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1 Answer

How should moisture/vapor wetting and drying be considered in this situation?

Details:
- Climate Zone 6, Marine setting
- Stand alone garage(1970's) to be converted to an overflow guest house w/ full bath no kitchen.
- Guest house to be used in summer only.
- Existing structure on a floating slab w/ no vapor barrier beneath, sitting poorly drained soils.
- 20' by 16' area w/ cathedral ceilings, 2x4 walls and 2x8 rafters
- 20 mil vapor barrier to be installed over slab (seams taped), may not be able to extend under existing perimeter walls.
-2x4 sleepers laid flat over 20 mil VB
-1 1/2" xps fitted between sleepers

In GBA Pro help | Asked By geoff summa | Jan 16 17
1 Answer

Cold Access Room - Gaps in Air Barrier

** Re-posting to the proper Q&A category **

Hi -

In Energy efficiency and durability | Asked By Joe Duchek | Jan 16 17
2 Answers

How should moisture/vapor wetting and drying be considered in this situation?

Details:
- Climate Zone 6, Marine setting
- Stand alone garage(1970's) to be converted to an overflow guest house w/ full bath no kitchen.
- Guest house to be used in summer only.
- Existing structure on a floating slab w/ no vapor barrier beneath, sitting poorly drained soils.
- 20' by 16' area w/ cathedral ceilings, 2x4 walls and 2x8 rafters
- 20 mil vapor barrier to be installed over slab (seams taped), may not be able to extend under existing perimeter walls.
-2x4 sleepers laid flat over 20 mil VB
-1 1/2" xps fitted between sleepers

In Energy efficiency and durability | Asked By geoff summa | Jan 16 17
1 Answer

Northern Michigan un vented, un air conditioned Cabin roof design.

Northern Michigan un vented, un air conditioned Cabin roof design.
After reading several articles, opinions and Blogs I have a better understanding of the moisture vapors that exist and the problems they can create in walls and especially the roof. But I’m a little unsure of the proper design and construction for my great lakes, shore line cabin roof design. I have detailed my current plan below. Could please you give input as to where my design plan is OK or deficient in proper vapor management for this environment and situation.

In GBA Pro help | Asked By mike bard | Jan 17 17
1 Answer

Mixing wall types (CMU and wood framing), comfort and acoustics?

HI all,

I'm considering a renovation/extension on a house built slab on grade with CMU walls in Austin, TX. The house was built around 1950, and the CMU block is pretty dense, much higher fill than modern CMU.

The plan is to use a "perfect wall" approach adding insulation/weather/rainscreen/siding outside the block. Think at least Pretty Good House insulation levels, perhaps PHIUS2015+.

In General questions | Asked By James Howison | Jan 18 17
2 Answers

Double Stud Wall with Mineral Wool Batts

All,

We have settled on a double stud wall design for our new house. We had planned to use dense pack cellulose to fill the cavity, with a goal of an R40 wall. Unfortunately, we've only been able to find one firm in our region (Billings, MT) that does dense pack cellulose and they've never done a twelve inch cavity like we are proposing. They are willing to try, but having read a few warnings on GBA about finding contractors experienced with dense pack, we're looking at other options.

In Green building techniques | Asked By Douglas Epperly | Jan 22 17
4 Answers

How thick a layer of closed cell spray foam under roof deck?

Our roof has 4" of rigid board closed cell foam with OSB (Atlas Nailbase) installed above the roof deck, but the seams between the sheets of foam were not sealed, as one can see in the attached picture. For those areas I can access, I started spraying closed cell foam on the underside of the roof deck - how thick a layer of spray foam under the roof deck do I need to have for reasonable insurance against moisture condensation at the seams of the Atlas OSB??

In Energy efficiency and durability | Asked By Jim Berry | Jan 18 17
2 Answers

Mini-split v Package Unit Humidity Control; Sizing and Configuration

I have a 1920's house in Tallahassee, Florida - 2x4 frame construction with shiplap siding, no vapor barrier or insulation except in the attic and one wall that was installed later (originally a screened in porch), and a fair number of windows. I have sealed the floor and walls of the dirt crawlspace using heavy plastic with vapor-barrier tape at the seams, but there is still appreciable air flow between the foundation wall and the girders. The main floor is ~1,600 sq. ft.; approximately ~600 sq. ft. of the attic has been finished into a bedroom and bath.

In Mechanicals | Asked By Ellery Sedgwick | Jan 20 17
4 Answers

Flashing tape for roof decking

We build houses for a Habitat for Humanity affiliate in a hurricane prone area along the Texas Gulf coast.
At a program on the FORTIFIED building certification, we saw something that intrigued us. They suggested taping the seams of the roof decking. This would prevent water damage in the event that the shingles were blown off in a wind storm. We started using such materials on the last few houses.

In Energy efficiency and durability | Asked By Steve Young | Jan 19 17
1 Answer

Northern Michigan un vented, un air conditioned Cabin roof design

Northern Michigan un vented, un air conditioned Cabin roof design.
After reading several articles, opinions and Blogs I have a better understanding of the moisture vapors that exist and the problems they can create in walls and especially the roof. But I’m a little unsure of the proper design and construction for my great lakes, shore line cabin roof design. I have detailed my current plan below. Could please you give input as to where my design plan is OK or deficient in proper vapor management for this environment and situation.

In GBA Pro help | Asked By mike bard | Jan 20 17
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