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1 Answer
Exterior poly iso or XPS for wall and roof assembly

I have plans for construction of a 15 x15 foot addition to my home in climate zone 5. The walls are currently designed as 6-5/8 inch Murus OSB polyurethane SIPs with adhesive spray foam in the panel joints, All Weather Flashing tape on the inner seams and Grace Vycor adhesive on the outer seams. Tyvek Drain wrap is over the SIPs to act as a small air gap. The drain wrap is covered by 2 inches of foil faced poly iso with 1x4 furring added to support UNA-CLAD steel siding. The entire wall assembly is roughly R 53 or so.

Asked By W. Timothy Ward | Dec 11 13
2 Answers
Minisplit blowers mounted low or high?

When your primary need for a minisplit system is heating rather than cooling, would it make sense to mount the blower low (near the floor) rather than high (at the ceiling)? I spoke to someone at Mitsubishi who explained that they were designed to go high, even for heating. But I don't totally buy it. Why design them that way if heat rises?
Daniel

Asked By Daniel Herskowitz | Dec 10 13
10 Answers
Help me understand my Manual J

My question is how to use this to ensure my equipment is sized correctly. I plan on using heat pumps to cool my house in the summer and heat my house down to 35-40 degrees. Once it's too cold for the heat pumps i plan on having back up propane furnaces kick in.
1st floor heating/cooling (hvac 1) is 43,393 btu and 2.1 ton
2nd floor heating/cooling (hvac 2) is 35,067 btu and 1.5 ton

How do I use the cooling tonnes to determine appropriate sizing of the heat pumps?
Also what size propane furnace would I get, would a variable furnace change anything? I'm guessing something like:

Asked By jason c | Dec 6 13
7 Answers
Unvented roof problem

I built a great room addition but didn't do my homework first. The outside of the roof is finished.

Due to weird angles, dormers, hips, etc., it is virtually impossible to vent this thing. Also due to all the weird features, the roof deck was completely covered with Ice & Water Shield before the metal roof was installed. So now I can't add foam to the outside, and the Ice & Water Shield will prevent any outward drying.

What do put in the 2x10 rafter bays that will work in zone 6? I was trying to avoid spray foam due to the cost, but is this my only option?

Asked By darren williams | Dec 10 13
4 Answers
Metal building for residences

I am looking for suggestions to guide my choice of the most appropriate type of green building choices for my area and my life stage. I currently own a home that we built ourselves 26 years ago. When I say "built ourselves" I mean we modified an existing house plan to meet our needs/budget and acted as our own contractor even though we did not have a contractors license. We owned our own land and I was able to put together an application with enough equity position that the bank allowed us to do that.

Asked By Cynthia Hall | Dec 11 13
2 Answers
Loose-pack versus dense-pack cellulose for a flat roof

Loose-pack cellulose has been recommended for the cockloft of our row house. The roof has a slight grade so that the cockloft height goes from about 1 foot to 2 feet (including the roof joists). We will have a vapor permeable air barrier below it. Is loose fill a better choice here than dense pack? If so, why?
Daniel

Asked By Daniel Herskowitz | Dec 10 13
0 Answers
DC Powered Deep Well

We have a 6" deep well - currently powered by 220V house power (that won't work with my 5KW genny - for reasons I cannot fathom).

After losing power again this weekend from the rain/ice storm - its time for an alternative.

So my question:

Would it be better to get an inverter and use the current AC powered pump - or change out the pump to a DC powered pump?

I have done a bunch of research on this and am not finding a definitive choice either way.

Appreciate any guidance.

Sean

Asked By Sean Cary | Dec 11 13
1 Answer
Why are my windows wet?

4 year-old 2800 SF home in Duluth (zone 7A). Very tight construction, Well insulated etc. Using a Venmar HE1.8 HRV running full blast. We still have 1-2 inches of condensation and some ice along the bottom of our windows when the temp is <0F at night. (low-E H-windows).

Is our HRV sized too small, or am I doing something wrong?

Asked By Jeffrey Lyon | Dec 11 13
22 Answers
Window condensation issue

I'm in the middle of constructing my home and have discovered a serious condensation / bulk water issue. First some background: We're in southern Maine. The envelope is a double 2x4 stud wall system 10.5" thick insulated with Roxul. Exterior air barrier is taped zipwall and interior air barrier is ADA with taped or gasketed seems and joints. No vapor barrier. We put in Intus Eforte UPVC windows.

Asked By Brian Beaulieu | Dec 8 13
1 Answer
Drywall and adobe

In New Mexico, adobe construction is very common. Having grown up in one I know the ups and downs of it. I have lived the last few years in a frame house and have come to understand their ups and downs as well. What I want to know is if you can afford the cost is it possible to build an adobe house and then construct frame walls within.

Asked By Ray Driver | Dec 10 13
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