As to the deterioration of brick - there are tests that can be done to see the resistance of the brick to freeze-thaw damage. Also, some of the bearing wall brick buildings I have been involved with in retrofits have been unheated for many years - either that was commensurate with their historic use, or they were abandoned for some time. I've worked on a number of New England mills. One in West Peterborough NH hadn't been occupied in years, there were no intact windows. Those walls had no internal heat to drive moisture to the exterior yet evidenced no spalling. Good brick, so no big worries about innies. It's really important to notice any failed detailing on the exterior that handled water and now is gone. On one building of several stories, a gutter downspout was gone, and below the place where the gutter dropped water into the once-present downspout the entire vertical line of mortar was gone in 4-6" wide strip! Everywhere else, perfectly intact.
Many parapets had stone coping that allowed water to get into failed mortar joints. In one four story 72,000 sf VT building one could push sections of parapets over by hand. Solution is repair (or removal sometimes) and a metal cap.
Are you a mason? I also did a small amount of work on an Old Mill in West Peterborough some years ago. I spent one day working with a mason. I wonder if that was you?!
Sadly, not a mason, an engineer. I did the thermal enclosure and HVAC consulting on that repurposing of the Union Mill into apartment units and retail space. 31 years ago now!
Yep! Same Mill. At the time I was friends with the crazy dude whose spearheaded that project. I helped clear out a lot of the trash in the middle before the project started and then I spent a day working with the Mason moving the scaffolding on one of the walls. A particularly interesting and crazy period of my life 😂👀
So many thoughts! I am outie all the way. I did my own house as an outie. I don't disagree with any of the arguments you're making here , it's just that they seem lopsided. On one side you have increased energy efficiency, carbon reduction, comfort, etc, etc, Etc. On the other side you have.... aesthetics? Sure, aesthetics are important but they don't come close to the amount of stuff that's on the other side of that teeter totter. As a Nova Scotian living in Toronto I personally detest the sameness of all the brick here. I've told people that in Halifax you can stumble home in the middle of the night three sheets to the wind and have no problem finding your home. Here in Toronto I still have to pay attention when I'm going to visit a friend so that I don't drive by their house! Not saying we should get rid of all the brick but there are tons and tons of entirely unexceptional brick houses in this city. Mine is one of them. Or was! Not only did I insulate from the outside but I actually removed the 150 year old bricks so that I could pile on more insulation without increasing the size of the house. And I sold the bricks for a dollar a piece so they are not cluttering up a landfill and they are being reinstalled in Heritage homes around the city. Why not take this approach with a substantial amount of the totally meh brick houses and use the bricks on the exceptional brick buildings. And one does not have to cover their insulation with stucco. In my case I used vertical wood siding and it looks terrific. Let's not aesthetic ourselves into 5° of warming, eh!
I was not saying vapour barriers are the solution for all building science problems. Good flashing is also critical for instance. But building insulated structures in Canada without a proper vapour barrier is certainly a recipe for disaster. It is possible to control water vapour when using external rigid insulation but it must be done properly - but when the reason for doing it is typically convenience it does not bode well for proper design and quality control...
But I'm curious to understand more about insulating outside with styrofoam. I understand the concept of insulating from the exterior and you outlined both approaches so well in this article. However, I can't get over using styrofoam. For example, across the Balkans, I see that this has become the standard for insulating. Using styrofoam in that capacity and volume raises a lot of concern, unless I'm missing something. Is this too short sighted of me to be so focused on a material the seems like a big polluter?
Lovely projects. The inside of the community centre looks so warm, I bet the community love it. I’m glad you made it to the conference and can share these with us.
Where does building with SIPS fall in this discussion? I'm guessing the structure won't last long enough to be considered venerable, but the insulation occupies a third space, right in the middle.
