Basement insulation - Revision history

Designing Buildings at 10:53, 16 December 2025

2025-12-16T10:53:30Z

← Older revision		Revision as of 10:53, 16 December 2025
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	# Bobenhausen, William. "Simplified Design of HVAC Systems”. Scholarly & Professional, Wiley, 1994.		# Bobenhausen, William. "Simplified Design of HVAC Systems”. Scholarly & Professional, Wiley, 1994.

−	= Related articles on Designing Buildings ~~Wiki.~~ =	+	= Related articles on Designing Buildings =

	* Basement excavation.		* Basement excavation.
Line 60:		Line 60:
	* Underground.		* Underground.

−	~~[[Category:Articles_needing_more_work]]~~ [[Category:DCN_Commentary]] [[Category:DCN_Guidance]] [[Category:DCN_Product_Knowledge]] [[Category:Construction_techniques]]	+	[[Category:DCN_Commentary]] [[Category:DCN_Guidance]] [[Category:DCN_Product_Knowledge]] [[Category:Construction_techniques]]

Editor at 11:10, 12 May 2023

2023-05-12T11:10:44Z

← Older revision		Revision as of 11:10, 12 May 2023
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	* P – perimetre of the slab edge in linear feet		* P – perimetre of the slab edge in linear feet
	* F – transmission heat loss per linear foot of slab edge		* F – transmission heat loss per linear foot of slab edge
−
−	~~--[[User:Bwhite8727\|Bwhite8727]]~~

	= References =		= References =

Designing Buildings at 06:55, 25 February 2021

2021-02-25T06:55:27Z

← Older revision		Revision as of 06:55, 25 February 2021
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	* Underground.		* Underground.

−	[[Category:Articles_needing_more_work]] [[Category:Construction_techniques]]	+	[[Category:Articles_needing_more_work]] [[Category:DCN_Commentary]] [[Category:DCN_Guidance]] [[Category:DCN_Product_Knowledge]] [[Category:Construction_techniques]]

Bwhite8727 at 17:07, 15 December 2020

2020-12-15T17:07:04Z

Editor: moved Basement Insulation to Basement insulation

2020-07-21T19:40:36Z

moved Basement Insulation to Basement insulation

← Older revision

Revision as of 19:40, 21 July 2020

Designing Buildings at 11:09, 6 July 2020

2020-07-06T11:09:47Z

← Older revision		Revision as of 11:09, 6 July 2020
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−	= ~~Basement Insulation To Limit Heat Loss/Gain~~ =	+	= Introduction =

−	~~The heat loss/gain through basement walls and below-grade foundations are studied.~~ Heat loss through the basement foundation accounts for 15% to 30% of the annual heat load in a two-storey house. If you want to improve the energy performance of your home then you should start by air sealing and insulating. The attic can account for ~25% of a home’s total heat loss and the basement ~20%. A considerable energy saver is the insulation of the ~~perimetre~~ of the slab and can save 10% to 20% on heating bills. In climates with mild winters, this saves $50 to $60/month for an 1800 sq–ft house using R–10 insulation. The cost for installation is $300 to $600 which gives a payback period of 5 to 10 years. It is assumed that basement walls that are below-grade have no infiltration and thus heat losses. However, for above-grade walls in the winter the sensible heat losses due to infiltration are ~½ to 3 times the conduction heat losses. For cooling, in the summer, these infiltration losses are halved.	+	Heat loss through the basement foundation accounts for 15% to 30% of the annual heat load in a two-storey house. If you want to improve the energy performance of your home then you should start by air sealing and insulating. The attic can account for ~25% of a home’s total heat loss and the basement ~20%. A considerable energy saver is the insulation of the perimeter of the slab and can save 10% to 20% on heating bills.

−	~~= Types Of Insulation =~~	+	In climates with mild winters, this saves $50 to $60/month for an 1800 sq–ft house using R–10 insulation. The cost for installation is $300 to $600 which gives a payback period of 5 to 10 years. It is assumed that basement walls that are below-grade have no infiltration and thus heat losses. However, for above-grade walls in the winter the sensible heat losses due to infiltration are ~½ to 3 times the conduction heat losses. For cooling, in the summer, these infiltration losses are halved.

