Hello all,

Discovered this forum in my search for information on tightening up my home and installing a heat pump.  I am soon to close on a raised ranch roughly 1700sq ft in a northern climate ( Maine ), the home was built in 2000, it is a foreclosure so I have some work to do to it ( heating system, flooring, roof,etc.) The house seems to have an average amount of insulation in the areas I can see, I did see a piece of 2" foam against the foundation in one spot as well.  I believe I am going to be putting a metal roof on the home and for a heating system I was thinking of a heat pump backed up by a pellet stove or two ( one for each floor ). 
My dilemma is not knowing what is behind the sheetrock for insulation and what would be the smart way to approach this?  I would love to gut the walls one room at a time and have spray foam done, but I am sure that the spray foam company could probable retire on what they would charge me for setting up and spraying one room at a time :-(.

What would be a wise first move I guess is the question that begs to be asked? 

If you REALLY want to know what's behind a wall, you could pop a small exploratory hole and put in a pin-hole camera.

If you, or someone you could hire, doesn't have access to that type of equipment, pick the room with the smallest facing on the exterior wall and open a hole big enough to see what's between the studs.

And yeah, if you're going to spray-foam, it makes more sense to "one and done" it than hit it piecemeal.

I am sure you can get a pretty good idea of whats in there by punching a few small holes between the studs. Your biggest eye opener will probably be found with a blower door though... After that, a heat loss analysis based on what you find might help you decide what is your biggest bang for the buck in insulation and heating...

Blower door? Please explain

A blower door test is where they install an electric blower in a door or window opening and pump air out of the house to a
EDIT. Wow i had this number wrong. Correct number is .2" water colunm/50 pascal difference between inside and outside air pressure(put the house under a Vacume).
By measuring the ammount of airflow out thru the blower at that pressure difference, you can get an idea how much air infiltration/leakage your structure has. Unless your 17 year old house is the exception to the rule, it probably has a lot of air leakage. Air infiltration can quickly become the major player in home energy consumption...

Contact the city and find out who inspected the house while it was being built. That wasn't that long ago. It should be on record. That should tell how how it was inspected/insulated.   

Posted By robinnc on 14 May 2017 06:14 AM
Contact the city and find out who inspected the house while it was being built. That wasn't that long ago. It should be on record. That should tell how how it was inspected/insulated.   

Haha this is rural Maine and in 2000 Maine had not even adopted BOCA building standards.

Thanks!  That is a great place to start, I will have to track down a company that does this.

Replacing batts with foam won't really give you much benefit--the thermal bridging through the studs won't be improved, and so you don't really get the full nominal value of the insulation. You are better off focusing on air sealing, attic insulation, and then if you want to improve the walls, adding insulation thickness either on the inside or the outside.

Yes and no.

If you're talking foam board.  Sure.

If you're talking blown foam.  It's not so easy.

1: With both batts and spray, you're NEVER getting the full nominal.  Additionally by itself it's neither an air or vapor barrier.

Fiberglass batts are nominal R13-R15 and mostly fill a 2x4 cavity at approximately 3.5 inches of depth..

2: 2 lb CCSF has a nominal rating of 6-6.5 per inch of depth.  So 3.5 inches is  is R21-R22.75 nominal.  So, even accounting for identical thermal bridges, you're still winding up with a better whole-wall insulation value in the end.

Also, it DOES act as an air/vapor sealant.



I DO agree that air sealing is probably a better choice of where to drop the fruits of your budget.

Attic insulation is iffy.  If you have a drafty house with cold rooms, simply dumping more insulation in the roof won't help.

In cases like that, adding insulation (either by reinsulating or adding insulation) is a good way to go.

If you're re-siding a house, exterior sheathing of insulation makes lots of sense.

If you're simply going to add insulation, you can also economize.

