WRB

How NOT to Install Windows in a New Home

Posted on March 03,2015 by ab3 in flashing

I see a lot of interesting stuff at construction sites and in people's homes. I also see stuff I never got to see because people send me photos. I like photos! Remember that ice chest someone had incorporated into a duct system? That was sent to me. So are the first two photos in this article.

Housewrap Tape Problems

Posted on March 03,2015 by JeffHoch in building tape

Every year we inspect thousands of homes with one brand or another of housewrap installed as the water-resistive barrier (WRB). As energy costs increase and energy code requirements become more stringent, we are seeing housewrap installations where the seams are sealed with tape. Many housewrap manufacturers have proprietary seam seal tapes that they sell for exclusive use with their housewrap system.

Testing Building Assemblies for Moisture Resistance

Posted on March 03,2015 by AlexWilson in climate chamber

When I was in Portland, Oregon, the week before last for the Living Future Conference, I had an opportunity to visit a facility in nearby Clackamas where building assemblies and components can be tested for water intrusion and water vapor penetration. One of the high points of being a researcher and writer is the opportunity to visit really cool manufacturing and research facilities, so I usually jump at the opportunity to visit something new. I wasn’t disappointed on my recent trip.

Understanding Air Barriers, Vapor Barriers, and Drainage Planes

Posted on March 03,2015 by ab3 in air barrier

Is housewrap a vapor barrier? What's the purpose of building paper? Who'll stop the rain? I've covered this topic in various forms before, but the confusion about what the different building materials do is so widespread that I have to keep coming back to it. I'm going to keep it simple here so maybe we can get a few more people to use the proper terms, and especially to know when not to use the term “vapor barrier” ... and when not to use it.

Two New Exterior Insulation Products for Walls

Posted on March 03,2015 by user-756436 in DuPont

Exterior wall insulation? That usually means rigid foam and furring strips — although occasionally, it means mineral wool insulation and furring strips. But there are other options. Two new products offer builders new ways to keep their wall sheathing warm.

How to Seal Sheathing Boards

Posted on March 03,2015 by ScottG in air-sealing

The use of plywood and OSB sheathing is a fairly recent phenomenon. Before these sheet goods became readily available, builders nailed wood boards to the frame of a house for sheathing, and it is a house with this type of sheathing that Nick Welch is trying to update. His 900-square-foot house in Climate Zone 4C is sheathed with 1x8 boards, apparently over a layer of asphalt felt. There is apparently no insulation in the wall cavities behind the sheathing. His plan of attack is to air-seal the house, then install foil-faced polyisocyanurate insulation over that. The question is how.

What’s New with Water-Resistive Barriers

Posted on March 03,2015 by AlexWilson in 475

I remember years ago — I hate to remember how many; it must have been around 1982 or 1983 — writing for New England Builder (now the Journal of Light Construction) about Tyvek housewrap. It was then a fairly new product — and really a new idea: a material that would wrap over the outside of a house to provide an air barrier and improve energy performance.

Does Your Air Barrier Work in Both Directions?

Posted on March 03,2015 by ab3 in air leakage

Do you want a good air barrier on your house? Of course you do. No one who knows anything at all about building science believes that old myth that a house needs to breathe. We want airtight houses, but then we want mechanical ventilation to bring in fresh air from outside (well, at least as fresh as you can get from your outside).

A New Encyclopedia Article on Water-Resistive Barriers

Posted on March 03,2015 by GBA Team in encyclopedia

GBA's library of articles and blogs continues to expand. The newest article to be added to the ever-deeper GBA Encyclopedia covers water-resistive barriers (WRBs).

Walls Without Water-Resistive Barriers

Posted on March 03,2015 by ScottG in asphalt felt

Unless a builder has opted for a Zip System wall or is willing to ignore building code requirements, a layer of housewrap or building felt typically covers any exterior sheathing before the siding is applied. This water-resistive barrier, or WRB, helps to protect the sheathing from damage in the event that water is driven past the siding.

