Indoor Air Quality & Healthy Building’s 2017

Indoor Air Quality (IAQ) in building’s is vital to our health and appears to be an area of confusion and unknowns so, I thought I start a holistic conversation to look at and break down the constituents of how to design new healthy buildings, and/ or renovate existing ones--to the best of our ability and knowledge, anyway. You’ll see even world class professionals do not have it all figured out, and are constantly learning new ways to improve future complex environments and buildings.

I’ll be attempting to greatly simply complex subject matters, redefine myths, and correct building practices involving complex building chemistry and physics, microbiology, structures, HVAC, building envelopes, flows, pressures, phase changes, mechanics of materials, electrical magnetic fields (EMF), grounding, etc. The focus will be building structures' related fungi-bacteria-corrosion, attempting to establish design criteria and guidelines rarely discussed nor understood by a lot of mainstream leaders (including builders, contractors, building scientists, advisors, etc.) still utilizing today's predominant practices until it is too late and the structure has rotted or health issues have resulted….less on human, pet, outdoor-generated bacteria and fungi.

Writing is not my best mode of communication so, please bear with me. Feel free to correct, add to, or ask questions. If there are none, I will keep posting for the interested readers.

There have been many attempts to define international standards, practices, for ventilation rates such as ASHREA 62.2 in buildings to rectify some of theses issues that fail, ongoing debates among building scientists, and there is a growing concern about the fungi and bacteria we breathe in from interior environments within buildings that infuse into the bloodstream under molecular partial pressures, as the industry begins to seal up these buidlings to levels known from Germany standards called PHPP (Pausivhaus) and recently the US, PHIUS, to improve the energy efficiency of buildings by design standards. We’ll discuss potable water supplies as more plastic species like PEX come to industry and correct some myths.

We’ll see it is not all about mold or replacing indoor air by natural or mechanical means. We'll correct some more myths. We’ll learn that structures are a big part of the problem and are unknown, too; some organic or ‘natural’ materials that were once thought to be fungi-resistant insulations, for example, aged, did not resist fungal growth, and now have become an issue. Also, healthy heating and cooling, starting with the envelope I like to refer to as 'the main passive_active building HVAC system second to the human body', and lastly, mechanical devices, why some envelopes love water (hydrophilic) and only get better while others hate it (hydrophobic) and get worse, balanced and unbalanced ducts, dust, crawl spaces, water intrusions, vapor pressures and flows, etc. I’ll also get into natural and mechanical heat and energy recovery ventilators gaining popularity today in a false attempt to solve IAQ, types of heat ex changers; exhaust fans, types of particle filters, and more.

I’ll be using the info to add to my latest blog below. Ultimately, I’ll attempt to apply what I can to a home I am CAD (Computer Aided Design) designing now, to be built soon, so we can see real applications. I’ll run some simulation models.

To get started, please watch the second video down on THIS http://www.isiaq.org/ page, a 2015 European (Netherlands) presentations by Dr. Miila Pitkaranta, microbiologist and building physicist, before posting. It will be the basis for further discussions and quality posts. I think the presentation is credible and professional. If you disagree, let me know. Also, please keep any questions or comments on topic on the current discussions. If we go too fast or get ahead of the building blocks to a holistic (whole, complete) understanding, it will get confusing. We’ll define terms as we go.

Other suggested reading from another permie thread is HERE http://science.nasa.gov/science-news/science-at-nasa/2000/ast26nov_1/ how NASA is struggling with unknowns: As a thirty-year aero-designer, I can add that we do not design to bacteria and fungi and we, too, have much to learn. Recently, I was involved in spore creation and testing on hydraulic components that was eating away seals, so we attempted to create the spore type in a lab to understand how they proliferated in that environment per a test standard, which for air and spacecraft is much more complex than homes. I can appreciate Dr Putkaranta, as her scope of knowledge in her discipline far exceeds my own. We see some of the same issues and suggested solutions in building and aerospace we can explore.
Also Breathable Walls. HERE https://permies.com/t/43637/natural-building/Breathable-Walls

Healthy Heating and Cooling, The body as HVAC, takes focus away from the thermostat puts it on the body:
HERE http://www.healthyheating.com/Human_Factors/Human_Factors.htm#.VYWTGPlViko

Take-away’s from Dr Pitkaranta Research,

1. it’s not just about mold, it is only one of many factors.

