Building paper and house wrap both help protect a home’s exterior walls from water that gets behind the siding. They are not siding, insulation, or substitutes for careful flashing. The main differences involve what they are made of, how they manage water and water vapor, and how they perform during installation and exposure to the weather. Understanding those differences helps homeowners and builders select a suitable water-resistive barrier (WRB) and use it as part of a complete wall system.
What Building Paper and House Wrap Do
Exterior siding is the first line of defense against rain, but wind-driven water can pass through joints, cracks, and openings. A WRB sits behind the siding and helps keep that water from reaching the wall sheathing and framing. A properly detailed barrier also allows water vapor to escape from the wall, depending on the product and the wall assembly.
Building paper and house wrap are two common WRB categories. Building paper usually refers to asphalt-saturated felt or a related asphalt-treated paper product. House wrap usually means a manufactured sheet or roll made from a polymer material, such as spun-bonded polyolefin. Product formulations vary, so the label and technical data sheet matter more than the category name alone.
Neither material can compensate for poorly installed windows, doors, roof-wall transitions, or penetrations. Those areas need flashing that directs water outward and integrates with the WRB. The objective is a continuous drainage plane, not simply a layer of material stapled over the sheathing.
Building Paper vs. House Wrap at a Glance
| Feature | Building Paper | House Wrap |
|---|---|---|
| Typical material | Asphalt-saturated felt or asphalt-treated paper | Polymer-based sheet or membrane |
| Water management | Sheds water when correctly lapped and detailed | Sheds water when correctly lapped, sealed, and detailed |
| Water-vapor behavior | Varies by product and moisture condition | Varies; many products are vapor-permeable, but ratings differ |
| Handling | Can be heavier, stiff, or prone to tearing when wet, depending on product | Often lightweight and available in wide rolls; can flap or tear if unsecured |
| Exposure limits | Product-specific; prolonged wetting can affect some products | Product-specific; UV and weather exposure limits apply |
| Best selection method | Check the standard, rating, and installation instructions | Check the product data, approved uses, and installation instructions |
How Building Paper Works
Traditional building paper is made from a paper base treated with asphalt to improve resistance to liquid water. A commonly encountered specification is asphalt-saturated organic felt complying with ASTM D226, with different types offering different properties. The specific product standard and label should be checked; not every material called “building paper” is equivalent to every other one.
Building paper sheds water mainly through its water-resistant surface and shingle-style installation. Upper courses overlap lower courses so water runs toward the exterior rather than behind the barrier. At corners and openings, correct laps and flashing details are essential. Paper that is reversed, torn, poorly fastened, or improperly integrated with flashing can create a path for water.
Building paper is frequently used behind certain siding systems, including stucco and masonry veneer, when the applicable code, product instructions, and wall design call for it. These assemblies may require multiple layers or a drainage space. The requirements are not interchangeable across siding types: a felt layer specified for one wall system should not automatically be treated as suitable for another.
How House Wrap Works
House wrap is a broad market term, not a single standardized recipe. Many products are made from nonwoven or woven polyolefin materials, while other WRBs include coated membranes or integrated sheathing products. Their intended function is to resist bulk water while allowing some water vapor to pass through. The degree of vapor transmission, strength, and exposure tolerance varies substantially by product.
Some house wraps have printed overlap lines, fastening zones, or instructions for taping seams. These features can make layout more straightforward, particularly across large wall areas. They do not eliminate the need to follow the manufacturer’s requirements for fasteners, seam treatment, window flashing, and maximum exposure before siding is installed.
House wrap also needs to be protected from wind damage during construction. Loose material can balloon, tear, or pull fasteners through the sheet. A product may be rated for a particular period of exposure to sunlight and weather, but that rating is not permission to leave it uncovered indefinitely. Builders should follow the stated exposure limit and repair damage before installing cladding.
Water Resistance and Drainage
A WRB is part of a water-management system, not a waterproof shell. Some rain can pass through siding, and the wall needs a reliable way to drain that water out. Shingle-style laps, properly integrated flashing, and an appropriate drainage space behind the cladding can all contribute. The details depend on the cladding, building design, climate, and code requirements.
Neither building paper nor house wrap is automatically more water-resistant in every application. Performance depends on the specific product and how it is installed. A high-quality material with open seams or reverse laps can perform worse than a more basic product installed with sound detailing. For walls exposed to heavy rain, builders should consider the entire assembly, including cladding, drainage provisions, flashing, and the WRB’s test performance.
Rain-screen systems add a gap or drainage path between cladding and the WRB. The gap can help water drain and promote drying, but its design must suit the cladding and project. A WRB should not be treated as a substitute for a designed drainage plane, especially in assemblies where the cladding itself absorbs or stores moisture.
Vapor Permeability and Wall Drying
Water vapor is different from liquid water. A material’s vapor permeance indicates how readily vapor passes through it under specified test conditions. Products sold as house wrap can have different permeance ratings, and building paper’s performance can also vary. Asphalt-treated materials may respond differently as they age or become damp, so broad statements such as “paper breathes more” or “house wrap always dries faster” are unreliable.
Vapor permeability matters because walls need a safe path to dry. That path may be inward, outward, or both, depending on the climate, interior vapor control, insulation, sheathing, and cladding. In cold climates, for example, indoor moisture can move toward cold exterior layers; in hot, humid climates, air conditioning and exterior humidity can create different moisture patterns. A barrier selected without considering the whole assembly may limit drying where it is needed.