−	~~There are many types~~ of insulation based on the application but the two main types are continuous and cavity. Continuous insulation runs continuously alongside the structural members, so unlike cavity insulation, it’s unaffected by thermal bridging. It’s generally foam board type (i.e. rigid foam or insulating boards) made of either polystyrene (extruded or expanded), polyisocyanurate, or polyurethane material. Cavity insulation is fitted between wood or metal structural members such as studs, joists (including rim joists), and beams. It’s a blanket type that comes in either batts or rolls that are attached to the inside surface of walls. Rigid fibreboard (i.e. rigid fibre or fibrous board) consists of flexible fibres, most commonly fibreglass. Mineral wool (i.e. ROCKWOOL®), however, has a similar R-value and beats out fibreglass as a fire retarder, it’s moisture resistant, and it’s more environmentally friendly.	+	= Types of insulation =

−	There are ~~three sections~~ of the ~~basement walls that need to be accounted for: the above-grade section; the below-grade~~ and ~~above~~ the ~~frost line; and the below-grade and below the frost line~~. ~~As opposed to an outside wall that~~ is ~~exposed to a uniform outside air temperature, a below-grade slab is exposed to the soil which varies in temperature depending on the depth from the surface~~. ~~The heat loss calculation is more complicated due to the soil temperature varying depending on the time~~ of ~~year~~, ~~the climate~~, ~~the make-up of soil, whether snow is on the ground, the amount of moisture in the soil, and the depth of the dirt from the ground level~~.	+	There are many types of insulation based on application but the two main types are continuous and cavity. Continuous insulation runs continuously alongside the structural members, so unlike cavity insulation, it’s unaffected by thermal bridging. It is generally foam board type (i.e. rigid foam or insulating boards) made of either polystyrene (extruded or expanded), polyisocyanurate, or polyurethane material.

−	~~= Construction Techniques =~~	+	Cavity insulation is fitted between wood or metal structural members such as studs, joists (including rim joists), and beams. It’s a blanket type that comes in either batts or rolls that are attached to the inside surface of walls. Rigid fibreboard (i.e. rigid fibre or fibrous board) consists of flexible fibres, most commonly fibreglass. Mineral wool (i.e. ROCKWOOL®), however, has a similar R-value and beats fibreglass as a fire retarder, it is moisture resistant, and it’s more environmentally friendly.

−	~~Construction techniques like~~ the ~~cores in concrete blocks promote vertical convection of heat~~. ~~This is beneficial but~~ an ~~8–inch concrete~~ wall ~~without insulation has~~ a ~~low resistance (R–1.11 & R–1.49 with~~ air ~~films). Due to the low resistance~~, ~~this warrants adding insulation. For~~ a ~~20′ x 30′ basement covered in a 2–inch beadboard (R–8), there~~ is ~~a 93% decrease~~ in ~~heat loss~~. ~~Using 3.5–inch fibreglass batting (R–11) decreases the~~ heat loss ~~further to 95%. This type of insulation~~ is ~~used in warmer climates, but if the climate is colder, a 4″ to 6″ (R–30) insulation is used. The addition of a reflective barrier~~ to the ~~wall adds 16% to~~ the ~~R–value and~~, if the ~~air space is reflective~~, ~~it adds 50% to~~ the R-~~value. Insulation placed on the interior~~ of ~~the exterior wall will give only slightly different R-values. For slab insulation at a 2–foot depth~~, ~~an R–value that~~ is ~~more than R–20 is not justified because heat will go around~~ the ~~insulation. Also~~, ~~insulating an 8–foot wall halfway down with R–10 is practically~~ the ~~same as insulating~~ the ~~8–foot wall with R–5. With heating and cooling loads competing~~, ~~this will provide earth coupling – less digging~~ and ~~insulation are needed~~.	+	There are three sections of the basement walls that need to be accounted for: the above-grade section; the below-grade and above the frost line; and the below-grade and below the frost line. As opposed to an outside wall that is exposed to a uniform outside air temperature, a below-grade slab is exposed to the soil which varies in temperature depending on the depth from the surface. The heat loss calculation is more complicated due to the soil temperature varying depending on the time of year, the climate, the make-up of soil, whether snow is on the ground, the amount of moisture in the soil, and the depth of the soil from the ground level.