2. Too much focus and research on surface and indoor air, more is needed on structures. “We do not fully understand what is going on in the structures”...circulating or exchanging air is a poor method of removing all fungi.

3. Fungi and bacteria growth is ubiquitous, wet and dry climates, some deleterious, some beneificial. There are common species but some are specific to global regions (eg: US, tropics, deserts, etc)

Common wall fungi types/areas,

-ICI (Insulation-Concrete-Insulation) on the inner foam ICF (Insulated Concrete Form) surface.

- Moisture Barrier Surfaces (plastics, foams) with zero or low perm (permeability) rating.

Note: I’ll explain why this occurs later; again please do not get ahead of me.

4. Microbial (derived from naturally occurring microorganisms, such as bacteria and fungi) niches are hidden in wall layers; more so in aging old buildings, can grow anywhere, dry or wet environments. For example, dusty ducts (once balanced), crawl spaces, organic insulations such as mineral wool insulations were identified that were once known anti-fungi but lost those properties due to age or environment.

- Note on myths: Again more later but take note that natural materials are not exempt. Also take note she did not mention any single spore type (e.g.: black mold, aka s.atra'. Common myth on water damaged building materials: root cause is not from “poor air circulation” surface moisture, rather a wide range of spores are found and as many corrective actions.

5. Ice dams on roofs/pipe leaks, water wicking down from roof under building’s from poor overhangs, guttering, etc….

6. Moist crawl space inner walls, basements. The microbial ecology in these areas is of great concern since unique communities have been found and are created due to physical conditions (humidity and temperatures primarily) that come to equilibrium in the many varied layers of the structures (wall, roof, foundations). More later.

7. Vacuum pressures due to exhaust fans, openings, that cause infiltrations, have identified a need for sealing and balanced HVAC, which is not easy. Average leakage rate 30-50 M3/h or 4 air changes per hour (ACH) when the average 270 cubic meter (100 square meters) building was tested. More later.

8. Last,but not least: how dirty dogs/kids with weaker immature immune systems can do well together within 'healthy' buildings but, put them in a toxic 'sick' home and the youngsters develop signs of asthma (also known as "reactive airway disease"). That clearly suggests the major impact buildings have on both the young and old.

These are the presentations the majority of building communities and/or sites ignore and/or do not understand, isolate into blogs/threads or discuss perm rating or r-values only since it makes more sense, losing sight of what is important--health of the human inhabitants--or, as Dr Pitkaranta stated, too much focus on ineffective ASHREA air flow rates, erroneously, rather than defining holistically. It takes what manufactures like EPS foam, ICF’s, some mineral wool, glass, cellulose, insulation types, or other building layer manufactures claim or “test” per some incomplete ASTM that is not quality third party-verified or controlled nor understood, and their sponsors support as “anti-fungi” and proves to be wrong, especially over time, leaving the general public or client misled.

I’m always amazed to see people, and I used to be among them, put $100’s of thousands into a building we should trust our health to but, yet do not know what questions to ask the builder, or architect, or they don’t know how to respond.

We want to stay focused on the research findings, what is supported by data or evidence, not non-professional blogs/sites, and use them as the basis for discussions, design criteria for future buildings. The basis for such are the long term research needs Dr. Pitkaranta and other integrated international professionals identified. To her, "job well done". We should all appreciate her and laud her profession's contributions.

Chew on all that a while. Time is limited for me but, I’ll be back. Now open for posting or get some peanuts & popcorn at the ranch concession stand, sit back and enjoy the show. At this time, please keep the discussion to correcting or adding to the notes above that attempt to capture what Dr. Pitkaranta stated, or anything else related you want to add to the discussion later.

Dr. Todd Mahr Radio Cast : https://reachmd.com/programs/focus-on-allergy/top-tips-for-environmental-control-and-triggers-at-home/4227/?utm_campaign=RMD_Daily_Newsletter_06212015&utm_medium=Email&utm_source=ExactTarget

I'll update the take away list as soon as I have time then will start taking a look at what we can do about it practically.

