Moisture intrusion (building envelope) - Revision history

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energy>Jmdonev at 06:04, 30 July 2026

2026-07-30T06:04:48Z

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	[[Category:Done ~~2017~~-07-01]]		[[Category:Done 2026-08-01]]
	[[File:Faults_&_Defects.PNG\|300px\|thumb\|Figure 1. Common places for moisture to intrude into a building.<ref>Wikimedia Commons [Online], Available: https://commons.wikimedia.org/wiki/File:Faults_&_Defects.PNG Accessed August 28th, 2017.</ref>]]		[[File:Faults_&_Defects.PNG\|300px\|thumb\|Figure 1. Common places for moisture to intrude into a building.<ref>Wikimedia Commons [Online], Available: https://commons.wikimedia.org/wiki/File:Faults_&_Defects.PNG Accessed August 28th, 2017.</ref>]]
	<onlyinclude>'''Moisture intrusion''' refers to [[water]] getting into a building ~~and~~ is one the most significant ~~factor~~ affecting the durability of a [[building envelope]], which is its ability to continue to perform its functions over time. </onlyinclude> Building moisture can cause mold, fungal growth and other microbial contamination, as well as corrosion, decay, rot and other moisture related deterioration. <ref> J. Lstiburek, "Relative Humidity," Building Science Corporation. Westfor, MA. RR0203: Relative Humidity. 2002 </ref> These issues can pose serious health risks for occupants, and will likely lead to costly repairs to correct the problems that first allowed moisture to invade the envelope.<ref> National Institute of Building Sciences. (2013). ''Building Enclosure Design Principles and Strategies'' [Online]. Available: http://www.wbdg.org/resources/buildingenclosuredesignstrategies.php </ref>		<onlyinclude>'''Moisture intrusion''' refers to [[water]] getting into a building. It is one of the most significant factors affecting the durability of a [[building envelope\|''building envelope'']], which is its ability to continue to perform its functions over time. </onlyinclude> Building moisture can cause mold, fungal growth, and other microbial contamination; as well as corrosion, decay, rot, and other moisture related deterioration.<ref> J. Lstiburek, "Relative Humidity," Building Science Corporation. Westfor, MA. RR0203: Relative Humidity. 2002 </ref> These issues can pose serious health risks for occupants, and will likely lead to costly repairs to correct the problems that first allowed moisture to invade the envelope.<ref> National Institute of Building Sciences. (2013). ''Building Enclosure Design Principles and Strategies'' [Online]. Available: http://www.wbdg.org/resources/buildingenclosuredesignstrategies.php </ref>

	==Causes==		==Causes==
	The basic causes of moisture intrusion ~~into buildings,~~ both liquid and vapor, include:<ref name=Book1> National Institute of Building Sciences. (2013). ''Moisture Management'' [Online]. Available: http://www.wbdg.org/resources/moisturemanagement.php </ref>		Figure 1 shows where moisture commonly intrudes into a building. The basic causes of moisture intrusion (both liquid and vapor) into buildings include:<ref name=Book1> National Institute of Building Sciences. (2013). ''Moisture Management'' [Online]. Available: http://www.wbdg.org/resources/moisturemanagement.php </ref>

	*'''Infiltration of rainwater/groundwater:''' significant amounts of moisture can enter a building through leaks in the [[Building envelope\|envelope]]. Rain and groundwater can be drawn into a building though capillary action, surface tension, gravity, wind, and differences in air pressure.		*'''Infiltration of rainwater/groundwater:''' significant amounts of moisture can enter a building through leaks in the [[Building envelope\|envelope]]. Rain and groundwater can be drawn into a building though capillary action, surface tension, [[gravity]], [[wind]], and differences in air [[pressure]].
			*'''Infiltration of moist outside air:''' humid air from outside the building can be introduced by [[Air infiltration and exfiltration \|air infiltration]] through openings in the envelope or through the [[HVAC]] system. This is a significant problem in hot and humid climates.
			*'''Moisture created within building:''' the daily activities of the occupants of a building and routine housekeeping procedures can generate additional moisture within the building itself.
			*'''Diffusion of water vapor through building envelope:''' differences in water vapor pressure between the inside and outside of a building can cause water vapor to pass through the [[building envelope]]. This is a significant problem in cold climates. Small amounts of moisture within a building will condense inside the cavities of cold walls during winter months.

