2 things are needed for success: 1) simple recipes builders can follow based on temperate zone 2) simple recipes owners of all other homes can follow based on temperate zone. And adjustments for truly older, pre-drywall homes too. If anyone treats old homes as a lost cause, i.e., nothing can be done, you lose, we all lose. These needs are so basic, so fundamental, any design agency (ahem) could afford to “give these secrets away” as packages while still running a profitable business. There’s that level of need! Thanks for this, and all such videos.
Your videos are excellent; thank you for posting them here! Information flow is focused and concise with useful graphics and descriptions. I usually play each video a few times. Your accuracy rating seems to be very high, as well. Less accurate construction videos regularly have obvious issues, like a host's failure to use eye protection, or some essential step being left out, or problems visible in the background that go unexplained. I am looking forward to reviewing all of the content you have shared!
@@ASIRIDesigns Thanks for your reply! I just read through the comments here; they are quite interesting. One of them makes me suspect that entry-level DIY viewers may not be ready for information-dense content like this. I suspect some contractors might also not be. Somebody might not know which question to start with, especially if you're covering multiple building zones on a complex topic. Then consider the confusion various contractors may create online by having different ideas about what works best. I suspect building inspectors themselves can contribute to the confusion, considering the stories I've heard as well as my own experience as a DIY homeowner. Condensation damage here along the Gulf Coast has drawn my attention since I repaired floor damage in my aunt's house more than twenty years ago. She was using a huge window air-conditioner in the large hall of a very old house that had no insulation under the floor. After investigating the damage, I realized that moisture from the warm, humid, crawl-space air was condensing through to the underside of the original floor linoleum and then rotting the subfloor. A layer of sturdy Masonite and then another vinyl flooring had concealed the problem for many years. Curiously, the damage extended from the AC, down the hall to the bedroom door, and then toward the bed. I realized that was apparently the result of using portable fans to direct the cold air.
Your videos are top-notch. Thank you. At the end of the day, aren't the best wall systems the ones that don't need any vapor barrier ? Hempcrete walls for exemple don't need any vapor barrier because hempcrete is vapor permeable. The hempcrete wall just needs a lime plaster on the outside for airtightness. No worries about potential air leakage...
I have a 1000sqft home in mobile alabama built in 1954. The condensate for my air conditioner went out a few years ago. After no AC overnight, starting it up in the morning made 2 5 gallon buckets of water in 2 hours.
@asiridesigns this was very informative, but you do mention climate a lot. Can you please do some videos (flat roof, stucco, “perfect” hot dry climate wall) on hot dry desert climate (Vegas). Construction here is pretty “basic” but the homes are not “comfortable.” Thanks!
Cold humid climate, coastal maine. Can I still use a smart vapor retarder if I can't put furring strips on the interior side of the wall for a service cavity/air gap? Can it directly sit up against the back of the drywall? Renovating an old house on the inside and there's an existing window on the wall, so I can't just make the wall come out more
Thank you for the clear explainations. Air leakage is such an underestimated problem. The "buildings need to breathe" mantra continues the damage. What is your solution for humid air present at the roof ridge while maintaining the air barrier?
Thanks for watching, and great question. There's a few ways to address humid air that accumulates at the ridge. You can either use a diffusion port (mostly for warmer climates but there are ways to design them for cold climates as well), run a dedicated supply and return for the attic space so that it receives conditioned air and exhausts that stale humid air, or install a dedicated dehumidifier for the attic space. Or you can specify a self-adhering roof underlayment that's vapor permeable and use a vapor permeable rigid insulation like mineral wool with an air gap to facilitate drying across the entire roof assembly.
Humidistat operated passive vents? Humidistats seem pretty cool and living in England I'm surprised I don't see more of them. I reckon a solar powered control panel could link together multiple areas in a house, regulating moisture in an intelligent way, with external sensors too the capability to go from passive venting to mechanical venting could be utilised too, maybe creating an efficient system that could be installed without altering the fabric too much. I do know that despite all the modern materials and know how, its still a problem in the uk that often gets overlooked and doesn't seem to have found a definite solution. Surely the quality of air we breathe is a primary consideration.
