Building green (problems)
Last Post 19 Aug 2014 01:20 PM by Dana1. 38 Replies.
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Dana1User is Offline
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15 Aug 2014 02:59 PM
In the US many new homes are built with the mind-set that it will only last 50 years, others are built to last for as long as the future owners care to maintain them, but they cost more to build (of course.)

There are many examples in the US of timber-framed buildings that are still in good condition more than 150 years after they were built as well brick buildings that are falling apart in less than 75 years. In Norway there are 1000 year old church buildings made of wood, in Italy there are masonry buildings that are more than 2000 years old. It's a matter of what you are used to, how it was built, and how well it is maintained.

In NL structural wood is an expensive import item, whereas sand, clay & straw for making brick is directly under your feet. Limestone has been mined in Maastricht for at least 1500 years, so of COURSE people in NL build with brick & masonry, and are very good at it, even when building on unstable ground. (The NL methods of driving pilings into compacted sand layers, with the tops of wood pilings always below the ground water level and stacking brick/stone on top of that for a foundation is a well-evolved local building method that isn't very common in other areas.)

In the US structural wood is relatively inexpensive and widely available. Even homes with brick on the exterior usually have a structural wall made of timber framing & plywood sheathing, but they come with their own special set of moisture issues, and it's difficult to build very-high performance structures that way due to the sever thermal bridging at the top of the foundation.

Masonry is not inherently air tight and needs air-sealing too. Sheet plywood or OSB has more seams to seal than poured concrete construction, but it's not difficult to get it right. I've read of ICF houses that tested above 5ACH/50 due to poor air sealing practices, and wood houses that tested under 0.5 ACH/50.

Making truly high thermal-performance brick-clad buildings with poured structural concrete walls is never going to be cheap, but it can be done we
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15 Aug 2014 05:19 PM
Posted By Dana1 on 14 Aug 2014 05:37 PM


The notion that "Heat/cold do not travel well horizontally." as asserted by 1blueheron is in stark contrast to the well established physics of heat transfer. Heat moves from warm to cold, and knows no direction.

Methinks there is some confusion here about heat-transfer via convection-driven infiltration, where the buoyancy of warmer air causes it to escape out of leaks at the top of the house in winter, drawing in denser colder air though leaks near the bottom of the house. This is commonly referred to as "stack effect", and how combustion flues work.


The notion that " Reflectivity, conductivity and mass are much more important in wall structure than "R" value is. " is similarly confused.
The very definition of R-value is the inverse of the entire thermal transfer (or U-factor) of the assembly. Reflectivity of the surface of wall assemblies is of almost vanishingly small importance, and the higher-R the assembly, the less important it becomes. Roof reflectivity is of some importance for energy use during the summer, but vanishingly small in the winter. Reflectivity of the either the exterior or interior side finishes/surfaces of walls is of immeasurably small importance to the total heat gain/loss or energy use. The thermal mass of the wall is of only secondary importance at the edge of zone 4/5, especially if that mass can't freely take/give heat to the rest of the house due to interior-side insulation as in the ICF case.



Dana,
I think we are speaking on two different levels of thought.  Mine general, yours specific.  Lord Kelvin banished the notion that heat could only travel from a hot body to a cold body in 1852.  This theory was the very basis for the modern day heat pump.  Heat rises and cold air falls.  This is called convection.  Just because you stop air infiltration in the envelope it does not mean that convection ceases to occur.  It merely sets up convective currents within the envelope.

Stack effect can be used for natural convective heating and cooling and has been used since the time of the cave dwellers. It is very efficeint requireing no mechanical assistance.  Thomas Jefferson used this to cool Monticello drawing earth cooled air from the basement in the summer up through a central hall and out the domed roof.  Not effective by today's standards of air conditioning but a vast improvement over homes of the period.

You inferred the opposite of what I was implying by my  Reflectivity, conductivity and mass are much more important in wall structure than "R" value is statement.  My intent was that if not properly placed and ordered, material R value is rendered ineffective.  If properly placed it can outperform the rated r-value sum of the components.

