A complete water management strategy will deflect water that comes in contact with the building envelope and divert that water down and away from the house. A well-sealed foundation or crawlspace will keep water from entering the home, but to finish the task of water management, you must also create a path for water to flow away from the home and be discharged at a safe distance. Allowing water to collect around the foundation will eventually lead to unacceptable levels of soil saturation and ultimately could overcome any water sealing practices used to protect the foundation.
To carry water away from the foundation, a footing drain system should be installed consisting of a perforated drain pipe also called drain tile that is located underground on the exterior side of the footings at a depth below the level of the basement slab or crawlspace floor. The perforations allow any surface or ground water that reaches the footing to flow into the drain tile and be carried away rather than pooling along the foundation wall.
To keep the pipe from getting clogged with silt, the pipe is wrapped with filter fabric Figure 1 then laid in a bed of washed stone that is also wrapped in filter fabric, also called geo-textile or landscape fabric Figure 2. The pipe surrounds the full perimeter of the house and is laid so that it is slightly sloped, allowing water entering anywhere along the perimeter to drain to a single collection point.
That collection point connects to an unperforated pipe that discharges the drain pipe to an above-grade location at least 10 feet away from the foundation or to a suitable alternative such as to a drywell or storm sewer. Or, the drain pipe can discharge into a sump pump located in the floor of the crawlspace or basement. The sump pump will then discharge the water either to daylight or to a suitable alternative such as to a drywell or storm sewer.
See Patio Slabs, Porch Slabs, Walks, and Driveways for more information about discharging water away from the foundation. A properly installed and functioning footing drain system will keep water moving away from the foundation to help maintain a dry basement or crawlspace. Poor installation of the pipe system often prevents it from accomplishing this important drainage function.
In order to ensure the drainage system is installed properly, it is important that only clean gravel, free of fines, be used in the trench around the drain tile. Also, a properly installed drain tile works in combination with the discharge of the water away from the foundation.
Therefore, see Patio Slabs, Porch Slabs, Walks, and Driveways for additional guidance in discharging water away from the foundation. Compliance The Compliance tab contains both program and code information. Code language is excerpted and summarized below. For exact code language, refer to the applicable code, which may require purchase from the publisher.
While we continually update our database, links may have changed since posting. Please contact our webmaster if you find broken links. Water-Managed Site and Foundation. Drain tile level or sloped to discharge to outside grade daylight or to a sump pump. If drain tile is on interior side of footing, then channel provided through footing to exterior side. In an existing home e. Additionally, a drain tile is not required when a certified hydrologist, soil scientist, or engineer has determined that a crawlspace foundation, or an existing basement foundation e.
Exhibit 1 Mandatory Requirements. Section R Drains must be provided around all enclosed concrete or masonry foundations that enclose habitable or usable spaces and retain earth.
Drainage tiles, gravel or crushed stone drains, perforated pipe or other approved means must be installed at or below the area to be protected and must discharge by gravity or mechanical means into an approved drainage system. Gravel or crushed stone drains to extent at least 1 foot beyond the outside edge of the footing and 6 inches above the top of the footing and covered with an approved filter membrane material. The top of drain tile open joints must be protected with strips of building paper, and the drainage tiles or perforate pipe must be placed on a minimum of 2 inches of washed gravel or crushed rock at least one sieve size larger than the tile joint opening or perforation and covered with at least 6 inches of the same material.
Retrofit: , , , , and IRC. Additions, alterations, renovations, or repairs shall conform to the provisions of this code, without requiring the unaltered portions of the existing building to comply with the requirements of this code, unless otherwise stated.
See code for additional requirements and exceptions. Appendix J regulates the repair, renovation, alteration, and reconstruction of existing buildings and is intended to encourage their continued safe use. If there is no retrofit-specific information for a section, that heading is not included. Water management is an important part of the design, construction, and ongoing maintenance of a home.
A complete water management strategy will deflect water that comes in contact with the building envelope and also divert the water down and away from the house where it can harmlessly flow away.
In an existing home, it is possible that no footing drain pipe was installed around the foundation of the home, or that if one was installed it has since gotten clogged by dirt or roots or broken by landscaping or other excavation activities.
Indicators of a missing, clogged, or broken drain pipe include water collecting in the basement or crawlspace. Contact your local dealer or call NV Waterproofing. When you have a footing drain installed, it generally drains to either a storm sewer, sump pump, or to the surface.
Storm sewers are notoriously ineffective. Additionally, the amount of water that a storm sewer can store is limited by its size. Once the storm sewer is full, where is the water going to go? Until the day that the drain clogs, a footing drain that discharges to the surface is a solution that can work.
However, this can only work in situations where the drain does not have to run uphill, as the water will not naturally flow out of it. Therefore, unless the ground drops off around your home more than feet, a downhill incline is not possible. If you have a sump pump installed, you can actively pump the water out of your house.
This reduces the need for a natural downhill incline and ensures that the water is being removed. Do you need to remove the ads? Foundation drain is an exterior drainage system installed on the outer face of the foundation wall and near the wall footing, covered with a layer of gravel, serving the purpose of draining out excess water seeping into the foundation.
The main component of a foundation drain is a perforated pipe laid all around the exterior foundation, which captures the excess water and drains it either towards the storm sewer or a catch basin or soak-pit at some distance from the building. The perforations are thousands of tiny holes or slits that allow the excess water to enter the pipe, and be drained away from the foundation of the structure. It is then covered by layers of gravel of graduated sizes and finally backfilled with soil.
The gravel allows water to flow towards the drainage pipe, without allowing dirt and debris to clog it up. A weeping tile porous pipe is installed in such a way that it slopes away from the structure and carries the water towards the main sewer system. For the design of a foundation drain, various factors are to be considered to ensure an effective draining of water.
Some of the factors are discussed below :. However, very well-drained soils are an exception and mixtures such as sand and gravel do not require drainage. In areas prone to heavy rains, drainage boards are used to drain off the water quickly to the perimeter drain by installing them on concrete foundation wall. This prevents the buildup of hydrostatic pressure next to the wall. Perimeter drains should be made from rigid drain tile or perforated pipe.
Although flexible corrugated plastic pipe can be used, care must be taken to prevent it from being crushed during backfilling. The moisture content of the soil placed near the foundation has a great effect on the water drainage from footing as the moisture content is dependent on the type of soil placed.
According to the U. Department of Housing and Urban Development, trees should be planted no closer to the foundation than their eventual height. This prevents tree roots from filling perimeter drains and inhibits the tree from sucking all the water from the soil, which could lead to settlement.
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