Wall insulation and moisture risk - Revision history

Editor at 19:12, 26 October 2020

2020-10-26T19:12:20Z

← Older revision		Revision as of 19:12, 26 October 2020
Line 108:		Line 108:
	* Designing out unintended consequences when applying solid wall insulation FB 79.		* Designing out unintended consequences when applying solid wall insulation FB 79.
	* Diagnosing the causes of dampness (GR 5 revised).		* Diagnosing the causes of dampness (GR 5 revised).
		+	* Electrical resistance meters.
	* IHBC articles.		* IHBC articles.
	* Moisture.		* Moisture.
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	* Ventilation.		* Ventilation.

−	[[Category:Conservation]]	+	[[Category:Conservation]] [[Category:DCN_Guidance]]

Designing Buildings at 16:02, 11 December 2019

2019-12-11T16:02:22Z

← Older revision		Revision as of 16:02, 11 December 2019
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	-----		-----
−	This article originally appeared in [~~http~~://www.ihbc.org.uk/~~page55~~/~~page58~~/~~index.html~~ IHBC's 2017 Yearbook]. It was written by Colin King, director of the Building Research Establishment (BRE).	+	This article originally appeared in [https://www.ihbc.org.uk/Yearbook/2017Yearbook/ IHBC's 2017 Yearbook]. It was written by Colin King, director of the Building Research Establishment (BRE).

	--[[User:Institute_of_Historic_Building_Conservation\|Institute of Historic Building Conservation]]		--[[User:Institute_of_Historic_Building_Conservation\|Institute of Historic Building Conservation]]

−	~~= Find out more =~~	+	= Related articles on Designing Buildings Wiki =
−		+
−	=== Related articles on Designing Buildings Wiki ===	+

	* BRE and Willmott Dixon project to retrofit of a 1920s semi-detached house.		* BRE and Willmott Dixon project to retrofit of a 1920s semi-detached house.

Editor at 15:25, 4 September 2018

2018-09-04T15:25:17Z

← Older revision		Revision as of 15:25, 4 September 2018
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	The current focus of attention in the UK building stock is towards the hard-to-treat or ‘HTT’ properties, those with a solid wall construction rather than a cavity between the two wall elements. They were often built using natural, local materials held together with mortar – typically lime-based – and other fine local aggregate to bind it together. The HTT properties have rightly been left alone until recent years. Their inherent moisture movement capacity (breathability) makes the introduction of modern materials risky if the process is not carefully considered, approached with a keen eye on the location of the building and undertaken with a degree of caution.		The current focus of attention in the UK building stock is towards the hard-to-treat or ‘HTT’ properties, those with a solid wall construction rather than a cavity between the two wall elements. They were often built using natural, local materials held together with mortar – typically lime-based – and other fine local aggregate to bind it together. The HTT properties have rightly been left alone until recent years. Their inherent moisture movement capacity (breathability) makes the introduction of modern materials risky if the process is not carefully considered, approached with a keen eye on the location of the building and undertaken with a degree of caution.

−	Until recently, the mainstream construction industry considered the performance of these buildings to be poor in comparison with more modern buildings constructed of cementitious or timber frame materials. However, recent and ongoing research indicates that the U-values of these older structures can be up to 30 ~~per cent~~ better than previously assumed. This further reduces the potential for savings from the introduction of internal or external wall insulation.	+	Until recently, the mainstream construction industry considered the performance of these buildings to be poor in comparison with more modern buildings constructed of cementitious or timber frame materials. However, recent and ongoing research indicates that the U-values of these older structures can be up to 30% better than previously assumed. This further reduces the potential for savings from the introduction of internal or external wall insulation.

