BUILDING PAPER

Building paper also referred as 'building wrap' is a coarse brown paper that is used in timber frame application on outside walls of wood frame buildings and can be applied beneath wood siding, stucco, brick, aluminium, vinyl, or any other type of siding. It is also used for temporary protection from dust and foot traffic. Other names for building paper include water, air, or vapor-control layers, depending on the product’s functionality. Building paper is supplied in black or grey rolls either 1x25m or 1x50mm size and comes in 2 main grades: BS 1521 and BS 4016. While BS 4016 grade is just one product - Type 2 Blue Breather Paper, the BS 1521 grades are normally taken to be A1F, B1F and B2, or variants such as FF1 Foil Faced Building Paper or Polybit Building Paper. Building paper has been the protectant of choice for over 100 years. Its strength comes from wood fibre and we all know that exposed wood can withstand decades of UV exposure. In addition, due to the fact that wood can expand and contract with variations in humidity levels, building paper can help prevent stresses on the stucco and masonry walls. If you do a good job with the installation and do it properly, the building paper will last forever. It is also pretty cheap. Average cost per roll as of 2022 is £48.

WHAT IS BUILDING PAPER USED FOR?

The purpose of building paper is initially to prevent wind from penetrating into a wall and secondly to act as a backup moisture barrier behind cladding. That is why it is frequently used between exterior wall sheathing and masonry siding and is intended for use on smooth substrates including plywood. It is mainly used as a weatherproofing layer in building construction, as a vapour check membrane and for temporary protection and separation where a tough, water resistant material is needed. By using building paper a separation layer is created between the stucco/masonry surface and the wall sheathing. This separation layer prevents water penetration and compensates for different coefficient rates of expansion between the wood sheathing and the masonry wall finishes. Breathable building paper is intended to be installed over the sheathing and behind the siding, no matter what siding you are using: wood, fiber cement, vinyl, brick and others. Typical uses for this product range include:

• Exclusion and Air Movement barriers,
• Cladding underlay in uninsulated buildings,
• Vapour check within insulated structures,
• Separation layer,
• Flat lead roofing underlay,
• Temporary protection,
• Bond Breaks, Draught and Damp.

BRITISH STANDARD FOR BUILDING PAPERS | TYPES OF BUILDING PAPERS

TYPES

British Standard specifies the quality, workmanship, dimensions and performance requirements for two classes of waterproof building papers. Each class is divided into two grades and each grade into two types as follows:
1) Class A. 
For building purposes, such as for the prevention of draughts or the ingress of water into wall or pitched roof structures but not for damp-proof courses such as are normally required by building byelaws. Class A papers are of two grades. They are:
a) Grade A1, having higher tensile strength and bursting strength test requirements.
b) Grade A2, having lower tensile strength and bursting strength test requirements.

2) Class B. 
For temporary purposes, such as for the protection of concrete during curing or as an underlay to concrete to prevent moisture being absorbed by the base. Class B papers are of two grades. They are:
a) Grade B1, having a higher bursting strength test requirement.
b) Grade B2, having a lower bursting strength test requirement.
All grades are sub-divided into the following types:
Types which are not reinforced with fibres – A1, A2, B1, and B2.
Types which have fibrous reinforcements – A1F, A2F, B1F and B2F.

BRITISH STANDARD

Building papers shall consist of one or more laminae of paper or felted fibre, with or without fibrous reinforcement, and shall incorporate a waterproofing medium. Paper shall conform to the requirements of Clause3 or Clause4, and be supplied in standard rolls of 50m length and in multiples of 50m and in widths of 1000mm, 1250mm, 1500mm, 2000mm and 2150mm. Half rolls of 25m length may also be supplied. Where the paper is reinforced by fibre there shall not be less than18 strands to 300mm, both lengthwise and crosswise. The tensile strength shall be not less than the appropriate values:
Strength in machine direction (lengthwise) per metre of width - Grades A1, A1F - 12.40kN/m.
Strength in machine direction (lengthwise) per metre of width - Grades A2, A2F - 8.80kN/m.
Strength in cross direction (crosswise) permetre of width - Grades A1, A1F - 7.20kN/m.
Strength in cross direction (crosswise) permetre of width - Grades A2, A2F - 5.20kN/m.
The bursting strength of the material shall be not less than:
Grades A1, A1F - 550kN/m2
Grades A2, A2F - 480 kN/m2
In terms of water penetration paper shall be free from staining after 24hours. Each roll of waterproof building paper shall be marked with the following markings:

1) The number of this British Standard, i.e.,BS1521.