For instance,  creating a shade canopy on a southern exposed wall in the summer using a peice of canvas with virtually no r-value can effect a large reduction in heat absorption.  Removing the shade during the daytime in the winter can allow passive solar gain to advantage.

As for mass, it can be utilized as a steady state thermal buffer.  If it is never allowed to fully heat up or fully cool down, it eliminates diurnal temperature swings which cause afternoon grid peaking in the summer and morning peaks in the winter.  I was not trying to advocate it as a radiator, such as in a passive trombe wall although they can be effective in certain areas and structures.

A 4" solid wood with a R-value of 5.6 performs equal to a standard stick and batt construction of R14.  A 6" wood wall is equivalent to roughly a R19 stick and batt.  If R-ratings are so reliable, how is this possible?  Simple, they work differently.  Fiberglass does not store thermal energy, it just resists thermal flow,  Wood absorbs, stores, and re-radiates thermal energy.  Proper placement is key to performance, not just adding up the R's.  Wouldn't you agree?

With ICF in my home,  2.5 EPS/6" concrete/2.5 EPS"  I do not want it to give or take heat from or too either side, I want it to function as a thermal buffer zone to ride out the peaks and dips of the days and seasons.  The foam insulates the concrete to help it maintain the buffer zone.  The concrete in my floor slab radiates warmth in the winter and cold in the summer to the inside while insulated from the ground.  This is effective use of thermal mass.  The roof is mill finish galvalume, it reflects solar gain during summer and winter. 

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15 Aug 2014 09:29 PM
Lord Kelvin banished the notion that heat could only travel from a hot body to a cold body in 1852.
Having received rigorous instruction in this field between 1981 and 1983, I wasn't aware that Lord Kelvin destroyed the Second Law of Thermodynamics more than a century previous.
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15 Aug 2014 09:35 PM
The way I'm seeing it; when I make the choice for ICF, I give up the idea of using my outside walls as thermal mass because when you say ICF you say inside insulation.

Let's assume I want a R60 wall. I know it's overkill in my climate zone, but just assume a R60 wall in this theoretical discussion.
Dana wrote insulation may be no thicker than 4" on the outside. The QuadLock side states the same. That's likely why the max they sell are 4"-4" blocks.
Thermal mass and high R-values often seen together in really green homes (to my understanding). Using the outside walls as thermal mass means I either use no ICF or remove the inner foam layer. That leaves me with max 4" on the outside. I'm never going to reach R60 that way. Even if ICF was sold with very thing outside R60 foam it's wouldn't be ok because of the temp properties of the material (as Dana stated in a long post).
All of the above makes me wonder: Are R60 thermal mass walls only possible with cavity walls?
Connersville IN - Lat 39.64 N - Zone 5A (near zone 4)
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15 Aug 2014 11:46 PM
Posted By Dana1 on 13 Aug 2014 05:28 PM
Posted By ICFHybrid on 13 Aug 2014 04:26 PM
Where does he get those wonderful graphs?

The wind direction images are found on  Weatherspark.com's averages page for nearby Shelbyville IN.

The Klingenberg wall diagram comes up on a web-images search on the terms:  klingenberg house

I had remembered the I-joist stud fiberglass fill + EPS stackup  she used in her own house in Urbana and thought it a good example of a very high performance house that had used no spray foam.

If you know what you're looking for, search engines can get you there pretty quickly. eg:

Carter Scott (a local builder near me) uses double-studwalls and lots & lots of open cell foam, building Net-Zero-Energy homes in a climate somewhat cooler than Connorsville IN. He basically frames it out for the necessary wall thickness, then has the foam guys blast-away at it:

http://www.greenbuildingadvisor.com/sites/default/files/Carter%20Scott%20-%20double%20stud%20wall.jpg

(^^ found by searching the terms: carter scott house ^^)

Most of his houses have R40-R50 walls, U0.20 windows and are heated with one mini-split per story, with NO auxilliary heating.  On some homes he will take that up to R60 using polyiso &/or 2-3" of ccSPF, but for most of them it's just 12-15" of open cell foam in double studwalls.

When spraying open cell foam a this thickness it is important to spray it in 5-6" lifts, not full depth in one shot. That keeps it from shrinking and cracking or catching on fire as it cures.