	*'''Infiltration of ~~moist outside air:''' humid air from outside the~~ building can be ~~introduced by [[Air infiltration and exfiltration \|air infiltration]] through openings in the envelope or through the [[HVAC]] system. This is~~ a ~~significant problem in hot and humid climates.~~		==Prevention & Control==
			The wall system of a building can be a primary protection against the various forms of moisture infiltration. The components of the wall system include:<ref name=Book1/>
	*'''Moisture created within building:''' the ~~daily activities~~ of ~~the occupants~~ of ~~a building and routine housekeeping procedures can generate additional moisture within~~ the ~~building itself.~~

	*'''~~Diffusion of water vapor through building envelope~~:''' ~~differences in water~~ vapor ~~pressure between the inside~~ and ~~outside~~ of a building ~~can cause water vapor~~ to ~~pass through~~ the [[Building envelope\|~~building~~ envelope]]. ~~This is a significant problem in cold climates~~. ~~Small amounts of moisture within~~ a ~~building will condense inside~~ the ~~cavities of cold walls during winter months~~.		*'''Exterior finishes:''' common materials of exterior walls include stucco, wood siding, concrete, and brick. These materials can limit moisture and vapor migration into and out of the building. They also contribute to the finish function of the [[Building envelope\|envelope]] and should be aesthetically pleasing.[[File:3-Bay Sangar - Damp-Proof Course (51070450303).jpg\|thumb\|400x400px\|Figure 2. The slate provides a non-porous layer that the water can't get through, it's referred to as a "damp proof course".<ref>Wikimedia Commons (2021). (Accessed July 29, 2026). ''3-Bay Sangar - Damp-Proof Course (51070450303)'' [Online]. Available: https://commons.wikimedia.org/wiki/File:3-Bay_Sangar_-_Damp-Proof_Course_(51070450303).jpg</ref><ref>Wikimedia Commons [Online], Available: https://commons.wikimedia.org/wiki/File:Brickwork_8.png</ref>]]

	~~==Prevention & Control==~~		*'''Vapor retarders:''' retarders include plastics (reinforced and flexible), aluminum, treated papers, and epoxies. They are not always required if other wall components can act as a sufficient barrier to vapor, such as the exterior finishes. Low [[porosity]] rock like slate can be used (see Figure 2) to create what is called a "damp proof course". This means that there's no path ("course") for the damp to get into the house.
	~~[[File~~:~~Brickwork_8~~.~~png\|300px\|thumb\|Figure 2~~. ~~The~~ slate ~~provides a non-porous layer that the water~~ can~~'t get through, it's referred~~ to as a 'damp proof course'~~.<ref>Wikimedia Commons [Online], Available: https://commons.wikimedia.org/wiki/File:Brickwork_8.png</ref>]]~~
	~~The wall system of a building can be one~~ the ~~primary protections against~~ the ~~various forms of moisture infiltration~~. ~~The components of the wall system include:<ref name=Book1/>~~

	*'''~~Exterior finishes~~:''' ~~common materials of exterior walls include stucco, wood siding, concrete,~~ and ~~brick~~. ~~These materials~~ can ~~limit moisture and vapor migration into and out~~ of the ~~building. They also contribute to~~ the ~~finish function~~ of ~~the [[Building envelope\|envelope]]~~ and ~~should be aesthetically pleasing~~.		*'''Air infiltration and rain barriers:''' play an important role in preventing air infiltration from winds and other weather conditions. Building envelope components working together can act as an air barrier. The performance of the barrier greatly diminishes as the number of joints, cracks, and crevices increases.