Dr. Pitkaranta Notes:

1. it’s not just about mold, it is only one of many factors.

2. Too much focus and research on surface and indoor air, more is needed on structures. “We do not fully understand what is going on in the structures”...circulating or exchanging air is a poor method of removing all fungi.

3. Fungi and bacteria growth is ubiquitous, wet and dry climates, some deleterious, some beneficial. There are common species but some are specific to global regions (eg: US, tropics, deserts, etc)
Common wall fungi types/areas,

-ICI (Insulation-Concrete-Insulation) on the inner foam ICF (Insulated Concrete Form) surface.
- Moisture Barrier Surfaces (plastics, foams) with zero or low perm (permeability) rating.
Note: I’ll explain why this occurs later; again please do not get ahead of me.

4. Microbial (derived from naturally occurring microorganisms, such as bacteria and fungi) niches are hidden in wall layers; more so in aging old buildings, can grow anywhere, dry or wet environments. For example, dusty ducts (once balanced), crawl spaces, organic insulations such as mineral wool insulations were identified that were once known anti-fungi but lost those properties due to age or environment.
- Note on myths: Again more later but take note that natural materials are not exempt. Also take note she did not mention any single spore type (e.g.: black mold, aka s.atra'. Common myth on water damaged building materials: root cause is not from “poor air circulation” surface moisture, rather a wide range of spores are found and as many corrective actions.

5. Ice dams on roofs/pipe leaks, water wicking down from roof under building’s from poor overhangs, guttering, etc….

6. Moist crawl space inner walls, basements. The microbial ecology in these areas is of great concern since unique communities have been found and are created due to physical conditions (humidity and temperatures primarily) that come to equilibrium in the many varied layers of the structures (wall, roof, foundations). More later.

7. Vacuum pressures due to exhaust fans, openings, that cause infiltrations, have identified a need for sealing and balanced HVAC, which is not easy. Average leakage rate 30-50 M3/h or 4 air changes per hour (ACH) when the average 270 cubic meter (100 square meters) building was tested. More later.

8. Last, but not least: how dirty dogs/kids with weaker immature immune systems can do well together within 'healthy' buildings but, put them in a toxic 'sick' home and the youngsters develop signs of asthma (also known as "reactive airway disease"). That clearly suggests the major impact buildings have on both the young and old.

Dr. James Sublett notes:
Clinical Professor & Section Chief, Pediatric Allergy, School of Medicine, University of Louisville, Louisville KY

9. Problem is too much humidity in most homes. Does not recommend mechanical devices; boil water on the stove instead.

10. Humidifiers are too hard to keep clean (contaminants) and rarely recommended (The same issues will exist with most commercial mechanical devices such as HRVs, ERVs (more later).

11. Dust mites and mold thrive on high humidity (keep no higher than 30%). (note: other sources recommend 40-50% for skins, eyes, etc, may depend on individual.

12. Carpeting potentially harbors triggers of allergy or asthma, particularly in bedrooms (smooth surface flooring best)
Note: Use high quality vacuum (wear a N-95 mask) reduces particles thrown back into air--particles are ‘stirred up’ for an hour

13. Particles less than <5 micron cause most problems (need more info on how to test a home)

14. Use canister or cyclonic filters or HEPA filter if carpet is present.
Note: HEPA filter room air cleaner size appropriate for room dimensions, clean air delivery rate (rate to match room size). Set up on a table inside room (most important for bedroom)

15. Pets: hair, dander, saliva, body secretions. Keep out of bedroom, off furniture. Use bed linens: allergy to dust mites

16. Encase mattress & pillow in mite-proof covers (finely woven fabric encasing)

17. Launder linens frequently in hot water to kill mites and eggs

18. Furnaces & air-conditioning systems - Filter on system MERV (range 11-12 recommended) and change every three months.

19. Avoid ionizers or ozone generators (ineffective at reducing particles)

I'm still working on a building integration write-up.