	When undertaken correctly, external wall insulation is an important measure in helping to reduce heat loss through solid wall buildings. It can also improve the health of occupants, protect buildings from adverse weather and, sometimes, improve appearance and value.		When undertaken correctly, external wall insulation is an important measure in helping to reduce heat loss through solid wall buildings. It can also improve the health of occupants, protect buildings from adverse weather and, sometimes, improve appearance and value.
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	== Ventilation ==		== Ventilation ==

−	Covering up ventilation by reducing infiltration rates and making the building less draughty is another common cause of risk. Understanding how the insulation will affect the ventilation of the inside is essential to ensure that it does not create unhealthy living conditions. If already installed, ventilation should always be checked for correct installation and operation at design capacity, and if not installed, assessed and installed where necessary. The main weakness in this area is not knowing how to assess that the building is in moisture balance and how much ventilation is adequate.	+	Covering up ventilation by reducing infiltration rates and making the building less draughty is another common cause of risk. Understanding how the insulation will affect the ventilation of the inside is essential to ensure that it does not create unhealthy living conditions.
		+
		+	If already installed, ventilation should always be checked for correct installation and operation at design capacity, and if not installed, assessed and installed where necessary. The main weakness in this area is not knowing how to assess that the building is in moisture balance and how much ventilation is adequate.

	== Rain during application ==		== Rain during application ==
Line 109:		Line 111:
	* Diagnosing the causes of dampness (GR 5 revised).		* Diagnosing the causes of dampness (GR 5 revised).
	* IHBC articles.		* IHBC articles.
		+	* Moisture.
	* Penetrating damp.		* Penetrating damp.
	* Rising damp.		* Rising damp.

Designing Buildings at 10:44, 10 June 2018

2018-06-10T10:44:42Z

← Older revision		Revision as of 10:44, 10 June 2018
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	* Damp proofing.		* Damp proofing.
	* Designing out unintended consequences when applying solid wall insulation FB 79.		* Designing out unintended consequences when applying solid wall insulation FB 79.
−	* ~~Hygrothermal~~.	+	* Diagnosing the causes of dampness (GR 5 revised).
	* IHBC articles.		* IHBC articles.
−	* Insulation specification.
	* Penetrating damp.		* Penetrating damp.
	* Rising damp.		* Rising damp.

Editor at 13:49, 20 April 2018

2018-04-20T13:49:29Z

← Older revision		Revision as of 13:49, 20 April 2018
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	When undertaken correctly, external wall insulation is an important measure in helping to reduce heat loss through solid wall buildings. It can also improve the health of occupants, protect buildings from adverse weather and, sometimes, improve appearance and value.		When undertaken correctly, external wall insulation is an important measure in helping to reduce heat loss through solid wall buildings. It can also improve the health of occupants, protect buildings from adverse weather and, sometimes, improve appearance and value.

−	However, it is easy to get it badly wrong, generating a much smaller reduction in heat loss than anticipated. Changes to the physical state of the structure can also cause damage to the building fabric (for example through mould, dry rot or wet rot) which can subsequently affect the health of the occupants by adversely affecting the indoor air quality. This is made more likely by current industry practice which rarely considers the assessment of adequate ventilation pre- and post insulation.	+	However, it is easy to get it badly wrong, generating a much smaller reduction in heat loss than anticipated. Changes to the physical state of the structure can also cause damage to the building fabric (for example, through mould, dry rot or wet rot), which can subsequently affect the health of the occupants by adversely affecting the indoor air quality. This is made more likely by current industry practice which rarely considers the assessment of adequate ventilation pre- and post insulation.

	One would think that the Building Regulations would be sufficient to cover this eventuality, but unfortunately Part F of the Building Regulations offers no real insight into safe or adequate levels of ventilation during the retrofit process, merely defaulting to a ‘make it no worse’ stance. However, without testing air permeability pre- and post-installation, it is almost impossible to decide whether it really is ‘no worse’. In most of the cases I have surveyed and investigated, ventilation was never on the radar of the workforce or procurement process.		One would think that the Building Regulations would be sufficient to cover this eventuality, but unfortunately Part F of the Building Regulations offers no real insight into safe or adequate levels of ventilation during the retrofit process, merely defaulting to a ‘make it no worse’ stance. However, without testing air permeability pre- and post-installation, it is almost impossible to decide whether it really is ‘no worse’. In most of the cases I have surveyed and investigated, ventilation was never on the radar of the workforce or procurement process.
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	The answer is to consider a more risk-conscious approach to the decision-making process and one that is focussed on moisture risk. When considering moisture risk in a built environment context it is vital that the presence of water is considered in in all its different states (ice, liquid water and water vapour).		The answer is to consider a more risk-conscious approach to the decision-making process and one that is focussed on moisture risk. When considering moisture risk in a built environment context it is vital that the presence of water is considered in in all its different states (ice, liquid water and water vapour).

