Resources

Code Outreach


The goal of our Code Outreach Program is to lobby for support and enforcement of residential building codes. These codes create regulations for residential and commercial construction and are intended to protect the property of the consumer. Code Outreach Representatives meet with city officials, engineers and building officials across the country to encourage enforcement of these codes.

Part of our efforts with Code Outreach is focused on creating a better world through the environmentally friendly practice of rain water harvesting. In addition to being environmentally friendly, rain barrels can actually help protect the foundation of a home through gradual watering of the permeable areas around the perimeter of a house. This practice of foundation “watering” works by attaching a soaker hose to the spigot on your rain barrel. This will allow excess water to be evenly dispersed throughout your yard.

To learn more about this check out the “Go Green” section under the Homeowners button or click here.

Building Code

Roof Drainage Building Codes & Standards

International Code Council – International Residential Code 2006


 Ch. 8 Roof-Ceiling Construction: Section R801

R801.3 Roof Drainage

“In areas where expansive or collapsible soils are known to exist, all dwellings shall have a controlled method of water disposal from roofs that will collect and discharge roof drainage to the ground surface at least 5 feet (1524 mm) from foundation walls or to an approved drainage system.”

International Residential Code 2000 Commentary

“Saturated expansive or collapsible soils can lead to foundation failures because their additional loads are imposed on the foundation wall. To minimize the potential for the soil adjacent to the foundation wall to become saturated due to roof drainage, the code requires that the roof drain 5 feet (1524 mm) from the foundation.”


 Ch. 4 Foundations: Section R401.3

R401.3 Drainage

“Surface drainage shall be diverted to a storm sewer conveyance or other approved point of collection so as to not create a hazard. Lots shall be graded to drain surface water away from foundation walls. The grade shall fall a minimum of 6 inches (152 mm) within the first 10 feet (3048 mm).”Exception:Where lot lines, walls, slopes or other physical barriers prohibit 6 inches (152mm) of fall within 10 feet (3048 mm), the final grade shall slope away from the foundation at a minimum slope of 5 percent and the water shall be directed to drains or swales to ensure drainage away from the structure. Swales shall be sloped a minimum of 2 percent when located within 10 feet (3048 mm) of the building foundation. Impervious surfaces within 10 feet (3048 mm) of the building foundation shall be sloped a minimum of 2 percent away from the building.

International Residential Code Commentary – 2000

Along with the proper support for a structure through the foundation system, adequate preparation of the building site is necessary to keep water drainage away from the supporting foundations. Proper site drainage is an important element in preventing wet basements, damp crawl spaces, eroded banks, and possible failure of a foundation system. One of the most important considerations is the arrangement of structures on a building site in a manner that retains natural drainage patterns and minimizes the alteration or disturbance to existing grades.
lotgrading

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If the designer keeps such factors in mind, the result will be a reduction of ground surface stabilization problems and opportunities for differential settlement through the reduction in the use of fills. A detailed treatment of drainage design is beyond the scope of this document; therefore, only rough guidelines can be provided for areas where a more comprehensive set of grading regulations does not exist.

As illustrated in Commentary Figures R401.3(1) and R 401.3(2) , drainage patterns should result in adequate slopes to approved drainage devices that are capable of carrying concentrated runoff. In some cases, control of concentrated roof runoff by gutters and downspouts may be needed, and if gutters and downspouts are used, provisions should be made to discharge runoff in order to prevent soil erosion. Refer also to Section R801.


