BASC Search | Building America Solution Center

Drainage techniques for slab-on-grade foundations

Publication Date

Tue, 01/01/2013 - 12:00

Rigid Foam Insulation Installed over Existing Foundation Slabs

Guide describing how to insulate an existing slab floor by adding rigid foam insulation over the slab then installing a floating subfloor.

Right – The seam between the slab and the foundation wall is sealed with urethane caulk.

A common method of addressing significant groundwater leakage in the foundation is to line the entire foundation assembly, including the slab, with a drainage layer.

Publication Date

Tue, 09/17/2024 - 12:00

To help keep the monolithic slab-on-grade foundation dry, the site’s surfaces is graded away from the structure, the slab is poured on a bed of gravel, and using a vapor barrier will separate the foundation from the sill plates.

Spray foam extends down the inside of the foundation wall to the uninsulated slab; because the wall lacked exterior perimeter drainage, the slab was cut and an interior footing drain was installed.

Publication Date

Mon, 07/01/2013 - 12:00

Spray foam insulation extends down the foundation wall to the slab, which has been retrofitted by cutting the slab to install drainage mat against the wall and a new perimeter footing drain, along with rigid foam plastic above the slab.

Publication Date

Mon, 07/01/2013 - 12:00

This house design in the Hot-Humid climate uses a slab foundation, masonry walls, and an Exterior Insulation Finish System (EIFS) cladding.

Publication Date

Thu, 09/01/2011 - 12:00

Any holes through the vapor barrier installed over the basement floor slab are thoroughly sealed as part of the foundation water barrier system.

Publication Date

Tue, 01/01/2013 - 12:00

A layer of pea gravel or crushed stone, 4 inches thick and sloped 5%, provides a pest-resistant ground break around the perimeter of a slab foundation

Publication Date

Mon, 03/01/2021 - 12:00

Spray foam extends down the foundation wall to the slab, which has been retrofitted by adding dimple plastic drainage mat and rigid foam insulation.

Publication Date

Mon, 07/01/2013 - 12:00

Patio Slabs, Porch Slabs, Walkways, and Driveways Slope Away from House

Guide describing how to correctly slope solid surfaces outside a home so rainwater flows away from the home.

Concrete Slab over Polyethylene

Publication Date

July, 2015

Video describing concrete slab over polyethylene barrier.

Building Enclosure: Foundation Overview

Right – The slab is coated with two coats of epoxy paint to minimize moisture transfer through the slab from the ground.

Slab Happy, BSI-059

Author(s)

Lstiburek Joseph W

Organization(s)

Building Science Corporation,

BSC

Publication Date

April, 2012

How hard can it be to insulate a flat sheet of concrete? I mean you only have three choices – on the top, on the bottom, or on the edge. OK, you might have some combination of the three as well.

Termite-Resistant Foundations and Walls

Guide describing techniques and measures for increasing the termite resistance of a home's foundations.

Right – A sump pump with a perforated sump pit was installed in the crawlspace slab to reduce water accumulation under the slab

Publication Date

Mon, 09/01/2014 - 12:00

Foundation Design Handbook

Author(s)

Carmody John,

Mosiman Garrett,

Handeen Daniel,

Huelman Patrick H,

Christian Jeffrey E

Organization(s)

Oak Ridge National Laboratory,

ORNL,

University of Minnesota

Publication Date

January, 2013

Handbook providing guidance on the design and construction of foundations for homes, including insulation, air sealing, and water management details for basements, crawlspaces, and slabs.

There is no polyethylene sheeting installed between the ground and the slab

Publication Date

Tue, 02/01/2011 - 12:00

Concrete slab over polyethylene sheeting as capillary break

Publication Date

Thu, 02/01/2018 - 12:00

Spray Foam Interior Insulation for Existing Foundation Walls

Guide describing how to insulate an existing foundation wall by adding spray foam insulation to the interior side of the wall.

There is polyethylene sheeting installed to provide a capillary break between the ground and slab

Publication Date

Tue, 02/01/2011 - 12:00

Right - Basement slab with a capillary break of either gravel or a drainage mat.

Publication Date

Thu, 02/01/2018 - 12:00

Capillary Break at Crawlspace Floor - Polyethylene Sheeting under Concrete Slab

Guide describing how to install a capillary break to help manage moisture in foundations.

A method for preventing waterproofing issues at the intersection of a concrete slab and a rock anchor.

Publication Date

Tue, 09/17/2024 - 12:00

Capillary Break Beneath Slab - Polyethylene Sheeting or Rigid Insulation over Aggregate or Sand and Geotextile Mat

Guide describing how to install a capillary break under a slab foundation using either polyethylene sheeting or rigid insulation installed over aggregate or over sand and geotextile matting.

Elevated slab construction with no water sensitive materials on first level

Publication Date

Sun, 10/01/2006 - 12:00

A method for preventing waterproofing issues at the intersection of a concrete column, concrete slab, and concrete pier.

Publication Date

Tue, 09/17/2024 - 12:00

The existing slab is retrofitted with epoxy paint, rigid foam insulation, sleepers (furring strips), and subfloor.

Publication Date

Sun, 06/01/2008 - 12:00

Right - Retrofit of an existing basement slab by adding dimple plastic mat, rigid foam insulation, and a floating subfloor.

The existing slab is retrofitted by coating with epoxy paint, then installing rigid foam insulation and a floating subfloor.

Publication Date

Mon, 07/01/2013 - 12:00

Final Grade Slopes Away from Foundation

Guide describing how to properly grade a site so water will flow away from the foundation.

A method for preventing waterproofing issues at the intersection of a concrete pier, concrete retaining wall, and concrete slab.