−	= ~~Where To Put The Insulation~~ =	+	= Construction techniques =

−	~~As for deciding where to put the insulation, if attached to the exterior this will be less expensive if below grade because it can be left uncovered; as such, no fire retarder~~ such as 5/8–inch drywall is required. Secondly, the major air leak at the sill wall is prevented with a good installation. Thirdly, the thermal mass remains available to the house for heating or cooling. Lastly, the foundation is protected from stresses caused by insulating. Reasons to go with interior insulation are frost heaves will develop in ~~the soil because the~~ heat ~~from the house is not there to warm up the soil~~. This can be particularly bad for block and stone foundations that cannot resist lateral forces. Foam insulation and backfilling with clean granular fill can prevent cracking because of freeze/thawing. Spalling can also occur. The possibility of an unheated basement falling below the freezing point may be important regarding pipes freezing. Heat is added to the basement by furnaces and boilers which are in the basement. Water heaters and laundry equipment, a source of heat, can be in the basement as well. As a rule of thumb, the basement temperature should be halfway between the outside and inside temperatures. Moisture control is important, so mould or bacteria do not grow. In all but ~~very arid climates,~~ a ~~vapour barrier is installed on the warm side of the wall~~. ~~The insulating material should not degrade structurally or thermally after long term exposure to the elements~~. ~~The barrier is usually a thin sheet of PET plastic~~. ~~The barrier prevents moisture from inside migrating into the wall where it condenses somewhere in the wall and greatly diminishes the R-values of the~~ insulation ~~and reflective barriers~~.	+	Construction techniques such as cores in concrete blocks promote vertical convection of heat. This is beneficial but an 8–inch concrete wall without insulation has a low thermal resistance (R–1.11 & R–1.49 with air films). This warrants adding insulation.

−	= ~~How To Calculate~~ Heat ~~Gain~~/~~Losses~~ =	+	For a 20′ x 30′ basement covered in a 2–inch beadboard (R–8), there is a 93% decrease in heat loss. Using 3.5–inch fibreglass batting (R–11) decreases the heat loss further to 95%. This type of insulation is used in warmer climates, but if the climate is colder, 4″ to 6″ (R–30) insulation is used. The addition of a reflective barrier to the wall adds 16% to the R–value and, if the air space is reflective, it adds 50% to the R-value. Insulation placed on the interior of the exterior wall will give only slightly different R-values.
		+
		+	For slab insulation at a 2–foot depth, an R–value that is more than R–20 is not justified because heat will go around the insulation. Also, insulating an 8–foot wall halfway down with R–10 is practically the same as insulating the 8–foot wall with R–5. With heating and cooling loads competing, this will provide earth coupling – less digging and insulation are needed.
		+
		+	= Where to put the insulation =
		+
		+	As for deciding where to put the insulation, if attached to the exterior this will be less expensive if below grade because it can be left uncovered; as such, no fire retarder such as 5/8–inch drywall is required. Secondly, the major air leak at the sill wall is prevented with a good installation. Thirdly, the thermal mass remains available to the house for heating or cooling. Lastly, the foundation is protected from stresses caused by insulating.
		+
		+	Reasons to go with interior insulation are that frost heaves will develop in the soil because the heat from the house is not there to warm up the soil. This can be particularly bad for block and stone foundations that cannot resist lateral forces. Foam insulation and backfilling with clean granular fill can prevent cracking because of freeze/thawing. Spalling can also occur.
		+
		+	The possibility of an unheated basement falling below the freezing point may be important regarding pipes freezing. Heat is added to the basement by furnaces and boilers which are in the basement. Water heaters and laundry equipment, a source of heat, can be in the basement as well. As a rule of thumb, the basement temperature should be halfway between the outside and inside temperatures. Moisture control is important, so mould or bacteria do not grow. In all but very arid climates, a vapour barrier is installed on the warm side of the wall. The insulating material should not degrade structurally or thermally after long term exposure to the elements. The barrier is usually a thin sheet of PET plastic. The barrier prevents moisture from inside migrating into the wall where it condenses somewhere in the wall and greatly diminishes the R-values of the insulation and reflective barriers.
		+
		+	= How to calculate heat gain/loss =

