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9 Answers

Slab insulation - do I understand the code requirements?

Question about slab insulation. The current slab has zero insulation on each side. That was no issue until now because it always an unheated garage. The slab is just that, a slab. No footing, no drainage.

Living in zone 5A and using the table Martin gave me in another thread I conclude I need:
- R-10 on the edge. --> 2.38" EPS or XPS*
- R-30 on top of the floor indoor. --> 7.14" EPS or XPS*

*= I use R4.2 for both EPS and XPS because I will use reclaimed foam. From what's I've understood XPS outgasses and it's R-value drops to that of EPS over time.

In Building Code Questions | Asked By Tony Tibbar | Jun 18 16
7 Answers

HVAC system sizing

Good day everyone. I'm in the process of building a new custom home in northern NJ. I'm trying to be as energy efficient as possible within budget. It's approximately 5000 Sqft under air, 2.5-story home with a finished basement (included in total sqft calc). I'm trying to properly estimate my HVAC system. The house has R19 insulation on the walls, and R30 in the attic. It has poured concrete foundation. There are 35 (Pella proline) windows in the house, all double-pane, along with 2 glass sliding doors. Exterior walls are 2x6 construction. Front door is R16 rated.

In Energy efficiency and durability | Asked By Eugene Shebayev | Jun 16 16
1 Answer

Enclosing the space under a deck

I have an interesting situation I'm trying to resolve. The home is in southern NY & my client had a deck built about 5 years ago which is fully enclosed below with concrete block walls & stone veneer. The space underneath the deck is unfinished & has at least 8'-9' of headroom & is just used for storage of outdoor furniture in the off season. The space has a few inches of gravel over earth.

In General questions | Asked By Brad DeMotte | Jun 17 16
2 Answers

Am I making a mistake building my house with a sealed attic?

I am building my own home and I want it to last for my son, and be energy efficient. My plan is to build it with a sealed attic with spray foam on the underside of the roof decking. On the top side I want to use a synthetic roof paper covered with a preferred radiant barrier. Then put down 1x4 vertical battens, and then a layer of 2x4 horizontal battens, and finally my metal roof.

In Energy efficiency and durability | Asked By Eric Dawson | Jun 16 16
3 Answers

Frigidaire Mini Split a good deal?

Looking at options for a 12,000 BTU mini split, I find the Firgidaire is about 1/2 the price of a Mitsubishi or Fujitsu. Does the price reflect quality?

In Green products and materials | Asked By David McNeely | Jun 16 16
6 Answers

Making the best of a misplaced vapor barrier

The project: an aluminum-bodied step van to be converted to a low-energy tinyhouse. It will move around once in a while, and needs to handle a range of climates.

The materials:
- heavy aluminum skin, built fairly air-tight (much tighter than corrugated RV siding)
- 4" thick fiber/paper-faced polyiso
- plywood interior panels, most likely
- a 100W heater/vapor generator that runs on potatoes and wine
- additionally heated by a woodstove when it's feasible, catalytic propane when it's not. I'm also looking into air-air heat exchangers.

In General questions | Asked By Geva edhrven | Jun 13 16
5 Answers

High humidity with high efficiency?

We received some excellent help from the members on this site one year ago when we updated the exterior of our home (June 2015). We ended up replacing our doors and adding these layers:

In General questions | Asked By Chad B | Jun 7 16
5 Answers

Does sub-slab insulation need to be secured and where does plastic go when concrete is the finish material?

I am using two 1" layers of reclaimed xps insulation under my slab, and it does not lay really flat. Is there a way to secure it to the gravel layer, and does it need to be? The concrete slab will have radiant heat in it.

In Green building techniques | Asked By Steve Wilson | Jun 16 16
5 Answers

What is best way to insulate a board-formed concrete wall?

The architect on this project ( residential modern home) designed one the rooms ( the study) of this all standard wood/stucco construction home to be built in 8in board formed concrete. Please correct me if I am wrong but, I believe this gives about an R2 for insulative properties. The rest of the house will have R21 insulation in between the 2x6 studs.

Ideally, the architect wants to see the board formed on both the exterior and interior walls of this room. If that is not possible, the interior could be drywalled.

In Energy efficiency and durability | Asked By Barbara French | Jun 16 16
9 Answers

CO2, VOC, RH, and CO ventilation controls for IAQ

I will have a Zehnder HRV in my house, and I'm installing an exhaust fan in my garage. I want the HRV to operate and provide ventilation based on what is required for air exchange. I would also like it and the garage vent fan to run automatically based on the level of airborne gases and humidity.

For the garage, are there exhaust fans that will operate based on CO levels, and not just when the garage door opens and closes?

In General questions | Asked By Brad Hardie | Jun 14 16
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