheet goods to seal holes around drain pipes under the tub (Source: Technology Fact Sheet - Air Sealing 1999).
Success
Holes around plumbing pipes should be visually checked to see if caulk, canned spray foam, and air blocking materials have been applied before insulation and drywall are installed. Blower door testing, which is conducted as part of the whole-house energy performance test-out, may help indicate whether holes for plumbing in exterior walls and floors have been successfully sealed.
Climate
No climate specific information applies.
Training
CAD
Compliance
Compliance
The Compliance tab contains both program and code information. Code language is excerpted and summarized below. For exact code language, refer to the applicable code, which may require purchase from the publisher. While we continually update our database, links may have changed since posting. Please contact our webmaster if you find broken links.
ENERGY STAR Single-Family New Homes, Version 3/3.1 (Rev. 11)
National Rater Field Checklist
Thermal Enclosure System.
4. Air Sealing (Unless otherwise noted below, “sealed” indicates the use of caulk, foam, or equivalent material).
4.1 Ducts, flues, shafts, plumbing, piping, wiring, exhaust fans, & other penetrations to unconditioned space sealed, with blocking / flashing as needed.
Please see the ENERGY STAR Single-Family New Homes Implementation Timeline for the program version and revision currently applicable in in your state.
DOE Zero Energy Ready Home (Revision 07)
Exhibit 1 Mandatory Requirements.
Exhibit 1, Item 1) Certified under the ENERGY STAR Qualified Homes Program or the ENERGY STAR Multifamily New Construction Program.
2009 International Energy Conservation Code (IECC)
Table 402.4.2 Air Barrier and insulation Inspection Component Criteria, Shafts, penetrations: Duct shafts, utility penetrations, and flue shafts opening to exterior or unconditioned spare are air sealed.
Plumbing and wiring: Insulation is placed between outside and pipes. Batt insulation is cut to fit around wiring and plumbing, or sprayed/blown insulation extends behind piping and wiring.
402.4.1 Air leakage, Building Thermal Envelope. The building thermal envelope should be constructed to limit air leakage. Methods used to seal between dissimilar materials should allow for differential expansion and contraction. Sources of infiltration (see listing below) should be caulked, gasketed, weather-stripped, or otherwise sealed with an air-barrier material, suitable film, or solid material:
- All joints, seams, and penetrations
- Utility penetrations
- Rim joist junction
- Other sources of infiltration.
2012 IECC R402.4 Air Leakage. The building thermal envelope should be constructed to limit air leakage.
R402.4.1 Building Thermal Envelope. Methods used to seal between dissimilar materials should allow for differential expansion and contraction.
Table R402.4.1.1 Air Barrier and Insulation Installation, Shafts/penetrations: Duct shafts, utility penetrations, and flue shafts opening to exterior or unconditioned space are air sealed.
Plumbing and wiring: Insulation is placed between the exterior of the wall assembly and pipes. Batt insulation is cut and fitted around wiring and plumbing, or for insulation that on installation readily conforms to available space such insulation shall fill all space between wall and piping/wiring.
Table R402.4.1.1 Air Barrier and Insulation Installation, Shafts/penetrations: Duct shafts, utility penetrations, and flue shafts opening to exterior or unconditioned space are air sealed. Air Barrier and Insulation Installation, Plumbing and wiring: Insulation is placed between the exterior of the wall assembly and pipes. Batt insulation is cut and fitted around wiring and plumbing, or for insulation that on installation readily conforms to available space such insulation shall fill all space between wall and piping/wiring.
Concealed sprinklers – Concealed fire sprinklers should only be sealed in a manner that is recommended by the manufacturer. Caulking or other adhesive sealants should not be used to fill voids between fire sprinkler cover plates and ceiling.
Table R402.4.1.1 Air Barrier, Air Sealing, and Insulation Installation, Shafts/penetrations: Duct shafts, utility penetrations, and flue shafts opening to exterior or unconditioned space are air sealed to allow for expansion, contraction, and mechanical vibration. The insulation shall be fitted tightly around utilities to maintain the required R-value. Plumbing and wiring: Insulation is placed between the exterior of the wall assembly and pipes. Batt insulation is cut and fitted around wiring and plumbing, or for insulation that on installation readily conforms to available space such insulation shall fill all space between wall and piping/wiring. Any holes created by wiring or plumbing shall be air sealed.
Retrofit: 2009, 2012, 2015, 2018, and 2021 IECC
Section R101.4.3 (in 2009 and 2012). Additions, alterations, renovations, or repairs shall conform to the provisions of this code, without requiring the unaltered portions of the existing building to comply with this code. (See code for additional requirements and exceptions.)
Chapter 5 (in 2015, 2018, 2021). The provisions of this chapter shall control the alteration, repair, addition, and change of occupancy of existing buildings and structures.
