How to Seal Basement Floors & Foundation Walls Against Water & Moisture InspectAPedia® -
Basement waterproofing guide to choices of sealants, membranes, drainage systems, basement de-watering systems, sump pumps
How to detect roof venting deficiencies, attic insulation defects, and attic condensation problems
This article discusses options for sealing basement or crawl space floors and walls, or other building foundation walls to stop water entry and to reduce interior moisture and mold risks.
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The photograph at page top shows a very wet basement foundation wall built of concrete block. The stain pattern extends high on the basement walls, down the full wall, onto the basement floor. Correcting this particular water entry problem should begin outside with roof drainage and surface runoff. This article discusses foundation wall and floor slab sealant options. .
Basement Concrete and Concrete Block Sealers for Basement Waterproofing
Basements are below grade and surrounded by soil. This soil absorbs water during rains and then releases it. The water can migrate through a block basement and even through solid concrete such as in walls and floors by capillary action.
This water that enters the basement can cause problems ranging from peeling paint to mold and mildew growth. Also, naturally occurring gasses that are released from soils can be transmitted into the basement. The interior basement air quality is lessened unless the walls and floors are sealed.
It is possible to seal the concrete or concrete blocks used in basement walls and floors and stop water and gas migration into a basement. In fact, it can be done from the interior of a home. Old homes and new homes alike can be sealed.
Using Exterior Foundation Coatings to Repair Foundation Wall Cracks & Leaks
As Carson Dunlop Associates' sketch shows, foundation crack leaks can be repaired from outside the foundation wall using a combination of asphalt-mopped dampproofing and a waterproof bituminous membrane that is then adhered to the wall surface.
Sodium Silicate Sealers for Floor & Foundation Wall Waterproofing
Sodium silicate is used in a water-based mixture to seal the basement walls and floors.
The sodium silicate penetrates up to 4” into the substrate.
After penetrating the sodium silicate reacts with the free lime content of the concrete or masonry . Concrete, concrete block and masonry has lime as a natural component in their composition.
This reaction between the sodium silicate and free lime produces a solid crystalline structure that fills the microscopic cracks and pores of the substrate. This hardens and densifies the concrete and masonry so that water vapor and gasses cannot migrate through by capillary action. Also, gasses are retarded from entering a basement. After curing, the substrate looks the same as if it were not sealed. There is no surface film or sheen to it.
Benefits of Sodium Silicate for Building Waterproofing
By sealing the basement walls and floors with sodium silicate water vapor will be stopped from entering into a basement. The basement will be dryer than before. This greatly improves the interior air quality of a home by retarding the growth of mold and mildew.
Since the surface of the walls and floors are hardened, they will have less dusting and chalking. Gas transmission will be reduced as well, further improving air quality.
Many people like to paint the floors and walls of their basements. If paint is applied to unsealed walls and floors, it is possible for the water vapor to get trapped under the paint. After a period of time the water vapor can break the bond between the paint and the substrate. This causes the paint to blister and peel.
After application of a sodium silicate the walls and floors can be painted without fear of the paint peeling and flaking. Also, adhesives for tiles or other floor coverings can be used.
Application of Sodium Silicate for Basement or Crawl Space Waterproofing
Sodium silicate is applied to bare concrete, concrete block or masonry. Anything that would prevent the sodium silicate from being absorbed must be removed. No grease, dirt, soil, adhesives, oil, sealer or paint can be on the surface to be sealed prior to application.
Application is done simply by using a garden sprayer, roller or brush. First dampen the surface with water using a mop or brush. Apply in areas 10’ x 10’ in several light coats. Apply each coat after 10-20 minutes. Concrete takes 2-3 coats, concrete block and masonry 3-4 coats. Do not over apply the sodium silicate since if all of the product is not absorbed it may leave a white residue. Wipe up any excess product.
For several days after application loose dirt will be pushed out of the substrate. This is normal and can be swept off.
