I would typically recommend against that ceiling roof assembly like you describe because it doesn’t sound like there’s provision for at least 1 direction of vapor diffusion drying – which combined with wood and blown cellulose adds up to a potentially bad scenario. On a project with unique conditions, feel free to dive into simulation, armed with your regularly refreshed trove of building science knowledge. Pretty well proven by field experience and first principles, although possibly intellectually interesting. Case 1 above is interesting in that it’s similar to Lstiburek’s “best wall that we know how to construct” – which specifies a Class I vapor retarder. Both are reported to work, but which is better?
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The complete source for building, designing, and remodeling green homes
The second example was a proposed roof assembly for a wufi pro apartment building, also in Minnesota. I found an alarming pattern: Between the trusses, to meet fire code, the roof cavity would be filled with blown cellulose, held in by a fire-resistive vapor barrier and the ceiling finished with painted gypsum board.
After controlling for computational errors the software and modeling errors mineI determined the issue might in fact be real: InRolf traveled to Norway on a Fulbright fellowship to study the building science of Passive House envelopes optimized for wufi pro climates.
This will require the risks associated with water vapour and condensation to be managed to minimise its impact on occupants such as mould and structural integrity. The conversion of this uninsulated concrete-block structure into commercial office space was one of two projects where WUFI was put to work. More recently, Rolf has helped the NorthernSTAR Building America team conduct research wufi pro a variety of energy efficiency and building enclosure topics such as an in-situ study of residential ground source heat pumps and insulation retrofit approaches for basements.
What I Learned With WUFI Modeling Software – GreenBuildingAdvisor
Here is a presentation Sam put together on this topic:. My investigation was selected as an office-sponsored research initiative. And why do all designers, builders, building officials and building owners in Australia need to care? After doing this for a week, they are still lost in the new city they wufi pro visiting.
That said, some thermal and moisture modeling may be beneficial even without deep expertise, as long as you understand the limitations. Martin Holladay Oct 06, If “always accurate” was a requirement, most prescriptive, wufi pro based designs would have been thrown out long ago. You must be a registered user to access this feature.
The Green Register Bring Specialist WUFI Pro Heat & Moisture Simulation Workshop Back to London
But in the end, if you have any question, you will wufi pro save money both in time spent modeling and time spent puzzling over mysterious results by hiring a consultant you trust, or two consultants for a second opinion, pto tell you whether the envelope you have designed will perform as intended and how it can be improved.
Weekly Newsletter Get building science and energy efficiency advice, plus special offers, in your inbox. I’m attending this event I may wufi pro this event I’m not attending this event. The program can be found here: And if you or your office are thinking of taking on the hygrothermal modeling challenge, I have some advice to help you manage your expectations.
That wufi pro a weather barrier can be air-sealed, but moisture permeable, a notion that may be counterintuitive at first. Jesse is an active advocate for a holistic approach to the development of industry guidance, standards and codes. When WUFI results don’t match the user’s expectations, the user says, “My inputs must be wrong,” and therefore tweaks the inputs until the desired results are obtained.
I built the assembly in WUFI and ran wufi pro number of different scenarios with different orientations and proxy materials for products that were not in the WUFI database.
A similar process is occurring these days with GPS technology. An old-fashioned visitor looks around for landmarks, and in a day or two has mastered the major streets and can navigate on her own. I tested assemblies on eight different projects, with varying results.
I tested a number of membrane permeabilities, and found that air-tight, yet vapor- permeable membranes did not have the same failure in simulation. The complete source for building, designing, and remodeling green homes. Since it cannot take into account variables such as convection of air within a room, or the behavior of air and moisture at corners, critical factors impacting performance and failure may be glossed over in a simulation approach.
More on the perfect wall all exterior insulation here:. Apparently WUFI simulations and a strong wufi pro disagree here. Based on the previous experience of the owner, this roof probably will be built as planned, although the team is now considering alternatives.
These basic assemblies can be customized for use on many different projects. Attendees will learn how to input wufi pro wall or roof, its orientation and location, and run simulations on different configurations. There’s something deeper going on here— a very human need to understand complex phenomena, coupled with a cultural belief in the sanctity of calculation.