Foreword by Ian Thompson, Editor
Today, Matt Risinger gives us 3 building tips to help produce a well built house that ensures longevity, safety, and comfort.
His number 1 is of course water management, the cornerstone of durability, detailing the essential control layers behind your home’s exterior. Hardly anything destroys a house quicker than water, inside and out.
From proper sheathing/cladding materials to best practices for sealing windows, doors, and penetrations, Matt outlines how to prevent water intrusion to avoid costly issues like mould and rot.
Next, he tackles HVAC placement, explaining why all equipment and ductwork must remain within the conditioned envelope of the house. By avoiding mistakes like running ducts through unconditioned attics or placing furnaces in garages, you can maintain efficiency, improve air quality, and ensure a healthier living environment.
Finally, Matt highlights the importance of air sealing and blower door testing, advocating for tight construction to control airflow and moisture.
Matt offers achievable air-tightness goals for Southern and Northern USA builders, while debunking the myth that houses can be “too tight – as long as they have proper air movement management that is.
Please remember that Matt is based in the USA, so apply your own tweaks for your house location.
Over to Matt.
3 Building Tips – Non-Negotiables For A Well Built House
Video Transcript
How do you define a well-built home? You know, in my mind, a well-built home is going to stand the test of time. It’s literally going to be around for future generations to thank you for building such a great house. It should last for hundreds of years and, in the meantime, be durable, safe, comfortable, healthy—that’s a big one—and, of course, efficient, which kind of comes by doing all the other things right.
Today, I’m going to give you 3 building tips, my 3 non-negotiables for a well-built house. Let’s get going.
3 Building Tips: Number one, and absolutely most important: if you’re going to build a well-built house, you have to take water management seriously. Now, in this house here, I’ve got two-foot overhangs, and, of course, we’re going to put gutters on this house. But what’s behind—what you can’t see—what’s behind this brick and this beautiful wood siding here are what really matter, because that’s a control layer that we’re not going to mess with for a long time. So we’ve got to get our water management correct. On this particular house, we use Zip System sheathing.
I’ve also done a lot of houses with OSB and plywood as well, but I can tell you that a house that’s well-built would not be built with cardboard sheathing. This is a garbage product that should not be used on American houses. We’ve got to stop using it. Yes, it meets code, but does that mean it’s the right thing to do? No. The problem with it is—well, there’s multiple problems—but in terms of water management, it’s really hard to take water management seriously when you’ve got cardboard sheathing.
Now, when it comes to water management, there are some things we want to think about. We need to deal with all of our penetrations. First off, windows—that’s a big penetration. Why? We’ve got a lot of those. We’ve got to put those in the house. We want that light in the house; we want it to be a beautiful house. But how are we going to deal with that hole in our envelope that’s dealing with water? Glass and glazings are particularly tricky. We need to make sure we’ve got a sill pan—that’s a non-negotiable. We’ve got to use our best practice methods for installing that window. We’ve got to have a head flashing over that window.
And then anything else that penetrates the house—let’s say on this side of the house I’ve got hose bibs—we need to make sure that those hose bibs are taken seriously, that we seal around anything that’s coming through that outer envelope. So that when the water comes from the sky—or even worse, the water comes from the sprinklers and hits the house—we’re going to make sure that that is sealed up and we’re not going to get water in there.
Any house built to modern codes with insulation on the inside means that water that gets into the house is going to cause problems. It’s going to cause rot; it may cause mold; it’s going to cause some type of degradation, and it’s not going to dry properly like your grandma’s house did that had no insulation and plenty of airflow. We can’t build like that anymore. So we need to pay attention to our water management strategies.
If you’re not going to use Zip System sheathing, another great option is a full peel-and-stick. If you’re in the South, I really like that peel-and-stick called Aluma Flash. It’s actually UV 240. If you’re in the North, there’s vapor-open versions of full peel-and-sticks, or consider a full fluid-applied. But whatever you do, you’ve got to take water management seriously. This is the litmus test for a well-built house, and as builders we know that 80% of construction defect litigation is all water-related, so we’ve got to take this seriously.