The latest USA NASA satellite data last year shows drastic improvements in OAQ (Outdoor Air Quality). Automobiles are the biggest contributor, and factories. People may want to reconsider using natural ventilation in some of these areas still. Yes we want to keep up the good work. Mid-west & East is the worse, and I thought CA was bad. I remember back in 70's growing up in Pomona Valley, CA we could not go out to recess due to "Smog Alerts" that do not exist today.

https://www.nasa.gov/content/goddard/new-nasa-images-highlight-us-air-quality-improvement/#.VY62RflViko

I may sound repetitive below in an attempt to simplify complex subject matter since people understand different ways. Feel free to correct, add, discuss...I started with the envelope. I'm taking alot of time to design one made out of wood, magnesium, and mineral wool insulation to built soon currently in Chief Architect CAD graphics_model. I'll post some pics as soon as we go over some basic concepts how this house will work...

1. Building Envelopes as HVAC (Heating, Ventilation, and Air Conditioning): (walls, ceilings, floors, interior or exteriors) I call Primary control surfaces (two, inner and outer, smaller are secondary. Whilst some utilized materials that love water (hygroscopic) and only improve in efficiency in its presence, others are water fearing (hygrophobic) microbial incubators for mold, dust mice, undesirable particles, etc…examples as Dr. Pitkaranta stated (EPS foam ICF, plastic sheets, barriers) that are not able to utilize desirable properties of thermal hygroscopic (water and vapor storing) materials and are the bulk of mainstream (common practices) construction.

The ideal envelope materials or goal for all interior surfaces is to stay dry to prevent microbials on surfaces both doctors agree, generate free heat and cooling. Ideally, this envelope would resist the majority of liquid water intake by its pore size, at the same time be permeable (transmit) enough water and/or liquid vapor for storage in ANY direction to regulate indoor relative humidity (30-50%, 70% max). On hot humid days this envelope would welcome water/vapor on its surface or through it (since water presence lowers r-value) so it can absorb, store, and evaporate (promote a liquid-to-gas phase change) while absorbing hot air/heat, cooling the envelope or rooms in the process, or, vaporize it like water in contact with a hot plate. On cold winter days, this envelope inhales cold, moist, or dry air, changes any liquid to vapor and is not bothered if dew or condensation occurs. If it did a liquid phase change again would occur and the hot wall (from a HVAC or a solar source) would again decrease r-value from liquid water, regenerate, or add heat from evaporation to dry it out.

In that process of exchanging energy, heat/cooling is generated due to a phase change (liquid to gas, or solid to liquid). This is a hidden heat/cold in the wall surface that is called “Latent” that is, not “sensible”, meaning it cannot be measured by a thermometer. Another term is enthalpy, or, an “adiabatic process” meaning no loss of energy to the surrounding atmosphere can be detected. The great thing about it is the more water and vapor, hot/cold, the larger temperature gradients, relative humidity, and pressures gradients (differences found in colder or hotter climates) the better it gets.

These hot/cold/moisture absorbent materials work under a different physics as we see than highly insulated, high r-value (or resistance to heat transfer), moisture resistant barrier wall types….On the contrary, the “mass wall types” (clay, lime, etc) do not function as well at high r-values. They are resistant to vapor or water films in a different way, that reduces r-value (since water films on its surface are thermally conductive) so that more heat can transfer from the hot/or cold surrounding atmosphere to dry the wall out. That creates energy, latent heat, and the process repeats itself without loss. Vapor barriers, plastics, foams, decrease the efficiency of this system.

I'll stop there for questions, comments....More on Envelopes as soon as I have time. If it does not make sense yet perhaps it will later.

I agree with you 100% Terry!

The perfect wall is not the foam encased assembly described by Dr.Joe, but the mud walls built for time immemorial in every corner of the globe. These are like evaporative coolers in the summer and in winter when interior humidity is much higher than outside, the walls condense water from the air which imparts the latent heat to the inside of the wall.

Absorption from water directly hitting the wall and adsorption from vapor passing through the wall can both be limited by reducing pore size on the skin of the wall. This can be achieved by about as many techniques as there are wall finishes; the most important thing is to reduce porosity but not close the interior of the wall off altogether.

Air quality can also be affected by pH and ionic charge of the wall surface. This will limit microbial activity and actually capture dust and other airborne particulate.

I believe the single most effective way to increase IAQ is to remove the mostly impermeable latex and other toxic finishes and replace them with breathable mineral plasters or paints. They change the way your house smells and reduce energy bills while reducing toxins in you and your home.

