Building Science Corporation

Anything by Joseph Lstiburek[0] will give you a good insight into best practices from an engineering and research perspective. He has a lot of stuff on his website[1] but it's it's not very discoverable. Look under the guidance tab but be prepared to hunt around. If you're interested in the legal requirements for construction--which, unfortunately, are not necessarily the same as currently understood best practices--buy the relevant building code documentation for your jurisdiction. [0] https://en.wikipedia.org/wiki/Joseph_Lstiburek https://www.youtube.com/watch?v=rem5WhFiiwU [1] https://www.buildingscience.com/

> Where did you learn about modern building best-practices? Do searches on "building science": * https://en.wikipedia.org/wiki/Building_science A consulting company specifically started around the concept because the founder, Joe Lstiburek, got tired of seeing the same problems over and over: * https://www.buildingscience.com * https://en.wikipedia.org/wiki/Joseph_Lstiburek This contractor based in Austin, TX, has a lot of good content: * https://www.youtube.com/user/MattRisinger/videos

I would recommend checking out the guidance and tips pages from the Building Science Corporation [0] [0]https://www.buildingscience.com/

I work in residential construction. Beginner friendly, 'find out if you find this interesting' kind of books: "This Old House: Restoring, Rehabilitating, and Renovating an Older House" by Bob Vila. An older book, only the carpentry is relevant today, but a nice picture-driven exploration of sensitive home renovation. "A Place of My Own: the Architecture of Daydreams" by Michael Pollan I didn't get a lot out of this because it was a pretty simple project that was being described, but it's a good look at the challenges of design, and a good primer if you're looking to do your own small project. Plus, Michael Pollan is an enjoyable writer. "House" by Tracy Kidder Follows the construction of a home in MA with a lot of builder perspective. Explores the common issues associated with running a small carpentry company frame to finish. There is also "The Apple Corps Guide to the Well-Built House" by Jim Locke which is written by a member of the firm profiled in "House" - haven't read it yet. "Last Harvest: How a Cornfield Became New Daleville" by Witold Rybczynski Follows the evolution of a farm field into a subdivision. . A little more challenging: "The City in History" by Lewis Mumford Best described as a "Tome" - a staple in intro level planning classes. "building Construction Illustrated" by Francis Ching A good illustrated primer on basic residential construction assemblies, will help with visualization of written descriptions and vocabulary. "Big House, Little…

Interesting the difference between UK and USA here. Spray foam applied directly underneath the roof deck is very common here and is a recommended assembly by building scientists, e.g. https://buildingscience.com/documents/digests/bsd-149-unvented-roof-as… Not sure if there is a significant climate difference in the UK that makes this construction more problematic, the article mentions moisture but the U.S. building scientists say 2 inches closed cell spray foam will block air and vapors from reaching the wood of the roof. Perhaps the issue is the open cell foam mentioned in the article - it seems that closed cell foam is the recommended type in the USA.

Lots of good papers available here: https://www.buildingscience.com/ The Handyman has lots of practical info: https://www.youtube.com/channel/UCtXVIqkc3iBk0bV5gvcNWgw

For anyone interested, Building Sciences Corp is a great resource on different methods to build functional, airtight, well insulated walls. Here's a starting point: https://www.buildingscience.com/documents/insights/bsi-001-the-perfect…

> Not sure if there is a significant climate difference in the UK that makes this construction more problematic, the article mentions moisture but the U.S. building scientists say 2 inches closed cell spray foam will block air and vapors from reaching the wood of the roof. Perhaps the issue is the open cell foam mentioned in the article - it seems that closed cell foam is the recommended type in the USA. Implementation details matter. From the OP's article: > At the root of the problem are cowboy traders who apply the foam without a full survey or appropriate expertise – but because of lenders’ caution, this is affecting other homeowners who had similar work. One potential problem that could occur is ridge rot: > Lots of attics insulated with open cell low density spray foam (Photograph 1, Photograph 2 and Photograph 3) are having problems – in hot humid climates, mixed humid climates, and cold climates. The problems are moisture related. The attics are “unvented” – open cell low density spray foam is installed directly on the underside of roof sheathing. The attics are humid. Very humid. Unacceptably humid. And the humidity collects at the upper portion of the attics. * https://buildingscience.com/documents/building-science-insights-newsle… > When you spray ocSPF into wall cavities from the interior the ocSPF can act as the air control layer and thermal control layer. It can’t act as the vapor control layer – it…