There is seldom a simple answer in building science. As you say "a number of challenges" so a number of answers in order to fully understand. It is important that the Rvalue of the exterior insulation be great enough to keep the sheathing above the dewpoint for the average temperature of the 3 coldest months, in order to avoid potentially harmful condensation within the wall. The wall should be sealed well enough to prevent water intrusion from outside, and a drainage plane is highly recommended. My brief comment is likely not enough to fully answer your question, but it should be a start. There are far more extensive explanations on BuildingScience.com
On the topic of "outies" I'm confused by the use of foil faces rigid sheathing in new & renovation applications. Doesn't adding a WP layer (& potently leaky VB) on the exterior introduce a number of challenges? I've spoken with vendors at Construction Trade shows & I just get double talk and no real answer to my concern about the potential for trapped moisture & the resulting mold issue.
It doesn't, because water vapor doesn't damage structures and cause mold, only liquid water does. Foil faced rigid insulation on the exterior keeps the structure warm enough to never condense water vapor.
Respectfully, I don't think you've really seen the rot & black mould that's caused by water vapour. I have seen too many poorly installed building assemblies that have been built by contractors who really don't understand building science. I've not been convinced by reps that shiny sheathing is a sound assembly practice. Ask the good people of New Orleans whose post Katrina homes had to be demo'd. I could be wrong about foil faced sheathing, but when the reps for the product don't seem to be able to explain how the product works, I give it a hard pass. ANY WHO, I'm retired so I don' really have to think about it. If I ever build another house it will be a passive house with 300mm thick walls without "high-tech" over engineered BS moon music oil industry poison of the week in a hard to explain wall assembly guff.
Respectfully, that damage was caused by liquid water, whether from bulk intrusion or condensation. I completely agree with you that too many assemblies have been installed by builders who don't understand building science, but am not sure what that has to do with foil faced foam board insulation. It's not some newfangled product, it's been on the market for over 50 years. As long as you don't do anything silly like using it as the sole water barrier on a wood frame house or installing it in conjunction with an interior vapor barrier (which I suspect to be the main culprit in failures), it's a tested and tried form of insulation.
You're 100% correct about the H2O, my point is where water vapour has a location to condense is where we gets problems. The flaw I see with this product is when used as a sheathing behind a rain screen. The applications I have seen on other job sites is tape is used on the exterior between panels. When moisture (vapour or liquid) does inevitably enter the wall cavity some will be trapped. Far better to have a well insulated wall cavity with a VB on the warm side and a vapour permeable water barrier behind a rain screen. PS, it is a relatively new product in the Canadian market. In the one renovation I worked on, the previous owner had it installed. The use of this product was partially responsible for major structural damage.
The important issue is properly controlling the vapour barrier. Builders find it easier to insulate on the outside so there’s a lot of justification to explain how this is better but really it’s just a matter of convenience and making more money so a lot of justification is created.
Water can enter the structure from outside as well as inside. The assumption that it doesn't happen seems really common in Canada for some reason. No, vapor barriers are not a magic solution to all building science problems.
Why should we assume that stucco on foam should look ugly? After all, stucco's appearance doesn't depend entirely on its substrate, and over the past couple of millennia we've seen many beautiful buildings executed in stucco, and there's no reason we can't do the same. You can even make the stucco look like brick or stone and it looks convincing as long as you don't do it cheap and lazy like having the entire wall be running bond or making the mortar joints 20mm thick.
For those willing to spend the money, there is a third option: facadism. Keep the exterior as is, but structurally disconnect it from the interior structure and ventilate behind it. Meanwhile, build a new structure to support to the interior and insulate outside of *that*. Sure, you'll lose a lot of space on the interior and a lot of money, but it preserves both the inside and outside.
I'm not doubting there are some nice building with "stucco" exteriors, unfortunately I've yet to experience them. Generally what I see are horrible EIFS boxes.
Good piece Lloyd. The insulation conundrum is a tough one to crack. I worry the complexity of the discussion intimidates people and delays action so I developed my own super-scientific categorisation of insulation (1-No-brainer, 2-While we are at it, 3- Ideal). It was one video in an ongoing series of how I am electrifying my house for free. I would love to know what you think: https://youtu.be/WH_d6tNIRn0?is=WOXuiM1yHq2q5Bxa
I've done a fair amount of both!
