Winnie Pretty Good House-Working with Huber’s Zip-R Sheathing

As builders and designers, we have so many ways we can improve the performance of a wall assembly.  Deeper wall cavities will allow for more insulation, double wall construction gains you the ability to move the air and/or vapor control to the middle of the wall leaving the inner framing cavity free for mechanical/electrical/plumbing (MEP) equipment.  Then there’s Building Science Corporation and Dr. Joe Lstiburek’s perfect wall, with the right ratio of continuous exterior insulation to interior cavity insulation that lessens the worries of vapor control.  Continuous exterior insulation can be designed in several ways, foam-based products, ridged mineral wool, wood fiber insulation, or nail base products.  And then there’s Huber’s Zip System R-sheathing, what we call on the jobsite, Zip-R.

Zip-R isn’t new, I first became aware of the product back in 2014.  What makes this product unique is that the continuous insulation layer is located between the exterior wall sheathing and framing.  This location simplifies the installation of CI and wall sheathing compared to the traditional location of the insulation, which is exterior of the wall sheathing.  And to add to the advantages of the product, in most applications, it is still a structural sheathing product when installed per Huber’s manufacturer’s instructions.  (Consult a structural engineer if there are any questions or concerns on a specific design or building location.)

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How to Attach Cladding When Using Continuous Insulation

This post originally appeared on the Green Building Advisor website.

One of the challenges with continuous insulation (CI) is how to attach cladding.  The cladding type and weight along with the type and thickness of the continuous insulation can affect the cladding attachment details.  This blog post will go over a few of the code requirements and discuss how the manufacturers of both the CI and cladding can help with prescriptive code compliance.

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Where to Locate the WRB when using Continuous Insulation-Inside or Out?

This post first appeared on the Green Building Advisor Website.

Right now, there’s a lot of interest in the residential construction market around continuous insulation (CI) strategies.  CI adds a layer of complexity to a build, and with it, questions.  How much insulation do I need?  How to fasten the insulation?  How to fasten the cladding?  How to integrate windows and doors?  What about vapor control?  And, this question, should the water resistive barrier (WRB) be at the sheathing layer or outboard the insulation?  The answer, it depends, but you have a lot of choices.

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Vapor Control in Walls with Continuous Insulation-IRC Chapter 7 vs Chapter 11

This article first appeared in the January/February 2024 issue of the Journal of Light Construction.  www.jlconline.com

The International Residential Building Code is supposed to provide clarity into how builders construct homes.  In the IRC’s own words, The IRC was created to serve as a complete, comprehensive code regulating the construction of single-family houses, two-family houses (duplexes) and buildings consisting of three or more townhouse units.”  Usually, the codes do a decent job giving us options on how we should build homes with the occupant’s safety and health as our number one priority.  Codes also address energy efficiency and building durability.  Sometimes though, codes can be quite confusing.  How we handle vapor retarders when using continuous insulation is one of those areas.

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How to Plan for Continuous (Exterior) Insulation on an Existing Homes

This post first appeared on the Green Building Advisor website.

When I purchased my small 1950’s vintage Cape Cod home in 2018, I knew I had a lot of work to improve its performance and comfort.  I was planning a multi-year, self-performed (and solo), deep energy retrofit.  A case study where I could learn and share the difficulties of such an endeavor. 

One of my goals was to improve the insulation levels of both the walls and roof.  I went back and forth trying to decide if I should add a layer of continuous insulation to the exterior.  After all, I was going to remove the existing siding and replace all the windows.  In the end, I decided against it.  The gable ends of my roof have no eave (see photos below), adding exterior insulation would have required me to rebuild a portion of the recently re-shingled 12/12 pitched roof.  I now regret that decision, more on that later.

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Cavity Only Insulation-A Correction to the 2021 IRC Energy Code

This post first appeared on the Green Building Advisor Website

I recently wrote a two-part article covering the benefits, challenges and code requirements for continuous insulation.  (You can read the articles here and here.)  In the first article, I referenced table R402.1.3 which is found in Chapter 11, Energy Efficiency.  The table shows the R-value and U-factor requirements for several building components and assemblies.  The table data was taken from the first edition printing of the 2021 IRC.  In the article, I stated, “Climate zones 1, 2, and 3 are unique in that they have the option of cavity-only insulation.  Climate zones 4 through 8 all are required to have some amount of continuous insulation.”  A reader on the Green Building Advisor Website, jimmybpsu, pointed out in the comments section of the article that he had a different version of table R402.1.3 which did allow for cavity only insulation in climate zones 4-8.  As it turned out, he was right.

My son Colter installing a R-30 Rockwool Batt.

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What You Need to Know About Continuous Insulation-Part 2

This post first appeared on the Green Building Advisor website.

In the first part of this continuous insulation blog, we covered building codes and some building science and how they relate to CI.  This second part will discuss some of the difficulties many builders have with how the details work.

I remember my first time using continuous insulation in a new home.  I had many questions; where to put the WRB, how to attach the cladding, how to address the windows and doors, and how much insulation to use.  That home is now more than a dozen years old without any complaints from the homeowner.  Would I change some of the details I implemented on that first CI home?  Absolutely!  But the design and execution all those years ago seems to be performing.

Photo by Armando Cobo

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What You Need to Know About Continuous Insulation-Part 1

This post first appeared on the Green Building Advisor website.

Living in a very cold climate where wintertime temperatures colder than -20°F aren’t uncommon, you would think contractors and homeowners in my market would be excited to use continuous insulation (CI) on every new home under constructed along with every existing home having the exterior cladding replaced.  In reality, I rarely see either happening.  Part of the reasoning, my state and local building codes don’t require CI.  Cost is another driving factor.  As both homeowners and builders become better educated on the benefits of CI, this should start changing, I’m advocating for its inclusion on projects I’m involved in.

There are many reasons to use continuous insulation.  Reduced energy consumption is one benefit, though lowering heating and cooling costs are, in my opinion, less important and a secondary reason to add CI.  Improving comfort (thermal and sound) and expanding durability are more important.  (I’ll get into durability in detail later in this article.)  Building codes have begun to align with building science and we are seeing more areas across the country adopt continuous insulation as part of the energy code.  The scary part for most builders is the unfamiliarity of installing insulation on the exterior of a wall.  What insulation can be used?  What thickness and R-value are required?  How do I detail window and door openings?  How do I secure the insulation?  How do I attach the cladding?  Where does the house wrap go?  What about other penetrations such as exhaust vents and electrical penetrations?  What about the vapor retarder?  We will be discussing these topics and more over the next two articles.  In this post, we will be discussing the building code requirements along with the building science principles covering CI. Continue reading “What You Need to Know About Continuous Insulation-Part 1”

Construction Design-The Anatomy of a Well-Built Wall

I’m a fan of mineral wool insulation, specifically the Rockwool brand.  Over the next few months, I’ll be writing a series of blog posts discussing tips, tricks and the tools used to work with this insulation made from rocks and steel slag a byproduct of the steel industry.  Before we get into those topics, I want to discuss the Rockwool products I use, the building science behind the how these products work in a wall and the characteristics of the insulation, all of which can create a well-built wall assembly.

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