A Few Caveats about Any Foundation Sealer or Weather Barrier Product - DF OPINION
Watch out: any surface coating, even a penetrating wall sealer such as discussed here, can fail if exposed to continued or chronic water and water pressure through the foundation wall.
The pressure from water, frost, or more significantly, the formation of efflorescent salts (see EFFLORESCENCE, Salts & White / Brown Deposits) can exert tremendous pressure, sufficient to separate a paint or other coating from a masonry foundation surface. Efflorescence has been cited in several paint failure studies where these forces were explored.
Some factors that affect the durability and thus success of any foundation coating or waterproofing coating include:
The cleanliness of the surface to which the coating is applied
Application of the sealer according to the manufacturer's instructions, including specifications of pre-cleaning, thickness, temperature, humidity at time of application
The degree of water intrusion or water presence on the exterior of the foundation wall
Climate, freezing temperatures
Chemistry of both the masonry wall and the water, affecting the formation of efflorescence
Chemistry, composition, and in some cases fiber reinforcement of the coating
Watch out: sodium silicate is an alkaline substance that can cause burns, eye, and skin damage. Quoting from a MSDS:
Causes moderate skin irritation. Spray mist
causes irritation to respiratory tract. Due to high pH of
product, release into surface water is harmful to aquatic life. ... Causes severe irritation to the eyes. ... Causes moderate irritation to the skin. ... Spray mist irritating to respiratory tract. ... May cause irritation to mouth, esophagus, and stomach. ... No known chronic hazards. Not listed by NTP, IARC or OSHA
as a carcinogen. ... Dries to form glass film which can easily cut skin. Spilled
material is very slippery. Can etch glass if not promptly
removed.
...
Human experience indicates that skin irritation occurs, particularly,
when sodium silicates get on clothes at the collar, cuffs or other areas
where contact and abrasion may occur.
The acute oral toxicity of this product has not been tested. - MSDS for Sodium Silicate from PQ Corporation
Also see this MSDS for Krystol Hydrostop WB [copy on file as /exterior/Krystol-hydrostop-wb.pdf ] - WB from Kryton Corporation.
Thanks to reader Stan Rosenbaum for alerting us to the need for care when working with sodium silicate.
Weather Barrier Coatings, Mastics, Sealants, Adhesives used on buildings, Building Sheathing & Building Foundation Coatings
AkroGuard,Omega Products, International, 1681 California Ave, Corona, CA 92881, Tel: 800-600-6634, 951-737-7447,
Fax: 951-520-2594, Quoting from the company's product description:
AkroGuard is a field applied, non-cementitious, [acrylic] flexible coating that when used with AkroFill creates a water-resistive barrier over approved substrates.
Basic Uses:
AkroGuard is designed for use as a water-resistive barrier and air barrier over approved substrates and with the AkroFlex EIF Systems. Complies with ICC-ES Acceptance Criteria for Water-resistive Coatings (AC212).
AkroGuard may be applied to the following substrates:
Thanks to reader J. Campbell for pointing out this product, March 2010.
Krystol Hydrostop, Kryton Corporation, "Crystalline Waterproofing" masonry sealer. MSDS for Krystol Hydrostop WB [copy on file as /exterior/Krystol-hydrostop-wb.pdf ] - WB from Kryton Corporation. Masonry sealer.
Krystol T1 and T2 waterproofing system is brush-applied onto concrete surfaces to become an integral part of the concrete. It contains Kryton's renowned waterproofing chemicals and is durable and self-sealing.
Vi-Cryl CP-10 (Trowel Grade) & Vi-Cryl CP-11 (Spray/Brush) Weather Barrier Coatings, Childers Corporation. We discuss the use of this coating at INSULATION LOCATION for BASEMENT WALLS. Quoting from the company's product literature [copy on file as /exterior/Vi_Cryl_cp-10-11.pdf ] - ,
VI-CRYL CP-10/11 weather barrier coating is unsurpassed for the
mechanical protection and weatherproofing of thermal insulations both
outdoors and indoors, in hot, cold, and dual-temperature service.