If you want to add insulation to pre-existing walls, reclaim your fiberglass batts where feasible.
Sandwich a 1" piece of foam between the stud and a 1x2 piece of furring.
Sprayfoam the first two inches which will air/vapor seal.
Finish filling the rest of the cavity with the reclaimed fiberglass.

You then wind up with a wall at a nominal 25-28 and air-sealed.
It won't provide a PERFECT thermal break.  But retrofit is seldom "perfect"
And the areas will be about as tight as you can get  without a complete tear-out on the building.

Posted By Dilettante on 21 May 2017 03:41 AM
Yes and no.

If you're talking foam board.  Sure.

If you're talking blown foam.  It's not so easy.

1: With both batts and spray, you're NEVER getting the full nominal.  Additionally by itself it's neither an air or vapor barrier.

Fiberglass batts are nominal R13-R15 and mostly fill a 2x4 cavity at approximately 3.5 inches of depth..

2: 2 lb CCSF has a nominal rating of 6-6.5 per inch of depth.  So 3.5 inches is  is R21-R22.75 nominal.  So, even accounting for identical thermal bridges, you're still winding up with a better whole-wall insulation value in the end.

Also, it DOES act as an air/vapor sealant.



I DO agree that air sealing is probably a better choice of where to drop the fruits of your budget.

Attic insulation is iffy.  If you have a drafty house with cold rooms, simply dumping more insulation in the roof won't help.

In cases like that, adding insulation (either by reinsulating or adding insulation) is a good way to go.

If you're re-siding a house, exterior sheathing of insulation makes lots of sense.

If you're simply going to add insulation, you can also economize.

If you want to add insulation to pre-existing walls, reclaim your fiberglass batts where feasible.
Sandwich a 1" piece of foam between the stud and a 1x2 piece of furring.
Sprayfoam the first two inches which will air/vapor seal.
Finish filling the rest of the cavity with the reclaimed fiberglass.

You then wind up with a wall at a nominal 25-28 and air-sealed.
It won't provide a PERFECT thermal break.  But retrofit is seldom "perfect"
And the areas will be about as tight as you can get  without a complete tear-out on the building.

A typical 2x4 framing fraction is about 25% of the wall area. The high nominal R20+ of 3.5" of cavity foam is largely bypassed by the much higher thermal conductivity of the ~R4.2 wood, the path that is conducting MOST of the heat when the cavity-R is that high. In "whole wall-R" terms rather than the nearly useless "nominal R" value, after factoring in the thermal bridging, the thermal performance of the wallboard, sheathing, siding, etc. a 2x4 /R13 or R15 wall is about R10.

Bumping it to an 2x4 / R22 with R6.3/inch closed cell foam in the cavity only bumps it to about R12. Sure, that additional R to is that's "...a better whole-wall insulation value in the end...", but you can achieve comparable or better performance using other methods & materials for a lot less money, and a lot less environmental damage. The improved whole-wall-R doesn't even bring that wall up to current code-minimum performance on a U-factor basis, even though it's given a pass since it makes it on a center-cavity R basis (for US climate zones 4 & 5, anyway.

Caulks & tapes can make a wood-sheathed assembly at least as as air tight as closed cell foam. At 3.5" half-pound open cell foam air seals as well as 2lb foam, using 1/4 the amount of polymer, and water rather than HFC245fa (a very powerful greenhouse gas) as the blowing agent.

Vapor barriers are two edges swords: Blocking (or severely impeding) vapor diffusion through a wall blocks both wetting and drying paths. Though closed cell foam cavity fill isn't particularly risky in most wall stackups, it can make the wall less resilient to things such as bulk moisture wetting.

Closed cell foam has been over-sold. It isn't a very "green" product, and it can usually be safely & economically designed out of the stackup at any targeted performance goal. In a full gut rehab there are usually much better places to put the money than 1000s of board feet of closed cell foam between studs, even if it's only a flash'n'fill.

