Insulation

A Vilified Insulation Material From the 1970s Returns

Posted on March 30,2015 by AlexWilson in foam insulation

In working on a major revision to The BuildingGreen Guide to Insulation Products and Practices (available bundled with a webcast), we’ve had an opportunity to dig into some of the lesser-known insulation materials on the market. Some of what we’re found has been surprising.

Smart Vapor Retarders

Posted on March 30,2015 by AlexWilson in polyethylene

Nowhere in building design has there been more confusion or more dramatic change in recommended practice than with vapor retarders. Thirty years ago, we were told to always install a polyethylene (poly) vapor barrier on the warm side of the wall. Then we were told to forget the poly and go with an airtight layer of drywall (airtight drywall approach). Insulation contractors, meanwhile, often said to skip the vapor barrier; we need to let the wall or ceiling cavity dry out. It made for a lot of confusion. And I’m not sure we’re totally out of the woods yet.

Getting to Know Spider Insulation

Posted on March 30,2015 by AlexWilson in blown-in fiberglass

We’ve just completed the installation of a relatively new and (at least in New England) little-known insulation material called Spider. As a reminder, the house we are renovating (really rebuilding) in Dummerston, Vermont, has provided an opportunity to try out dozens of innovative products and materials that I’ve long researched and written about in Environmental Building News.

Air Leakage Degrades the Thermal Performance of Walls

Posted on March 30,2015 by user-756436 in Building Science

For the past five years, researchers at the Building Science Corporation (BSC) in Massachusetts have been testing the thermal performance of a variety of wall assemblies as part of an ambitious project to develop a new metric to replace R-value. (I last reported on the project in my August 2011 article, A Bold Attempt to Slay R-Value.)

Insulation to Keep Us Warm — Not Warm the Planet

Posted on March 30,2015 by AlexWilson in climate change

I’ve been pretty vocal about a big problem with some of our most common insulation materials: that they are made using blowing agents that are highly potent greenhouse gases. All extruded polystyrene (XPS) and most closed-cell spray polyurethane foams (SPF) are made with HFC (hydrofluorocarbon) blowing agents that have global warming potentials (GWPs) many hundreds of times greater than that of carbon dioxide. (My apologies for contaminating this column with so many acronyms!)

Insulation: good news, bad news

Expanded Cork — The Greenest Insulation Material?

Posted on March 30,2015 by AlexWilson in cork

I’m always on the hunt for the latest, most interesting, and most environmentally friendly building materials, and I have particular interest in insulation products — partly because many conventional insulation products have significant environmental downsides.

How to Insulate a Basement Wall

Posted on March 30,2015 by user-756436 in basement

Here at GBA, we regularly receive questions from readers about the best way to insulate a basement wall. Since these questions pop up frequently, it’s time to pull together as much information as possible on this topic. In this article, I’ll try to explain everything you always wanted to know about insulating basement walls.

How to Insulate and Air Seal an Attic Hatch

Posted on March 30,2015 by user-1048334 in air leak

There’s a subset of issues in the realm of home efficiency that falls into the category “out of sight/out of mind.” The boiler in the basement, how much insulation is in the attic … as long as these issues stay out of your view, no problem. So what’s up with attic hatches, then? Even though attic hatches can be huge air leaks and sources of radiant heat loss, they are rarely fixed. An attic hatch is usually located in a hallway or closet where the homeowners see it daily. Yet...

How Much Air Leakage in Your Home Is Too Much?

Posted on March 30,2015 by ab3 in air leakage

Whether you want to build a new home or fix an old one, the way to ensure that you get the best performance is to do the building envelope right. That means installing the right amount of insulation and installing it well, and it means having an air barrier with minimal leakage. But how do you know when you've done enough air sealing? How tight is tight enough?

A Recap of ACI’s 2012 National Conference

Posted on March 30,2015 by CarlSeville in ACI

The 2012 ACI National Home Performance Conference was held in Baltimore at the end of March, and was yet again another marathon geekfest. With almost twenty concurrent sessions running from 8 a.m. to 5 p.m., followed by more sessions lasting until 8 p.m., it is a feat of endurance to attend this almost week-long event. This year there appeared to be an underground movement (Twitter handle: #ACIafterdark) that threw late-night parties, although I never managed to figure out where they were. Heat-pump water heaters

A Real Chainsaw Retrofit

Posted on March 30,2015 by user-756436 in Chainsaw retrofit

When workers need to insulate the walls and roof of an existing building with exterior rigid foam, it often makes sense to cut off the roof overhangs first. With the eaves and rakes removed, wrapping the building in rigid foam is a snap. The missing roof overhangs can later be rebuilt by scabbing the necessary framing on the outside of the foam.

Evolving Opinions on Green Building

Posted on March 30,2015 by CarlSeville in fiber cement

I still remember using spray foam insulation in my early green renovation projects – it was almost magic! It sealed and insulated in one shot. It made it easy to finish attics and avoid most of the problems with fiberglass batts that were the common insulation on our jobs.

How to Choose Insulation

Posted on March 30,2015 by CarlSeville in air sealing

[Editor's note:This is an excerpt of the “Insulation and Air Sealing” chapter of Carl's new textbook, Green Building. Carl's publisher, Cenage Learning, has allowed us to make the whole chapter available as a free download.]

Fiberglass versus Cellulose

Posted on March 30,2015 by user-1048334 in batt

The two least expensive and most commonly used residential insulation are fiberglass and cellulose. Granted, fiberglass is about 50 times more common — but a distant second is still second. Unless the homeowner opts for spray foam, the insulation choice usually comes down to fiberglass vs. cellulose. So what are the advantages and disadvantages of each one? How are they similar and how are they different?

The High Cost of Deep-Energy Retrofits

Posted on March 30,2015 by user-756436 in deep energy retrofit

How much does it cost to perform a deep-energy retrofit at a 100-year-old single-family home? Thanks to a recent study in Utica, New York, we now know the answer: about $100,000.

The research was sponsored by New York State Energy Research and Development Authority (NYSERDA), an agency that administers programs funded by public benefit charges tacked onto electric utility bills. The program paid for deep-energy retrofits at four wood-framed buildings in Utica, New York.

How Much Insulation Is Enough?

Posted on March 30,2015 by AlexWilson in climate zone

I'm often asked the question, "How much insulation should I install in my house"? It's a great question. Let me offer some recommendations: First of all... it depends. It depends to a significant extent on where you live. And it depends on whether we're talking about a new house or trying to squeeze insulation into an existing house. To simplify the discussion, let's assume, for the time being, that we're talking about new construction

Fastening Furring Strips to a Foam-Sheathed Wall

Posted on March 30,2015 by user-756436 in foam sheathing

UPDATED March 1, 2012 If you’re building a house with foam sheathing, and your siding is installed over vertical rainscreen strapping installed on top of the foam, how should you attach the strapping? Most builders screw the strapping through the foam into the studs; so far, so good. But what length screws should you use? And how closely should you space the screws?

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