crawl space

Does a Crawl Space Make Sense?

Posted on May 07,2015 by ScottG in crawl space

Michael Geoghegan is designing a house for a mixed, humid climate and he plans on using an insulated crawl space.

All About Basements

Posted on May 07,2015 by user-756436 in basement

Foundation discussions can get heated. For some reason, builders often dig in their heels when the topic of slabs versus crawl spaces versus basements comes up. It’s time to declare a truce. It’s perfectly possible to build a great house on any one of these three foundation types, as long as everything is properly detailed. Each type of foundation has advantages as well as disadvantages. If you have a foundation type that you prefer, that’s great. I’m not going to try to change your mind.

What’s the Best Way to Insulate Crawl Space Walls?

Posted on May 07,2015 by ScottG in crawl space

Andy Chappell-Dick is at work on a house in Climate Zone 5 where the task at hand is to upgrade a crawl space by adding insulation as well as a membrane to block the infiltration of moisture. The catch? The owners want to avoid the use of rigid foam insulation if at all possible.

Foundations — Part 2

Posted on May 07,2015 by ChrisBriley in basement

Phil and I have returned to continue our discussion on foundations. In Part One, we covered slabs and frost walls, and in this part we cover basements and crawl spaces.

The Highlights:

**Do you really need a basement?** If there's no programmatic need for a basement (like the need for a workshop), then perhaps you can do without one. **Insulation: Inside or outside?** There are many reasons to insulate on either side. We weigh the pros and cons.

Beware of This Expensive Ventilation Scam

Posted on May 07,2015 by ab3 in basement

How much does an exhaust fan cost? Search online and you can find lots of them that move 200 cubic feet per minute (cfm) for $100 to $150. But, if you put one in a semi-attractive (emphasis on the "semi") package, create some fancy marketing materials, and target people who don't know much building science, you can charge $1,200 to $1,700 for that same fan. At least that seems to be the business plan for these three companies.

Five Ways to Deal with Crawl Space Air

Posted on May 07,2015 by ab3 in crawl space

If you have a home with a crawl space — or are building or buying one — you have several options on what to do with that particular foundation type. Most crawl spaces are vented to the outdoors, but over the past decade, encapsulating the crawl space (as shown in the photo here) has gained favor among builders of green and energy efficient homes. It's often seen as the best way to eliminate the moisture problems that often result from vented crawl spaces. But what do you do about the air down there?

Problems with Crawl Spaces

Posted on May 07,2015 by user-1048334 in crawl space

Crawl spaces are like the Loch Ness monster: talked about, rarely seen, and potentially a bit scary. The crawl space is that empty, barely accessible pit under the house filled with swampy water, cobwebs and spiders the size of dinner plates. (That link was the Google result for “spiders the size of dinner plates.” Enjoy). At least that’s what we imagine.

Vented Crawl Spaces and the Psychrometric Chart Are Not Friends

Posted on May 07,2015 by ab3 in crawl space

Really, the argument about whether you should vent a crawl space in a humid climate is over. Advanced Energy's research project from 2002 proved that closed crawl spaces outperform vented crawl spaces. A quick look at the psychrometric chart below shows that the argument should never have existed in the first place. (Click the image to see an enlarged version.)

How to Insulate a Basement Wall

Posted on May 07,2015 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.

(At Least) Six Things Are Wrong With This Crawl Space

Posted on May 07,2015 by user-1068097 in building code

Last week, GBA published a photo of a crawl space in an old house under the headline, “What's Wrong With This Picture?” The photo showed an unvented crawl space in a cold climate. The home was built in 1885. This crawl space is attached to an adjacent concrete-floored basement. The foundation walls are made of mortared limestone.

What’s Wrong With This Crawl Space?

Posted on May 07,2015 by user-1068097 in crawl space

The photo shows an unvented crawl space in a cold climate. The home was built in 1885. This crawl space is attached to an adjacent concrete-floored basement. The foundation walls are made of mortared limestone. Even in the small area captured in the photo, there are a number of problems that compromise energy efficiency, building durability, and life safety. Next week, we will post the answers that a Building America team, NorthernStar, came up with.

An Open Discussion on Closed Crawl Spaces

Posted on May 07,2015 by CarlSeville in closed crawlspace

This post is just an observation that I hope will stimulate some conversation about the subject of closed crawl spaces. This evolved out of conversations with two builders—one a high-end custom outfit and the other an affordable builder. Both of them had been certifying their homes to EarthCraft House standards and were building with closed crawl spaces. On the same day last week I heard from both builders that they were having moisture problems in their closed crawl spaces, were reluctant to continue building them, and were considering returning to vented designs.

Building an Unvented Crawl Space

Posted on May 07,2015 by user-756436 in crawl space

Residential foundations vary widely from one corner of the U.S. to another. Builders in some regions love basements, while builders in other regions swear by slabs on grade. Although most builders have a theory to explain these regional preferences, the main reason for these variations is habit, not logic. In areas of the country where basements are rare, there usually aren’t any technical barriers to building basements; and up north, where basements rule, it’s perfectly possible to build on a slab.

Fine Home Building Sealing a Crawl Space

7 Steps to an Energy-Efficient House: 1. The Basement

Posted on May 07,2015 by Betsy Pettit in basement

Editor's introduction: With energy prices rising again, many homeowners are planning energy-efficiency improvements to their homes. But most people are unsure of where to begin, and even seasoned builders don’t always know which priorities should rise to the top of the list. Betsy Pettit, an architect at [Building Science Corporation](, recommends starting where you can get the most bang for the buck.

Air Barrier or Vapor Barrier? - Building Science Podcast

Posted on May 07,2015 by JoeLstiburek in air barrier

_This podcast series is excerpted from a two-day class called "Building Science Fundamentals" taught by Dr. Joe Lstiburek and Dr. John Straube, of Building Science Corporation._

The Hardest Insulating Job Ever

Posted on May 07,2015 by AlexWilson in crawl space

I’ve done a bunch of home weatherizing and insulating projects over the years; let me tell you about the worst.

Well, They Got It Half Right

Posted on May 07,2015 by user-756436 in crawl space

At the International Builder’s Show, several demonstration homes have been set up in the parking lot outside the Las Vegas convention center. The Environments for Living show home has a display promoting the advantages of ventless conditioned crawl spaces; so far, so good. But instead of following best-practice advice and insulating the crawl space walls with rigid foam, the Environments for Living home designers chose to install fiberglass batts between the floor joists — a feature proudly displayed behind a Plexiglas viewing panel.

Green Basics Foundation Types
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