A race against the cold

As far as winters go, we’ve been pretty lucky over these past several years with fewer snowstorms and milder temperatures overall. But it looks like this winter could be a colder one, and I need to get the insulation on my new home buttoned up before the snow arrives.

Luckily I’m working on the last piece of my insulation system, which would be the interior insulation. As you know, I’ve been using advanced wall construction techniques in the design of my new home. When the system is complete, I’ll have an envelope that allows for near-complete control of the indoor temperature, which means my wife and I will have a better seat at the table when it comes to facilitating indoor comfort.

For the interior insulation, I’m using a product called Roxul ComfortBatt. It’s a mineral wool product - that is, an inert material made from ground up stone. Roxul is a great product - it doesn’t absorb moisture or support combustion, and mold and mildew don’t grow on it. In addition, it’s also great for colder climates. I want moisture to be able to work its way out of my home, and Roxul will facilitate that. It’s also not itchy like fiberglass insulation.

Once the interior insulation is complete, all of the space inside of my new home, from the basement to the roof rafters, will be conditioned space. My mechanical systems and ductwork will be in conditioned space too, which will put less of a strain on the systems and allow me to optimize my indoor comfort.

I think we’ll definitely manage to beat the cold. What do you think about my insulation system? Join the conversation and let us know!

Showing 8 reactions

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  • Dave Sweet
    Thanks for the compliments, Jeff!
  • Dave Sweet
    Hi Michael,

    Thank you for commenting. Yes, mineral wool and fiberglass share some attributes, I chose mineral wool because I thought it was the superior choice for my application and was impressed by some of the qualities mineral wool has that fiberglass lacks. Certainly, mineral wool isn’t always the best choice – I guess it depends.
  • Dave Sweet
    Hi John, Thanks for your comment! Poplar Network has a good article about the sustainability of mineral wool insulation that I found interesting. This might be a good place to start!

  • Peter Meridew
    Make sure to leave an air space [1 1/2" recommended] between your roof sheathing & the rafter insul. batts. This will allow your roof/attic to ventilate between the soffit vents & the ridge vents to remove moisture.
    Can’t see this from your photo
    PETER M – Nanaimo, BC
  • Jeffrey Stanley Stevens
    I live in Norway And of course we have our share of the cold. We are advised to use 25cm of insulation in the roof. The best solution is 20 cm. between the rafters then have horizontal 2 × 2 ( 5cm X 5cm) at the right spacing for your insulation (57 cm. here). That way you get a good place to anchor your ceiling , you will eliminate the cold bridge of your rafters and if you place your condensation sheild on the rafters you will also get it out of reach of puncturing nails and screws . Your work looks very good. Best wishes Jeff
  • Michael Bergen Jr, P.E.
    Dave, I believe that you are a little misinformed about fiberglass insulation. All of the “features” that you mentioned about mineral wool insulation do apply to fiberglass — moisture absorption, ability of microorganisms to sustain life, etc. Fiberglass passes and exceeds all of those same ASTM standards. Fiberglass is also classified as a “mineral wool”. The manufacturers make the distinction with rock wool versus fiberglass. Fiberglass can also be made from, depending on manufacturer and location, up to 50% or more post-consumer recycled glass. (Beer bottles reformed into energy savings!) I also noted in your video about the bulkiness of rock wool batts. Fiberglass has excellent packing density versus installed density. When you open a package of fiberglass it expands like those old “snakes in a can” gag gifts. So you can get much more installed in one trip and that savings also translates to lower trucking costs to ship the products to local distribution as well as the installers from the distribution or warehouse. As for PPE, the same recommedations are made for fiberglass as rock wool. Particulate respirator for nuisance dust, long sleeves, long pants, safety glasses — all the same.
  • John Gellatly
    I’d love to know the comparative sustainability and net embodied energy of mineral wool insulation versus fiberglass insulation. Seems that mineral wool is a bit of a premium, would like to know if there are compelling arguments to its use that normal customers will accept, and thus pay for the premium.
  • Dave Sweet