Double Stud Wall Construction

54fighting · 05-07-2022, 06:28 PM

Anyone employed this method of insulating a home?

John Mercier · 05-07-2022, 08:17 PM

Yes. The 1948 cottage that is currently owned by my nephew was rebuilt by my brother and I using the double stud method.

jeffatsquam · 05-08-2022, 05:36 AM

Quote:

Originally Posted by 54fighting

Anyone employed this method of insulating a home?

Yes, 2x4 exterior wall 5 inch gap then 2x4 interior wall r40 in the walls r60 in the roof you can heat the house with a match. Actually a Russian fireplace is the main source of heat.

John Mercier · 05-08-2022, 06:47 AM

The newer technique is to use 2x4 construction with a rigid insulation on the exterior... usually another two inches... to prevent the ''bridging'' effect.

But other than the attic on a single story home... most of the heating/cooling is lost through air transfer. So many build tight and use an ERV.

This only works if you control the air loss through everything including your daily actions. If it is a space that you enter/leave repeatedly... the loss will be through the air transfer when the door opens.

Fargo · 05-08-2022, 08:42 AM

That’s a great way to build an energy efficient home. You’ll need professional help in order not to have issues all the systems, heating, cooling, humidity, air exchanges etc. A good source for information is passivhausMaine. The state of Maine is ahead of the curve when building high performance residential and commercial property in the USA.

BroadHopper · 05-08-2022, 08:49 AM

John is right about air loss. Most stick-built homes have tremendous air loss!
You can check with NH Energysaves for reliable energy audits on your project.

This excerpt is from one of the top builders in North America. Gives you an idea what the latest trend. The build is so airtight, that an air exchanger is needed to keep the air fresh.

Our cellulose is made from recycled newspaper and shipping boxes, which is an excellent way to upcycle unwanted paper products. The cellulose is densely packed into every panel and does not settle during shipping because it is already so heavily compacted. In addition to being a great use of recycled paper, cellulose has superior insulating, sound deadening, and fire resistance properties compared to fiberglass.

We also prefer cellulose insulation because of its hygroscopic properties, which means it is very good at managing moisture and works with other layers in the panel, including the smart vapor permeance of the OSB (oriented strand board). This semi-vapor open assembly allows for drying in both directions, making it ideal for all climates. Our building systems rely on continuous mechanical ventilation to manage interior humidity.

In comparison, fiberglass insulation is hydrophobic, meaning that it repels moisture, which then gets absorbed into the wood around it and often results in mold.

Our air-tight building assemblies are designed to optimally manage moisture to keep bulk moisture out and the amount of vapor that diffuses through them, is very low.

John Mercier · 05-08-2022, 09:49 AM

Sorry.
My comments tend to be for those renovating homes to become more energy efficient.

DickR · 05-08-2022, 10:31 AM

Our home, built 2010-11, has a double-stud exterior. Wall insulation is dense-packed cellulose to R40 or so, attic floor is loose-blow cellulose to R60. Then there is 4" foam under the basement slab and on the foundation walls. Windows are a mix of triple-pane casement and fixed glass (avg U=0.17). Only the doors have just double-pane glass.The house is extremely tight; ventilation to provide fresh air and keep interior humidity down in winter is provided by heat recovery ventilator (HRV - basically an air-to-air heat exchanger).

Heat for the house is by ground source heat pump ("geothermal"), with capacity just two tons, for about 4K sqft conditioned space. When it's around zero outside, the system still keeps the place at temperature in just first stage, at about 75% of capacity. Power for the system costs about $6-700 for the whole heating season. In summer, the heat pump is reversed for AC; worst-case conditions call for less than one ton of capacity.

I did what I could to determine bump in construction cost over "just to code" construction. After the framing was up, I asked the lead framer how much extra time he thought the double framed exterior took. He thought about a day and a half. Overall, the cost bump for "superinsulated" was on the order of 5%, which was what others have indicated.

For more reading on the subject of building to much better than code, go to greenbuildingadvisor.com and do a search on "pretty good house."

Fargo · 05-08-2022, 02:34 PM

Pretty Good House book will be available late June. A must read for anyone interested in building an energy efficient home without breaking the bank. Available on Amazon.

John Mercier · 05-08-2022, 04:40 PM

I think that is just an update.
The PGH concept has been around for a while now; and needed an update.

The BeOpt software created ''issues'' in its original format.

Even the new Grace Vycor Env-S... while much better than the older system... still lacks the important feature of the HydroGap.

And the R8 and R11 window dreams of a decade ago have gone right down the drain. The optical vinyl couldn't handle the heat load of being trapped between the glass.

54fighting · 05-09-2022, 04:01 PM

For all the helpful replies.

I'm remodeling an old post and beam house. It has beadboard sheathing on the exterior wall and shingles on top of that. It's all in good shape so I'm focused on insulating from the inside and making the house as insualted and tight as possible (with the use of an ERV or HRV). If I have the space the double stud method seems like a viable option to insulate well and cut down on thermal bridging.

05-07-2022, 06:28 PM	#1
54fighting Member Join Date: Aug 2021 Posts: 37 Thanks: 1 Thanked 7 Times in 7 Posts	Double Stud Wall Construction Anyone employed this method of insulating a home?

05-08-2022, 08:42 AM	#5
Fargo Senior Member Join Date: Apr 2004 Location: Lake Winni Posts: 215 Thanks: 36 Thanked 130 Times in 38 Posts	Double stud That’s a great way to build an energy efficient home. You’ll need professional help in order not to have issues all the systems, heating, cooling, humidity, air exchanges etc. A good source for information is passivhausMaine. The state of Maine is ahead of the curve when building high performance residential and commercial property in the USA.