2009 International Residential Code (IRC)
Section P2606.1 General. Roof and exterior wall penetrations to be made water tight. Joints at the roof, around vent pipes, to have lead, copper or galvanized iron flashings or approved elastomeric material.
N1102.4.1 Air leakage, Building Thermal Envelope. The building thermal envelope should be constructed to limit air leakage. Methods used to seal between dissimilar materials should allow for differential expansion and contraction. Sources of infiltration (see listing below) should be caulked, gasketed, weather-stripped, or otherwise sealed with an air-barrier material, suitable film, or solid material:
- All joints, seams, and penetrations
- Utility penetrations
- Rim joist junction
- Other sources of infiltration.
Table N1102.4.2 Air Barrier and insulation Inspection Component Criteria, Shafts, penetrations: Duct shafts, utility penetrations, and flue shafts opening to exterior or unconditioned space are air sealed.
Plumbing and wiring: Insulation is placed between outside and pipes. Batt insulation is cut to fit around wiring and plumbing, or sprayed/blown insulation extends behind piping and wiring.
Section P2606 Penetrations. The annular space between the outside of a pipe and an opening in a building envelope wall, floor, or ceiling assembly penetrated by a pipe shall be sealed with caulking material or foam sealant or closed with a gasketing system. Caulking material, foam sealant or gasketing system shall be designed for the conditions at the penetration location and shall be compatible with the pipe, sleeve and building materials in contact with the sealing materials. Annular spaces created by pipes penetrating fire-resistance-rated assemblies or membranes of such assemblies shall be sealed or closed in accordance with the building portion of the code.
Section P2607.1 General. Roof and exterior wall penetrations to be made water tight. Joints at the roof, around vent pipes, to have lead, copper or galvanized iron flashings or approved elastomeric material.
Table N1102.4.1.1 Air Barrier and Insulation Installation, Shafts/penetrations: Duct shafts, utility penetrations, and flue shafts opening to exterior or unconditioned space are air sealed. Table N11402.4.1.1 Air Barrier and Insulation Installation, Plumbing and wiring: Insulation is placed between the exterior of the wall assembly and pipes. Batt insulation is cut and fitted around wiring and plumbing, or for insulation that on installation readily conforms to available space such insulation shall fill all space between wall and piping/wiring.
Section P2606 Penetrations. The annular space between the outside of a pipe and an opening in a building envelope wall, floor, or ceiling assembly penetrated by a pipe shall be sealed with caulking material or foam sealant or closed with a gasketing system. Caulking material, foam sealant or gasketing system shall be designed for the conditions at the penetration location and shall be compatible with the pipe, sleeve and building materials in contact with the sealing materials. Annular spaces created by pipes penetrating fire-resistance-rated assemblies or membranes of such assemblies shall be sealed or closed in accordance with the building portion of the code.
Section P2607.1 Pipes Penetrating Roofs. Roof and exterior wall penetrations to be made water tight. Joints at the roof, around vent pipes, to have lead, copper or galvanized steel flashings or approved elastomeric material.
Table N1102.4.1.1 Air Barrier and Insulation Installation, Shafts/penetrations: Duct shafts, utility penetrations, and flue shafts opening to exterior or unconditioned space are air sealed. Air Barrier and Insulation Installation, Plumbing and wiring: Insulation is placed between the exterior of the wall assembly and pipes. Batt insulation is cut and fitted around wiring and plumbing, or for insulation that on installation readily conforms to available space such insulation shall fill all space between wall and piping/wiring.
Concealed sprinklers – Concealed fire sprinklers should only be sealed in a manner that is recommended by the manufacturer. Caulking or other adhesive sealants should not be used to fill voids between fire sprinkler cover plates and ceiling.
Retrofit: 2009, 2012, 2015, 2018, and 2021 IRC
Section R102.7.1 Additions, alterations, or repairs. Additions, alterations, renovations, or repairs shall conform to the provisions of this code, without requiring the unaltered portions of the existing building to comply with the requirements of this code, unless otherwise stated. (See code for additional requirements and exceptions.)
Appendix J regulates the repair, renovation, alteration, and reconstruction of existing buildings and is intended to encourage their continued safe use.
Retrofit
SCOPE
In existing homes, air seal around all plumbing and piping installed through walls, ceilings, and flooring to prevent air leakage and moisture movement between unconditioned and conditioned space. Sealant (e.g., caulk, fire-retardant caulk, fire-rated spray foam, etc.) should be compatible with all adjoining surfaces and meet the fire and air barrier specifications according to code.
- Air seal the following:
- service water heating supply and drain lines and other mechanical heating and cooling system piping
- piping vents
- all other plumbing penetrations (e.g., kitchen sink water lines and drains, dishwasher connections, bathroom sinks, toilet, washing machine).