3 Building Tips: Number two, all of your HVAC equipment must be within the air-conditioned envelope of the house. This furnace right here, mounted in a hallway—not in an outside wall—it’s an up flow unit, and all the ductwork above us is in a sealed, conditioned attic space. So there’s no ductwork going outside. We must maintain all of our ductwork—all of our furnaces—within the air-conditioned envelope.
3 Building Tips – Continue Reading
It’s really common in the South, because we do slab-on-grade, to see furnaces and sometimes just ductwork outside of the envelope, and that leads to big problems. How dumb is it to run this furnace, let’s say in air conditioning mode, with 60-degree air in the ductwork up into a hot attic that might be 130, 140 degrees, and also maybe really humid like it is often down here in the South? It’s a recipe for condensation; it’s a recipe for seeing black stuff grow somewhere in your HVAC system, and that will not lead to a healthy house. So set your home up for success by making sure all of the ductwork is within the air-conditioned envelope.
I’m also thinking about you builders that do crawl spaces. You know, the northern builders have it right by building a basement, oftentimes putting their HVAC equipment in the basement, and then blowing up through the house. If you’re building crawl spaces, consider building that just like a basement—a short basement. It needs to be a sealed, conditioned crawl space so all of your ductwork is within the envelope of the house.
Lastly, let’s end with garages. You know, in a lot of parts of the country, it’s really common to see a furnace in the garage with ductwork running from the garage into the house. That’s a really bad idea because all ductwork—all furnaces—are leaky, and we don’t want that air that’s in the garage being picked up and thrown into the house. Think about that homeowner that’s storing gasoline or the lawn mower or whatever nasty stuff in the garage. Would you want those fumes pumped into the house? No.
We’ve got to make sure that there’s no ductwork between the house and the garage, and we never want to mount a furnace in the garage space. If you want to heat and cool your garage, consider a mini-split. We’ve got a Carrier system up here in the ceiling—this is a recessed linear mini-split; it’s covered for construction—but when we finish up, we’ll commission that, and I’ve only got a Freon line running to the outside for that unit. It’s going to heat and cool this garage space totally independently from the house—no sharing of ductwork. That’s the way to go if you want to heat and cool your garage. Don’t share any ductwork; it’s really, really dumb.
And lastly, I want to leave you with this. When we mentioned earlier that ductwork, when it goes outside of the envelope, depressurizes the house. When that house gets depressurized, we’re naturally wanting air to make up that vacuum because we shoved some air out into our attic space, and that’s bringing air in through all the places that we don’t want.
When we build a tight house—which we’re talking about here—we want to bring in a separate ventilation system. Check out our other videos on that. But lastly on this point, make sure you bring all of your ductwork into the HVAC space.
3 Building Tips: Number three, we’ve got to do blower door tests on our houses, and we really need a tight house. We want to see a blower door score of two ACH50 or better, ideally one or better. Now, for those of you in the South like me, we have a code that says as of 2021 that we need to score a five ACH50 or less. Frankly, that’s really leaky, especially with a hot humid environment outside. When that air leaks into our houses, it’s often going to find a cold condensing surface and drop the water in that moisture-laden air, which means you’ve got dew forming and condensation forming in places you don’t want it.
So when people say these houses are built too tight, tell them no—that’s a misnomer; that’s not true. We need tight houses in order to gain control and have a healthy indoor environment. So that being said, Southern builders, I want to see at least a two. Northern builders, consider getting to one or less—that’s a really good goal. You’re going to be within the top 1 or 2% of the houses built in America this year if you build a house to those standards. That’s going to be at least 50 or 60% better than code if you’re in the South, and if you’re in the North you already have to build to a three ACH50, so getting down to a two is totally doable.
Check out our other videos; there’s lots of information out there on how to get a well air-sealed house. Guys, check out our videos on Build Science 101 and 201 if you want more on any of these topics. We’re giving a free education to you—as builders, as people that are going to build a house, as remodelers, as students—and it’s the 101 and 201 series on our website. You can actually earn a certificate of completion if you take our quizzes, and this is great free information. Follow these three non-negotiables, and you’re on your way to a well-built house.
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