	When using a program (i.e. REScheck) to calculate the gains/losses through a basement wall at least 50% of the wall must be below grade. Basement walls that enclose heated spaces are part of the building envelope. The area of the wall should exclude windows and doors. For increased accuracy, the basement floor area should have the exterior wall thickness subtracted. An approximate method for calculating heat loss through a basement is given by the equation: qem = EF x U x A, where EF is a correction factor for a below-grade wall and A is the area of the basement walls. Heat gain/loss coefficients for above-grade basement walls are given as U–factors and below-grade as F–factors [Btu / (hr–ft–°F)]. For the foundation, the heat loss is conducted away from the centre out to the perimetre of the slab:		When using a program (i.e. REScheck) to calculate the gains/losses through a basement wall at least 50% of the wall must be below grade. Basement walls that enclose heated spaces are part of the building envelope. The area of the wall should exclude windows and doors. For increased accuracy, the basement floor area should have the exterior wall thickness subtracted. An approximate method for calculating heat loss through a basement is given by the equation: qem = EF x U x A, where EF is a correction factor for a below-grade wall and A is the area of the basement walls. Heat gain/loss coefficients for above-grade basement walls are given as U–factors and below-grade as F–factors [Btu / (hr–ft–°F)]. For the foundation, the heat loss is conducted away from the centre out to the perimetre of the slab:

Editor at 10:02, 16 June 2020

2020-06-16T10:02:22Z

← Older revision		Revision as of 10:02, 16 June 2020
Line 45:		Line 45:
	* Basements in buildings.		* Basements in buildings.
	* Crawl space.		* Crawl space.
		+	* Insulation.
	* Right of support.		* Right of support.
	* Substructure.		* Substructure.

Editor at 10:01, 16 June 2020

2020-06-16T10:01:10Z

← Older revision		Revision as of 10:01, 16 June 2020
Line 26:		Line 26:
	* P – perimetre of the slab edge in linear feet		* P – perimetre of the slab edge in linear feet
	* F – transmission heat loss per linear foot of slab edge		* F – transmission heat loss per linear foot of slab edge
		+
		+	--[[User:Bwhite8727\|Bwhite8727]]

	= References =		= References =
Line 34:		Line 36:
	# Bobenhausen, William. "Simplified Design of HVAC Systems”. Scholarly & Professional, Wiley, 1994.		# Bobenhausen, William. "Simplified Design of HVAC Systems”. Scholarly & Professional, Wiley, 1994.

−	~~--[[User:Bwhite8727\|Bwhite8727]] 19:26, 05 Jun 2020~~ (~~BST~~)	+	= Related articles on Designing Buildings Wiki. =
		+
		+	* Basement excavation.
		+	* Basement Excavation (Restriction of Permitted Development) Bill.
		+	* Basement impact assessment.
		+	* Basement v cellar.
		+	* Basement waterproofing.
		+	* Basements in buildings.
		+	* Crawl space.
		+	* Right of support.
		+	* Substructure.
		+	* Underground.

−	[[Category:Articles_needing_more_work]]	+	[[Category:Articles_needing_more_work]] [[Category:Construction_techniques]]

Bwhite8727 at 18:32, 5 June 2020

2020-06-05T18:32:37Z

← Older revision		Revision as of 18:32, 5 June 2020
Line 29:		Line 29:
	= References =		= References =

−	# Norton, Paul. "Types of Insulation"~~, Energy~~.~~gov~~. [https://www.energy.gov/energysaver/weatherize/insulation/types-insulation https://www.energy.gov/energysaver/weatherize/insulation/types-insulation].	+	# Norton, Paul. "Types of Insulation". U.S. Department Of Energy. [https://www.energy.gov/energysaver/weatherize/insulation/types-insulation https://www.energy.gov/energysaver/weatherize/insulation/types-insulation].
	# Berner, Mike, "Common Types of Insulation, and When to Use Them". [https://www.familyhandyman.com/heating-cooling/common-types-of-insulation-and-when-to-use-them/ https://www.familyhandyman.com/heating-cooling/common-types-of-insulation-and-when-to-use-them].		# Berner, Mike, "Common Types of Insulation, and When to Use Them". [https://www.familyhandyman.com/heating-cooling/common-types-of-insulation-and-when-to-use-them/ https://www.familyhandyman.com/heating-cooling/common-types-of-insulation-and-when-to-use-them].
−	# "~~InspectAPedia®~~". [https://inspectapedia.com/Energy/Basement_Heat_Loss.php https://inspectapedia.com/Energy/Basement_Heat_Loss.php].	+	# "Basement Heat Loss Guide". [https://inspectapedia.com/Energy/Basement_Heat_Loss.php https://inspectapedia.com/Energy/Basement_Heat_Loss.php].
	# Bobenhausen, William. "Simplified Design of HVAC Systems”. Scholarly & Professional, Wiley, 1994.		# Bobenhausen, William. "Simplified Design of HVAC Systems”. Scholarly & Professional, Wiley, 1994.