It should be noted that if you have an existing building and you would like to determine the total R-values of the building envelope, this can often be easily accomplished without knowing anything about the building material that were actually used in the original construction. All you need is an IR temperature gun to measure the interior and exterior surface temperature of the building envelope, know the indoor temperature, and apply some math. Any existing building envelope R-value can be calculated using this equation:

R = 0.64 (Tis - Tes) / (Ti - Tis)

where R is the building envelope R-value, Tis is the interior surface temperature of the building envelope, Tes is the exterior surface temperature of the building envelope, and Ti is the indoor temperature. This equation assumes that the indoor air film R-value is 0.64 and that both the indoor and outdoor temperatures are reasonably constant for a couple hours prior to measuring the interior and exterior surface temperatures. This approach is very accurate for 2x and SIP construction, but may be less accurate for ICF construction because the thermal mass effect time lag associated with ICF is typically much longer than the time that the outdoor temperature stays reasonably constant prior to measuring the interior and exterior surface temperatures. Furthermore, the effective R-value performance of ICF is often vastly different than the conventional R-value and is highly dependent on the daily outdoor temperature variation as explained in the instructions for our ICF Performance Calculator.

Posted By Dana1 on 30 May 2017 06:23 PM

Closed cell foam has been over-sold. It isn't a very "green" product, and it can usually be safely & economically designed out of the stackup at any targeted performance goal. In a full gut rehab there are usually much better places to put the money than 1000s of board feet of closed cell foam between studs, even if it's only a flash'n'fill.

Good advice, I see your finally starting to listen. If you look at the embodied environmental impacts of any foam including extracting or polymerization from crude oil, styrene and it's monomers, manufacturing processes, extrusions, all the chem treats, lack of component and system level hot box & field testing that proves it is not supporting fungi, outgasing VOCs, MVOC, etc, alone and it's applications (concrete, wood, metal, adhesives & sealants, renders, chem treats, etc) it is clear it is not the best choice nor understood. EPS and most foams do not break down for hundreds of years in land fills making it's way into marine life and recycling it far and few between. Code does not account for this. The only way for it to pass standards by analysis usable in code is to test it in it's site configuration showing 100% permanently encapsulated and for it's life cycle free seeing air, excessive heat & humidity/liquid, you can see in the report below some common spores don't even need much of that. That won't happen by most if not all current applications.

Definitely NOT a "Green" material. ICF/SIPS or placing it incorrectly interstitial exasperating the issues. There are better materials to design sandwich layered or construction bond assemblies that takes the proper analysis by material and process engineers and other support roles, or, serious health risk can result we are seeing all over the AEC industry alone. In 2011 it is estimated 15-40% of American homes are sick and that has grown I'm sure:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3131638/

Sailaways post such a mess it's not worth another key stroke. Makes sense I find no such thermal testing, practice of whats preached, on the Borst website or any other testing or home builds. http://www.borstengineeringconstruction.com/Consulting.html

For it follow proven standards that does not include handing a DIY a IR gun and simple equation. Max annualized cyclic loads will be of most interest per the test standards (ISO< ASTM) and that data has to be extracted properly or using it can be VERY misleading. For the proper equations see ISO or ASTM standards or accurate CFD fluid dynamic models like WUFI, Therm, etc. Sorry Borst all that proven protocol is not going to be replaced by your calculators especially with no proven tested building's they were developed to on your site to get your sites SEO up.

Industry standard ISO 13790 be a good place to start: https://www.iso.org/standard/41974.html

Also, look @ ASTM C518 & ASTM C 177 for steady state. For dynamic more annualized data logging is needed @ max load or a chamber.

Although much more accurate & easier to use today's software algorithms used by most industry pros (BSC, ORNL, ASHRAE, DOE, NEEA) that use it as a basis along with local weather TMY data.