I would better be able to follow your presentations if you were more consistent with conventions in your drawings - either always have the exterior surface on the left, or always have the exterior surface on the right. As it is, every time I see one of your drawings, I have to pause and evaluate which direction things are, because that convention keeps changing from one drawing to the next. (Thank you for your high quality presentations.)
I'm still confused: why not always use a vapor open air barrier, ie; Zip sheathing or something like @2 perms? Let moisture dry to the inside or outside.
A lot of the time we try to design our assemblies to be vapor open, but there many times when we need to "throttle" the flow inwards and outwards. We don't want too much moisture to pass through at once, otherwise it could cause problems interstitially. For example, if we have a reservoir cladding like brick or stucco in a hot humid climate, we want to slow down that inward flow so that we don't get condensation on the backside of the drywall. Another example is in a flat roof system, in which the impermeable roof membrane is exposed to the exterior environment. We don't want moisture drying upwards and getting trapped underneath that membrane, as this often leads to roof rot in those assemblies. Refer back to the list of questions I listed at 4:19 to determine whether you need something permeable or impermeable.
Curious why there is no filter fabric on the soil side of the dimple mats? Without that, you are not creating a space for the water to flow downward to a drain.
Asking advice. Plan on building a house with double stud 2×4 walls with 3 1/2" in between. R15 mineral wool for a total r45 with ziga majrex on the inside of the exterior framing as a smart vapor retarder. Should I use zip sheathing or cdx on the exterior? There will be a rain screen behind the siding. This is in 6a zone with humid summers. Thanks for any advice
i was wondering how much nail perforations through taped seam sheathing affect the the air barrier, when siding it seems unavoidable to miss studs, especially when doing shingles, does anyone have any insight into this, also i know siga majvest claims self sealing, but i assume an exterior membrane like that is the solution, or perhaps this is a negligible affect?
I’m surprised that at this late point in the era of the post WWII building materials, specifically the move from woodlath- plaster wall finishing to the domination of gypsum board, that the absolute preponderance of the paper faces of gypsum noted to cultivate mold, mildew, etc. is still unaddressed. Maybe it’s just me.
You didn't have those problems when you lived in a drafty, poorly insulated house. We build our houses as tight as cars and we know what happens when we sit in a car with the windows rolled up and no venting to the outside. It is true that houses gotta breath, but not through leaky walls.
The rule of thumb is that an exterior air barrier must be 6 times more permeable than an interior vapour barrier in colder climates. The introduction of improperly installed (no gaps between sheets) OSB sheathing and insulated foam board insulation on the outside (taped) creates double vapour barrier which will doom the structure (I have witnessed rot and mold within 2 years of occupancy). Something I have theorized is that by introducing contolled air gaps within the structure and connecting the space to mechanical ventilation it may be possible to neutralize air pressure across the assembly thus interupting the flow of water vapour in either direction. While there is the question of increasing heat loss / gain this can be compensated by locating the air gap inbound of the dew point location and isolated from any fibre type insulation.
I wonder what's more useful and/or cost effective - the dehumidifier/erv combo + standard WRB, OR a completely sealed building envelope (example: zip system w/monopoly framing for a super tight assembly) ? The reason I ask is because I wonder if a simple vapor permeable WRB like HydroGap SA (which also acts to a lesser degree as an air barrier) + a dehumidifier is just as effective as a zip system house 🧐 - Climate = coastal southeast, subtropical
In your video, you recommended a 'semi-impermeable' WRB for hot and humid climates, however even Zip which is a great air-barrier is between 12-16 perms, making it semi-permeable...How do you achieve the recommended 'semi-impermeable' assembly? - is an additional vapor retarder needed on top of sheathing OR is 10-16 perms sufficient? - My understanding was that low perm WRBs are sufficient - for example HydroGap SA is 12perms
Some good basic information, however, oversimplifies the current reality. 1) Nowhere in the code is the reference vapor barrier - everything is a vapor retarder. 2. Current building codes require external insulation - none of the examples demonstrate this, and it DOES change where the dew point shows up 3. No matter the climate zone - the phrase "it Depends" needs to be applied - the video showed and discussed understanding the moisture source and climate zone considerations, however, if you build to code with external insulation, it is recommended to run a WUFI to assist in validating the correct sequence of products.