05-08-2022, 08:49 AM	#6
BroadHopper Senior Member Join Date: Oct 2004 Location: Laconia NH Posts: 5,571 Thanks: 3,209 Thanked 1,101 Times in 793 Posts	Air loss John is right about air loss. Most stick-built homes have tremendous air loss! You can check with NH Energysaves for reliable energy audits on your project. This excerpt is from one of the top builders in North America. Gives you an idea what the latest trend. The build is so airtight, that an air exchanger is needed to keep the air fresh. Our cellulose is made from recycled newspaper and shipping boxes, which is an excellent way to upcycle unwanted paper products. The cellulose is densely packed into every panel and does not settle during shipping because it is already so heavily compacted. In addition to being a great use of recycled paper, cellulose has superior insulating, sound deadening, and fire resistance properties compared to fiberglass. We also prefer cellulose insulation because of its hygroscopic properties, which means it is very good at managing moisture and works with other layers in the panel, including the smart vapor permeance of the OSB (oriented strand board). This semi-vapor open assembly allows for drying in both directions, making it ideal for all climates. Our building systems rely on continuous mechanical ventilation to manage interior humidity. In comparison, fiberglass insulation is hydrophobic, meaning that it repels moisture, which then gets absorbed into the wood around it and often results in mold. Our air-tight building assemblies are designed to optimally manage moisture to keep bulk moisture out and the amount of vapor that diffuses through them, is very low. __________________ Someday may never be an actual day.

05-08-2022, 02:34 PM	#9
Fargo Senior Member Join Date: Apr 2004 Location: Lake Winni Posts: 215 Thanks: 36 Thanked 130 Times in 38 Posts	Double stud Pretty Good House book will be available late June. A must read for anyone interested in building an energy efficient home without breaking the bank. Available on Amazon.

05-09-2022, 04:01 PM	#11
54fighting Member Join Date: Aug 2021 Posts: 37 Thanks: 1 Thanked 7 Times in 7 Posts	Thanks For all the helpful replies. I'm remodeling an old post and beam house. It has beadboard sheathing on the exterior wall and shingles on top of that. It's all in good shape so I'm focused on insulating from the inside and making the house as insualted and tight as possible (with the use of an ERV or HRV). If I have the space the double stud method seems like a viable option to insulate well and cut down on thermal bridging.

05-07-2022, 08:17 PM	#2
John Mercier Senior Member Join Date: Jun 2021 Posts: 3,369 Thanks: 3 Thanked 594 Times in 490 Posts	Yes. The 1948 cottage that is currently owned by my nephew was rebuilt by my brother and I using the double stud method.

05-08-2022, 06:47 AM	#4
John Mercier Senior Member Join Date: Jun 2021 Posts: 3,369 Thanks: 3 Thanked 594 Times in 490 Posts	The newer technique is to use 2x4 construction with a rigid insulation on the exterior... usually another two inches... to prevent the ''bridging'' effect. But other than the attic on a single story home... most of the heating/cooling is lost through air transfer. So many build tight and use an ERV. This only works if you control the air loss through everything including your daily actions. If it is a space that you enter/leave repeatedly... the loss will be through the air transfer when the door opens.

05-08-2022, 09:49 AM	#7
John Mercier Senior Member Join Date: Jun 2021 Posts: 3,369 Thanks: 3 Thanked 594 Times in 490 Posts	Sorry. My comments tend to be for those renovating homes to become more energy efficient.

05-08-2022, 10:31 AM	#8
DickR Senior Member Join Date: Apr 2008 Location: Moultonborough Posts: 750 Thanks: 4 Thanked 259 Times in 171 Posts	Our home, built 2010-11, has a double-stud exterior. Wall insulation is dense-packed cellulose to R40 or so, attic floor is loose-blow cellulose to R60. Then there is 4" foam under the basement slab and on the foundation walls. Windows are a mix of triple-pane casement and fixed glass (avg U=0.17). Only the doors have just double-pane glass.The house is extremely tight; ventilation to provide fresh air and keep interior humidity down in winter is provided by heat recovery ventilator (HRV - basically an air-to-air heat exchanger). Heat for the house is by ground source heat pump ("geothermal"), with capacity just two tons, for about 4K sqft conditioned space. When it's around zero outside, the system still keeps the place at temperature in just first stage, at about 75% of capacity. Power for the system costs about $6-700 for the whole heating season. In summer, the heat pump is reversed for AC; worst-case conditions call for less than one ton of capacity. I did what I could to determine bump in construction cost over "just to code" construction. After the framing was up, I asked the lead framer how much extra time he thought the double framed exterior took. He thought about a day and a half. Overall, the cost bump for "superinsulated" was on the order of 5%, which was what others have indicated. For more reading on the subject of building to much better than code, go to greenbuildingadvisor.com and do a search on "pretty good house."

The Following User Says Thank You to DickR For This Useful Post:
BroadHopper (05-09-2022)

05-08-2022, 04:40 PM	#10
John Mercier Senior Member Join Date: Jun 2021 Posts: 3,369 Thanks: 3 Thanked 594 Times in 490 Posts	I think that is just an update. The PGH concept has been around for a while now; and needed an update. The BeOpt software created ''issues'' in its original format. Even the new Grace Vycor Env-S... while much better than the older system... still lacks the important feature of the HydroGap. And the R8 and R11 window dreams of a decade ago have gone right down the drain. The optical vinyl couldn't handle the heat load of being trapped between the glass.