Here are some examples of some companies that know how to test and what you should expect to see on any site or person claiming to be a test engineer and/or has a resume doing it,

http://www.smtresearch.ca/case-studies/passive-house-performance-monitoring

https://buildingscience.com/documents/special/thermal-metric

http://energy350.com/projects/#NEEA

http://www.smtresearch.ca/case-studies/passive-house-performance-monitoring

https://wufi.de/en/
https://windows.lbl.gov/software/therm/therm.html      (less accurate than WUFI)

Wow...and thank you Moderator! It is very clear to me that Parahomes is NOT an engineer or NOT even a licensed contractor. He likely works around test engineers just enough to pick up some of their jargon, but he clearly doesn’t use engineering terms or engineering methodology correctly. He certainly isn’t a professional engineer because his State Board of Engineering would certainly revoke his license for behaving this way to the public and the engineering community. As per State law, our professional engineering license and construction contractor license information is on our website for our customers to verify. So Yes, I would fully agree that he is an anonymous troll, LOL!

Posted By sailawayrb on 05 Jun 2017 05:32 PM
Wow...and thank you Moderator! It is very clear to me that Parahomes is NOT an engineer or NOT even a licensed contractor. He likely works around test engineers just enough to pick up some of their jargon, but he clearly doesn’t use engineering terms or engineering methodology correctly. He certainly isn’t a professional engineer because his State Board of Engineering would certainly revoke his license for behaving this way to the public and the engineering community. As per State law, our professional engineering license and construction contractor license information is on our website for our customers to verify. So Yes, I would fully agree that he is an anonymous troll, LOL!

Does not surprise me you are gullible (I have other words I'd like to use, trying to be nice) enough to think you are thanking a moderator. The moderator or my "jargon, or flashing and bragging about your license won't change the fact you have no test reports showing your experience thermally testing a building and your advice is WAY off period!

You must think ppl out here are dumb enough to believe just because somebody was able to get a license they are competent and all the accurate Engineering is on your website the top pros never visit so you try DIYs. The better Engineers are creating new innovations I don't see on your website. You push ICF toxic foam too but have no testing of homes to show it is safe.

You do have one good idea though, somebody should point your licensing board to your post and put an end to your destructive advice that always points people to your site, my bet since you can't get locals to buy it. Hmmmm!

“You must think ppl out here are dumb enough to believe just because somebody was able to get a license they are competent and all the accurate Engineering is on your website the top pros never visit so you try DIYs. The better Engineers are creating new innovations I don't see on your website...”

Says the anonymous arshole who doesn’t have a website and who we now know doesn’t even have a degree or license in engineering or construction either... Yeah...that’s the person I will trust to give me good engineering or construction info...

Posted By ParaHomes on 06 Jun 2017 11:52 AM
You do have one good idea though, somebody should point your licensing board to your post and put an end to your destructive advice that always points people to your site, my bet since you can't get locals to buy it. Hmmmm!

Actually and regrettably, demand for our services always outstrips our capability to accept many new clients every year as stated on our website. This is precisely why we created and made our DIY calculators available to the public. They are far better than getting scammed by incompetent and unlicensed companies and individuals such as yourself as stated in the calculator instructions. I am also sorry to say that we hardly get any new clients from GBT. I would venture a guess that less than 0.1% of people building energy efficient buildings even know that GBT exists. So if that’s your goal for participating on GBT, you may want to rethink it. Most of our new clients come directly to us from word of mouth referrals from previous clients after hearing about us or seeing our actual work first-hand. Somehow I also don’t think that your demeanor and marketing approach will make participating on GBT very successful for you either.

Anyhow, I would strongly encourage you to please report our specific behavior which concerns you to our licensing authorities as soon as possible:

Oregon Construction Contractor Board (OCCB)

Oregon State Board of Examiners for Engineering & Land Surveying (OSBEELS)

Oregon Water Resources Department (OWRD)

Please be advised that OCCB, OSBEELS and OWRD only accept and action reports made by reputable parties that they can actually verify. We very much look forward to learning your identity and working with you to resolve your concerns.