Some valid points, but the video's intention was to break down the differences in vapor barriers and air barriers. I will say, if you need to run a WUFI model, you're doing it wrong. WUFI spits out whatever answer you want, it cannot account for complex 3 dimensional air flow networks. Vapor and condensation is very simple to design for using first principles.
😮M notDUMB! This"PRESENTATION" like many others leaves me wondering wtf? Diy'ers need:FACTS,USEFUL data,straight,concise insructions.clearly the intent is of this vid is2frustr8 diy'ers in2 paying a-hole contractors!
The whole video is nonsense as is the latest trend in wrapping yourself in plastic sheet. Literally the worst thing one could do. This is only a trend in certain countries. Yet everywhere else they manage air and moisture just fine with no mold whatsoever, they live in very healthy buildings which are very cheap to heat or cool down and many of them don't need forced cooling at all even in 40° + Celsius . None of them are wrapped in plastic, in fact if any real science ever gets done it will immediately show how bad of idea that is, summer or winter. The so called research mentioned here isn't science, it's a fact manipulation. There is a lot to be said for basics and building properly, we wouldnt have to worry about air barriers at all. One way vapour barrier on the outside can be beneficial in certain builds, but if you absolutely depend on air barrier then you have a different kind of a problem, ab is only masking up those problems while adding new ones.
2 things are needed for success:
1) simple recipes builders can follow based on temperate zone
2) simple recipes owners of all other homes can follow based on temperate zone.
And adjustments for truly older, pre-drywall homes too. If anyone treats old homes as a lost cause, i.e., nothing can be done, you lose, we all lose.
These needs are so basic, so fundamental, any design agency (ahem) could afford to “give these secrets away” as packages while still running a profitable business. There’s that level of need!
Thanks for this, and all such videos.
Your videos are excellent; thank you for posting them here! Information flow is focused and concise with useful graphics and descriptions. I usually play each video a few times. Your accuracy rating seems to be very high, as well. Less accurate construction videos regularly have obvious issues, like a host's failure to use eye protection, or some essential step being left out, or problems visible in the background that go unexplained. I am looking forward to reviewing all of the content you have shared!
Thank you so much! Glad to hear it was helpful.
@@ASIRIDesigns Thanks for your reply! I just read through the comments here; they are quite interesting. One of them makes me suspect that entry-level DIY viewers may not be ready for information-dense content like this. I suspect some contractors might also not be. Somebody might not know which question to start with, especially if you're covering multiple building zones on a complex topic. Then consider the confusion various contractors may create online by having different ideas about what works best. I suspect building inspectors themselves can contribute to the confusion, considering the stories I've heard as well as my own experience as a DIY homeowner.
Condensation damage here along the Gulf Coast has drawn my attention since I repaired floor damage in my aunt's house more than twenty years ago. She was using a huge window air-conditioner in the large hall of a very old house that had no insulation under the floor. After investigating the damage, I realized that moisture from the warm, humid, crawl-space air was condensing through to the underside of the original floor linoleum and then rotting the subfloor. A layer of sturdy Masonite and then another vinyl flooring had concealed the problem for many years. Curiously, the damage extended from the AC, down the hall to the bedroom door, and then toward the bed. I realized that was apparently the result of using portable fans to direct the cold air.
Your videos are top-notch. Thank you.
At the end of the day, aren't the best wall systems the ones that don't need any vapor barrier ?
Hempcrete walls for exemple don't need any vapor barrier because hempcrete is vapor permeable. The hempcrete wall just needs a lime plaster on the outside for airtightness. No worries about potential air leakage...
A video on interstitial space condensation would be interesting.
Thank you, this was very informative.
