Specially formulated primer for use with BITUTHENE® membranes and GCP underlay on green concrete or damp substrates

Product Description

BITUTHENE® Primer B2 is a rubber-based primer in solvent specially formulated to provide good initial adhesion of BITUTHENE® waterproofing membranes and GCP underlay.

In addition, its patented formulation promotes the adhesion of BITUTHENE® membranes to green concrete and damp surfaces.

The VOC (Volatile Organic Compound) content is 440 g/L and it meets the U.S. E.P.A. Volatile Organic Compound Emissions Standards for Architectural Coatings.

Architectural and industrial maintenance regulations limit the VOC content in products classified as architectural coatings. Refer to technical letters at for the most current list of allowable limits.


BITUTHENE® Primer B2 is used to prime green concrete (less than seven day cure for normal structural concrete). It is also used to prime damp concrete, masonry or wood surfaces on which BITUTHENE® waterproofing membranes or GCP underlay will be applied.

BITUTHENE® Primer B2 is used for vertical and horizontal applications at 25 ºF (-4 ºC) or above.


BITUTHENE® Primer B2 Property Value
Unit Size 5 gal (18.9 L) tub
Weight 44 lbs (20 kg)/pail
Units per pallet 48 pails
Coverage 250–300 ft2/gal (6–8 m2/L)

Drawings are for illustration purposes only. Please refer to for specific application details.

Application Procedures

Safety, Storage and Handling Information

BITUTHENE® products must be handled properly. Vapours from solvent-based primers and mastic are harmful and flammable GCP Protection Board Adhesive is extremely flammable. For these products, the best available information on safe handling, storage, personal protection, health and environmental considerations has been gathered. SDSs (Safety Data Sheets) are available at and users should acquaint themselves with this information. Carefully read detailed precaution statements on product labels and the SDS before use.


BITUTHENE® Primer B2 may be applied by roller or brush. Use a heavy nap roller made of natural material, such as lamb’s wool.

Apply it to clean, dirt free, frost-free surfaces at a coverage rate of 250–350 ft2/gal (6–8 m2/L). Do not apply to frozen concrete or to areas with standing or visible water. Do not use during wet weather. Allow Bituthene Primer B2 to dry one hour or until tackfree. Dry time may be longer in cold temperatures. Deep puddles of primer should be avoided as this will lengthen drying time. Rollers or brushes should be dipped into pans. Avoid pouring primer directly onto a horizontal substrate. Do not apply directly to Bituthene membrane.

In general, priming should be limited to an area that can be covered with membrane within 24 hours. Areas that accumulate significant amounts of dust or dirt must be reprimed before membrane is applied.

Although it may be used on green concrete and damp surfaces, moisture may become trapped under the membrane. This may result in blistering, particularly on warm, sunny days. Therefore, cover the membrane, as soon as possible, to minimise blistering. If blistering occurs, allow membrane to cool and re-roll with a heavy roller. Blisters over 4 in. (100 mm) in diameter should be cut and patched.

Clean tools with white spirit at the end of each day. White spirit is a combustible liquid and should be used only in accordance with the manufacturer’s safety recommendations. Do not use solvents to clean hands or skin. | United Kingdom customer service: +44 (0) 1480 478421

We hope the information here will be helpful. It is based on data and knowledge considered to be true and accurate, and is offered for consideration, investigation and verification by the user, but we do not warrant the results to be obtained. Please read all statements, recommendations and suggestions in conjunction with our conditions of sale, which apply to all goods supplied by us. No statement, recommendation or suggestion is intended for any use that would infringe any patent, copyright or other third party right.

BITUTHENE, HYDRODUCT, and PREPRUFE are trademarks, which may be registered in the United States and/or other countries, of GCP Applied Technologies Inc. This trademark list has been compiled using available published information as of the publication date and may not accurately reflect current trademark ownership or status.

© Copyright 2018 GCP Applied Technologies Inc. All rights reserved.

This document is only current as of the last updated date stated below and is valid only for use in the United Kingdom. It is important that you always refer to the currently available information at the URL below to provide the most current product information at the time of use. Additional literature such as Contractor Manuals, Technical Bulletins, Detail Drawings and detailing recommendations and other relevant documents are also available on Information found on other websites must not be relied upon, as they may not be up-to-date or applicable to the conditions in your location and we do not accept any responsibility for their content. If there are any conflicts or if you need more information, please contact GCP Customer Service.

Last Updated: 2022-11-24