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8 Answers

Solar array positioning in Charleston, SC

Our home builder positioned our solar arrays facing east and southeast, but the angle is pitched east on both. One bank of panels are partially blocked by a large oak tree to the east, the roof of the building to the south, and a 2 level garage which partially obstructs the array (12 in each bank) eastward. The other array is pitched east and catches a glimmer of southern exposure sun, but is partially blocked by other large live oak trees to the south,

Asked By F White | Nov 24 15
3 Answers

How to create and air seal

We recently purchased a house that has a room with cathedral ceiling covered on the inside with cedar siding. This room, which was an addition has its own electric forced air furnace. Unfortunately, the builder of this room did not install a air barrier or even drywall under the siding, but did insulate the cavity above. This allows the thin cedar to leak at all of the joints. Blower door test and smoke confirmed the leakage.

I see two alternatives:

1. Remove the roof deck and apply spray foam from above, install a new deck and roof.

Asked By Dan Csomos | Nov 27 15
4 Answers

Vapor barior on SIPs in a hot humid climate

We have been asked to repair siding on a sips panel house in a hot humid climate. Our client has been advised to have us put a vapor barrier over the panels before installing the siding. This will essentially put the OSB between two vapor barriers... in a hot humid climate. This does not seem like a good idea. What do you think?

Asked By Hugh Stearns | Nov 20 15
2 Answers

Foam insulating a roof that has 1x8 sheathing with large gaps between the boards?

I have a sixty year-old house, and want to spray foam in the attic, on the underside of the roof. The roof sheathing consists of 1 x 8 boards, and the spacing between the boards varies from 1/4" to 1/2". There is an ice and water shield underlayment and asphalt shingles on the roof. I have two questions: When the foam is applied will it expand through the gaps in the sheathing and cause the underlayment and shingles to lift? Do I somehow need to seal the gaps before the foam is applied? Will it make a difference if I choose to use open or closed cell foam?

Asked By Ron | Nov 18 15
4 Answers

Air quality sensor / controller?

After much time spent thinking about an air exchange system retrofit for my home, I'm amazed at the installed cost, and am left questioning the necessity of it all. I reputable installer has quoted me $3,500 to $4,000 for a HRV-based air exchange system, so I'm wishing for a cheaper and/or more scientific way to determine my home's ventilation needs, other than something that just vents continuously regardless of conditions.

This article intrigued me:

Asked By Ryan Griffin | Nov 20 15
5 Answers

External air barrier and batt insulation

If batt insulation is used along with an internal air barrier (drywall system) do I still need an external air barrier? I mean, if there were no good air barrier on the outside, wouldn't cold air from the outside blow into the fiberglass or rockwool and kill its insulation properties, regardless of how tight the drywall barrier was?

Asked By Jack | Nov 20 15
7 Answers

Obscured glass entry door and solar heat gain

This is a weird question, but who else would I ask, but all of you. I want to know if there is privacy glass that still offers decent solar heat gain, and if one type is better than another.

The front of my home faces South and also faces the street on a city block. I want a glass entry door for natural light and solar heat gain in the winter (yard is shaded in summer) Provia makes Quad pane doors 2.5" thick that seem like they might fit the bill with U values as low as 0.13 (the same as my windows, coincidentally):

Asked By Ryan | Nov 17 15
2 Answers

How to use polyiso as interior insulation on a pole barn?

I have an unfinished pole barn with board and batten siding in Pennsylvania. I'd like to insulate the inside with polyiso panels, because that way I won't have to frame out the walls, and the polyiso will create a handy air barrier and thermal break. I can also find used 3" panels for ~$20 around here. My plan is to glue 3 inches of polyiso directly to the inside of the Purlins, tape the seams, then screw OSB, plywood, or drywall on top with long screws. These screws will go all the way through the foam to the barn's 2x4 purlins.

Asked By Jack | Nov 17 15
32 Answers

Vapor barrier or vapor retarder paint on open-cell spray foam?

I have seen some tout using the vapor barrier paint directly on open-cell foam before covering with Sheetrock, but as of late a general air of negativity towards that approach. I intended to use MemBrain under my drywall, but the open cell installer claims the paint works just as good for half the cost. What are thoughts on this? The stack up is a 2x6 wall with 2x2 interior Mooney strapping for a 7" thick OC foam fill wall over Zip board, taped of course. Then followed by a fired out ventilated assembly with Hardi siding.

Asked By Joe Suhrada | Oct 29 15
1 Answer

Blown-in insulation on open vaulted ceiling

I am had built with the plan to blow in insulation, and now that Im about to do it my mind is struggling with some physics.

I ceiling joist to the roof rafters with the help of an engineer to vault my upstairs bedrooms. This leaves me with a void of half the difference shown in the diagram attached. My question is will 5/8 drywall secured at 16" on center handle the load of blown in cellulose? If the insulation blows in as shown by the shaded area there shouldn't be any more than 18-20" over an given area. My biggest concern of course is how this would settle over time.

Asked By Marcus | Nov 17 15
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