Chapter 16 – Interior spaces: Insulation, vapor barrier and sheetrock installation

Chapter 16 – Interior spaces: Insulation, vapor barrier and sheetrock installation

 

I can’t believe I’m writing this, but I already miss my framing crew!  They have packed up their trailer of tools and have moved off the site. They have completed their job for me and are on to the next Blue Ridge Energy Systems home under construction in Waynesville, NC.  The good news is that I now have a parking spot at the house!!  Don’t you think the homeowner deserves a reserved parking spot?!

In all sincerity, my quote for this blog chapter goes out with special affection to all the crew including Jammie, Matt, Bryan, Randy, Blake, and Sydney, as well as Andy Presley and Jamie Shelton.  I hope you know how much I appreciate your professional skills and personal kindnesses to me.  All of you are simply amazing at what you do!

I would maintain that thanks are the highest form of thought; and that gratitude is happiness doubled by wonder.  GK Chesterton

South window awnings

South window awning

 

The exterior framing and trim is complete.  You can now see the awnings above the lower south facing windows. (Don’t worry.  The awning supports will be painted black!)  This shading prevents the hot summer sun from coming into the house and is angled so that the warm winter sun does come in.  That’s the fundamental concept behind passive solar design.  All the upper clerestory windows are shaded by the three foot overhang of the roof.

The SmartSiding in the recessed front entry has been installed (a second coat of paint will follow).  The covered back porch now has its red ceiling and black trim.  The steel I-beam has been sealed to prevent rusting.  So, let the stucco begin!!

 

 

 

 

Back porch among the rhododendrons

Back porch nestled among the rhododendrons

 

Now to the progress on the interior of the house.  All the walls have been insulated and the vapor barrier installed.  (The ceiling insulation will be blown in after the spalted maple ceiling is installed to support the insulation.)

Randy applies polyurethane to spalted maple for the ceilings

Randy applies polyurethane to spalted maple for the ceilings

First let’s talk about insulation.  Insulation is installed to keep the conditioned air inside the house in order to reduce your heating and cooling costs and to provide maximum comfort.  There are lots of  “hot” new insulation products on the market – open and closed cell foam, recycled denim, and hay bales, to name a few. But we have used traditional unfaced fiberglass.  Why?  The house is meant to be energy efficient at the lowest possible cost and fiberglass is much cheaper than the alternatives.  Foam insulation has a tendency to pull away from the walls over time, leaving voids.  Denim insulation compresses over time, leaving voids at the top of the walls. Hay bales in this wet climate?  Who are you kidding?!  So we have R-19 in the walls and will have R-50 in the ceilings.  Remember we also insulated the cement slab.  Snug as a bug in a rug!!

Unfaced fiberglass insulation in the walls

Unfaced fiberglass insulation in the walls.
The ceiling insulation will be blown in after the ceiling is installed.

The use of a vapor barrier is somewhat controversial in this climate, but Blue Ridge Energy Systems has installed one on every home for the past thirty years and to date there is zero evidence of dry rot or mold inside the wall cavities of any of their homes.  Here’s the deal: A vapor barrier is 6 mil plastic sheeting.  It is readily available and cheap.  It is installed CONTINUOUSLY behind the sheetrock.  I believe its use is the single most critical factor in reducing infiltration and maximizing a home’s performance.

This concept is measured in air changes per hour (ACH).  It’s a measure of how many times the air within a defined space is replaced in one hour.  Old, drafty homes leak like a sieve.  The air probably changes 10 to 20 times per hour.  You might as well leave the door open!  A code-compliant house will experience 4 to 5 ACH’s.  An Energy Star house will experience 3 to 5 ACH’s.  A Blue Ridge Energy Systems house will see 0.1 ACH!  That is a significant cost savings over the life of the home because you are not continually having to recondition all that air infiltrating from the outside!  Keep in mind we will use a heat recovery ventilator to allow fresh air into the house, but that air is preconditioned for temperature balance and the ventilation is controlled!

Continuous vapor barrier sealed at seams, outlets, fixtures, windows

Continuous vapor barrier from under the framing is taped at seams, outlets, fixtures, windows and doors

So why don’t builders use a vapor barrier?  The concern is that as warm air moves through the exterior wall and comes in contact with the cooler interior surface, moisture will be released inside the wall cavity, creating a spawning ground for mold.  During the energy crisis in the 70’s, many builders experimented with plastic sheeting, often to disastrous results.  BRES continued to use the vapor barrier and here’s the difference:  The vapor barrier is continuous.   It wraps under the framing and up the walls.  It is meticulously taped and sealed at every seam, outlet, light fixture, window and door.  The vapor barrier is always on top of the insulation and directly behind the sheetrock. AIR DOES NOT PASS FROM THE INSIDE TO THE OUTSIDE THROUGH THE WALL.  An exterior wall temperature will not vary from the indoor air temperature by more than a degree or so and that is not enough difference to create dry rot or mold inside the wall.

I would be the first to tell you to avoid using a vapor barrier if you have hired budget subcontractors with no experience in this practice.  I tried it once and absolutely gave up!!  I saw only disaster ahead. However, this crew has been installing a vapor barrier successfully for more than 30 years now.  They know how to do it and how to do it well.  It is an integrated system that requires fastidious attention to detail, not only to the poly sheeting, but to the framing, exterior sheathing, insulation, window installation, and sheetrock hanging.  But the results are well worth the effort.  The materials and labor will pay for itself in a few months time, and the monthly savings on energy costs every month thereafter is REAL money!!  A 3500 square foot Blue Ridge Energy Systems home can be heated and cooled for $200 PER YEAR!!

Ernesto and his crew are busy installing the sheetrock.  I can’t even begin to describe the difference this makes in defining the interior spaces!  All the sheetrock was hung in only two days of work!!  Of course they still need to tape the joints, mud over the joints and screws, and apply the knockdown finish that I want.  But what a crew and what a superb installation with very little waste of materials!!

Great room with sheetrock

Great room with sheetrock

The guest bedroom highlights the sawtooth roof design

The guest bedroom highlights the sawtooth roof design

 

 

 

 

 

 

 

 

 

 

 

 

 

Master bath has interesting architecture and soaring ceilings

Master bath has interesting architecture and soaring ceilings

 

I am thrilled with this house!  I can actually imagine moving in one of these days!!

Mignon Durham is a retired computer consultant, avid art and craft collector, founder of Toe River Project Access, and founder of Toe River Valley Watch. She has always been fascinated with what makes a place feel like home, and she hopes this blog will enlighten your own personal journey home.