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March 19, 2013 25 Comments

Insulating rooms above garages: The Mike Holmes way VS the Urbandale way

mikeI recently received the following question from a reader:

” Hi there, after watching Holmes on Homes I was wondering when Urbandale will use spray foam insulation on the above garage floor instead of leaving the gap with heat duct.  There is a big concern that if any seal is not done right like around electrical or lights that carbon monoxide could accumulate in that space and send co2 in the air ducts to the furnace and then back through the whole house.  Seems like a risky practice and the spray foam is so much more effective and we would end up with higher garage ceiling by doing it this way.”

Mike Holmes is a big fan of spray foam.  And why not?  Spray foam is a very versatile building product that seals and insulates at the same time.  Because it expands, spray foam can be used to fill the smallest of cracks, or also large wall cavities.  It’s a great product, but it’s also very expensive.  Now, Holmes doesn’t have to worry about the price of spray foam because he’s sponsored by the spray foam manufacturer.  For those of us that have to pay for it, it’s best to be judicious in how and where it’s applied.

The rooms above garages require a lot of attention to the construction details.  There is a lot of area that is exposed to the cold, and you also have to make sure that it is completely sealed so that car exhaust can’t leak into the living areas.  Many builders will insulate the floor similar to an exterior wall, with only R28 – R32 batt insulation and a sheet of poly separating the room from the cold.  If you’ve ever walked barefoot in one of these rooms, you’ll realize that this just doesn’t cut it.  Using spray foam in the floor cavity is a superior choice.  A builder would typically install about 5 inches of spray foam, which provides R30 – R32 insulation and completely seals the floor from air leaks.  Urbandale’s approach is a little different.  We use R40 batt insulation with a sealed poly air barrier, but then we also run the heating ducts into the cavity above the insulation and below the floor.  This heated plenum ensures that rooms above the garage stay warm.  We also use spray foam, but we use it sparingly as needed in the areas that are difficult to seal, such as by any steel beams.   All of our houses are tested for air leaks, so there’s no chance of fumes making their way into the living areas.  Our approach allows for more insulation and warmer floors than Holmes’ approach, and it’s also less expensive to build!

Don’t get me wrong – I’m actually a big fan of Mike Holmes and I respect how he has increased consumer knowledge of construction and energy efficiency.  Holmes once wrote an article that called out Urbandale specifically as an example of a better builder for our commitment to the R-2000 program so I’m very grateful for that.  When I served as the Vice Chair of the R-2000 Renewal Steering Committee I pushed to get Natural Resources Canada to hire Holmes as the spokesperson for the R-2000 program.   The thing you have to remember though is that first and foremost Holmes is making a TV show.  Because of this, he tends to over promote his sponsors (hey – who wouldn’t?) and he doesn’t necessarily acknowledge the very real role that budgets play in choosing between construction options.

Posted by Matthew

25 Responses to "Insulating rooms above garages: The Mike Holmes way VS the Urbandale way"

  1. Julie says:

    Thank you M. Sachs! I am the reader who add asked about this as we just purchased a single home from Urbandle in RSS and my husband and I love to watch Mike Holmes tv show… Maybe a bit too much lol!

    We appreciate the time that you took to inform us on the Urbandale way and we look forward to our new home.

  2. Sebastian says:

    Just looked at the MSDS for Walltite:

    I don’t know if I would feel OK with this much foam siting above my kids room with residual solvents off gassing over time… Section 15 is also a red flag.

  3. Matthew Sachs says:

    Hi Sebastian,
    That’s a good point to consider. I can’t really comment on it because I don’t know enough about any possible health effects of spray-foam off-gassing. I guess there’s a trade-off and you would have to consider the pros and cons of a tight seal versus potential off-gassing. The MSDS report you linked to is a little concerning to say the least!

  4. finance help says:

    Wow, incredible blog layout! How long have you been blogging for?

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  5. Matthew Sachs says:

    Thanks for the kind words. I’ve been blogging since June 2010. I try and update it about once a month but really it’s whenever something comes up that I feel is worth posting. I really appreciate your comments!

  6. Hello! This is kind of off topic but I need some advice from an established blog.
    Is it hard to set up your own blog? I’m not very techincal but I can figure things out pretty quick. I’m thinking
    about setting up my own but I’m not sure where to begin. Do you have any points or suggestions? Thanks

  7. Kurt says:

    Hello there! I could have sworn I’ve visited this site before but after looking at many of the posts I realized it’s new to me.
    Anyways, I’m certainly happy I came across it and I’ll be bookmarking it and checking back

  8. Matthew Sachs says:

    Thanks Kurt, that’s very kind of you to say. Now the pressure is on for me to write more posts!!

  9. Matthew Sachs says:

    Unfortunately I can’t give you much good advice because I actually hired a developer to set up my blog for me. I can tell you that wordpress and google.blogspot both offer free blogging services that are very easy to set up. If your blog is more geared towards pictures then you may want to look at tumblr as well. Wish I could be of more help! Best of luck.

  10. Thai says:

    Hi, I am just wondering, do you need to ventilate space between the garage and the room above. It has been spayed foam but still about 8 to 10 between the drywall and the foam.

  11. Matthew Sachs says:

    If you’ve used enough spray foam (ie at least 5 inches) then no, you don’t need to ventilate the space. Having a space for ventilation isn’t a bad thing, but it’s not necessary. Hope this helps!