The one caveat is; you can't have a buried vapor barrier in the assembly. Metal in the assembly will rust eventually, but I have worked on 100+ year old breathable walls with metal lath, brick ties and nails that have lasted well because they dry out quickly. They were all rusty but not rusted through by any means.

All Blessings,
Bill

Bill, good stuff! I was hoping you'd show up and help me explain this stuff. I suggest the building industry stops listening to Dr Joe and his kind and starts listening and designing to what microbiologist and REAL building physicist practitioners like Dr Pitkaranta, and Dr. Sublets offering's. At the end of the day, it is all about IAQ, health, & comfort. As the four of us outlined is not about high r-value, permeability, air sealing or Air Changes per Hour (ACH) which is the bulk of what they design to these days. If they knew what they were doing they would never recommend materials that did not accomplish the goals as stated above. Their second reaction to determine ventilation rates based on ASHRAE 62.2, debate over it since it is not clear. That is why Dr Joe developed BSC-01. Both specs makes no reference to the above and will not work in some areas of the world. Both specs do however sell alot of mechanical devices such as HRV's/ERV's, fans, and filters to try and take out the junk they tell people to put into building's as seen in their design guides. We'll take a closer look at these mechanical devices soon now that we are developing the basis of how they work. As we described the ideal envelope naturally does what these devices do mechanically but, better since it is larger and does not rely entirely on air flow. As a matter of fact, we want just enough air flow through the wall to dry it out, not loose substantial conditioned air and that has to do with material properties above and thickness. Therefore the air sealing methods they subscribe to do not work in this ideal envelope. The air changes per hour are small .2, .3 ACH and not based on whole house rates, but rather through envelope rates that can not be measured by blower door test. Hydrophobic envelope designs get ruined by moist convective air flow through them that is why there is massive costly efforts to seal all stud, rafter, joist bays, with cheap microbial open cell foams and caulks that pass toxic particles to IAQ. It should be the other way around, design building's to manage microbial and toxins, use ventilation IF and where it is effective since it can make matters worse. As Bill said, we also do not want thermal or electrical conduction in our walls as in high doses of corrosive steel rebar and fasteners.

Bill you have been in alot of natural homes. Since you mentioned ion charges and particle attractions, PH, and pore sizes, etc... I have not done the research on odors yet (pet, cooking ,etc) do these homes reduce the need for cook top hood fans and high exhaust rates? Dr Sublet referred to ozone filters and why he does not recommend their use if you want to explain how odors are removed that be great. I know some people don't mind them, others are sensitive, and opening up windows does not always work, they can attached to structures and stay there from what I understand anyway. We use ozone machines for nasty fire restoration jobs and shellac since I'm not sure what else would be effective. We cannot seal those charcoal odors up when we rebuild. My understanding is they remove the odor molecule from the air, structure and drop it to the ground? Just think how much easier a fire restoration job would be and how safer for fire fighters if we used better non-combustible-conductive, slow burn, materials. Most code requires 2-3 hour burns which is the it takes to get out of the building.

Building Envelopes as HVAC Part 2:

Due to air sealing envelops ("build tight ventilate right" myth) and a lack of understanding of these principles that apply to passive (no mechanicals) mass envelopes first and foremost, without any mechanical devices, the industry standards are to add active (mechanicals). HRV’s (Heat Recovery Ventilators, ERV’s (Energy Recovery Ventilators) (air circulators), fans, vents, heat exchangers, humidifiers, dehumidifiers, HVAC, etc, in part to meet air exchange standard ASHREA 62.2 ventilation rates. Because of the lack of properties of high insulation low mass envelopes that do not breathe in this respect, mechanical devices are getting bigger and more expensive that still do not improve IAQ resulting in a vicious cycle the mechanical manufactures and their sponsors only benefit from.

High r-value walls with barriers act like HRV’s, to what level depends on heat resistance or r-value, that do not have the latent heat or energy heating and/or cooling property, hence, these mainstream walls and HRVs combo’s can accumulate more microbial from recirculation of outdoor air in and out. These wall types will not remove them since they can be buried in between wall layers (siding, tyvek, sheathing, insulation, drywall, latex paints). Mass or monolithic walls on the other hand, or low layered walls, of the described materials properties above do not have as many issues, although care has to be taken with any material inorganic or organic natural materials (ie: mineral wool, more on insulation later) to not pass any microbial into the air streams.