As to the deterioration of brick - there are tests that can be done to see the resistance of the brick to freeze-thaw damage. Also, some of the bearing wall brick buildings I have been involved with in retrofits have been unheated for many years - either that was commensurate with their historic use, or they were abandoned for some time. I've worked on a number of New England mills. One in West Peterborough NH hadn't been occupied in years, there were no intact windows. Those walls had no internal heat to drive moisture to the exterior yet evidenced no spalling. Good brick, so no big worries about innies. It's really important to notice any failed detailing on the exterior that handled water and now is gone. On one building of several stories, a gutter downspout was gone, and below the place where the gutter dropped water into the once-present downspout the entire vertical line of mortar was gone in 4-6" wide strip! Everywhere else, perfectly intact.
Many parapets had stone coping that allowed water to get into failed mortar joints. In one four story 72,000 sf VT building one could push sections of parapets over by hand. Solution is repair (or removal sometimes) and a metal cap.
Are you a mason? I also did a small amount of work on an Old Mill in West Peterborough some years ago. I spent one day working with a mason. I wonder if that was you?!
Sadly, not a mason, an engineer. I did the thermal enclosure and HVAC consulting on that repurposing of the Union Mill into apartment units and retail space. 31 years ago now!
Yep! Same Mill. At the time I was friends with the crazy dude whose spearheaded that project. I helped clear out a lot of the trash in the middle before the project started and then I spent a day working with the Mason moving the scaffolding on one of the walls. A particularly interesting and crazy period of my life 😂👀
So many thoughts! I am outie all the way. I did my own house as an outie. I don't disagree with any of the arguments you're making here , it's just that they seem lopsided. On one side you have increased energy efficiency, carbon reduction, comfort, etc, etc, Etc. On the other side you have.... aesthetics? Sure, aesthetics are important but they don't come close to the amount of stuff that's on the other side of that teeter totter. As a Nova Scotian living in Toronto I personally detest the sameness of all the brick here. I've told people that in Halifax you can stumble home in the middle of the night three sheets to the wind and have no problem finding your home. Here in Toronto I still have to pay attention when I'm going to visit a friend so that I don't drive by their house! Not saying we should get rid of all the brick but there are tons and tons of entirely unexceptional brick houses in this city. Mine is one of them. Or was! Not only did I insulate from the outside but I actually removed the 150 year old bricks so that I could pile on more insulation without increasing the size of the house. And I sold the bricks for a dollar a piece so they are not cluttering up a landfill and they are being reinstalled in Heritage homes around the city. Why not take this approach with a substantial amount of the totally meh brick houses and use the bricks on the exceptional brick buildings. And one does not have to cover their insulation with stucco. In my case I used vertical wood siding and it looks terrific. Let's not aesthetic ourselves into 5° of warming, eh!
I was not saying vapour barriers are the solution for all building science problems. Good flashing is also critical for instance. But building insulated structures in Canada without a proper vapour barrier is certainly a recipe for disaster. It is possible to control water vapour when using external rigid insulation but it must be done properly - but when the reason for doing it is typically convenience it does not bode well for proper design and quality control...
But I'm curious to understand more about insulating outside with styrofoam. I understand the concept of insulating from the exterior and you outlined both approaches so well in this article. However, I can't get over using styrofoam. For example, across the Balkans, I see that this has become the standard for insulating. Using styrofoam in that capacity and volume raises a lot of concern, unless I'm missing something. Is this too short sighted of me to be so focused on a material the seems like a big polluter?
Lovely projects. The inside of the community centre looks so warm, I bet the community love it. I’m glad you made it to the conference and can share these with us.
Where does building with SIPS fall in this discussion? I'm guessing the structure won't last long enough to be considered venerable, but the insulation occupies a third space, right in the middle.
There is seldom a simple answer in building science. As you say "a number of challenges" so a number of answers in order to fully understand. It is important that the Rvalue of the exterior insulation be great enough to keep the sheathing above the dewpoint for the average temperature of the 3 coldest months, in order to avoid potentially harmful condensation within the wall. The wall should be sealed well enough to prevent water intrusion from outside, and a drainage plane is highly recommended. My brief comment is likely not enough to fully answer your question, but it should be a start. There are far more extensive explanations on BuildingScience.com
Joe is definitely a fan of outies.