Bwhite8727 at 18:26, 5 June 2020

2020-06-05T18:26:42Z

← Older revision		Revision as of 18:26, 5 June 2020
Line 33:		Line 33:
	# "InspectAPedia®". [https://inspectapedia.com/Energy/Basement_Heat_Loss.php https://inspectapedia.com/Energy/Basement_Heat_Loss.php].		# "InspectAPedia®". [https://inspectapedia.com/Energy/Basement_Heat_Loss.php https://inspectapedia.com/Energy/Basement_Heat_Loss.php].
	# Bobenhausen, William. "Simplified Design of HVAC Systems”. Scholarly & Professional, Wiley, 1994.		# Bobenhausen, William. "Simplified Design of HVAC Systems”. Scholarly & Professional, Wiley, 1994.
		+
		+	--[[User:Bwhite8727\|Bwhite8727]] 19:26, 05 Jun 2020 (BST)

	[[Category:Articles_needing_more_work]]		[[Category:Articles_needing_more_work]]

← Older revision		Revision as of 17:07, 15 December 2020
Line 1:		Line 1:
	= Introduction =		= Introduction =

−	Heat loss through the basement foundation accounts for 15% to 30% of the annual heat load in a two-~~storey~~ house. If you want to improve the energy performance of your home then you should start by air sealing and insulating. The attic can account for ~25% of a home’s total heat loss and the basement ~20%. A considerable energy saver is the insulation of the perimeter of the slab and can save 10% to 20% on heating bills.	+	Heat loss through the basement foundation accounts for 15% to 30% of the annual heat load in a two-story house. If you want to improve the energy performance of your home then you should start by air sealing and insulating. The attic can account for ~25% of a home’s total heat loss and the basement ~20%. A considerable energy saver is the insulation of the perimeter of the slab and can save 10% to 20% on heating bills.

−	In climates with mild winters, this saves $50 to $60/month for an 1800 sq–ft house using R–10 insulation. The cost for installation is $300 to $600 which gives a payback period of 5 to 10 years. ~~It is assumed that basement~~ walls ~~that~~ are ~~below-grade~~ have no infiltration ~~and thus heat losses~~. However, for ~~above-grade~~ walls in the winter the sensible heat ~~losses~~ due to infiltration are ~½ to 3 times the conduction heat ~~losses~~. For cooling, in the summer, these infiltration losses are halved.	+	In climates with mild winters, this saves $50 to $60/month for an 1800 sq–ft house using R–10 insulation. The cost for installation is $300 to $600 which gives a payback period of 5 to 10 years. Underground walls are assumed to have no infiltration. However, for aboveground walls in the winter the sensible heat loss due to infiltration are ~½ to 3 times the conduction heat loss. For cooling, in the summer, these infiltration losses are halved.

	= Types of insulation =		= Types of insulation =

−	There are many types of insulation ~~based on application~~ but the two main types are continuous and cavity. Continuous insulation ~~runs~~ continuously alongside the structural members, so ~~unlike cavity insulation,~~ it’s unaffected by thermal bridging. It is generally foam board ~~type~~ (i.e. rigid foam or insulating boards) made of either polystyrene (extruded or expanded), polyisocyanurate, or polyurethane material.	+	There are many types of insulation, but the two main types are continuous and cavity. Continuous insulation, unlike cavity insulation, lies continuously alongside the structural members, so it’s unaffected by thermal bridging. Continuous insulation is generally foam board (i.e. rigid foam or insulating boards) made of either polystyrene (extruded or expanded), polyisocyanurate, or polyurethane material.