I have a 1000sqft home in mobile alabama built in 1954. The condensate for my air conditioner went out a few years ago. After no AC overnight, starting it up in the morning made 2 5 gallon buckets of water in 2 hours.
And that was with all of the windows and doors closed all night and morning.
Great explanation of such important topic
@asiridesigns this was very informative, but you do mention climate a lot. Can you please do some videos (flat roof, stucco, “perfect” hot dry climate wall) on hot dry desert climate (Vegas). Construction here is pretty “basic” but the homes are not “comfortable.” Thanks!
Awesome video! Great content. Thank you for the educational content!
Cold humid climate, coastal maine. Can I still use a smart vapor retarder if I can't put furring strips on the interior side of the wall for a service cavity/air gap? Can it directly sit up against the back of the drywall? Renovating an old house on the inside and there's an existing window on the wall, so I can't just make the wall come out more
Thank you for the clear explainations. Air leakage is such an underestimated problem. The "buildings need to breathe" mantra continues the damage. What is your solution for humid air present at the roof ridge while maintaining the air barrier?
Thanks for watching, and great question. There's a few ways to address humid air that accumulates at the ridge. You can either use a diffusion port (mostly for warmer climates but there are ways to design them for cold climates as well), run a dedicated supply and return for the attic space so that it receives conditioned air and exhausts that stale humid air, or install a dedicated dehumidifier for the attic space. Or you can specify a self-adhering roof underlayment that's vapor permeable and use a vapor permeable rigid insulation like mineral wool with an air gap to facilitate drying across the entire roof assembly.
Humidistat operated passive vents?
Humidistats seem pretty cool and living in England I'm surprised I don't see more of them.
I reckon a solar powered control panel could link together multiple areas in a house, regulating moisture in an intelligent way,
with external sensors too the capability to go from passive venting to mechanical venting could be utilised too, maybe creating an efficient system that could be installed without altering the fabric too much.
I do know that despite all the modern materials and know how, its still a problem in the uk that often gets overlooked and doesn't seem to have found a definite solution.
Surely the quality of air we breathe is a primary consideration.
I would better be able to follow your presentations if you were more consistent with conventions in your drawings - either always have the exterior surface on the left, or always have the exterior surface on the right. As it is, every time I see one of your drawings, I have to pause and evaluate which direction things are, because that convention keeps changing from one drawing to the next.
(Thank you for your high quality presentations.)
What about a situation like Prince Edward Island in Canada where you have up to -40* in the winter and up to +36* with high humidity in the summer? 🙏
I'm still confused: why not always use a vapor open air barrier, ie; Zip sheathing or something like @2 perms? Let moisture dry to the inside or outside.
A lot of the time we try to design our assemblies to be vapor open, but there many times when we need to "throttle" the flow inwards and outwards. We don't want too much moisture to pass through at once, otherwise it could cause problems interstitially. For example, if we have a reservoir cladding like brick or stucco in a hot humid climate, we want to slow down that inward flow so that we don't get condensation on the backside of the drywall. Another example is in a flat roof system, in which the impermeable roof membrane is exposed to the exterior environment. We don't want moisture drying upwards and getting trapped underneath that membrane, as this often leads to roof rot in those assemblies. Refer back to the list of questions I listed at 4:19 to determine whether you need something permeable or impermeable.
Great Vid ! Gracias Amigo !😁!
Curious why there is no filter fabric on the soil side of the dimple mats? Without that, you are not creating a space for the water to flow downward to a drain.
Asking advice. Plan on building a house with double stud 2×4 walls with 3 1/2" in between. R15 mineral wool for a total r45 with ziga majrex on the inside of the exterior framing as a smart vapor retarder. Should I use zip sheathing or cdx on the exterior? There will be a rain screen behind the siding. This is in 6a zone with humid summers. Thanks for any advice
i was wondering how much nail perforations through taped seam sheathing affect the the air barrier, when siding it seems unavoidable to miss studs, especially when doing shingles, does anyone have any insight into this, also i know siga majvest claims self sealing, but i assume an exterior membrane like that is the solution, or perhaps this is a negligible affect?