However, since it is a ‘breathing’ coating (vapors under pressure will
pass through it) it should only be used over insulations in lowtemperature,
or dual-temperature service when the insulations
themselves are vapor barriers.
VI-CRYL CP-10/11 has also found use
throughout the thermal insulation industry as a coating used over closed
cell polyethylene and polyurethane foam insulations. Industry
experience has demonstrated that all weather barrier coatings may
blister when applied over polystyrene board. This effect may be limited
by the use of white colored coatings.
VI-CRYL CP-10/11 weather barrier
coating in its Metallic Gray color is the ideal companion product to
Aluminum and Stainless Steel Jacketing. VI-CRYL CP-10/11 gives
superior mechanical and chemical protection to any irregular shape or
surface where the application of Childers Metal Jacketing Systems is impractical.
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Additional technical contributors & reference sources for this article are listed below.
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Aaron Kuertz is with Applied Technologies, Fairfield, OH 45018, 877-APPLY-IT (277-5948). (513) 939-3767. Mr Kuertz has been in the waterproofing industry since 1998. Applied Technologies is a manufacturer of waterproofing products used by both professional contractors and homeowners alike. For more information on Hydra Block™ water-based concrete and masonry penetrating sealer used for concrete and concrete block basement sealing, see Applied Technologies at www.appliedtechnologies.com
Kryton Corporation, 1645 Kent Ave., Vancouver BC Canada VSP 2S8 - 604-324-8280 email: info@kryton.com
PQ Corporation, P.O. Box 840. Valley Forge, PA 19482-0840, is a producer of sodium silicate. Quoting: PQ Corporation is a leading producer of silicate, zeolite, and other performance materials serving the detergent, pulp and paper, chemical, petroleum, catalyst, water treatment, construction, and beverage markets. It is a global enterprise, operating in 19 countries on five continents, and along with its chemical businesses, includes Potters Industries, a wholly owned subsidiary, which is a leading producer of engineered glass materials serving the highway safety, polymer additive, metal finishing, and conductive particle markets.
Thanks to reader Stan Rosenbaum for discussing sodium silicate hazards - June 2010
Childers Corporation, Specialty Construction Brands, Inc., producer of Vi-Cryl [copy on file as /exterior/Vi_Cryl_cp-10-11.pdf ] - water based vinyl-acrylic mastic coating for thermal insulation, 315 South Hicks Rd., Palatine IL 60067 800-231-9541 or 800-338-2975
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 2010, $69.00 U.S., is available from Carson Dunlop. The Home Reference Book is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. InspectAPedia.com ® author/editor Daniel Friedman is a contributing author. Field inspection worksheets are included at the back of the volume.
"The Elimination of Unsafe Guardrails, a Progress Report," Elliott O. Stephenson, Building Standards, March-April 1993
"Are Functional Handrails Within Our Grasp" Jake Pauls, Building Standards, January-February 1991
Access Ramp building codes:
UBC 1003.3.4.3
BOCA 1016.3
ADA 4.8.2
IBC 1010.2
Access Ramp Standards:
ADA (Americans with Disabilities Act), Public Law 101-336. 7/26/90 is very often cited by other sources for good design of stairs and ramps etc. even where disabled individuals are not the design target.
ANSI A117.4 Accessible and Usable buildings and Facilities (earlier version was incorporated into the ADA)
ASTM F 1637, Standard Practice for Safe Walking Surfaces, (Similar to the above standards)
American Plywood Association, APA, "Portland Manufacturing Company, No. 1, a series of monographs on the history of plywood manufacturing",Plywood Pioneers Association, 31 March, 1967, www.apawood.org
Asbestos: How to find and recognize asbestos in buildings - visual inspection methods, list of common asbestos-containing materials
Asbestos products and their history and use in various building materials such as asphalt and vinyl flooring includes discussion which draws on Asbestos, Its Industrial Applications, D.V. Rosato, engineering consultant, Newton, MA, Reinhold Publishing, 1959 Library of Congress Catalog Card No.: 59-12535 (out of print).