	*'''~~Vapor retarders~~:''' retarders include plastics (reinforced and flexible), aluminum, treated papers, and epoxies. They are not always required if other wall components can act as a sufficient barrier to vapor, such as the exterior finishes. Low [[~~porosity~~]] ~~rock like slate can be used~~, ~~see figure 2~~, ~~to create what's called~~ a ~~'damp proof course'. This means that there's no path (course) for the damp to get into the house~~.		*'''Insulation:''' special types of [[insulation]], such as closed cell and non-hydroscopic insulation, can help reduce high moisture levels that can develop in walls. The insulation acts as a vapor barrier depending on its thickness.

	*'''~~Air infiltration and rain barriers~~:''' ~~play~~ an important ~~role~~ in ~~preventing air infiltration from winds~~ and ~~other weather conditions~~. ~~Building envelope components working together can act an~~ air ~~barrier~~. The ~~performance of~~ the ~~barrier greatly diminishes as~~ the ~~number of joints, cracks, and crevices increases~~.		*'''Interior finishes:''' the [[permeability]], or ability of a material to allow liquids and gases to pass through it, is an important consideration for interior wall finishes.
			::*Generally, in hot and humid climates the permeability of the interior finish should be much higher than that of the exterior finish. This will allow moisture that enters the wall to migrate to the inside of the building where the moisture will be removed by the air conditioning system.
			::*The reverse is true for cold climates; the exterior finish should have a higher permeability than the interior finish.

	*'''Insulation:''' special types of [[insulation]], such as closed cell and nonhydroscopic insulation, can help reduce high moisture levels that can develop in walls. The insulation acts as a vapor barrier depending on its thickness.		== For Further Reading ==

	*~~'''Interior finishes:''' the~~ [[~~permeability~~]]~~, or ability of a material to allow liquids~~ and gases to pass through it, is an important consideration for interior wall finishes. Generally, in hot and humid climates the permeability of the interior finish should be much higher than that of the exterior finish. This will allow moisture that enters the wall to migrate to the inside of the building where the moisture will be removed by the air conditioning system. The reverse is true for cold climates; the exterior finish should have a ~~higher permeability than the interior finish.~~		* [[Building envelope]]
			* [[Air infiltration and exfiltration]]
			* [[Porosity]]
			* [[Permeability]]
			* Or explore a [[Special:Random\|random page]]

	==References==		==References==
	{{reflist}}		{{reflist}}
	[[Category:Uploaded]]		[[Category:Uploaded]]

Jmdonev: 1 revision imported

2017-08-29T01:47:39Z

1 revision imported

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Jmdonev at 22:20, 28 August 2017

2017-08-28T22:20:44Z

← Older revision		Revision as of 22:20, 28 August 2017
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	[[Category:Done ~~2015~~-06-01]] [[~~category~~:~~check images~~]]		[[Category:Done 2017-07-01]]
	<onlyinclude>'''Moisture intrusion''' is one the most significant factor affecting the durability of a [[building envelope]], which is its ability to continue to perform its functions over time.</onlyinclude> Building moisture can cause mold, fungal growth and other microbial contamination, as well as corrosion, decay, rot and other moisture related deterioration. <ref> J. Lstiburek, "Relative Humidity," Building Science Corporation. Westfor, MA. RR0203: Relative Humidity. 2002 </ref> These issues can pose serious health risks for occupants, and will likely lead to costly repairs to correct the problems that first allowed moisture to invade the envelope.<ref> National Institute of Building Sciences. (2013). ''Building Enclosure Design Principles and Strategies'' [Online]. Available: http://www.wbdg.org/resources/buildingenclosuredesignstrategies.php </ref>		[[File:Faults_&_Defects.PNG\|300px\|thumb\|Figure 1. Common places for moisture to intrude into a building.<ref>Wikimedia Commons [Online], Available: https://commons.wikimedia.org/wiki/File:Faults_&_Defects.PNG Accessed August 28th, 2017.</ref>]]
			<onlyinclude>'''Moisture intrusion''' refers to [[water]] getting into a building and is one the most significant factor affecting the durability of a [[building envelope]], which is its ability to continue to perform its functions over time. </onlyinclude> Building moisture can cause mold, fungal growth and other microbial contamination, as well as corrosion, decay, rot and other moisture related deterioration. <ref> J. Lstiburek, "Relative Humidity," Building Science Corporation. Westfor, MA. RR0203: Relative Humidity. 2002 </ref> These issues can pose serious health risks for occupants, and will likely lead to costly repairs to correct the problems that first allowed moisture to invade the envelope.<ref> National Institute of Building Sciences. (2013). ''Building Enclosure Design Principles and Strategies'' [Online]. Available: http://www.wbdg.org/resources/buildingenclosuredesignstrategies.php </ref>