I’m surprised that at this late point in the era of the post WWII building materials, specifically the move from woodlath- plaster wall finishing to the domination of gypsum board, that the absolute preponderance of the paper faces of gypsum noted to cultivate mold, mildew, etc. is still unaddressed.
Maybe it’s just me.
You didn't have those problems when you lived in a drafty, poorly insulated house. We build our houses as tight as cars and we know what happens when we sit in a car with the windows rolled up and no venting to the outside. It is true that houses gotta breath, but not through leaky walls.
The rule of thumb is that an exterior air barrier must be 6 times more permeable than an interior vapour barrier in colder climates. The introduction of improperly installed (no gaps between sheets) OSB sheathing and insulated foam board insulation on the outside (taped) creates double vapour barrier which will doom the structure (I have witnessed rot and mold within 2 years of occupancy). Something I have theorized is that by introducing contolled air gaps within the structure and connecting the space to mechanical ventilation it may be possible to neutralize air pressure across the assembly thus interupting the flow of water vapour in either direction. While there is the question of increasing heat loss / gain this can be compensated by locating the air gap inbound of the dew point location and isolated from any fibre type insulation.
I wonder what's more useful and/or cost effective - the dehumidifier/erv combo + standard WRB, OR a completely sealed building envelope (example: zip system w/monopoly framing for a super tight assembly) ?
The reason I ask is because I wonder if a simple vapor permeable WRB like HydroGap SA (which also acts to a lesser degree as an air barrier) + a dehumidifier is just as effective as a zip system house 🧐 - Climate = coastal southeast, subtropical
Appreciate your thoughtful content btw 💪
A good building envelope can save a poorly designed HVAC system, but very rarely can a good HVAC system save a bad envelope.
In your video, you recommended a 'semi-impermeable' WRB for hot and humid climates, however even Zip which is a great air-barrier is between 12-16 perms, making it semi-permeable...How do you achieve the recommended 'semi-impermeable' assembly? - is an additional vapor retarder needed on top of sheathing OR is 10-16 perms sufficient? - My understanding was that low perm WRBs are sufficient - for example HydroGap SA is 12perms
Some good basic information, however, oversimplifies the current reality. 1) Nowhere in the code is the reference vapor barrier - everything is a vapor retarder. 2. Current building codes require external insulation - none of the examples demonstrate this, and it DOES change where the dew point shows up 3. No matter the climate zone - the phrase "it Depends" needs to be applied - the video showed and discussed understanding the moisture source and climate zone considerations, however, if you build to code with external insulation, it is recommended to run a WUFI to assist in validating the correct sequence of products.
Some valid points, but the video's intention was to break down the differences in vapor barriers and air barriers. I will say, if you need to run a WUFI model, you're doing it wrong. WUFI spits out whatever answer you want, it cannot account for complex 3 dimensional air flow networks. Vapor and condensation is very simple to design for using first principles.
😮M notDUMB! This"PRESENTATION" like many others leaves me wondering wtf? Diy'ers need:FACTS,USEFUL data,straight,concise insructions.clearly the intent is of this vid is2frustr8 diy'ers in2 paying a-hole contractors!
What's the problem?
The whole video is nonsense as is the latest trend in wrapping yourself in plastic sheet. Literally the worst thing one could do. This is only a trend in certain countries. Yet everywhere else they manage air and moisture just fine with no mold whatsoever, they live in very healthy buildings which are very cheap to heat or cool down and many of them don't need forced cooling at all even in 40° + Celsius . None of them are wrapped in plastic, in fact if any real science ever gets done it will immediately show how bad of idea that is, summer or winter. The so called research mentioned here isn't science, it's a fact manipulation.
There is a lot to be said for basics and building properly, we wouldnt have to worry about air barriers at all.
One way vapour barrier on the outside can be beneficial in certain builds, but if you absolutely depend on air barrier then you have a different kind of a problem, ab is only masking up those problems while adding new ones.