On the topic of "outies" I'm confused by the use of foil faces rigid sheathing in new & renovation applications. Doesn't adding a WP layer (& potently leaky VB) on the exterior introduce a number of challenges? I've spoken with vendors at Construction Trade shows & I just get double talk and no real answer to my concern about the potential for trapped moisture & the resulting mold issue.
It doesn't, because water vapor doesn't damage structures and cause mold, only liquid water does. Foil faced rigid insulation on the exterior keeps the structure warm enough to never condense water vapor.
Respectfully, I don't think you've really seen the rot & black mould that's caused by water vapour. I have seen too many poorly installed building assemblies that have been built by contractors who really don't understand building science. I've not been convinced by reps that shiny sheathing is a sound assembly practice. Ask the good people of New Orleans whose post Katrina homes had to be demo'd. I could be wrong about foil faced sheathing, but when the reps for the product don't seem to be able to explain how the product works, I give it a hard pass. ANY WHO, I'm retired so I don' really have to think about it. If I ever build another house it will be a passive house with 300mm thick walls without "high-tech" over engineered BS moon music oil industry poison of the week in a hard to explain wall assembly guff.
Respectfully, that damage was caused by liquid water, whether from bulk intrusion or condensation. I completely agree with you that too many assemblies have been installed by builders who don't understand building science, but am not sure what that has to do with foil faced foam board insulation. It's not some newfangled product, it's been on the market for over 50 years. As long as you don't do anything silly like using it as the sole water barrier on a wood frame house or installing it in conjunction with an interior vapor barrier (which I suspect to be the main culprit in failures), it's a tested and tried form of insulation.
You're 100% correct about the H2O, my point is where water vapour has a location to condense is where we gets problems. The flaw I see with this product is when used as a sheathing behind a rain screen. The applications I have seen on other job sites is tape is used on the exterior between panels. When moisture (vapour or liquid) does inevitably enter the wall cavity some will be trapped. Far better to have a well insulated wall cavity with a VB on the warm side and a vapour permeable water barrier behind a rain screen. PS, it is a relatively new product in the Canadian market. In the one renovation I worked on, the previous owner had it installed. The use of this product was partially responsible for major structural damage.
The important issue is properly controlling the vapour barrier. Builders find it easier to insulate on the outside so there’s a lot of justification to explain how this is better but really it’s just a matter of convenience and making more money so a lot of justification is created.
Water can enter the structure from outside as well as inside. The assumption that it doesn't happen seems really common in Canada for some reason. No, vapor barriers are not a magic solution to all building science problems.
Why should we assume that stucco on foam should look ugly? After all, stucco's appearance doesn't depend entirely on its substrate, and over the past couple of millennia we've seen many beautiful buildings executed in stucco, and there's no reason we can't do the same. You can even make the stucco look like brick or stone and it looks convincing as long as you don't do it cheap and lazy like having the entire wall be running bond or making the mortar joints 20mm thick.
For those willing to spend the money, there is a third option: facadism. Keep the exterior as is, but structurally disconnect it from the interior structure and ventilate behind it. Meanwhile, build a new structure to support to the interior and insulate outside of *that*. Sure, you'll lose a lot of space on the interior and a lot of money, but it preserves both the inside and outside.
I'm not doubting there are some nice building with "stucco" exteriors, unfortunately I've yet to experience them. Generally what I see are horrible EIFS boxes.
Good piece Lloyd. The insulation conundrum is a tough one to crack. I worry the complexity of the discussion intimidates people and delays action so I developed my own super-scientific categorisation of insulation (1-No-brainer, 2-While we are at it, 3- Ideal). It was one video in an ongoing series of how I am electrifying my house for free. I would love to know what you think: https://youtu.be/WH_d6tNIRn0?is=WOXuiM1yHq2q5Bxa