European Products for Building Tight Homes

Posted on March 03,2015 by user-756436 in air sealing

A new distributor of building products from Europe has set up shop in Brooklyn, New York. The company, called Four Seven Five, was recently founded by a trio of Passivhaus consultants: Floris Keverling Buisman, Sam McAfee, and Ken Levenson. Four Seven Five plans to import air-sealing products and ventilation fans from Germany, as well as HVAC equipment from Denmark.

What Were They Thinking?

Posted on March 03,2015 by CarlSeville in Batts

I’ve been doing HERS ratings and green building certifications for several years now, and I have run across some pretty scary things during inspections that sometimes make me wonder what everyone was thinking. Now, I was a contractor for a long time, and I understand the challenges of getting things done on time, correctly, and within the budget, and by no means am I trying to minimize those challenges. What does amaze me is how little attention some contractors and trade contractors pay to the details as their projects are underway.

Where Does the Housewrap Go?

Posted on March 03,2015 by user-756436 in drainage plane

Let’s say you’re building a house with plywood or OSB sheathing. You plan to install 2 or 4 inches of rigid foam on the exterior of the wall sheathing, followed by vertical rainscreen strapping and siding. Where does the housewrap go? Depending on who you talk to, you get two different answers:

  • It goes between the rigid foam and the vertical strapping, or
  • It goes between the sheathing and the rigid foam.

All About Water-Resistive Barriers

Posted on March 03,2015 by user-756436 in asphalt felt

UPDATED on September 18, 2013 By now, almost all builders know the importance of installing a water-resistive barrier (WRB) behind siding. Most types of siding leak, so it’s a good idea (and a code requirement) to install a WRB to protect your wall sheathing from any wind-driven rain that gets past the siding. A WRB can be vapor-permeable, like Tyvek, or vapor-impermeable, like foil-faced polyisocyanurate. As long as the wall assembly is designed to dry out when it gets wet, either vapor-permeable or vapor-impermeable WRBs work well.

New Green Building Products — September 2010

Posted on March 03,2015 by user-756436 in can light

In this new-product roundup, I'll look at a cover for recessed can lights, a new caulk for polyethylene, and several new water-resistive barriers (WRBs) that promise better performance than Tyvek or Typar. A fire-resistant hat for recessed can lights A Delaware manufacturer named Tenmat is selling an airtight hat for recessed can lights. Tenmat light covers are made from mineral wool; according to the manufacturer, they are fire-resistant.

Using Rigid Foam As a Water-Resistive Barrier

Posted on March 03,2015 by user-756436 in foam sheathing

Do foam-sheathed walls also need housewrap? There’s no simple answer to the question. It is possible to use foam sheathing as a water-resistive barrier (WRB). However, those who choose this route should know:

  • Some brands of foam have been approved for use as a WRB, while others have not.
  • Even if you choose a code-approved foam, you can run afoul of your local building inspector if you don't follow strict fastening and seam-sealing details.

Green Building Vocabulary Disputes

Posted on March 03,2015 by user-756436 in jargon

As any builder knows, construction terms vary from job site to job site; one carpenter’s furring strip is another carpenter’s strapping. Like carpenters, building scientists are inconsistent when it comes to technical terms — in part because building science is a relatively young field. In new fields of learning (including building science), vocabulary generally wanders at first, and eventually converges once consensus is reached. Reaching agreement on technical terms is useful. It helps achieve a desirable goal: efficient communication.

Housewrap in a Can: Liquid-Applied WRBs

Posted on March 03,2015 by user-756436 in housewrap

When it’s time to cover wall sheathing with a water-resistive barrier (WRB), most residential builders choose plastic housewrap, asphalt felt, building paper, or rigid foam sheathing. Some commercial builders, however, choose a fifth option: a liquid-applied building wrap. Liquid-applied WRBs come in a bucket and are applied to wall sheathing or concrete blocks with a roller or a spray rig. These products cure to form a tenacious, flexible coating that seals small cracks and penetrations.

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