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21 Answers

High humidity in between floor space in 2-story home in Zone 3A

Our home has a "crawl" space in between the first floor and second floor, all of our AC duct which is insulated is in this area. It appear to be well insulated, and is the same temperature as the house most of this time, within 1 degree or 2.

The issue is the humidity in this area is 30% higher than inside the house most of the time. The humidity in the house can be as high 58% in this humid season right now, but in the crawl space it is as high 89-90%. It seems like it should not be this different?

Asked By Momndad | Aug 18 17
10 Answers

Mild climate; expensive cellulose — What to do?

I am getting ready to go to Engineering for a new house in Raleigh, NC.

HDD - 3247 and going down....On border of zone 3 and 4. Technically in 4 but 20 miles from the 3/4 border.

Being in the South, everyone worries about cooling but we usually have 3x the cost in heat (based on last energy audit).

Asked By User-6902085 | Aug 18 17
7 Answers

Crawlspace with cellulose insulation - Go or no go?

Greetings GBA folks,

From Columbia SC. Please help determine whether blown in Cellulose between the floor joists is recommended.

Here are the parameters measured in the 20 year old crawlspace:

1. Current moisture content of the joists is at 18 %
2. Relative humidity is at 72%
3. Foundation is drained professionally well down to the footers - no current issue with water, or termites
3. Crawlspace is awaiting contractor to install 20mil vapor barrier to 1400 sqft dirt floor area

Asked By FusionHome | Aug 20 17
2 Answers

What is the lifespan of a ductless minisplit?

I was chatting with my contractor and he said that heat pumps have a life span of only 10 years. Is this true? Or does it depend on the manufacturer? I live in Maine - not sure if that would affect things. Thank you. -Karen

Asked By Karen Harter | Aug 22 17
5 Answers

Wall construction questions — stucco

We are building a house in Asheville NC, climate zone 4A, 2,600’ elevation. I’ve read many GBA articles on stucco and wall construction – all good stuff. We will have stucco exterior walls on our house with at least 3’ overhangs, and we are considering the following wall construction:

• Drywall
• Intelligent membrane (do we need one)?
• 2” x 6” stud bays filled with either Mineral Wool, or blow in Cellulose
• Huber 1-1/2” Zip R Sheathing
• Benjamin Obdyke 10 mm Rain Slicker
• Water resistive vapor permeable barrier (which is best)?
• Stucco Lathe
• Hard coat stucco

Asked By Nancy Broadbear | Aug 21 17
9 Answers

Limited budget: Dense-packed cellulose or Zip R-3?

We are building a custom house in central Maryland, which is in Climate Zone 4 and has adopted the 2015 IECC.

Our budget is already stretched pretty far, so it looks like we can only afford one of these upgrades to our walls:

(1) Dense-pack cellulose insulation (instead of inexpensive fiberglass batts - exact R-value unknown)

(2) Zip R-3 (instead of regular Zip)

Which of these options would the Green Building Advisor Community recommend?

Asked By User-6890381 | Aug 21 17
17 Answers

3/12 pitch roof insulation

Hi all.
I sent a question and got a reply on a 2/12 pitch roof.

I have an architect working on my plans now. It is a single-slope roof at the widest part (of 32 or so feet).

I originally was going with 3/12 pitch, but he thought 2/12 would be a lower roof at the tall end, so I said fine!

Now, looking at the problems with 2/12, I asked to go back to the 3/12 pitch. So: If I go 3/12, would I (or should I) use R-60 fiberglass? It will have 24 in. parallel trusses.

Would I still need a cupola? (Zone 6, lower Michigan.)

This is TMI for my small brain...


Asked By Robertsoave | Aug 19 17
3 Answers

I would appreciate a review of an air-source heat pump quote

zone 7 Kenora Ontario, Canada.

I asked for a quote for an ASHP unit that would work for the time being as well as in the near future when the house is expanded...

Some background....

1-short term.. (with the building as is)

-to heat and cool my existing home, 850 sq ft 2x6 framed 20 yr old bungalow on conditioned 5 ft insulated crawlspace...

I completed an online manual J about a year ago and determined as best I could a heat load of about 25000 btu.


Asked By Tim Brown | Aug 19 17
7 Answers

Average quality built homes needing makeup air because they are airtight

I have a question in regards to homes being built (not necessarily green homes) that are subject to the new energy code with air sealing and blower door tests. These homes are being built with average, code minimum building materials and after a blower door test it is showing the house is tight enough to require make up air.

Seeing as these are not green homes, there was no plan in place ahead of time for a system to bring fresh air into the house. Are you seeing this as a problem in other states as well?

Asked By Brian Ducharme | Aug 17 17
5 Answers

How would homeowners find a truly green contractor?

Where or how would a homeowner be able to find a licensed contractor knowledgeable in the practices and topics discussed on this site, or even green building and healthier building materials in general? Had hoped to be moved in before the holidays and I'm told there is roughly only one month or less of work remaining to be done... but I can't even find a contractor or subcontractors to do it. Maybe I'm searching in all the wrong places? Any advice or help would be immensely appreciated.

Asked By Natasha Reeves | Aug 21 17
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