	==Causes==		==Causes==
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	*'''Infiltration of rainwater/groundwater:''' significant amounts of moisture can enter a building through leaks in the [[Building envelope\|envelope]]. Rain and groundwater can be drawn into a building though capillary action, surface tension, gravity, wind, and differences in air pressure.		*'''Infiltration of rainwater/groundwater:''' significant amounts of moisture can enter a building through leaks in the [[Building envelope\|envelope]]. Rain and groundwater can be drawn into a building though capillary action, surface tension, gravity, wind, and differences in air pressure.

	*'''Infiltration of moist outside air:''' humid air from outside the building can be introduced by [[Air infiltration/exfiltration \|air infiltration]] through openings in the envelope or through the HVAC system. This is a significant problem in hot and humid climates.		*'''Infiltration of moist outside air:''' humid air from outside the building can be introduced by [[Air infiltration and exfiltration \|air infiltration]] through openings in the envelope or through the [[HVAC]] system. This is a significant problem in hot and humid climates.

	*'''Moisture created within building:''' the daily activities of the occupants of a building and routine housekeeping procedures can generate additional moisture within the building itself.		*'''Moisture created within building:''' the daily activities of the occupants of a building and routine housekeeping procedures can generate additional moisture within the building itself.
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	==Prevention & Control==		==Prevention & Control==
			[[File:Brickwork_8.png\|300px\|thumb\|Figure 2. The slate provides a non-porous layer that the water can't get through, it's referred to as a 'damp proof course'.<ref>Wikimedia Commons [Online], Available: https://commons.wikimedia.org/wiki/File:Brickwork_8.png</ref>]]
	The wall system of a building can be one the primary protections against the various forms of moisture infiltration. The components of the wall system include:<ref name=Book1/>		The wall system of a building can be one the primary protections against the various forms of moisture infiltration. The components of the wall system include:<ref name=Book1/>

	*'''Exterior finishes:''' common materials of exterior walls include stucco, wood siding, concrete, and brick. These materials can limit moisture and vapor migration into and out of the building. They also contribute to the finish function of the [[Building envelope\|envelope]] and should be aesthetically pleasing. ~~<br />~~		*'''Exterior finishes:''' common materials of exterior walls include stucco, wood siding, concrete, and brick. These materials can limit moisture and vapor migration into and out of the building. They also contribute to the finish function of the [[Building envelope\|envelope]] and should be aesthetically pleasing.

	*'''Vapor retarders:''' retarders include plastics (reinforced and flexible), aluminum, treated papers, and epoxies. They are not always required if other wall components can act as a sufficient barrier to vapor, such as the exterior finishes. ~~<br />~~		*'''Vapor retarders:''' retarders include plastics (reinforced and flexible), aluminum, treated papers, and epoxies. They are not always required if other wall components can act as a sufficient barrier to vapor, such as the exterior finishes. Low [[porosity]] rock like slate can be used, see figure 2, to create what's called a 'damp proof course'. This means that there's no path (course) for the damp to get into the house.