Publication Date

Tue, 09/17/2024 - 12:00

Right – The drain slopes away from the foundation and terminates at the proper distance

Publication Date

Tue, 02/01/2011 - 12:00

An uninsulated (or existing insulated) basement slab is retrofitted to reduce moisture transmission by sealing with epoxy paint.

Publication Date

Thu, 09/10/2015 - 12:00

Impervious surfaces like patio slabs, sidewalks, and driveways that are within 10 feet of the home should slope away from the house.

Right - The existing basement slab is retrofitted by installing a dimple plastic drainage mat, rigid foam insulation, and a floating subfloor.

Publication Date

Mon, 07/01/2013 - 12:00

Right – Polyethylene sheeting is laid over aggregate and over footing to provide a capillary break between the ground and the slab and between the footing and the stem wall

Polyethylene sheeting covers the aggregate and extends down and under the footing to provide a capillary break between the ground and the slab and monolithic footing

DWG

PDF

Wrong – Drain pipe has been cut and foundation penetration has not been properly sealed

Publication Date

Tue, 02/01/2011 - 12:00

Exterior Insulation for Existing Foundation Walls

Guide describing how to insulate a new foundation wall or an existing foundation wall by adding rigid insulation to the exterior side.

Rigid insulation and water control layers are installed on the exterior of a flat foundation wall; spray foam insulates the rim joist

Publication Date

Mon, 07/01/2013 - 12:00

Wrong – The footing drain pipe should end at least 10 feet from the foundation if above ground or should drain into a drywell or storm sewer.

No Vapor Retarders on Interior Side of Air-Permeable Foundation Insulation

Vapor retarder plastic should not be installed over fibrous insulation on basement or crawlspace walls unless rigid foam or spray foam is installed directly against the concrete, behind the blanket insulation.

Good water management practices like sloping grade away from house, and installing gutters, perimeter drain pipe, a capillary break, and free-draining soils or drainage mat protect the foundation from water saturation.

Publication Date

Thu, 03/01/2012 - 12:00

Water Management of Existing Basement Floor

Guide describing how to retrofit an existing basement floor or slab to reduce moisture issues.

Below-Grade Water Management for Urban Sites

Guide describing methods to manage groundwater in and around urban multifamily buildings.

Footing Drain Pipe

Guide describing how to help drain water away from the perimeter footing.

Measure Guideline: Guidance on Taped Insulating Sheathing Drainage Planes

Author(s)

Grin Aaron,

Lstiburek Joseph W

Organization(s)

Building Science Corporation,

BSC

Publication Date

September, 2014

Measure Guideline research report providing simple, long term, and durable solutions when using tapes and flashing membranes in conjunction with the exterior face of rigid polymeric foam sheathing to create the drainage plane of a wall system.

Site Drainage Practices to Minimize Localized Flooding

Guide describing steps that builders can take to reduce the likelihood of standing water and localized flooding around the foundation of a home during rainy conditions, with links to several full guides providing detailed instructions for improving water management in new and existing homes.

Easy access

Publication Date

Tue, 05/01/2012 - 12:00

Trapezoid swale design

Drainage and waterproofing system components in a basement, footing detail

Publication Date

Tue, 01/01/2013 - 12:00

Drainage and waterproofing system components of a basement, sill detail

Publication Date

Tue, 01/01/2013 - 12:00

Crawl space drainage: crawl space below grade

Publication Date

Tue, 01/01/2013 - 12:00

Crawl space drainage: crawl space below grade with dual drains

Publication Date

Tue, 01/01/2013 - 12:00

Crawl space drainage: crawl space floor at or above grade

Publication Date

Tue, 01/01/2013 - 12:00

Water intrusion

A damp crawlspace

Drainage and waterproofing system components in a basement, single perimeter drain system, footing detail

Publication Date

Tue, 01/01/2013 - 12:00

Wrong – Polyethylene sheeting does not completely cover the aggregate and the footing

Right – Polyethylene sheeting completely covers the aggregate and the footing with no tears or open seams

Wrong – Polyethylene sheeting does not extend beyond edge of aggregate to separate the footer from the stem wall which will be poured next

West Virginia Stormwater Management and Design Guidance Manual

Organization(s)

West Virginia Department of Environmental Protection

Publication Date

May, 2012

Manual showing how to properly use grass swales to manage excess water runoff.

Poor drainage conditions can enable water to pool around the home.

Insulation for Existing Crawl Space Floors

Guide describing how to upgrade a crawlspace floor in an existing home by adding insulation.

There is no polyethylene sheeting installed in the crawlspace

Publication Date

Tue, 02/01/2011 - 12:00

The seams of the rigid insulation are not taped and it will not provide a complete capillary break

Publication Date

Tue, 02/01/2011 - 12:00

There is 6 mil. polyethylene sheeting installed and sealed in the crawlspace

Publication Date

Tue, 02/01/2011 - 12:00

Wrong – Driveway is not sloped away from the house

Publication Date

Tue, 02/01/2011 - 12:00

Wrong – No polyethylene sheeting vapor barrier is installed on the crawlspace floor

Publication Date

Tue, 02/01/2011 - 12:00

Right – Driveway is installed to slope water away from the house

Publication Date

Tue, 02/01/2011 - 12:00

Wrong – The final grade does not slope away from the house

Publication Date

Tue, 02/01/2011 - 12:00

Right – The final grade slopes away from the house

Publication Date

Tue, 02/01/2011 - 12:00

Comprehensive water management features include a capillary break (≥ 6-mil polyethylene sheeting) at all crawlspace floors

Publication Date

Fri, 05/01/2009 - 12:00