(HRV) work off sensible heat while (ERV) that recover moisture or maintain indoor humidity are more efficient and work off both sensible (measurable) and latent (hidden heat and cold). HRV’s can collect microbial and need filters (MERV 11-12). Aluminum and plastic polymers are often used. ERV’s like hygroscopic mass walls ARE Merv filters by design and can use materials like clay, lime, silicon gels) that depend on materials. Scuba filters (more details later on molecular sieves, desiccants) work under the same principles.

In order for that whole idea to work in the envelope we need a way to store heat/cold in the wall or as a sink. Think of giving the water that gets into the wall as getting in a heat bath or radiant heat hot sauna as moist hot or cold moves through the material to find equilibriums as Dr. Pitkaranta pointed out, but the mass wall uses this energy in an effective way to reduce microbials. When the wall dries it’s concentration of mass is restored or increases to function as a heat/cold sink. This reservoir will have a heat capacity depending on the thickness of the wall and material properties such as its heat capacity, or, ability to hold and pass heat. It’s moisture content or max holding capacity (like a bathtub) will be another factor, most materials are 20-30% by volume or weight, the bigger that number the higher the temperature gradient, again the more efficient the latent energy or enthalpy of the system.

The interior wall thickness (1-4”) and exterior wall thickness (1-4”) function independent of one another in mass wall. Two hygroscopic mass systems are reacting to their perspective frequencies of intake and exhaust. 12 inch (300 MM) has become an industry standard or starting point to maintain this separation by core materials. In some cases, core materials are the same as surface materials. In other designs, like SIPS (Structural Insulated Panels, SCIP (Structural Concrete Insulated Panels) or ICF (Insulated Concrete Forms) the skin material can vary to increase durability and resilience...All of these designs can be produced with natural materials. Sealers, coating, paints, should maintain similar breathable properties of the appropriate pore size, to allow breathable surfaces and access to the core system. By doing so the surface will maintain dryness and not collect microbials.

Up next Part 3: Sample Wall Systems. How to design and build supplemental HRV/ERV ventilation system.

Terry Ruth wrote:
Bill you have been in alot of natural homes. Since you mentioned ion charges and particle attractions, PH, and pore sizes, etc... I have not done the research on odors yet (pet, cooking ,etc) do these homes reduce the need for cook top hood fans and high exhaust rates? Dr Sublet referred to ozone filters and why he does not recommend their use if you want to explain how odors are removed that be great. I know some people don't mind them, others are sensitive, and opening up windows does not always work, they can attached to structures and stay there from what I understand anyway.

Below is an excerpt from the American Clay website. "Natural clay maintains an incredibly dense molecular structure and shape, giving it the capacity to produce a self-generated negative charge upon hydration. Even the simple evaporation of water from clay has the capacity to produce negatively charged particles in the air. This means that when your walls breathe, or hydrate slightly with changes in humidity and slowly dry out, your interior space is being steeped in negative ions.

Negative ions are proven to produce positive biochemical reactions in humans. A negative charge in a space acts on our capacity to absorb and utilize oxygen, causing us to have more energy and feel invigorated. Negative ions also have been proven to increase levels of the mood chemical serotonin, helping to alleviate depression, relieve stress, and boost our feelings of well being.

Surrounding your interior environment with unsealed clay plasters, or clay paints, that produce Negative Ions will not only help neutralize the electromagnetic effect created by computers, appliances and synthetic plastics, but also will help eliminate static charge on walls. Your walls stay clean and will not attract dust! Also, by having clay plaster on a wall, you are helping to filter air of pollen and dander. The negative charge emitted by clay causes particulates in the air to clump together and literally fall to the floor where they can be vacuumed up."

This should hold true of other breathable mineral plasters like lime, gypsum, etc. I have also noticed that a lot of the dust will stay on the wall, where it can be easily dusted off. Theeffect seems to increase with smoother walls, presumably because Van Der Waals forces only act at a short distance.