Asbestos Identification and Testing References
Asbestos Identification, Walter C.McCrone, McCrone Research Institute, Chicago, IL.1987 ISBN 0-904962-11-3. Dr. McCrone literally "wrote the book" on asbestos identification procedures which formed
the basis for current work by asbestos identification laboratories.
Stanton, .F., et al., National Bureau of Standards Special Publication 506: 143-151
Pott, F., Staub-Reinhalf Luft 38, 486-490 (1978) cited by McCrone
Building Research Council, BRC, nee Small Homes Council, SHC, School of Architecture, University of Illinois at Urbana-Champaign, brc.arch.uiuc.edu. "The Small Homes Council (our original name) was organized in 1944 during the war at the request of the President of the University of Illinois to consider the role of the university in meeting the demand for housing in the United States. Soldiers would be coming home after the war and would be needing good low-cost housing. ... In 1993, the Council became part of the School of Architecture, and since then has been known as the School of Architecture-Building Research Council. ... The Council's researchers answered many critical questions that would affect the quality of the nation's housing stock.
How could homes be designed and built more efficiently?
What kinds of construction and production techniques worked well and which did not?
How did people use different kinds of spaces in their homes?
What roles did community planning, zoning, and interior design play in how neighborhoods worked
"An Example of Colonial Paneling", Norman Morrison Isham, The Metropolitan Museum of Art Bulletin, Vol. 6, No. 5 (May, 1911), pp. 112-116, available by JSTOR.
Dust from the World Trade Center collapse following the 9/11/01 attack: the lower floors of this building contained spray-on fire-proofing asbestos materials.
"Energy Savers: Whole-House Supply Ventilation Systems [copy on file as /interiors/Energy_Savers_Whole-House_Supply_Vent.pdf ] - ", U.S. Department of Energy energysavers.gov/your_home/insulation_airsealing/index.cfm/mytopic=11880?print
"Energy Savers: Whole-House Exhaust Ventilation Systems [copy on file as /interiors/Energy_Savers_Whole-House_Exhaust.pdf ] - ", U.S. Department of Energy energysavers.gov/your_home/insulation_airsealing/index.cfm/mytopic=11870
"Energy Savers: Ventilation [copy on file as /interiors/Energy_Savers_Ventilation.pdf ] - ", U.S. Department of Energy
"Energy Savers: Natural Ventilation [copy on file as /interiors/Energy_Savers_Natural_Ventilation.pdf ] - ", U.S. Department of Energy
"Energy Savers: Energy Recovery Ventilation Systems [copy on file as /interiors/Energy_Savers_Energy_Recovery_Venting.pdf ] - ", U.S. Department of Energy energysavers.gov/your_home/insulation_airsealing/index.cfm/mytopic=11900
"Energy Savers: Detecting Air Leaks [copy on file as /interiors/Energy_Savers_Detect_Air_Leaks.pdf ] - ", U.S. Department of Energy
"Energy Savers: Air Sealing [copy on file as /interiors/Energy_Savers_Air_Sealing_1.pdf ] - ", U.S. Department of Energy
Falls and Related Injuries: Slips, Trips, Missteps, and Their Consequences, Lawyers & Judges Publishing, (June 2002), ISBN-10: 0913875430 ISBN-13: 978-0913875438 "Falls in the home and public places are the second leading cause of unintentional injury deaths in the United States, but are overlooked in most literature. This book is unique in that it is entirely devoted to falls. Of use to primary care physicians, nurses, insurance adjusters, architects, writers of building codes, attorneys, or anyone who cares for the elderly, this book will tell you how, why, and when people will likely fall, what most likely will be injured, and how such injuries come about. "
Fiberglass: Indoor Air Quality Investigations: Health Concerns About Airborne Fiberglass: Fiberglass in Indoor Air from HVAC ducts, and Building Insulation
Humidity: What indoor humidity should we maintain in order to avoid a mold problem?