Woah! 12 to 15 inches of spray foam in all exterior walls and rafters? And are the toilets made of gold?
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16 Aug 2014 12:15 AM
Dana is right; there really is a predominant attitude in US construction that everything is built in a temporary fashion, not really expected to last forever, nor even long term. So most everything gets built with wood, or wood chips.

But this termite map is another reason to go non-wood. People are going to tell you not to worry about termites, because you will be encouraged to sign a contract for a pest control company to apply poison twice a year.
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16 Aug 2014 01:13 AM
That termite maps closes the deal for me. No wood... Perhaps wood in pressure cooked black carbolineum will stop them :-)
Are there certain types of insulation termites eat?

What's that black box and wires/hoses? Not electricity I hope.
Connersville IN - Lat 39.64 N - Zone 5A (near zone 4)
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16 Aug 2014 07:46 AM
Termites will tunnel through (but not necessarily eat) just about anything that they can chew on. There are documented cases of them tunneling through the foam in ICF and SIP's. I had my ICF forms strapped in cardboard, sitting in the woods before I got started. The termites ate the cardboard, and tunneled about an inch into the ICF. Whether they will tunnel 12' to the roof structure is debatable. I treated my soil, and am under a termite contract just to be sure. They also have to get through the dimpleboard and stick-on waterproofing, too. That's subterranean termites- dry wood termites fly, and can be found anywhere. I've seen antique furniture with termites. I suppose you could build a house with all steel framing and concrete floors and roof.

Our house in FL was concrete block, with no insulation in the walls, but we got termites anyhow. They came up through a crack between the main slab and the garage slab, tunneled through the drywall, and started on the interior wood framing.
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16 Aug 2014 08:28 AM
There is soooo much I'm not used too. The only thing we know here is wood worm. But they are quite rare and were usually kept away by 'painting' wood with petroleum.
They like antique furniture too. But that's good because the value goes up with each hole they make :-)
http://www.cbc.ca/news/canada/toronto/spray-on-insulation-a-highway-for-termites-experts-warn-1.1392079
Connersville IN - Lat 39.64 N - Zone 5A (near zone 4)
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16 Aug 2014 10:03 AM
Posted By jdebree on 16 Aug 2014 07:46 AM
...I suppose you could build a house with all steel framing and concrete floors and roof...
Yes! Or at least just take out all the wood.
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16 Aug 2014 10:06 AM
Posted By NewHoosier on 16 Aug 2014 01:13 AM

...What's that black box and wires/hoses? Not electricity I hope...
Yes that is electricity. That is all going to be submerged in foam that gets sprayed on as a liquid, then expands and hardens in place.

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16 Aug 2014 10:12 AM
Here all those boxes are accessible. They are all hidden behind things like switches, ceiling lights etc.
Everything in pipes. Unprotected wiring means the building inspector shoots you on the spot :-)
http://upload.wikimedia.org/wikipedia/commons/f/f9/Lasdoos.jpg
http://nl.wikipedia.org/wiki/Lasdoos#mediaviewer/Bestand:Centraaldoos.JPG
Connersville IN - Lat 39.64 N - Zone 5A (near zone 4)
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16 Aug 2014 10:21 AM
Posted By NewHoosier on 16 Aug 2014 10:12 AM
Here all those boxes are accessible. They are all hidden behind things like switches, ceiling lights etc.
Everything in pipes. Unprotected wiring means the building inspector shoots you on the spot :-)
http://upload.wikimedia.org/wikipedia/commons/f/f9/Lasdoos.jpg
http://nl.wikipedia.org/wiki/Lasdoos#mediaviewer/Bestand:Centraaldoos.JPG
Yes but he shoots you with tulip bulbs 

The box and the connections will be accessible from the front via a plate, but the plastic coated wiring between the boxes will not be (but those are all continuous runs).

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16 Aug 2014 10:37 AM
Here new wires can be put in the pipes is needed. For example an outlet is missing (at least) one wire to if the outlet is replaced by a switch or switch outlet combination.
Connersville IN - Lat 39.64 N - Zone 5A (near zone 4)
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16 Aug 2014 01:40 PM
That electrical wiring is Non-Metallic (NM) sheathed cable and commonly known as Romex (a long standing name brand of this type of wiring).

