r/PassiveHouse

Working on a Passive House in Climate Zone 5A. The plan is to use vinyl lap siding as the cladding, but we are struggling to determine the best way to install this, given that the wall assembly includes 3" of rigid foam board insulation between the sheathing and the siding.

We have been struggling to get installation guidance from vinyl siding manufacturers, as this installation with this thickness of foam is not explicitly called out in their technical materials.

Looking for recommendations on installation (e.g., should we use furring strips, nail directly into sheathing/studs through the foam, etc.) and recommendations on siding brands. Thank you in advance!

Hi all,
We’re currently final stages of planning our passive house build. It’s two stories, 205sqm. North/south orientation, fully sealed with MHRV.

The house is in Perth, Australia, so hot summers and mild winters. Summer can get up to multiple days of 40+, with minimums in mid teens. I’m assuming heating will never be an issue in winter.

We have two options with cooling . Either a fully ducted system on two levels, or just placing units in main areas and allowing the flow to cool down other rooms.

My question is, would option two be enough? we went down the passive house route as we didn’t want to rely on dumping cold air into the house constantly, rather just to need to take the edge off. But there’s also an issue of ‘if we don’t fit it during the build, it’s extremely hard to retro fit.’ However, I’m not convinced a fully ducted air conditioner system (16kw or so) working at a fraction of its capacity is good use of resources and money.

Happy to hear your thoughts, especially those in similar climates. Happy to provide plans via DM if you’d like

I live in a zone 6 climate so a heater (i was thinking a rocket mass heater) really feels necessary. There are short days during winter (about 6hrs at 70%) so I'm not sure if thermal mass is even worth designing around or if I should focus on insulation for the northern wall.

would it be efficient to have the northern wall be filled with 8" of a straw/clay mixture for high insulation and (1) 110 gallon aquarium tank filled with rain water as a trombe wall? A part of me wants to have the northern wall be a dry stack CB structure for the thermal mass and use snow as insulation on the outside if it snows.

So far the non-negotiables seem to be: Swedish Skirt/insulating the foundation and a sloped roof (30% seems to be the consensus)

I know insulation and thermal mass are opposite processes so I'm wondering if there's one I should prioritize. I'd hate to do a bunch or research and designing on something that doesn't actually change temp.

Looking for recommendations for a building science consultant or architect experienced with phased retrofit work in mixed-humid climate zone 4A (Eastern Panhandle of WV / Berkeley County area, though remote consulting could also work).

We purchased a 1984 pier-and-beam home and after purchase uncovered some concealed structural, moisture, and termite damage that had been concealed by the seller. The issues appear localized rather than systemic, and we’re using the opportunity to thoughtfully rebuild portions of the house with better envelope details rather than just patching things cosmetically again.

Current/planned scope includes:
- structural repairs
- replacing T1-11 and adding proper WRB + rainscreen
- likely exterior insulation
- window replacement/reinstallation strategy
- cathedral ceiling / roof assembly considerations
- air sealing and durability improvements
- phased DIY approach with contractor support where needed

I’m pretty experienced with DIY and renovating, so considering doing as much of the work myself as I can. I’ve been going through the Build Science 101, 201 and 301 courses on YouTube and have a pretty good idea of how to approach things. Mainly need someone to bounce questions off of and to be the Building science adult in the room to make sure I don’t mess anything up too bad.

Someone who works virtual and is familiar with my climate zone would be great.

I’m looking less for “full custom architecture” and more for someone strong in retrofit building science, sequencing, and assembly detailing who is comfortable consulting with an engaged homeowner.

Any recommendations for consultants, architects, or builders who are especially good at this kind of work?

For those of you who may be interested, on May 14 we're hosting a free webinar on Passive House construction details at and below grade.

More info here:

https://1yt00.share-na2.hsforms.com/2Xz6-KI65TaOF_qlwhbjR0w

For context- Atlanta, GA Climate Zone 3A (warm, humid)

We are building several passive houses right now, and I am working to rewrite our standard specifications for ALL of our projects.

For new homes, it is "easier" to do a passive house since we are starting from scratch. Not easy- just easier.

Where I struggle is with remodels. I'd love to remodel from the outside in and add continuous insulation, but that's no longer feasible on houses that aren't 100% gutted. If we are doing an addition, I know that there is no payback on energy efficiency if the rest of the house still needs work. Is there an argument to be made about sheathing failure?

We've been doing some modeling, and my suggestion was a minimum of 2 in of continuous insulation on a 2 x 6 wall filled with insulation. This seems to make the models happy for passive house 😄

Most of the "high-performance" (non- passive house) builders in this climate state that continuous insulation is not needed to prevent failure; it is mostly for energy efficiency.

This is for walls- I'll start another thread for my issues with roofs. I'd love your feedback, and if we solve this, I might make a video, and you all would get 100% credit!

The 2 options I am considering:

1. 2 x 6 with 2" mineral wools on the outside of the sheathing

2. 2 x 6 wall with 2 x4 staggered for mostly continuous insulation inside the wall.

For both, our vapor and air barrier would be on the exterior of the sheathing.

Efficient House Features

Passive Construction: A house designed to use minimal energy for heating, utilizing insulation and heat recovery.

Smart Home Technology: Automation systems that manage lighting and heating to maximize savings.

Modular Architecture: Quickly constructed, eco-friendly homes with high energy efficiency.

I created a passive house website, but I won't share it for transparency.

I have been passionate about Passive homes since I learned about them in or around 2017. I sometimes pick up a Dwell magazine or visit their website to learn about what's new. I follow Matt Risenger on YouTube even though I am not a builder.

Are there any sites you visit or magazines you read?

Hi,

I recently passed the PHIUS CPHC certification exam after signing up for and attending the PHIUS CPHC training program ( online courses and 2 weeks of in-person seminars). My hope was to take the momentum and knowledge from having taken this course and go straight to the Passive House Institute exam. Ideally, I do not want to pay for another online course but I recognize that there might be significant differences between the PHIUS exam content and the Passive House Instititute Exam content. Has anyone had experience taking both tests? If so what would you recomend focusing on going into the Passive House Institute Exam? Are there any comprehensive resources like a textbook or study guide that you would recomend that cover all of the relevant information in more detail. (other than the "learning targets" document available from the Passive House Institute website.) I appreciate any advise or insight you want to provide. Thanks!