Texas Administrative Code

Rule 535.228: Standards of Practice: Inspection Guidelines for Structural Systems

(a) Foundations – the Inspector shall: (8)report as in need of repair conditions or symptoms that ay indicated the possibility of water penetration that are present and visible, such as improper grading around foundation walls or plumbing leaks; and (9)report as in need of repair conditions that are present and visible and may be adversely affecting foundation performance, such as erosion or water ponding. (h) Roof, roof structure and attic. The inspector shall: (11) report as in need of repair deficiencies in visible installed gutter and downspout systems.
Title 22 Examining Boards
Part 23 Texas Real Estate Commission
Chapter 535 General Provisions
Subchapter R Real Estate Inspectors


National Association of Home Builders

NAHB Model Green Home Building Guidelines – click herepdf

Version I, Section 2.2 Enhance Durability and Reduce Maintenance Install drip edge at eave and gable roof edges. Intent: The drip edge directs roof runoff water into the gutters and away from the fascia and roof sheathing. Install gutter and downspout system to divert water at least 5’ away from foundation and from there into the overall onsite drainage area. Intent: Moisture intrusion of foundations is avoided by moving runoff water beyond the foundation.

U.S. Green Building Council

LEED for Homes Program

Water Efficiency: Credit #1 Water Reuse – Maximum Points: 2

There are no mandatory requirements. Optional requirements include:

1.1 Design and install of rainwater harvesting system which includes the collection of surface and roof run-off for irrigation uses. (1 Point) 1.2 Design and install gray water re-use system, with minimum of dedicated clothes washer with 2 inch drain directed to subterranean drain field for landscape irrigation. (1 Point)

USGBC Rationale: 50% of potable water use in a home may be for maintenance of lawns and gardens. This credit promotes the re-use of indoor waste water and rainwater to help meet landscape water demands.

Materials and Resources: Credit #4 Durability Plan – Maximum Points: 3

The mandatory requirement is:

4.1 Prepare a detailed durability plan per the design process in Exhibit MR4-A.

Optional requirement:

4.2 Verify implementation of durability plan via third party inspection as described in Exhibit MR4-C. The synergy between durability, energy efficiency, and indoor air quality are inextricably linked in high performance homes. Moisture management becomes more critical as energy management reduces the buildings overall drying potential.“

Moisture can be a major cause of indoor environmental problems (e.g., mold)”. The point value of this credit therefore reflects the related indoor environmental benefits of improved water management at the foundation, exterior walls, and roof.

Water management of the property (i.e., both lot and structure) is a combination of surface and ground water management, with the dual goals of protecting the structure from water as well as keeping as much water as possible on the site in order to limit the burden on municipals infrastructure, recharging the aquifer, etc. To the greatest extent possible, the site and landscape should be designed with these goals in mind. The durability plan is intended to prevent damage to the home by water – both surface and ground – that can not be effectively managed at the site level, as well as to protect the structure from other damage functions.

USGBC Rationale is that durability problems can substantially shorten the life of assemblies, systems, and/or materials in a home and indeed the home itself. While the development and implementation of a durability plan can not guarantee improved durability, there are a number of precedents in the insurance industry, in particular, supporting the premise that a prescribed process aimed at improving durability can indeed correlate to improved performance, as measured by decreases in warranty claims for durability-related building defects and failures.


Energy Star

Indoor Air Package Pilot Specification – April 4, 2005

1. Moisture Control Required Measures References Water Managed Roofs

1.1Provide Minimum No. 30 roof felt under layment or equivalent.

1.2 In IECC 2004 Climate Zones 5 and higher, provide self sealing water protection membrane ice flashing over the sheathing at the eave extending 2 feet inside the exterior wall plane.

1.3 Provide metal drip edge at all exposed roof decking.

1.4 Provide self-sealing bituminous membrane at all eaves, valleys and penetrations except in climates with less than 20 inches annual rainfall.

1.5 Provide Insulated wind baffle or other air barrier to block wind washing at all attic eave bays in roof assemblies with soffit vents.

1.6 Provide step flashing at all intersections of roof and walls with the exception of continuous flashing at metal and rubber membrane roofs. Metal “kick-out” flashing shall be provided at the end of roof/wall intersections to direct water away from wall. Drainage plane above shall be directed water flow onto and not behind flashing. Intersection wall siding shall terminate a minimum of 2 inches above roof. HUD/NAHB specs for gutters and downspouts

1.7 Direct roof water from house with either:

Guttering and downspouts shall empty to lateral piping that deposit(s) water on finish grade a minimum of 5 ft. from foundation, or in limited spaces, deposit to underground catchment system that carries water 10 ft. from foundation.