−	Cavity insulation is fitted between wood or metal structural members ~~such as~~ studs, joists (including rim joists), and beams. It’s a blanket type that comes in either batts or rolls that are attached to the inside surface of walls. Rigid ~~fibreboard~~ (i.e. rigid ~~fibre~~ or fibrous board) consists of flexible ~~fibres~~, most commonly ~~fibreglass~~. Mineral wool (i.e. ROCKWOOL®), however, has a similar R-value and beats ~~fibreglass~~ as a fire retarder, ~~it is~~ moisture resistant, and it’s more environmentally friendly.	+	Cavity insulation is fitted between wood or metal structural members like studs, joists (including rim joists), and beams. It’s a blanket type that comes in either batts or rolls that are attached to the inside surface of walls. Rigid fiberboard (i.e. rigid fiber or fibrous board) consists of flexible fibers, most commonly fiberglass. Mineral wool (i.e. ROCKWOOL®), however, has a similar R-value and beats fiberglass as a fire retarder, it’s moisture resistant, and it’s more environmentally friendly.

−	There are three sections of the basement walls that need to be accounted for: the ~~above-grade~~ section; the ~~below-grade~~ and above the frost line; and the ~~below-grade~~ and below the frost line. As opposed to an outside wall ~~that is~~ exposed to a uniform outside air temperature, a ~~below-grade~~ slab is exposed to the soil which varies in temperature depending on the depth from ~~the surface~~. The heat loss ~~calculation~~ is more complicated ~~due to~~ the soil temperature ~~varying~~ depending on the ~~time of year~~, ~~the~~ climate, ~~the make-up of~~ soil, ~~whether snow is on~~ the ~~ground, the amount of~~ moisture in the soil, ~~and~~ the depth of the soil from the ground ~~level~~.	+	There are three sections of the basement walls that need to be accounted for: the aboveground section; the belowground and above the frost line; and the belowground and below the frost line. As opposed to an outside wall exposed to a uniform outside air temperature, a belowground slab is exposed to the soil which varies in temperature depending on the depth from grade. The calculation of heat loss is more complicated, as the soil temperature varies depending on the season, climate, soil condition, the moisture content in the soil, the depth of the soil from grade, and whether there is snow on the ground.

	= Construction techniques =		= Construction techniques =

−	Construction techniques ~~such as~~ cores in concrete blocks promote vertical convection of heat. This is beneficial but an 8–inch concrete wall without insulation has a low thermal resistance (R–1.11 & R–1.49 with air films)~~. This~~ warrants adding insulation.	+	Construction techniques like cores in concrete blocks promote vertical convection of heat. This is beneficial but an 8–inch concrete wall without insulation has a low thermal resistance (R–1.11 & R–1.49 with air films) and warrants adding insulation.

−	For a 20′ x 30′ basement covered in a 2–inch beadboard (R–8), there is a 93% ~~decrease~~ in heat loss. Using 3.5–inch ~~fibreglass~~ batting (R–11) decreases the heat loss further to 95%. This type of insulation is used in warmer climates, but if the climate is colder, 4″ to 6″ (R–30) insulation is used. The addition of a reflective barrier to the wall adds 16% to the ~~R–value~~ and, if the air space is reflective, it adds 50% ~~to the R-value~~. Insulation placed on the interior of the exterior wall will give ~~only~~ slightly different R-values.	+	For a 20′ x 30′ basement covered in a 2–inch beadboard (R–8), there is a 93% reduction in heat loss. Using 3.5–inch fiberglass batting (R–11) decreases the heat loss further to 95%. This type of insulation is used in warmer climates, but if the climate is colder, 4″ to 6″ (R–30) insulation is used. The addition of a reflective barrier to the wall adds 16% to the R-value and, if the air space is reflective, it adds 50%. Insulation placed on the interior of the exterior wall will give slightly different R-values.

−	For slab insulation at a 2–foot depth, an ~~R–value~~ that is more than R–20 is not justified because heat will go around the insulation. Also, insulating an 8–foot wall halfway down with R–10 is practically the same as insulating the 8–foot wall with R–5. With heating and cooling loads competing, this will provide earth coupling – less digging and insulation are needed.	+	For slab insulation at a 2–foot depth, an R-value that is more than R–20 is not justified because heat will go around the insulation. Also, insulating an 8–foot wall halfway down with R–10 is practically the same as insulating the 8–foot wall with R–5. With heating and cooling loads competing, this will provide earth coupling – less digging and insulation are needed.

