Insulation

I’ve been reading a lot about different types of insulation. Off the top of my head I don’t remember any drastic cost or r-value differences so I won’t talk much about those. Oh, and speaking of r-value, I’ve read a lot of tiny house blogs from the states that don’t need to worry about having a high r-value. Well, I need to make sure my house is ready for winter in Canada, so r-value is important.

I have been referring to these helpful pages about r-value when considering my insulation:

Map of zones: http://s3.amazonaws.com/eakes-production/assets/13266/original.jpg?1260507533

Chart of r-values for each zone: http://s3.amazonaws.com/eakes-production/assets/13268/original.jpg?1260507533

Notice how at the bottom of the chart page it says “Check local building codes…”? I’ll have to do that. I want to be aware of the codes and build to code as much as possible, but it’ll be difficult to get a super high r-value without making my floor, walls, and roof very very thick. I have limited indoor space, so I don’t want to cut into that anymore than necessary.

I’m probably going to end up living in zone B or C, so I’ll need 24-40 r-value in the roof, 16-27 in the walls, and 26-40 in the floor. I doubt I’ll be able to get up to 40, but in such a small house the heating bill shouldn’t be too high anyway. Tiny Refuge (link in the sidebar) is in Quebec, and I believe Natalie added 2″ of insulation on the top of the roof and 1″ on the outside of the walls to get extra r-value, so I might consider doing something similar. The issue for me is that the floor and roof need to be thicker than the walls, but both of them cut into head space and I’m trying to avoid that.

Here are the insulation options I know of:

Fiberglass insulation (batts). The pink stuff. Pretty much everyone thinks this stuff is crap, but some of the bad rep it gets is from poor installation. That said, fiberglass still isn’t the best idea. I remember, as a little kid visiting my grandparents’ house, they had some exposed fiberglass insulation in their garage and we were told never to touch it. All those little pieces of glass get on you and cause irritation. The batts also compress over time which means the top of your wall won’t be insulated. If they get wet, they lose their r-value altogether. They require time and care to install, so people usually don’t install them well or correctly.

Rigid foam board insulation. They look like sheets of styrofoam, and some brands have silver foil on them that acts as a radiant barrier. There are different types but I won’t get into them. Basically, the higher quality kind has a higher r-value and doesn’t get damaged as easily, but it’s more expensive. Rigid foam is good for r-value, but it’s really hard and time-consuming to install. You have to cut each sheet for each wall cavity and you have to cut around any wires or electrical boxes. I don’t think they sell thicker than a 2″ board, so the builds I’ve seen have used two boards to fill the wall cavities, which means double the cutting. And then you have to fill all the cracks with spray foam and it’s difficult to not use too much or too little. Spray foam’s a mess too. Overall, not a fun option for the do-it-yourselfer.

Spray foam insulation. I think there are machines you can rent to do this yourself, but generally the spray-in stuff requires a certified installer, and your r-value depends on how well it’s installed. A big issue with this one is that it’s a bunch of very unhealthy chemicals. Some people don’t want to have a ton of chemicals in their walls, even if the insulation isn’t supposed to off-gas however many hours after the install. WALLTITE is an eco-friendly version of spray foam (and it’s purple!) that uses recycled plastic and is supposed to still have all the pros of spray foam. However, you will still probably need someone to install it for you, and that can be expensive. Spray foam also makes your house air-tight, so you’d have to install an air circulation system.

Wool insulation (loose, but I believe they’ve started making batts). The loose insulation takes time to install, but this is an eco-friendly option. There is the concern that it might compress and leave the top part of the wall empty like fiberglass does, especially with the vibrations of driving.

Denim insulation (batts). I was considering this one for a while. It’s eco-friendly and I could easily install it myself with no itching, but I’m wary of it being good enough to insulate my house year round. Maybe that’s an unfounded worry, but I don’t want to live in a house where I’m constantly worried if I made the right choice for my insulation.

Stone wool or mineral wool insulation (batts). This is my choice, specifically the brand Roxul. Roxul is made of recycled and natural materials, it’s off the charts resistant to fire compared to other types of insulation, and it can breathe a little without absorbing water because it’s water repellent. Mold and mildew can’t grow, little animals can’t live in it, it’s non-corrosive, and it’s free of a lot of bad chemicals. It fills wall cavities really well and doesn’t slump over time like fiberglass. It’s easy to cut and install. They manufacture batts that fit between 16″ OC studs as well as ones that fit 24″ OC studs. The r-value ranges from 14 (2 x 4 studs) to 32 (2 x 10 studs). Now, that means that my floor and roof should probably be thicker than 6″. I’m going to do some sketches and play with ceiling height a bit and see how things go, but Roxul is my #1 choice even if my roof and floor are thicker. It’s available at one of my local hardware stores (there are a surprising amount of hardware stores close to where I live). I won’t have to hire someone and I won’t have to deal with spray foam or loose wool. And I wanted something that was eco-friendly – Roxul earns LEED points.

I’m by no means an expert on any of these types of insulation. This is just a summary of my thoughts and what I’ve read. I hope it was helpful!

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  1. Trackback: Money Pains And A Little Excitement | Lovely Little Dream

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