−	All buildings and their inhabitants require a level of moisture to be healthy. Efforts should always be made to balance moisture by a combination of fabric protection, heating and ventilation –whether planned or through infiltration such as draughts and gaps in the structure or through physical vents. Solid wall or HTT buildings were constructed to deal with moisture differently than modern buildings and so need to be treated differently. In particular, their construction materials let moisture (as rain and humidity) in and out without the resistance of barriers or cavities.	+	All buildings and their inhabitants require a level of moisture to be healthy. Efforts should always be made to balance moisture by a combination of fabric protection, heating and ventilation –whether planned or through infiltration such as draughts and gaps in the structure or through physical vents. Solid wall or HTT buildings were constructed to deal with moisture differently than modern buildings and so need to be treated differently. In particular, their construction materials let moisture (as rain and humidity), in and out without the resistance of barriers or cavities.

	Again, looking at the regulations it would be reasonable to assume that they are written to protect the fabric of the building and the health of the occupants. However, this is not always the case and other companion guides to the Building Regulations such as BS5250:2011 Code of Practice for Control of Condensation in Buildings are weak in their understanding of breathable structures and only deal adequately with modern buildings or with one aspect of moisture, like condensation.		Again, looking at the regulations it would be reasonable to assume that they are written to protect the fabric of the building and the health of the occupants. However, this is not always the case and other companion guides to the Building Regulations such as BS5250:2011 Code of Practice for Control of Condensation in Buildings are weak in their understanding of breathable structures and only deal adequately with modern buildings or with one aspect of moisture, like condensation.
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	* Condensation.		* Condensation.
	* Damp in buildings.		* Damp in buildings.
		+	* Damp proofing.
	* Designing out unintended consequences when applying solid wall insulation FB 79.		* Designing out unintended consequences when applying solid wall insulation FB 79.
	* Hygrothermal.		* Hygrothermal.

Editor at 14:58, 5 March 2018

2018-03-05T14:58:51Z

← Older revision		Revision as of 14:58, 5 March 2018
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	{\|		{\|
−	\|[[File:Poorly_installed_external_wall_insulation.jpg\|link=File:Poorly_installed_external_wall_insulation.jpg]]	+	\| [[File:Poorly_installed_external_wall_insulation.jpg\|link=File:Poorly_installed_external_wall_insulation.jpg]]
	\|-		\|-
−	\|Poorly detailed external wall insulation resulting from a failure to extend the roof-line of this traditionally constructed building.	+	\| Poorly detailed external wall insulation resulting from a failure to extend the roof-line of this traditionally constructed building.
	\|}		\|}

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	{\|		{\|
−	\|[[File:Cold_bridge_through_external_wall_insulation.jpg\|link=File:Cold_bridge_through_external_wall_insulation.jpg]]	+	\| [[File:Cold_bridge_through_external_wall_insulation.jpg\|link=File:Cold_bridge_through_external_wall_insulation.jpg]]
	\|-		\|-
−	\|Standard detail around a telephone junction box introducing a large cold bridge and the potential for moisture damage	+	\| Standard detail around a telephone junction box introducing a large cold bridge and the potential for moisture damage
	\|}		\|}

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	* Solid wall insulation.		* Solid wall insulation.
	* Solid Wall Insulation: Unlocking demand and driving up standards.		* Solid Wall Insulation: Unlocking demand and driving up standards.
		+	* Structural waterproofing consultant.
	* The Institute of Historic Building Conservation.		* The Institute of Historic Building Conservation.
	* Understanding dampness.		* Understanding dampness.

Editor at 11:13, 26 September 2017

2017-09-26T11:13:10Z

← Older revision		Revision as of 11:13, 26 September 2017
Line 10:		Line 10:
	When undertaken correctly, external wall insulation is an important measure in helping to reduce heat loss through solid wall buildings. It can also improve the health of occupants, protect buildings from adverse weather and, sometimes, improve appearance and value.		When undertaken correctly, external wall insulation is an important measure in helping to reduce heat loss through solid wall buildings. It can also improve the health of occupants, protect buildings from adverse weather and, sometimes, improve appearance and value.