> Wouldn't you need some sort of "heat shield" offset from the outer walls for your approach to work at night, if at all? Or if not, why are we still covering homes with big chunks of styrofoam, polyurethane and mineral wool? If a home is well-built, the wall assembly already includes a physical gap between the structural sheathing or exterior insulation (if present) and whatever cladding materials you're using.[0] That gap allows for airflow and drainage behind your cladding, so that the water that gets behind it--and it will--can drain out and everything can dry. That gap would help create something of a thermal break (the cladding isn't attached directly to the house but to furring strips with a very low surface area), but it would still heat up the air in the gap itself. In that case, reflective paints would probably still be beneficial. That said, I think their greatest benefit would probably be in roofing. Metal roofs, for example, also require an air gap[1] behind they can get extremely hot. 0. https://buildingscience.com/documents/enclosures-that-work/high-r-valu… 1. https://www.youtube.com/watch?v=yesjnBnPt0A

Here’s an extremely snarky take, from an author who is very much an expert in the field: https://buildingscience.com/documents/building-science-insights/bsi-15…

When looking at the diagrams for an ideal wall [1], I am reminded of diagrams of capacitors from Physics classes. This got me to thinking that two conductive vapor barrier with a dialectic/insulator sandwiched between them, such as aerogel, would work well as a wall element, and a capacitor storage device for a house. [1][https://buildingscience.com/documents/insights/bsi-001-the-perfect-wal…

Water in liquid form (e.g., rain) will (mostly!) go down with gravity, and so overhangs will help a lot, as will proper grade sloping away from your foundations. Water in vapour form will be more diffuse and be everywhere the air is. Further, your cladding / water control layer (which deals with rain (and UV)) generally needs to be open to air so that it can dry properly: * https://en.wikipedia.org/wiki/Rainscreen so that can lead to moist air getting places that water may not, and if you don't have insulation between the warm-moist outside and the cool-dry inside: * https://buildingscience.com/documents/insights/bsi-001-the-perfect-wal… problems can start.

I think both of you are correct, you can have a tight building, but you need to have a way to get the moisture away from both sides of the vapor barrier. There are definitely been cases in the past 30 years were buildings were built tight without correctly considering removing moisture. https://buildingscience.com/documents/insights/bsi-001-the-perfect-wal…

> How does that work exactly? Here's how I understand it: I would have to cover an entire building with some sort of a skeleton (layer) of wood, with an air gap in between. And it will cause the rain drops to slide down to the ground instead of the wall absorbing it. You have external cladding to protect against bulk water, UV; it is generally metal siding, brick, stucco. You then have a >5mm air gap between that cladding and the next layer of your building: * https://www.buildingscience.com/documents/insights/bsi-001-the-perfect… This is because moisture will either get through the cladding, or the cladding itself will absorb water (brick, stucco), and needs a way to dry. You don't need a lot of space behind the clapping, but you need something: * https://en.wikipedia.org/wiki/Rainscreen * https://www.dupont.com/products/tyvek-drainvent-rainscreen.html

Moisture is the #1 destroyer of buildings in its various forms. https://www.buildingscience.com/bookstore/books/moisture-control-resid… Moisture control and mitigation is a very important part of building to last, and building to minimize maintenance and energy usage (simplistic "insulate everything and seal all air leaks" can result in a doomed structure).

That's not true, if you have spacers behind the wood it should dry properly and last a long time. See https://www.buildingscience.com/documents/insights/bsi-001-the-perfect…

There's an entire field and organizations that study and develop contstruction technologies... https://www.buildingscience.com/documents/insights/bsi-001-the-perfect…

https://www.buildingscience.com/documents/insights/bsi-001-the-perfect… Green building design is normally ~90% conservation outlined in the link above and 10% green energy sourcing

But then we already knew that. https://www.buildingscience.com/documents/insights/bsi-007-prioritizin…

At least one building science expert (Joseph Lstiburek) reccomends a decentralized approach for HVAC, with tightly sealed individual units: https://www.buildingscience.com/documents/digests/bsd-110-hvac-in-mult… Although I do wonder how that works with something like district heating/cooling systems, which seem to rely on centralized boilers and chillers to move thermal energy between buildings.