Lighting, proper use of: proper aiming of a good flashlight can disclose hard to see but toxic light or white mold colonies on walls.
Pergo AB, division of Perstorp AB, is a Swedish manufacturer or modern laminate flooring products. Information about the U.S. company can be found at http://www.pergo.com where we obtained historical data used in our discussion of the age of flooring materials in buildings.
Plank House Construction: weblog from plankhouse.wordpress.com/2009/01/25/plank-house-construction/ and where plank houses were built by native Americans, see
Large 1:6 Scale Plank House Construction / P8094228,
Photographer: Mike Meuser
06/12/2007 documented at yurokplankhouse.com where scale model Museum quality Yurok Plank Houses are being sold to raise money for the Blue Creek - Ah Pah Traditional Yurok Village project.
Re-Bath, tub lining products is a bath tub relining manufacturer and distributor located in Tempe, Arizona - see rebath.com
Slips, Trips, Missteps and Their Consequences, Second Edition, Gary M. Bakken, H. Harvey Cohen,A. S. Hyde, Jon R. Abele, ISBN-13: 978-1-933264-01-1 or
ISBN 10: 1-933264-01-2,
available from the publisher, Lawyers ^ Judges Publishing Company,Inc., www.lawyersandjudges.com sales@lawyersandjudges.com and also from the InspectAPedia Bookstore (Amazon.com)
The Stairway Manufacturers' Association, (877) 500-5759, provides a pictorial guide to the stair and railing portion of the International Residential Code. [copy on file as http://www.stairways.org/pdf/2006%20Stair%20IRC%20SCREEN.pdf ] -
How to Clean Moldy Wood Framing & Sheathing How to clean/seal mold from/on exposed lumber or plywood subfloor or roof sheathing indoors - some suggestions based on our field and laboratory research
Lighting, proper use of: proper aiming of a good flashlight can disclose hard to see but toxic light or white mold colonies on walls.
Manufactured & Modular Homes: Modular Building Systems Association, MBSA, modularhousing.com, is a trade association promoting and providing links to contact modular builders in North America. Also see the Manufactured Home Owners Association, MHOAA, at www.mhoaa.us. The Manufactured Home Owners Association of America is a National Organization dedicated to the protection of the rights of all people living in Manufactured Housing in the United States.
Stuff that is not mold but is often mistaken for it - things you may not want to test. Also, not all "black mold" is toxic - here are examples of harmless black mold.
Mold-Resistant Building Practices, advice from an expert on how to prevent mold after a building flood and how to prevent mold growth in buildings by selection of building materials and by anti-mold construction details.
Slips, Trips, Missteps and Their Consequences, Gary M. Bakken, H. Harvey Cohen, Jon R. Abele, Alvin S. Hyde, Cindy A. LaRue, Lawyers and Judges Publishing; 2 edition (April 2006), ISBN-10: 1933264012 ISBN-13: 978-1933264011
Steps and Stairways, Cleo Baldon & Ib Melchior, Rizzoli, 1989.
"The Dimensions of Stairs", J. M. Fitch et al., Scientific American, October 1974.
"Weather-Resistive Barriers [copy on file as /interiors/Weather_Resistant_Barriers_DOE.pdf ] - ", how to select and install housewrap and other types of weather resistive barriers, U.S. DOE
Weaver: Beaver Board and Upson Board:
Beaver Board and Upson Board: History and Conservation of Early Wallboard, Shelby Weaver,
APT Bulletin, Vol. 28, No. 2/3 (1997), pp. 71-78, Association for Preservation Technology International (APT), available online at JSTOR.