	*'''Air infiltration and rain barriers:''' play an important role in preventing air infiltration from winds and other weather conditions. Building envelope components working together can act an air barrier. The performance of the barrier greatly diminishes as the number of joints, cracks, and crevices increases.		*'''Air infiltration and rain barriers:''' play an important role in preventing air infiltration from winds and other weather conditions. Building envelope components working together can act an air barrier. The performance of the barrier greatly diminishes as the number of joints, cracks, and crevices increases.

J.williams: 1 revision imported

2015-08-26T21:31:22Z

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J.williams at 16:57, 12 August 2015

2015-08-12T16:57:00Z

New page

[[Category:Done 2015-06-01]] [[category:check images]]
<onlyinclude>'''Moisture intrusion''' is one the most significant factor affecting the durability of a [[building envelope]], which is its ability to continue to perform its functions over time.</onlyinclude> Building moisture can cause mold, fungal growth and other microbial contamination, as well as corrosion, decay, rot and other moisture related deterioration. <ref> J. Lstiburek, "Relative Humidity," Building Science Corporation. Westfor, MA. RR0203: Relative Humidity. 2002 </ref> These issues can pose serious health risks for occupants, and will likely lead to costly repairs to correct the problems that first allowed moisture to invade the envelope.<ref> National Institute of Building Sciences. (2013). ''Building Enclosure Design Principles and Strategies'' [Online]. Available: http://www.wbdg.org/resources/buildingenclosuredesignstrategies.php </ref>

==Causes==
The basic causes of moisture intrusion into buildings, both liquid and vapor, include:<ref name=Book1> National Institute of Building Sciences. (2013). ''Moisture Management'' [Online]. Available: http://www.wbdg.org/resources/moisturemanagement.php </ref>

*'''Infiltration of rainwater/groundwater:''' significant amounts of moisture can enter a building through leaks in the [[Building envelope|envelope]]. Rain and groundwater can be drawn into a building though capillary action, surface tension, gravity, wind, and differences in air pressure.

*'''Infiltration of moist outside air:''' humid air from outside the building can be introduced by [[Air infiltration/exfiltration |air infiltration]] through openings in the envelope or through the HVAC system. This is a significant problem in hot and humid climates.

*'''Moisture created within building:''' the daily activities of the occupants of a building and routine housekeeping procedures can generate additional moisture within the building itself.

*'''Diffusion of water vapor through building envelope:''' differences in water vapor pressure between the inside and outside of a building can cause water vapor to pass through the [[Building envelope|building envelope]]. This is a significant problem in cold climates. Small amounts of moisture within a building will condense inside the cavities of cold walls during winter months.

==Prevention & Control==
The wall system of a building can be one the primary protections against the various forms of moisture infiltration. The components of the wall system include:<ref name=Book1/>

*'''Exterior finishes:''' common materials of exterior walls include stucco, wood siding, concrete, and brick. These materials can limit moisture and vapor migration into and out of the building. They also contribute to the finish function of the [[Building envelope|envelope]] and should be aesthetically pleasing. <br />

*'''Vapor retarders:''' retarders include plastics (reinforced and flexible), aluminum, treated papers, and epoxies. They are not always required if other wall components can act as a sufficient barrier to vapor, such as the exterior finishes. <br />

*'''Air infiltration and rain barriers:''' play an important role in preventing air infiltration from winds and other weather conditions. Building envelope components working together can act an air barrier. The performance of the barrier greatly diminishes as the number of joints, cracks, and crevices increases.

*'''Insulation:''' special types of [[insulation]], such as closed cell and nonhydroscopic insulation, can help reduce high moisture levels that can develop in walls. The insulation acts as a vapor barrier depending on its thickness.

*'''Interior finishes:''' the [[permeability]], or ability of a material to allow liquids and gases to pass through it, is an important consideration for interior wall finishes. Generally, in hot and humid climates the permeability of the interior finish should be much higher than that of the exterior finish. This will allow moisture that enters the wall to migrate to the inside of the building where the moisture will be removed by the air conditioning system. The reverse is true for cold climates; the exterior finish should have a higher permeability than the interior finish.

==References==
{{reflist}}
[[Category:Uploaded]]