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8 Answers

Insulation for 1:12 standing seam metal roof

Hello all,
Newbie to GBA but we are interested in building an efficient home. We live on the edge of zones 4 and 5 in Illinois. 100% of the exterior will be EIFS. The plan is for our exterior walls to be 2x6 with cellulose in the cavity and rigid foam over the sheathing.

My question is about how to ventilate our standing seam metal roof (1:12 pitch). Our architect didn't seem to have a good grasp on green building techniques.

My questions to architect:

In General questions | Asked By Kevin Hoene | Jul 22 15
0 Answers

How much energy does the evaporator coil waste?

While working through Manual D calculations I was surprised at how much of the total static pressure from a blower motor is dropped through the air conditioning evaporator coil. In my case I had a drop of .3 iwc at the coil for a total external static pressure of .7 iwc at 990 cfm. That's almost half of the blower load being used to push air through a coil that in my climate (zone 5) is just in the way most of the year.

In Mechanicals | Asked By Jonathan Dalton | Jul 28 15
3 Answers

Insulate ducts in conditioned basement?

I have been air sealing my ducts as best I can with mastic. I now have the first 4 feet or so of supply duct from the furnace sweating pretty good whenever it's on. This is all in the basement, which we use as another family room like area, don't use it as much as the first and second floor, but a fair amount.

In the summer it's freezing with the air conditioning on and the ducts sweat for a few feet, as mentioned.

In the winter, however, it's still a little chilly, certainly not overly warm.

In Energy efficiency and durability | Asked By Jeremy M | Jul 27 15
6 Answers

Is a ductless minisplit appropriate for a house with primary wood heat?

I am contemplating installing a ductless mini-split heater in our new build house in Southeast Alaska. The climate is of course very wet, with fairly cool summers and fairly mild winters with the occasional cold snap.
We heat primarily with wood. Is a mini-split heater an appropriate choice when the wood stove is expected to do 80% of the work of heating? We want an auxiliary heater that will simply limit how cold the house will get while we are away for a long day or a weekend (to 50 degrees or so), but will not run at all when the wood stove is going.

In Mechanicals | Asked By Justin Smith | Jul 23 15
32 Answers

More confused....open vs. closed spray foam for my climate zone


I want to finish off my third floor. My house is in Richmond, VA - Climate Zone 4 - (right in the middle of the zone). House was built in 1993. The attic is walk up and rafter built with 2x8s. Here are some pics of the space:

In Energy efficiency and durability | Asked By Joe Watson | Jul 21 15
5 Answers

Insulation for condensation control changes from IRC 2009 to 2012

I'm building a small house in Portland Oregon, climate zone 4C marine (according to 2009 IRC). I have 2x12 rafters with blown cellulose, then a layer of taped plywood sheathing for air barrier, then 3" of XPS followed by another layer of ply and the roofing on top of that. Since the ceilings are vaulted, it's an unvented attic situation, so I'm worried about moisture. I've got R36 in the cellulose and R15 in the XPS.

In Building Code Questions | Asked By Tom Frisch | Jul 26 15
15 Answers

Proper way to detail bottom edge of rigid foam next to sill plate

I am going to be installing 2" of rigid foam over my OSB sheathing soon and I have two concerns. The current one is what is the most DIY friendly method to protect that bottom edge of foam that is under the siding, but next to the ground near the sill plate? I want to prevent bugs of course, but also keep moisture out too. I see videos of pros using aluminum flashing but they have fancy breaks and coils of it. Is there a DIY alternative? Local supply store would be Menards if there is a certain product to suggest. Thanks.

In Green products and materials | Asked By Nicholas C | Jul 25 15
4 Answers

How much more efficiently does a ductless mini-split perform below peak demand?

My Manual J load calculation for my the 960 sf house I'm building in central Arizona shows a heating load of 13,535 BTU and a cooling load of 11,860 BTU.

I'm debating between two ductless mini-splits:
Panasonic E12NKUA with inverter: 12,000 BTU Cooling 13,800 BTU Heating, 20 SEER 10.6 HSPF
Panasonic E18NKUA with inverter: 17,100 BTU Cooling 20,400 BTU Heating, 18 SEER 8.5 HSPF

In Mechanicals | Asked By Jeff Cooper | Jul 27 15
2 Answers

Flat roof insulation

Here is the Chicago area.
If I can't ventilate the flat roof, then what happens?
what if I am using the fiber insulation and radiant barrier together..?

In Energy efficiency and durability | Asked By Mansig Yoon | Jul 26 15
5 Answers

Closed-cell foam in a 65-year-old Cape Cod roof?

We recently removed all of the vinyl siding and homasote from our cape. We installed R15 fiberglass in the walls - there was not insulation previous to this, just homasote. In addition, we replaced all of the windows with double glazed argon gas filled low E windows.

In Energy efficiency and durability | Asked By Michael Boice | Jul 24 15
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