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66 Answers

Attic is hot after closed-cell spray foam was installed

Finished attic with 4 foot knee wall , duct located in knee wall to support 2 floor,extremely hot, BASF spray tite 2 inches with spray foam wraped around rafter in knee wall but with Sheetrock on ceiling just 2 in foam In cavity . Suggestions to handle heat issue. Richmond Virginia all attic seal very well thinking heat coming from rafters under Sheetrock. Thermal convection coming from rafters. Worked done in the winter, crawl space also done, house built 1994 colonial 2 story with garage with room above with dormer. Also in crawl space does it really need supply vent and return vent

Asked By Mark Hippchen | Jun 27 15
6 Answers

Solar orientation design trade-offs — tough decisions

I have the unique opportunity to build an net-zero spec house for an investor in my local area. It's a 1450 sq ft. ranch with a garage on a slab. Building to "pretty awesome" house principles. Air-tight, High R, Triple glazed euro windows, etc etc.

My dilemma is the trade-offs between curb appeal, design functionality and optimum solar orientation for solar PV and glazing.

Asked By Ben Freed | Jul 6 15
19 Answers

Boiler upgrade recommendation?

I’m currently looking to upgrade my old boiler as it developed a small crack and is leaking. My current boiler is a P-468U-wt (151,000 btu/hr) Weil-McClain oil-fired boiler with a 40-gallon hot water holding tank.

I’m getting two different suggestions from two of my plumbers and would love some input on their recommendations. One recommends replacing it with an Energy Kinetics System 2000 and the other one is suggesting a Navien Combi-boiler.

Asked By Joe Pavia | Jul 1 15
6 Answers

Dense-packed cellulose in exterior walls

I have a 100+ year old home and there is currently no insulation in the walls. There is vinyl siding on the exterior and I think it was installed over the old wood siding. I am considering having dense-packed cellulose blown into my 2x4 exterior walls. Am I going to have a moisture problem if I do so? I've read conflicting opinions. I would appreciate any advice you can offer.

Asked By T S | Jul 2 15
8 Answers

Relative value of air sealing at exterior sheathing

I am trying to understand the relative value of air sealing at the sheathing. To do this lets consider cost as the benchmark. I realize that there is value beyond cost but this is an easily quantifiable benchmark and the one that seems most resonate with my clients.

Asked By Hugh Stearns | Jul 1 15
15 Answers

Interesting SIP alternative

Came across this site EZ Sip (http://structuralinsulatedpanels.com/).

My original retirement house plan was the standard 2x6 wall framing, Roxul batt interior, with 1/2" ply exterior wall then 2" of Roxul then the furring strips with appropriate siding.

After seeing this concept and the associated savings in construction time, I am now in a bit of a quandary. Method does seem to meet interior and exterior insulation values, as well as issues of stud bleed through. Having ply on out side resolves potential accumulation of moisture due to dew point issues.

Asked By William Oldaker | May 19 15
18 Answers

General questions re: building in Zone 7

Long time reader, first question...(I apologize in advance for length).

I will be building in the next year or so, this is my 5th home I have had built and have managed all my previous builds, so I know a LITTLE about building, but not even close to a professional. I live on the very Southern edge of Zone 7 in Central Minnesota (in fact, Zone 6 boundary is about 2 miles South of me). We have some hot, humid days in the summer, but obviously heating in winter is much more intense.

Asked By Brad VanVickle | Feb 14 15
3 Answers

Do sumps pumps and drain tiles create a self fulfilling prophecy?

This may seem like an odd question so let me explain myself, and to be clear it is mostly philosophical and out of curiosity.

I own/have owned/lived in many different buildings in the Chicago area. My parents house is also nearby.

Asked By Michael D | Jul 6 15
1 Answer

Recap: Insulate shop with polyiso between rafters

(Removed from an old thread with a similar title -- I decided to repost this as a separate question)

I am back working on my shop. To recap, it's a small 12' x 20' detached shop, in Mass., vaulted ceiling, well-vented at ridge and soffit, using 2" cut-and-cobble polyiso installed below plastic vent channels in each rafter bay, it's a low ceiling with no room to put the polyiso below the rafters.

Asked By Tom R | Jul 7 15
7 Answers

Insulate shop with polyiso between rafters?

Hi Folks ...

[I am new here, but have read through enough posts to see that what I'm asking about seems to be within the normal range of discussion, but not answered directly by anything I could find.]

I am in MA (zone 5). I have a 12' x 20' prefab shed that is used as a workshop. It was insulated with fiberglass batts between the 2x4 (yes, 2x4) rafters. There was 3/8" plywood below these covering the rafters, but not all the way up to the peak -- top foot or so on each side was just the open insulation face.

Asked By Tom Rawson | Dec 29 14
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