> In modern houses the solution is to have an airtight layer of plastic sheeting between the insulation and drywall [...] In a building that will be air conditioned, putting plastic sheeting between the insulation and drywall is a bad idea. The problem is that any moisture in the (comparatively warmer) insulation cavity will condense on the (comparatively cooler) plastic sheeting, wetting out the insulation and causing mold and rot. They also prevent the wall from drying to the inside. It works fine in cold climates that are do not install air conditioning, as I assume is the case in Finland. In the majority of the US, even up to the Canadian border, many new houses have AC. https://www.buildingscience.com/documents/digests/bsd-106-understandin…

You also aren't going to put a fleet of little one-ton units on the roof Sure you are! Or, well, you could. I lived in Chicago condo that had 20 or so one-per external units on the roof. Some arguments in favor of this approach here: http://buildingscience.com/documents/digests/bsd-110-hvac-in-multifami…

Sure climate matters, however your assertion seems to be incorrect. > Almost all Passivhauses rely on: very heavy insulation, R-40 to R-60 walls, R-50 to R-90 roofs, and often R-30 to 50 sub-slab insulation, triple-glazed low-e windows, and exceptional avoidance of thermal bridges (except for wood framing) ... from [1] While Minnesota requires significantly less insulation: > Wood frame wall insulation: R-20 or 13+5 (CZ6), R-21 (CZ7) Foundation or crawl space insulation: R-15 insulation for concrete masonry foundations and R-10 applied to the exterior of the wall; R-10 continuous insulation is allowed on the exterior of the foundation wall if the air leakage rate is below 2.6 ACH50 Duct insulation: Depending on the location, R-3.3 to R-8 and vapor or weather retarder might be required from [2] To compare to a much more comparable climate. In Sweden the U-value (metric units) of a window must be better than 1 W/m^2K, Minnesota building standard requires a U-factor (imperial) of better than 0.32 Btu/h·ft2·F which corresponds to a U-value (metric units) of 1.82 W/m^2K. Note lower is better, so for a similar climate the European code requires almost twice as good windows. [1] https://buildingscience.com/documents/insights/bsi-025-the-passivhaus-… [2] https://www.tradesmance.com/career-central/minnesota-insulation-code

Structural Insulated Panels - SIPs (which I think is what you are talking about) have arguments in their favor as they actually benefit from many of the upsides of building things in factories vs on an individual/onsite basis. These do not seem like they'll realize any of those (since you are just prefabing a component comparable to a sheet or board as opposed to a whole wall). SIPS absolutely do have issues with leakage, the same as any construction method. Joints, penetrations, windows, etc. can all be sources, same as in traditional framing, the difference is again that plywood / osb / glued together wood scraps are atrocious at handling moisture. I do think they are interesting though, more reading for the curious below. https://buildingscience.com/documents/enclosures-that-work/high-r-valu… One of the benefits of SIPs for airtightness is that the layer that provides that is built in (or atleast can be) at the factory. This eliminates alot of the variables that hurt airtightness when you are building onsite (working in temps/humidity where seals don't get installed right, poor workmanship, etc.).

I'm not sure where you're located, but here in the US you can build the building you're describing (a square house with a gable roof, without eaves if you want the roof to terminate at the wall) pretty easily with regular dimensional lumber framing. Barndominiums generally imply steel framing and requires heavy equipment, at least to hoist the steel beams into place. They are less easy to build and maintain than a stick-framed home, in my opinion. A simple incarnation of a latter could be thrown up by two hobbyists, if it's small enough. Lstiburek's "perfect wall"[0] may be of interest to you. Simply put, layered from the inside to the outside, it's drywall, wood studs (with batt insulation), sheathing (plywood or OSB), plastic house-wrap over the sheathing to serve as an air and vapor barrier, some depth of external insulation on top of that in the form of boards, then finally the exterior cladding. [0]: https://buildingscience.com/documents/insights/bsi-001-the-perfect-wal…