- Seal all gaps and holes to unconditioned space with caulk or canned spray foam. For larger gaps, rigid blocking material can be cut to fit over the gap and sealed in place with caulk or spray foam.
See the U.S. Department of Energy’s Standard Work Specifications (SWS) for more on sealing penetrations. All global worker safety and health and safety air sealing specifications in DOE’s Standard Work Specifications (SWS) should be followed.
DESCRIPTION
How to Air Seal Holes around Plumbing
- Use caulk or canned spray foam to seal piping holes through the top plates, bottom plates, rim joists, and subfloor. In existing homes, these areas might not be easily accessible. Piping might be accessed from the attic, basement, or crawlspace depending on the construction of the home. Or access during bathroom and kitchen remodels.
- Use caulk to seal around the plumping pipe penetrations, and supply and drain lines in exterior and interior walls.
- Clean the area of any debris or dirt.
- Apply a layer of caulk and use a paint knife or spatula to smooth out the caulk; the caulk material should be flush with the dry wall with any gaps filled in (silicone caulk is suggested).
- For faucet pipes through exterior walls, install a rubber gasket or flashing around the pipe on the exterior wall, if possible, in addition to caulking. Integrate the gasket or flashing with the house wrap above the pipe.
- Check plumbing vent pipes for cracks and seal with caulk or acoustical sealant.
- For bath tubs, showers, and sinks, seal the hole around the drain pipe.
- Gain access from the basement or crawlspace if accessible, or during bathroom and kitchen remodels.
- Apply caulk or expanding foam around the hole.
- If the gap around the pipe is wider than an inch, use a solid material like sheet metal, plywood, or rigid foam to fill the hole. Fasten in place with adhesive or short screws and seal with caulk or spray foam.
See the Training Tab for a video on how to air seal attic plumbing pipes.
COMPLIANCE
Alterations
2015 IECC R501.1.1 / IRC N1107.1.1 Alterations – General. Alterations to an existing building or portion of a building should comply with Sections R502/N1108, R503/N1109, or R504/N1110. Unaltered portions of the existing building are not required to comply.
R503.1/N1109.1 General. Alterations to any building or structure should comply with the requirements of the code for new construction. Alterations should not negatively impact conformance of a building or structure to the provisions of this code; that is, code conformance should be the same as existed for the building or structure prior to the alteration. Alterations should not create an unsafe or hazardous condition or overload existing building systems. Alterations should be such that the altered building or structure uses no more energy than the existing building or structure prior to the alteration.
R503.2/N1103.2 Change in space conditioning. Any non-conditioned or low-energy space that is altered to become conditioned space must be brought into full compliance with this code. R503.1.1/N1109.1.1 Building Envelope. Building envelope assemblies that are part of the alteration must comply with Sections R402.1.2/N1102.1.2 (Insulation and Fenestration Table) or R402.1.4/N1102.1.4 (U-factor Alternative), and Sections R402.2.1/N1102.2.1 through R402.2.12/N1102.2.12, R402.3/1/N1102.3.1, R402.3.2/N1102.3.2, R402.4.3/N1102.4.3 and R402.4.4/N1102.4.4.
2012 IECC and 2012 IRC and 2009 IECC and 2009 IRC
2012 IECC/IRC, Section R101.4.3/N1101.3 and 2009 IECC/IRC, Section 101.4.3/N1101.4.3 Alterations – General. Alterations to an existing building or portion of a building should comply with the provisions of the code as they relate to new construction without requiring unaltered portion(s) of the existing building to comply with this code.
See Compliance tab.
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More Info.
Access to some references may require purchase from the publisher. While we continually update our database, links may have changed since posting. Please contact our webmaster if you find broken links.
The following authors and organizations contributed to the content in this Guide.
Pacific Northwest National Laboratory
Building Science Corporation, lead for the Building Science Consortium (BSC), a DOE Building America Research Team
Sales
Tight Air Sealed Home = Comprehensive Draft Protection
Poorly air-sealed homes are less comfortable and cost more to maintain because they provide a pathway for drafts, cold spots, moisture, and insects into the home. Comprehensive draft protection includes a continuous air barrier around the whole house along with caulking and sealing in all holes and cracks. This includes around wiring, plumbing, ducts, and flues; where wall framing meets flooring; around windows; where drywall meets top plates and sill plates; where rim joists meet foundation walls and subfloors; etc. Spray foam insulation can be used at rim joists, floors above unconditioned space, and in attics to insulate and air seal at the same time.
Sales Message
Comprehensive draft protection minimizes air flow that can undermine a complete high-performance insulation system. What this means for you is less wasted energy along with enhanced comfort, health, quiet, and durability. Wouldn’t you agree it would be a shame to only get a partial return on your investment in advanced insulation?