In dry climates with less that 20 inches annual rainfall as shown in EEBA Builder Guides, provide minimum 18” roof overhangs that deposit water to grade sloped away from home.

References

Copper Development Assn. Design Handbook, Sec. 4

Moisture Control Handbook

IRC

EBBA Builder Guide

Moisture Control Handbook

EEBA Builder Guide

EEBA Water management Guide

IRC code 801.c

EEBA Builder Guides

HUD/NAHB specs for gutters and downspouts

Moisture Control Handbook

IRC

Moisture & Durability


Moisture is the greatest threat to the durability of your home. Over time exposure to moisture can lead to corrosion of building components, insect habitation, wood rot and mold. Moisture can also affect indoor air quality and, without proper drainage, could lead to foundation failure. It is essential that rainwater be diverted away from buildings. Gutters and downspouts are a critical line of defense against foundation problems. Absence of gutters can result in a range of issues from foundation wall failure to cracked foundations and wall joints.

Senox has concluded that the most critical element of optimal gutter performance is eliminating gutter debris. Therefore, we are developing products and methods that will provide solutions for long-term roof drainage and collection needs.

Durability Issues

Results of Durability Issues

Moisture Poor Surface Drainage
Sunlight Corroded Electrical Wiring
Temperature Roof Damage
Insects Insects
Extreme Weather Poor Overall Building Preservation
Wear & Tear Structural Problems

 

Moisture Control Related Documents & Reports


Durability By Design – A Guide for Residential Builders and Designers


U.S. Department of Housing and Urban Development

This guide was written by the NAHB Research Center, Inc. with support from U.S. Housing and Urban Development. It is intended to raise awareness and understanding of building durability as a design consideration in housing. The guide covers basic concepts of durability and presents recommended practices for matters of moisture management, UV protection, Insects, decay, corrosion, and natural hazards.

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Building Moisture and Durability


U.S. Department of Housing and Urban Development

This project set out to develop a set of recommendation for future research on moisture problems in housing. The research recommendations were developed following a review and analysis of the extensive technical literature concerning the problems created by bulk water and excessive water vapor in houses, and the solutions to those problems.

“Working gutters and downspouts are a critical line of defense against foundation moisture problems in large parts of the country. Lack of gutters causes problems ranging from wet basements to foundation wall failure. Clogged downspouts or clogged gutters due to lack of maintenance result in overflows with similar consequences. Yet the International Residential Code has no requirements for installing gutters on pitched roofs, and no placement or sizing requirements for downspouts.”
 
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Building America Best Practices Series


U.S. Department of Energy

This Building America Best Practices guide book is a resource to help builders large and small build high-quality, energy-efficient homes that achieve 30% energy savings in space conditioning and water heating in the hot and humid climate. The savings are in comparison with the 1993 Model Energy Code. The guide contains chapters for every member of the builder’s team. There is also a chapter for homeowners on how to use the book to provide help in selecting a new home or builder.

Volume 1 (8.1MB) pdf
buildingamerica

Healthy and Affordable Housing


Building Sciences Corporation

The fundamental principles of groundwater control are to keep rainwater away from the foundation wall perimeter and to drain groundwater with sub-grade perimeter drains before it gets to the foundation wall. This applies to slabs, crawlspaces and basements (see Figures 8a, 8b and 8c) regardless of whether they are newly constructed or undergoing rehabilitation.

Full Text PDF (1.2 MB)pdf
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Preventing Moisture in Below Grade Walls


Moisture Control in Buildings

Shelter Ecology, Inc. & Environmental Building News

This guide was written by the NAHB Research Center, Inc. with support from U.S. Housing and Urban Development. It is intended to raise awareness and understanding of building durability as a design consideration in housing. The guide covers basic concepts of durability and presents recommended practices for matters of moisture management, UV protection, Insects, decay, corrosion, and natural hazards.

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