	= Where to put the insulation =		= Where to put the insulation =

−	As for deciding where to put the insulation, ~~if attached~~ to the exterior ~~this will be less expensive if below grade~~ because it can be left uncovered; as such, no fire retarder ~~such as~~ 5/8–inch drywall is required. Secondly, the major air leak at the sill wall is prevented with a ~~good~~ installation. Thirdly, the thermal mass remains available to the house for heating or cooling. Lastly, the foundation is protected from stresses caused by insulating.	+	As for deciding where to put the insulation, it is less expensive to attach it to the exterior belowground because it can be left uncovered; as such, no fire retarder like 5/8–inch drywall is required. Secondly, the major air leak at the sill wall is prevented with a proper installation. Thirdly, the thermal mass remains available to the house for heating or cooling. Lastly, the foundation is protected from stresses caused by insulating.

−	~~Reasons to go with interior~~ insulation ~~are that~~ frost heaves ~~will develop in the soil~~ because the heat from the house is ~~not~~ there to warm up the soil. ~~This can be particularly bad~~ for block and stone foundations that cannot resist lateral forces. ~~Foam~~ insulation and backfilling with clean granular fill can prevent cracking ~~because of freeze/~~thawing~~. Spalling can also occur~~.	+	Interior insulation prevents frost heaves from developing because the heat from the house is there to warm up the soil. Frost heaves are problematic for block and stone foundations that cannot resist lateral forces and spalling can occur. However, foam insulation and backfilling with clean granular fill can prevent cracking caused by freezing and thawing.

−	~~The~~ possibility of an unheated basement falling below the freezing point may be important regarding pipes freezing. Heat is added to the basement by furnaces and boilers which are in the basement. Water heaters and laundry equipment, a source of heat, can be in the basement as well. As a rule of thumb, the basement temperature should be halfway between the outside and inside temperatures. Moisture control is important, so ~~mould~~ or bacteria do not grow. In all but ~~very~~ arid climates, a ~~vapour~~ barrier is installed on the warm side of the wall. The insulating material should not degrade structurally or thermally after long term exposure to the elements. The barrier is usually a thin sheet of PET plastic. The barrier prevents moisture from inside migrating into the wall where it condenses somewhere in the wall and greatly diminishes the R-values of the insulation and reflective barriers.	+	Avoiding the possibility of an unheated basement falling below the freezing point may be important regarding pipes freezing. Heat is added to the basement by furnaces and boilers which are in the basement. Water heaters and laundry equipment, a source of heat, can be in the basement as well. As a rule of thumb, the basement temperature should be halfway between the outside and inside temperatures. Moisture control is important, so mold or bacteria do not grow. In all but arid climates, a vapor barrier is installed on the warm side of the wall. The insulating material should not degrade structurally or thermally after long term exposure to the elements. The barrier is usually a thin sheet of PET plastic. The barrier prevents moisture from inside migrating into the wall where it condenses somewhere in the wall and greatly diminishes the R-values of the insulation and reflective barriers.

	= How to calculate heat gain/loss =		= How to calculate heat gain/loss =

−	When using a program (i.e. REScheck) to calculate the ~~gains/losses~~ through a basement wall at least 50% of the wall must be ~~below grade~~. Basement walls that enclose heated spaces are part of the building envelope. The area ~~of the wall~~ should exclude windows and doors. For increased accuracy, the basement floor area should have the exterior wall thickness subtracted. An approximate method for calculating heat loss through a basement is given by the equation: qem = EF x U x A, where EF is a correction factor for a ~~below-grade~~ wall and A is the area of the basement walls. Heat ~~gain/~~loss coefficients for ~~above-grade~~ basement walls are given as U–factors and ~~below-grade~~ as F–factors [Btu / (hr–ft–°F)]. For the foundation, the heat loss is conducted away from the ~~centre~~ out to the ~~perimetre~~ of the slab:	+	When using a program (i.e. REScheck) to calculate the loss through a basement wall, at least 50% of the wall must be belowground. Basement walls that enclose heated spaces are part of the building envelope. The wall area should exclude windows and doors. For increased accuracy, the basement floor area should have the exterior wall thickness subtracted. An approximate method for calculating heat loss through a basement is given by the equation: qem = EF x U x A, where EF is a correction factor for a belowground wall and A is the area of the basement walls. Heat loss coefficients for aboveground basement walls are given as U–factors and belowground as F–factors [Btu / (hr–ft–°F)]. For the foundation, the heat loss is conducted away from the center out to the perimeter of the slab:

	Qsc = F x P		Qsc = F x P