−	However, it is easy to get it badly wrong, generating a much smaller reduction in heat loss than anticipated. Changes to the physical state of the structure can also cause damage to the building fabric (for example through mould, dry rot or wet rot) which can subsequently affect the health of the occupants by adversely affecting the indoor air quality. This is made more likely by current industry practice which rarely considers the assessment of adequate ventilation pre- and post insulation. One would think that the Building Regulations would be sufficient to cover this eventuality, but unfortunately Part F of the Building Regulations offers no real insight into safe or adequate levels of ventilation during the retrofit process, merely defaulting to a ‘make it no worse’ stance. However, without testing air permeability pre- and post-installation, it is almost impossible to decide whether it really is ‘no worse’. In most of the cases I have surveyed and investigated, ventilation was never on the radar of the workforce or procurement process.	+	However, it is easy to get it badly wrong, generating a much smaller reduction in heat loss than anticipated. Changes to the physical state of the structure can also cause damage to the building fabric (for example through mould, dry rot or wet rot) which can subsequently affect the health of the occupants by adversely affecting the indoor air quality. This is made more likely by current industry practice which rarely considers the assessment of adequate ventilation pre- and post insulation.
		+
		+	One would think that the Building Regulations would be sufficient to cover this eventuality, but unfortunately Part F of the Building Regulations offers no real insight into safe or adequate levels of ventilation during the retrofit process, merely defaulting to a ‘make it no worse’ stance. However, without testing air permeability pre- and post-installation, it is almost impossible to decide whether it really is ‘no worse’. In most of the cases I have surveyed and investigated, ventilation was never on the radar of the workforce or procurement process.

	{\|		{\|
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	=== Location ===		=== Location ===

−	Where is the building? Does it get a lot of wind and rain? Is one side more exposed than the others? A building on a cliff in Wales is very different from one on a London street. The more exposed the building is, the more care should be taken over detailing – extended overhangs, wider gutters, proper splash protection and mastic-free seals around windows, for example. In exposed locations the exposure of walls to wind driven rain should be assessed using BS 8104 – this is vital for determining material suitability. Other factors such as proximity to sources of deposition (such as industrial outlets, motorways and other sources of airborne pollution) should also be considered at an early stage because they will reduce the robustness and effectiveness of the insulation.	+	Where is the building? Does it get a lot of wind and rain? Is one side more exposed than the others? A building on a cliff in Wales is very different from one on a London street. The more exposed the building is, the more care should be taken over detailing – extended overhangs, wider gutters, proper splash protection and mastic-free seals around windows, for example.
		+
		+	In exposed locations, the exposure of walls to wind driven rain should be assessed using BS 8104 – this is vital for determining material suitability. Other factors such as proximity to sources of deposition (such as industrial outlets, motorways and other sources of airborne pollution) should also be considered at an early stage because they will reduce the robustness and effectiveness of the insulation.

	=== Significance ===		=== Significance ===
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	* Damp in buildings.		* Damp in buildings.
	* Designing out unintended consequences when applying solid wall insulation FB 79.		* Designing out unintended consequences when applying solid wall insulation FB 79.
		+	* Hygrothermal.
	* IHBC articles.		* IHBC articles.
	* Insulation specification.		* Insulation specification.

Designing Buildings at 13:14, 1 August 2017

2017-08-01T13:14:39Z

← Older revision		Revision as of 13:14, 1 August 2017
Line 109:		Line 109:
	* Solid Wall Insulation: Unlocking demand and driving up standards.		* Solid Wall Insulation: Unlocking demand and driving up standards.
	* The Institute of Historic Building Conservation.		* The Institute of Historic Building Conservation.
		+	* Understanding dampness.
	* Ventilation.		* Ventilation.

	[[Category:Conservation]]		[[Category:Conservation]]

Designing Buildings at 10:29, 23 May 2017

2017-05-23T10:29:18Z

← Older revision		Revision as of 10:29, 23 May 2017
Line 13:		Line 13:

	{\|		{\|
−	\|[[File:~~Poorly installed external wall insulation~~.jpg]]	+	\|[[File:Poorly_installed_external_wall_insulation.jpg\|link=File:Poorly_installed_external_wall_insulation.jpg]]
	\|-		\|-
	\|Poorly detailed external wall insulation resulting from a failure to extend the roof-line of this traditionally constructed building.		\|Poorly detailed external wall insulation resulting from a failure to extend the roof-line of this traditionally constructed building.
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	{\|		{\|
−	\|[[File:~~Cold bridge through external wall insulation~~.jpg]]	+	\|[[File:Cold_bridge_through_external_wall_insulation.jpg\|link=File:Cold_bridge_through_external_wall_insulation.jpg]]
	\|-		\|-
	\|Standard detail around a telephone junction box introducing a large cold bridge and the potential for moisture damage		\|Standard detail around a telephone junction box introducing a large cold bridge and the potential for moisture damage
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	-----		-----
−	This article originally appeared in IHBC's 2017 Yearbook. It was written by Colin King, director of the Building Research Establishment (BRE).	+	This article originally appeared in [http://www.ihbc.org.uk/page55/page58/index.html IHBC's 2017 Yearbook]. It was written by Colin King, director of the Building Research Establishment (BRE).

	--[[User:Institute_of_Historic_Building_Conservation\|Institute of Historic Building Conservation]]		--[[User:Institute_of_Historic_Building_Conservation\|Institute of Historic Building Conservation]]

Designing Buildings at 10:25, 23 May 2017

2017-05-23T10:25:55Z

← Older revision		Revision as of 10:25, 23 May 2017
Line 11:		Line 11:

	However, it is easy to get it badly wrong, generating a much smaller reduction in heat loss than anticipated. Changes to the physical state of the structure can also cause damage to the building fabric (for example through mould, dry rot or wet rot) which can subsequently affect the health of the occupants by adversely affecting the indoor air quality. This is made more likely by current industry practice which rarely considers the assessment of adequate ventilation pre- and post insulation. One would think that the Building Regulations would be sufficient to cover this eventuality, but unfortunately Part F of the Building Regulations offers no real insight into safe or adequate levels of ventilation during the retrofit process, merely defaulting to a ‘make it no worse’ stance. However, without testing air permeability pre- and post-installation, it is almost impossible to decide whether it really is ‘no worse’. In most of the cases I have surveyed and investigated, ventilation was never on the radar of the workforce or procurement process.		However, it is easy to get it badly wrong, generating a much smaller reduction in heat loss than anticipated. Changes to the physical state of the structure can also cause damage to the building fabric (for example through mould, dry rot or wet rot) which can subsequently affect the health of the occupants by adversely affecting the indoor air quality. This is made more likely by current industry practice which rarely considers the assessment of adequate ventilation pre- and post insulation. One would think that the Building Regulations would be sufficient to cover this eventuality, but unfortunately Part F of the Building Regulations offers no real insight into safe or adequate levels of ventilation during the retrofit process, merely defaulting to a ‘make it no worse’ stance. However, without testing air permeability pre- and post-installation, it is almost impossible to decide whether it really is ‘no worse’. In most of the cases I have surveyed and investigated, ventilation was never on the radar of the workforce or procurement process.
		+
		+	{\|
		+	\|[[File:Poorly installed external wall insulation.jpg]]
		+	\|-
		+	\|Poorly detailed external wall insulation resulting from a failure to extend the roof-line of this traditionally constructed building.
		+	\|}

	The answer is to consider a more risk-conscious approach to the decision-making process and one that is focussed on moisture risk. When considering moisture risk in a built environment context it is vital that the presence of water is considered in in all its different states (ice, liquid water and water vapour).		The answer is to consider a more risk-conscious approach to the decision-making process and one that is focussed on moisture risk. When considering moisture risk in a built environment context it is vital that the presence of water is considered in in all its different states (ice, liquid water and water vapour).
Line 39:		Line 45:

	Has the building got a complicated shape or details which make it difficult to be sure that there won’t be leakage or cold bridging? Does this form have heritage value? If it is complicated, it may be better not to insulate or to consider internal wall insulation.		Has the building got a complicated shape or details which make it difficult to be sure that there won’t be leakage or cold bridging? Does this form have heritage value? If it is complicated, it may be better not to insulate or to consider internal wall insulation.
		+
		+	{\|
		+	\|[[File:Cold bridge through external wall insulation.jpg]]
		+	\|-
		+	\|Standard detail around a telephone junction box introducing a large cold bridge and the potential for moisture damage
		+	\|}

	=== Condition ===		=== Condition ===