With ICF, you can run electrical conduit in the wall cavities prior to pouring the concrete and then set your electrical outlet and switch boxes in the foam. Conduit is what is commonly used in commercial construction, but rarely in residential construction due to the additional material and labor cost. What is commonly done in ICF residential construction is that channels are cut in the foam after the wall is poured and the NM type electrical cable is inserted directly into this channel and intermittently secured with spray foam. The electrical box is typically set so that its face is ~1/2" past the face of the rough wall (either wood or foam in this case). Then when the 1/2" drywall is applied to the interior side of the wall, the face of the box is flush with the interior finished wall.

Retrofitting wiring in ICF exterior walls would be difficult. However, the interior walls are generally open cavity 2x4 wood or steel studs and wiring changes on these internal walls can be made at a later date if either the top or bottom of the wall is accessible.

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18 Aug 2014 02:34 PM
Posted By ICFHybrid on 15 Aug 2014 09:29 PM

Lord Kelvin banished the notion that heat could only travel from a hot body to a cold body in 1852.

Having received rigorous instruction in this field between 1981 and 1983, I wasn't aware that Lord Kelvin destroyed the Second Law of Thermodynamics more than a century previous.


ICFHybrid,

You must have failed the course or you would know that Kelvin did not destroy the Second Law but along with Clausius actually wrote it.  Just kidding...

The Second Law does not preclude the travel of heat from a cold body to a warm body as the earlier Caloric Theory and First Law of thermodynamics did, just the opposite in fact, it allows it with entropy. Heat can travel to a cold body from a warm body but not without efficiency loss or entropy. If it was impossible, we would not have refrigerators or heat pumps. The 2nd law merely explains how the process of the First Law can be reversed.

All I was stating is that heat is not restricted in its travel to a colder body as long as energy can be expended. Kelvin made this clear. We do have refrigerators. It is also important to note that the First and Second laws deal with isolated systems and are theoretical for the purpose of motivation in the study of heat engines (Carnot cycle). It has been widely applied outside the use of heat engines and improperly so.

Perhaps you can tell us how Kirchoff's Law  is actually more relevant to this discussion.


Hoosier,

Thermal mass and thermal resistivity are two different animals. They are confusing you. Don't try to apply R-values to ICF walls, Log walls, bodies of water, Trombe walls Etc. You will only frustrate yourself and get a headache. If you want to use the thermal mass of exterior walls to heat a home, they must have more exposure to heat than they do cold or you must have a means of insulating them during exposure to cold that is removable when exposed to heat. If you don't they will eventually cool off and you will have no heat to pass through. During the winter your nights are longer than your days so you will loose more heat than you gain. The wall will never warm up enough to heat the home and your home will end up having to heat the cold exterior wall by use of some form of energy.

The virtue of thermal mass is its ability to absorb radiated energy, act like a battery and buffer the effects of rapid temperature swings. The longer the daily or seasonal temperature swing is, the greater the mass you must have or you must expend energy to actively manage the properties of the thermal mass or supplement it.

Think of a swimming pool. It gains solar heat during the daytime and then looses heat to the atmosphere at night. If a solar blanket is placed over it at night (expending mechanical energy) it can conserve the daytime heat through the night. If a solar blanket is placed on it during the night, it retains energy in the form of cooling during the day due to its night time emissivity.

You can use thermal mas in your home by actively either exposing, shading or insulating the thermal mass. Increasing absorptive properties through color change, or conductivity can effect efficiency of the material.

The benefits of ICF in Indiana would be 1) excellent performance preventing moisture/air infiltration 2) low internal diurnal temperature swings due to insulated thermal mass which acts as a buffer zone from both sides 3) excellent performance in high wind conditions 4) steady state performance with little/ no loss of performance over time due to settling, compression, offgassing, moisture absorption, condensation etc. 5) excellent STC ratings 6) good performance/cost of construction ratio.