2) The grade of paper (e.g.,B1F).

3) The length of the roll in metres. If the roll is wrapped, the markings shall be on the wrapping. If the roll is not wrapped, the markings shall be either on the roll itself or on a substantial label attached firmly to the roll. Papers complying with the requirements of this British Standard are likely to vary in permeability to water vapour.

  
BUILDING PAPER INSTALLATION

Building papers are either mechanically attached, self-adhere or liquid, pre-attached to a composite wall product. When applying building paper to exterior walls, or even roof sheathing if using tarred roof felt paper, it should be lapped similar to applying siding or shingles to a wall or roof. For example the first layer of building paper should be applied to the lower level walls, or the bottom edge of the roof. The next course that sits above the lower layer should be lapped over it by approximately 5 inches.

MANUFACTURERS

The most popular brands of building papers are Novia^® and Dupont Tyvek^®. Both come in multiple roll sizes and are installed by simply stapling with a hammer tacker. We stock the full range of premium quality Novia building papers including A1F, B1F, B2, Polybit (Polythene Coated A1F) and FF1 Foil Faced Building Paper.

DUPONT TYVEK^®

Dupont Tyvek^® Housewrap is made of high-density polyethylene fibres for long-term protection against the elements. This durable, lightweight breathable membrane is windtight and water resistant and designed for use in new build, refurbishment or extension projects. DuPont^™ Tyvek^® Housewrap is the ideal breathable membrane for timber frame wall systems and is also suitable for steel frame and concrete wall construction. It is surface-applied and should be fixed directly to the sheathing ply/OSB, insulation or blockwork.

NOVIA^®

A1F Standard Building Paper - 1000mm x 25m, 1000mm x 50m- is a traditional reinforced kraft paper bitumen-bonded laminate manufactured using wet strength kraft paper meeting the technical requirements of BS 1521, Class A1F waterproof building papers. Typically used as a vapour-check, underlay on uninsulated cladding, separation layer, bond break, air movement barrier or for temporary protection.

Polybit – Enhanced A1F Building Paper - 1000mm x 25m Polybit is a clear polythene coated version of A1F Standard Building Paper. Typically used where conditions require a material with additional strength and durability for example, vapour checks, underlay on uninsulated cladding, flat lead-sheet underlay, timber floor DPM and heavy-duty temporary protection.

B1F Building Paper - 1250mm x 50m B1F is a lower-grade variant of A1F Standard Building Paper. A traditional reinforced kraft paper bitumen-bonded laminate that meets the technical requirements of BS 1521, Class B1F waterproof building papers. Typically used for separation layers under insulated screeds where some toughness is required during laying, temporary protection applications and for garden buildings.

B2 Building Paper - 1000mm x 100m- is a traditional non-reinforced black PE-coated kraft building paper used within the construction industry, and meets the requirements of BS 1521, grade B2. Typically used for temporary protection, concrete shuttering, floor screed break layers and as an external cladding render backing in timber frames. An excellent low-cost material with good grease and solvent resistance.

Novia FF1 Premium Foil Faced Building Paper is a low-emissivity foil faced, scrim-reinforced premium building paper used in a wide range of user-defined applications where rubber and plastic are unsuitable.

Novia 509B Reinforced Kraft Paper Union Liner 1.8m x 50m

Novia Floorguard 500micron Cardboard Roll

Novia VC2T Reinforced Synthetic Laminate

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