Terry Ruth wrote: We use ozone machines for nasty fire restoration jobs and shellac since I'm not sure what else would be effective. We cannot seal those charcoal odors up when we rebuild. My understanding is they remove the odor molecule from the air, structure and drop it to the ground? Just think how much easier a fire restoration job would be and how safer for fire fighters if we used better non-combustible-conductive, slow burn, materials. Most code requires 2-3 hour burns which is the it takes to get out of the building.

I have noticed that most smells are reduced or removed from the air, but this is a slow process and larger inputs as in the case of a fire restoration can overwhelm the process. Though somewhat effective for soot smell removal, other techniques will be required as well.

Hi Terry,

Thanks for taking the time to better inform the Permies community about breathable mass wall performance and all the side benefits of a traditional building system.

My home has 24" thick adobe walls with no insulation. This performs extremely well in hot weather and even better in mixed temperatures, but not as well in the dead of winter. I have long thought about a layer of insulation on the exterior, but I don't think we are cold enough here in Northern Utah to make it worthwhile. I think in extremely cold places, I would add a breathable insulation like stone wool board and plaster over that.

It has been hot here, record setting hot! My little adobe home has not exceeded 76F inside; this is with no air conditioning, but a whole house fan does pull in the cool morning air. It rained a bit the last couple of days and the indoor temp right now if 67F. If daytime high temps are over 100F for a month or more and it does not rain, which cools the walls by evaporation, then the indoor temp may get back to the hi 70's. I think a super hi-tech air tight home with very hi r-values and an HRV could perform this well, but after 120 years (the age of my home) these systems would no longer perform properly and the risk of mold, etc. would probably mean that the hi-tech home would already be in the dump.

So to recap

Traditional/breathable - efficient, durable and healthy.

Modern hi-tech - efficient, not very durable, susceptible to molds and fungi and not healthy as they have no way to remove all the toxins that modern homes are built with from the air, water and wall and floor coverings.

All Blessings,
Bill

Great stuff Bill. I think we are putting the pieces of the puzzle together as far as I know anyway. I'm no doctor but from what I understand the particle or molecules that get into the blood stream are based on partial pressure of the gasses in the building, their molecular weight. Above my head. If interested there are some good u-tube videos on the math. Point is the myth, that is not about temperature, or relative humidity, pressure drives the particles into the blood stream depending on molecular weights. Opening windows does not necessarily solve. Exhaust or recirculating fans can make worse depending on filtration.

I'm in the high CA desert on work assignment with night time lows in high 70's, day above 100F. There is alot of earth construction out west here. Orlando National Research Lab has a mass calculator that compares HVAC loads between high mass concrete and high insulation. Cold Chicago and Orlando I think it was showed the highest drop in HVAC loads. No mass to the interior had the highest loads, ICF foam the second, 2-4 inches of concrete the best in ten different US climate zones. The first 2" showed a lower drop than the second 2" in some climate zones meaning 2" was enough 4" a waste of money.

I did a cold climate back yard test of Rammed earth with a 50 F temp gradient across a 12" (300 mm) wall did not thermal bridging. Cheap test but what I could tell is most of the radiant heater loaded slow and when I dug it out after 24 hours I was about 2" in depth.

Bill, your thoughts? Thermal bridging or cold infiltration from a poorly sealed envelope (windows, doors, penetrations)

What do you consider a high tech home wall?

I was looking through an aviation fuel handbook at my other job and noticed some familiar terms,

-Water Contamination and Prevention

-Solids Contamination and Prevention

Microbial Contamination and Prevention

-Out-Gasing

-Toxicity

Be nice if we had such a handbook for homes

The 10 U.S. Cities With the Best—and Worst—Air Quality

http://www.realtor.com/news/trends/big-cities-with-best-and-worst-air-quality/?identityID=558b3b87edb2841d2b000310&MID=2015_1023_WeeklyNL&RID=3330327022&cid=eml-2015-1023-WeeklyNL-blog_1_airquality-blogs_trends

Now we just need a study of the homes in good outdoor air how bad is the indoor air and visa-versa.

Grandmas house breathed, and froze in winter, any diversion from natural is erroneous.

Hi Terry, can you post a sample wall system for a thin-wall stick construction?