Cons of ICF in Indiana would be 1) Embodied energy in production of concrete/steel 2) GWP of pentane from production of EPS forms 3) Carbon/fossil fuel emissions due to transportation of forms, concrete and steel.


Your idea of evaportative cooling is not completely off-base as some might lead you to believe. This is why I ask you to look at the Optimair Dry2Cool system. It is relatively new to market and uses new materials and technologies to produce evaporative cooling in hot humid climates where previously they were not very efficient. It is supposed to be in use in your country but should work well for Indiana summers as well. It is at least worth a look.



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19 Aug 2014 02:26 AM
Reading your "Benefits of ICF" it seems like I'm not confusing R-values with thermal mass at all.
As for the cons; that's almost impossible to prove/disprove because imo the embodied enery needs to be viewed over the total lifespan of the building, including its maintenance. Wood has less embodied energy, but has to be replaced more often. It needs termite prevention, which usually means chemicals with embodied energy and a contractor using gas to drive to the house. Just zooming in on one aspect rarely gives a correct view.

Just my 2 cents
Connersville IN - Lat 39.64 N - Zone 5A (near zone 4)
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19 Aug 2014 10:04 AM
You must have failed the course or you would know that Kelvin did not destroy the Second Law


I thought that was what I said.

"I wasn't aware that Lord Kelvin destroyed the Second Law of Thermodynamics"
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19 Aug 2014 01:20 PM
Posted By ICFHybrid on 19 Aug 2014 10:04 AM
You must have failed the course or you would know that Kelvin did not destroy the Second Law


I thought that was what I said.

"I wasn't aware that Lord Kelvin destroyed the Second Law of Thermodynamics"



Heat pumps do not affect the well-understood physics of heat transfer in the slightest. 

Heat does not rise- it moves from hot to cold, even when you're talking about air-convection as the mechanism of heat transfer.

Heat transfer across building assemblies is also well understood & well modeled, at least a the level of detail relevant to energy use, peak loads, etc.

[edited to add]

"A 4" solid wood with a R-value of 5.6 performs equal to a standard stick and batt construction of R14.  A 6" wood wall is equivalent to roughly a R19 stick and batt.  If R-ratings are so reliable, how is this possible?  Simple, they work differently.  Fiberglass does not store thermal energy, it just resists thermal flow,  Wood absorbs, stores, and re-radiates thermal energy.  Proper placement is key to performance, not just adding up the R's.  Wouldn't you agree?"

Actually, no, I don't agree.

There are very few species of wood that have a steady-state R-value of R5.6, (most coniferous species would test in the R4.5-R5 range @ 4", in an ASTM C518 test, most hardwoods ~R4 give or take. See Table 4.7, pp 13-14.). Those species that might test at R5.6  don't still have sufficient thermal mass to match the performance of a properly built (~R10-ish whole wall) R14 batt wall in any US climate north of US zone 1 (where it might be close).  An (R10) R14 batt wall still has more than 25% of the thermal mass of the solid 4" wall.

If the performance of a  4" solid wood wall was so superior, the heat transfer at the 25% framing fraction would ENHANCE rather than detract from the thermal performance, since 3.5" of wood + 0.5" sheathing adds up to 4" of solid wood.  But in fact the 25% fraction that is wood is responsible for a disproportionate amount of the heat transfer through the assembly, in either a steady state or dynamic modeling of the problem.

I'll agree that the thermal mass of low-density fiberglass is so low as to be irrelevant from a dynamic performance modeling point of view, but so what?  R13/3.5" of cellulose has enough thermal mass to measure, but that's also not worth modeling- a third order effect that barely moves the needle, in the statistical noise on the rest of the assembly.  The mass effect of the cellulose isn't very relevant even in high R assemblies, compared to the relevance of it's steady state R value.

A lot of stick-built batt insulated homes are poorly executed, with serious air leakage, many gaps or compressions in the batts etc, but even at the low end 1-sigma tick on the bell curve I'd hazard it would still outperform an 4" of solid wood built to perfection in most US climates.  I'd hazard that that ideal R5-ish 4" solid wood wall performs at about R5.6 in dynamic modeling for some climates, but not R10, or even R8.
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