For complex walls, such as those with exterior foam, vapor-retarding interior finishes, or moisture-sensitive cladding, a building professional can evaluate the assembly. Product permeance data and local climate conditions are more useful than relying on the generic labels “paper” and “wrap.”
Durability, Installation, and Job-Site Conditions
Building paper may be less convenient to handle in some conditions. Certain products can wrinkle, tear, or become difficult to work with after wetting. Other products are designed for more demanding use. House wrap is often lighter and comes in wide rolls, which can speed coverage, but it can be vulnerable to wind, punctures, and damage if left unsecured. These are tendencies, not guarantees; product construction and installation methods matter.
Installation should follow the manufacturer’s instructions, including the required overlap, fastening pattern, seam treatment, and exposure limit. Fastener type and spacing can vary. Some products require cap fasteners or tape at seams; others specify different methods. Unapproved tapes or sealants may not adhere reliably or may conflict with warranty requirements.
Openings require particular care. The WRB and flashing should be layered so water drains outward, with sill, jamb, and head details coordinated with the window or door manufacturer’s instructions. Pipes, vents, electrical boxes, and other penetrations also need compatible flashing. Simply cutting an X in the barrier and leaving the edges untaped can expose the sheathing to water.
Code Requirements and Product Standards
U.S. building codes generally require a water-resistive barrier behind exterior wall coverings, subject to specific exceptions and assembly requirements. The exact rules depend on the locally adopted code edition, amendments, building type, and cladding. Model-code language is updated over time, and local jurisdictions may adopt it on different schedules, so code compliance should be verified with the local building department or a qualified professional.
Standards can help distinguish products and intended performance. ASTM D226, for example, covers asphalt-saturated organic felt used in roofing and waterproofing applications; a product’s stated compliance and approved wall use should be confirmed. ASTM E2556 addresses mechanically attached, flexible, water-resistive barriers intended for use behind exterior wall coverings. Other standards may apply to particular materials or assemblies. A standard reference alone does not establish that a product is appropriate for every wall.
Some claddings or systems have additional requirements. Stucco, masonry veneer, and manufactured cladding may call for specific layers, drainage features, or installation details. The governing code, approved plans, product evaluation reports, and manufacturers’ instructions should be considered together. Where these documents differ, the project team should resolve the conflict before installation rather than assuming one generic rule applies.
Cost and Practical Considerations
Material price is only one part of the cost comparison. Roll size, coverage, fasteners, seam tapes, labor, waste, repairs, and required accessories all affect installed cost. House wrap’s wider rolls may reduce the number of seams on some projects, while building paper may fit familiar local practices or particular cladding specifications. Labor savings depend on the crew, layout, weather, and wall complexity.
Homeowners comparing bids should ask for the exact product name, its intended use, the installation method, and how windows and penetrations will be flashed. A quote that says only “house wrap” or “felt paper” does not identify the product’s performance or the quality of the detailing. Replacing a WRB during a siding project can also reveal damaged sheathing or hidden moisture problems that require separate repairs.
How to Choose Between Building Paper and House Wrap
The right choice is the material that meets the project’s code and cladding requirements and can be installed correctly as part of a complete wall assembly. A practical selection process includes the following steps:
- Identify the cladding and assembly. Check whether the siding, stucco, veneer, or other finish specifies a particular WRB, number of layers, or drainage space.
- Confirm local requirements. Review the adopted code, approved plans, and any local amendments. Ask the building department or project professional when requirements are unclear.
- Compare product data. Review water-resistance claims, vapor permeance, strength, exposure limits, approved applications, and relevant standards.
- Plan transitions and openings. Choose a system that can be integrated reliably with flashing at windows, doors, corners, roofs, and penetrations.
- Consider installation conditions. Account for wind, rain, schedule, crew experience, and the time the material may remain exposed before siding goes on.
- Follow instructions consistently. Use specified fasteners, laps, tapes, and repair methods; do not mix components unless the manufacturers allow it.
Building paper may be a sound choice when its specifications suit the cladding and local requirements, and the installer can provide the required layering and flashing. House wrap may be a sound choice when its product ratings suit the wall and its installation details are followed. Neither is universally better. The most dependable result comes from a compatible product, a continuous drainage plane, and workmanship that keeps water moving outward.
Common Questions About Building Paper vs. House Wrap
Can house wrap go over building paper?
Adding one WRB over another is not automatically beneficial. Multiple layers can change drainage and drying behavior, and the outer layer may trap water if the assembly is not designed for it. Some wall systems require multiple layers, while others do not. Follow the cladding instructions, code, and project design rather than stacking materials by default.
Can building paper replace house wrap?
It may be possible when the specific paper product is approved for the application and satisfies the applicable code and cladding requirements. The terms are not interchangeable for every project. The product’s documentation and required installation details determine whether it is suitable.
Which material lasts longer?
Service life depends on exposure, product quality, installation, and whether the wall stays dry. Both materials are generally intended to be protected behind cladding, not left exposed as permanent exterior finishes. Following exposure limits and promptly repairing damage helps reduce construction-period risk.
Is either one a vapor barrier?
Not necessarily. “Vapor barrier” is often used loosely, but vapor-control materials are classified by permeance, and WRBs vary in how much vapor they allow through. The product data sheet provides the relevant rating. A wall’s vapor-control strategy should be designed for the climate and full assembly, not inferred from the product’s name.