Design & Construction Resources
How To Stay Airtight Without A Service Cavity
Intro / Caveat As you may know, 475 recommends you use a service cavity on the interior of high performance, airtight building envelopes. We've enumerated the values of service cavities...
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Airsealing Beam Penetrations
Joist Connections Add Up Plaster is a great airtightness solution for party walls. But connections to the joists need to be addressed. This Ecostruct project achieved 0.23ACH50 after this plaster...
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The 8 Golden Rules for Foam-Free Unvented Asphalt Shingled Roofs
When insulating a wood roof structure, 475's goal, as always, is to build in the most healthy, structurally sound and ecologically friendly way – thereby achieving truly high performance. This...
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Historic Masonry: Notes and Details
475 in many ways started with historic masonry retrofits, and with our HQ surrounded by Brownstone Brooklyn, we are helping a great many of these 100+ year old buildings get...
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2 Simple Ways To Airseal Wires & Pipes
It's great watching the Proof is Possible Tour. We have an addition to the information given by Corbett Lunsford in their last progress video. See our response video below.
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Yes, Unvented Roof Assemblies Can Be Insulated With Fiberglass - A WUFI Post
And Not Just In Climate Zones 2B & 3B: Cold Climates Too A post on August 21st, 2015 on GreenBuildingAdvisor.com, Martin Holladay asked the question, Can Unvented Roof Assemlies Be...
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The Service Cavity: Making Airtight Construction Easy
We are making homes as airtight as possible. This is because airtightness greatly effects indoor air quality, thermal comfort, and energy efficiency - while protecting the enclosure from moisture damage...
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Blower Door Metrics Explained: ACH50 vs CFM50/SF
The following was written in 2015 and is a critique of a single document that Building Science Corporation and PHIUS collaborated on. Very good enclosure airtightness is a cornerstone characteristic...
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Insulating Historic Masonry Buildings Safely: How WUFI Can Help
With the rising popularity of Passive House and EnerPHit renovation in brownstone and brick masonry renovations in the US and Canada, the question comes up time and time again: What...
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Heavy-Duty Window Flashing by Chris Corson Using Extoseal Encor
We had the opportunity to meet up with Chris Corson, Technical Director for EcoCor High Performance Building Systems (formerly, EcoCor Design / Build), on a significant new project in Woodstock,...
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475 Does WUFI®: Mold Potential and Historic Masonry Retrofits in Climate Zone 6 (Burlington, VT)
475 Does WUFI®: Mold Potential and Historic Masonry Retrofits in Climate Zone 6 (Burlington, VT) A key piece of the puzzle as we decarbonize our building stock is successfully retrofitting...
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Can't vent at valleys and dormers? Use a smart vapour retarder (not foam)
Can't vent at valleys and dormers? Use a smart vapour retarder (not foam) Straight gable roofs are easy to vent, and ideally would be vented. But often we end up...
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Keeping Sheathing Dry in High-R Double-Stud Walls - a WUFI study
Double-stud walls have become a popular and cost efficient way to build well-insulated envelopes: two 2x4's spaced apart easily makes a R-40+/10.5" thick wall. Such walls also include a thermal...
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Unvented Flat Roofs: A Technical Discussion
Flat roofs have often been built with the insulation all on top of the vapour closed drainage plane - as this avoids dew point condensation issues inboard of the roofing....
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A high performance roof should be vented - how to do this properly
Vented roofs work, and are the best solution to eliminate many issues that appeared when we started to insulate buildings - 'leaks' caused by condensation, mold, water damaged sheathing and...
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Integrating a window in the airtight layer - brick/brownstone retrofit case
Windows and doors are inherently the weakest link in our buildings' enclosures. Even with the use of great triple pane glass, super-spacers and thermally broken frames, you would be hard-pressed...
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Blower Door Protocol for Passive House Certification
Automated blowerdoor test according to EN13829 with DG700 manometer controlled by laptop Building air-tightness below 0.6 air changes per hour at 50 pascals pressure (0.6ACH50) is a simple target that...
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Blowing dense-packed cellulose, it's like magic
Infrared image of Cellulose bays not completely filled with densepack behind sheetrock. With Pro Clima's reinforced intelligent membranes INTELLO Plus, DB+ and the exterior vapour open SOLITEX Plus WRB -...
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How to install dense-pack cellulose with Intello Plus airtight membrane
Recently we have gotten a number of questions regarding the installation of dense-pack cellulose in conjunction with the installation of Intello Plus (and DB+) airtight membrane(s). With a big assist...
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