I’m working on detailing out a smallish house in Greenfield, MA. We probably won’t go full Passive House on this but we will look at what additional costs and detailing it would take. And if we’re close…

We are doing some novel (to me) stuff for the shell of the house that, I suspect, will become more standard practice for me in years to come.
Here are some “progress print” detail drawings from the plan set. My drawings tend to look a bit different than most architect’s drawings due to two things: The time I spent wielding a hammer and trying to interpret my own drawings and the fact that I have worked as a sole practitioner for so long and have developed my own graphic style. I should add to that a third thing – my knowledge of building science informed best practices.

building section and details illustrating air barrier location and definition

The first thing you will notice about these drawings is actually the most important thing. The red and blue dotted lines represent the weather resistant barrier and the air barrier respectively. If your drawings don’t have at least the air barrier called out in the sections, (and continuous around the thermal envelope) The drawings are incomplete. I have been getting picky in my detailing about how to make the air barrier both easy to achieve and durable. In my opinion, relying on painted sheetrock to serve as an air barrier just doesn’t cut it – certainly not for the next 100 years.

Many builders and architects in the Northeast US are still building 2×6 walls with fiberglass batts and a poly vapor barrier. That’s how I learned to do it when I was just starting out in the 90’s. I also opened up a number of walls built that way that were full of mold.

    Good

builders don’t build this way anymore. Check the Building Science Corporation website for some pictures of what can go wrong.

One part of building science is probability and statistics. I often hear builders say “I’ve always built that way and I’ve never had any problems” – that you know about. But those builders are only looking at 50 or 100 projects. Luck plays a part here. What happens when you look at thousands or even tens of thousands? You start to see some patterns emerge and you start to see the luck factor drop out of the equation. You are able to formulate some best practice standards for a number of things including durability, air quality, energy use and even catastrophic failure. I prefer to work with builders who are informed about building science and involved in the discussion.

That’s easy here in the Southeastern Vermont area home of Building Green area, home of Building Green and SEON which sponsors a well-attended monthly building science discussion group and learning circle. – If anyone wants to get something like this started in their own community, send Guy an email at the address in their website.

I owe it to my clients to help them get the best constructed project possible. That, in addition to the most functional, aesthetically appropriate, finely crafted project possible.
– Oh and the budget thing too –
Detailing such as represented in these drawings is also very much about budget. The goal is to bump up the levels of insulation, air tightness, r value of windows etc. so that we can eliminate the traditional boiler and heat distribution system in favor of a minisplit heat pump which is more of an appliance than a system and dramatically less expensive. (I think this link is a GBA pro only link – subscription) For those without a subscription try this alternative Ideally, it becomes a wash cost wise but with the added bonus of very low monthly heating and cooling costs. Those savings alone can represent hundreds of dollars per month.

2 Comments

  • Rick says:

    I Robert,

    Love your work! Just curious- Did the 32″ OC for the TJIs not work? It seems like a great cost saver but I would worry about ‘bellying’ from the dense pack. Did you try it and then fill in the gaps with more TJIs?

    Thanks!

  • bob says:

    We were already at 16″ o.c. for the 2×4 studwall as per code so our choices for the TJI’s were 16″ or 32″ in order to screw through to a stud. The cellulose expert thought we would be okay with 32″ depending on our installer. So we played it safe. There would probably have been a bit too much bellying I suspect. We could have been okay with that with a thicker strapping than 3/4″ Next round I’m going to try 2×8’s spaced 3/4″ off the sheathing and insulating the 2×4 service cavity. that should be quicker easier and cheaper and still result in r40 or so. This is a good example of shooting for Passive House and when we realized it was just a bit too far out of the budget when the numbers came in, having some time to reconsider some basic detailing. I try to build those “pause” moments into my contracts and schedules

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Robert Swinburne in Brattleoboro, VT on Houzz
Robert Swinburne in Brattleoboro, VT on Houzz

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Robert Swinburne Architect, LLC AIA, NCARB, CPHD, DAD bob@swinburnearchitect.com 802.451.9764
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