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20 Answers

Standard HVAC vs. minisplits?

Is it possible to install a regular ducted HVAC system that is comparable (as efficient) to a ductless mini split system?

In Mechanicals | Asked By Steve Stemper | Mar 14 16
1 Answer

A slab repair or something bigger?

In our bathroom vanity cabinet, you can see the pipes going straight into the ground. The tile was never finished out around the pipes. Lately after it rains, our bathroom smells very musty (btw, this is on the first floor). Could this solution be simply to seal the hole or could there be another greater issue?

In NAHB Class Discussion | Asked By Brandy Mccombs | Mar 16 16
8 Answers

FPSF - Superinsulated slab

I'm finalizing the details on a build I'm starting at the end of the month using a FPSF and super-insulated slab.

Project is in climate zone 6B. I previously posted when this project originally began (before it got shelved for awhile) regarding Alan Gibson's details and the vapor barrier under the slab.

In Green building techniques | Asked By JMS Build | Mar 15 16
32 Answers

When does triple glazing make sense?

I'm designing a home that will be built in Zone 6 and I'm trying to decide between double or triple glazed windows. While the home will not be super insulated (R33 walls, R60 ceiling), it will have correct solar orientation, compact form, less than 0.6 air changes per hour at 50 Pascals pressure, reduced thermal bridging and efficient HVAC systems. Obviously, in this scenario, more insulation in the thermal envelope would provide a better ROI than triple glazing.

In General questions | Asked By Brad Lystad | Feb 28 16
18 Answers

How do I insulate an unvented roof with a T&G ceiling? Also: question on wall detail

I have read many of the articles on low slope unvented roofs and still am unclear. I need to know if both those plans work and if not, what is the solution. I am in CZ6 Utah cold winter below zero and hot summer up to 95 degrees and very dry. 1/12 pitch roof, monopitch south to north, south being the taller side. Passive solar design with south windows,

Plan from exterior to interior:

In Energy efficiency and durability | Asked By Steve | Jan 14 16
9 Answers

Dense-packed cellulose insulation settling and support

In our pre-certified Passive House we used densepack cellulose insulation in the walls of all three above-ground levels.

The first two level's walls are sheetrocked. When we did our first IR camera scan, we noted some settling and re-filled the tops of the walls. We'll repeat the scan this Fall to see if more settling has occurred.

In Green building techniques | Asked By Len Moskowitz | Sep 8 15
7 Answers

Surface 4 low-e... condensation issues?

I'm just about to order windows for a project, and leaning towards spec'ing some of the units as double-pane with low-e on surfaces 2 and 4. My sales rep is trying to get current information on exactly which coatings are available, but it appears to be Cardinal 180 on surface 2 and i81 or similar on surface 4. He mentioned that there was uncertainty about the surface 4 coating because there had been some condensation issues when this product line came out.

In General questions | Asked By David Meiland | Apr 10 13
2 Answers

Global warming potential of SPF products

I'm admittedly only nominally aware of the potential for certain spray polyurethane foam products to contain materials (in the form of certain blowing agents like HFC) which may contribute to global warming. Similar 2-part SPFs are being used by some foundation and highway repair contractors to stabilize soils and subgrades below buildings and highway slabs. Basically these SPFs are injected through drilled ports in a slab or pavement to improve the subgrade bearing capacity, and raise or level slabs which have settled or rotated.

In Green products and materials | Asked By Jamie O'Kelley | Mar 15 16
5 Answers

Questions on building an attic storage deck

Hi folks,

I'm embarking on my next project, which is to build an insulated storage deck in my vented attic. First some context:

This is an addition to the house, which comprises a sunken fireplace room over a crawl space and a 2 car garage over a slab. Then there is a stick framed attic over both of these spaces. The walls are 2x4 studs in these rooms, and the ceiling is made of 2x6's.

In General questions | Asked By Ryan O'Rourke | Mar 11 16
2 Answers

Disable attic fan or leave alone?

I recently bought a house that has an attic fan on a thermostat that seems to run whenever the outside temperature gets above about 70. The house was constructed in 1958, and is 2x6 wood frame on 16" centers. The attic has about 2-3" of blown-in cellulose, is pitched (I don't know the pitch but it's about average for a typical suburban house), and has a gable vent on each end (L-shaped house), soffit vents, and ridge vents.

This is in Albuquerque, NM, where it's very dry and very hot in summer (90-110 degrees is a normal high from May - September).

In Energy efficiency and durability | Asked By Gen Lawson | Mar 14 16
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