  12. Robyn says:

    My son’s bedroom sits above our garage and it is sweltering in the summer and freezing in the winter. I had a window guy come in and take a look to see if we needed better windows and he said our windows were fine. He did suggest that we look into how much insulation there is between the garage ceiling and the bedroom floor. I cut a small hole in the garage ceiling and found one layer of the pink fiberglass insulation. It seemed to fill the space between the ceiling and floor and joists. However, when I pushed up on it, I could tell that there is room for a whole lot more insulation. Should I add additional insulation to the garage ceiling – perhaps another layer or two of the pink stuff or blow in some insulation? Do you think it is worth it? I was thinking of cutting a piece of the dry wall at one end and just shoving more insulation in. I don’t want to spend thousands of dollars and think I could do it myself. What do you suggest?

  13. Matthew Sachs says:

    Hi Robyn,
    I wouldn’t rush to fill the cavity completely with insulation until you’ve looked at all the other possibilities first. We generally like to leave a small air gap between the floor and the insulation to allow for air movement, so it is quite likely built that way intentionally. The first thing I would do would be to get an HVAC technician to come in and check that your ductwork is properly balanced. It’s possible that you simply aren’t getting enough air through the ducts. Hopefully this is the cause, because that is the easiest thing to fix. The most likely cause however, is a leak in your air and vapour barrier that is allowing cool air in the winter (and warm air in the summer) to fill the cavity below the floor. If this is the case, it may be a little tougher to pinpoint the exact location of the leak. If you could get your hands on an infrared camera you could look for a cold or hot spot which could indicate the source of the leak, or you could try a smoke test. To do this you would have to pressurize the house with a blower door and use a smoke pencil to try and find the leak. I recognize that both of those solutions are a bit more involved which is why I would recommend checking the ductwork balancing first.

    I hope this helps. If you do pinpoint the cause and find a good solution I’d love to hear about it.


  14. Robyn says:

    Thanks for your reply. I am glad there is something else I can do before ripping my ceiling apart and trying to add more insulation and seal the joists, etc. I will check with an HVAC person first. Thanks again!

  15. Kevin says:

    Hey Robyn, I basically have same situation as you.. I love to hear how you tackled this solution.

  16. Guylaine Jean-Gagnon says:

    Great post! I stumbled upon it looking for a proper way to insulate the floor and walls of my heated garage (heated just above freezing point). This is a new construction, still in the design phase. The garage will be attached to the house, with two exterior walls and two walls adjacent to the house, and a room above. I am thinking of using blown cellulose for insulation, as it seems like an affordable and efficient solution. Heating will be radiant hot wated on first floor (slab on grade), with fan convectors for the second floor. Does that mean I can fill the whole joist cavity over the garage with insulation? I also have a question about the the vapour barrier: Do I put it on the exterior walls of the garage (warm side), or only on the walls between the garage and the house (warm side)? Surely it won’t be both?
    Thanks for this wonderful Canadian content blog!

  17. Matthew Sachs says:

    Thanks for the kind comments. I’m really glad to hear the post has been helpful.

    Assuming there is no duct work in the cavity, I think it is a good idea to fill the whole cavity with blown cellulose insulation. For the vapour barrier, your garage is only being heated slightly, and you don’t have any sources of moisture inside the garage (eg no showers, sinks, etc), so I would not treat this as interior space. The vapour barrier should go on the warm side of the walls adjacent to the house only.

    Best of luck with your build! I’m sure it will be a very exciting process for you.


  18. Maurice Huet says:

    I have been building my homes since I was 23 years old and have built always with the intention to improve house design with the right fix not the most expensive, and spray foam is a terrific product and has its place but no product has solved the insulation envelope completely yet. I prefer to treat the house as a system and in the past 2 houses, I have treated the house envelope as a shell and as a liner….somewhat like a ski coat…..the exterior protects you from the elements and the interior keeps the heat from escaping, as air travels from hot to cold……I have built many energy efficient homes and realize that the best home design also has to be cost effective. I am from Calgary and have been an innovator my entire life…..60 years, and believe that we need to find the right solutions and people tend to follow what they read, or are told without question, builders and government and I like to ask the question why are we doing it this way…..nice to hear that you guys put though into the equation.

  19. Roger says:

    I have cold floors in room above double garage. Joists were spray foamed (1/2lb), but there were 16 IC large recessed lights that must have been installed post house build. Lot of insulation was removed around and above each light and wires by installer. This garage does not have dropped ceilings and ceiling height is 10′.

    I removed all the insulation and bared the joist cavities (12″ deep), replaced with much smaller recessed lights and am planning on using OC R40 batt insulation and finish with 5/8″ drywall.
    Is this considered sealed? or can I use poly at underside (garage side), since no washrooms etc above.
    Is this best approach? in terms of warmth
    or should I use 1/2lb foam that will also seal + insulate?
    If foam is suggested, what is temp range when foam is applied.


  20. Matthew Sachs says:

    Hi Roger,
    Either approach should work well, though the spray foam will certainly be more expensive. If you go with the R40 batts then definitely use poly as well and seal the poly. This is to minimize the chance of exhaust fumes getting in the house.

    I can’t comment on the best temp to apply the spray foam. You would have to check the manufacturer’s specs.

    Hope this helps and good luck with the renos!


  21. Sophie says:

    Excellent blog post! 2 questions:

    1-would the recommendation to insulate withR40 change based on whether the garage is heated or not?

    2- can you recommend some products or information on how to get a proper seal?

    I have a 1950s bungalow with a garage in the basement, unheated and the exterior walls are not insulated. We put new fiberglass insulation in, which drastically improved the situation, but it’s still a bit cold. We put a vapor barrier, but did not pay attention to the seal.

    Thanks for the advice

  22. Matthew Sachs says:

    Hi Sophie,
    Even if the garage is heated, I would probably still consider it “exterior” space, and therefore I would still recommend to insulate and seal it. The reason is that garage doors only have an insulation value of around R-10 or so (which is not a lot), and when you open them you’re letting in a lot of cold air. More importantly, you want to make sure that this area is properly sealed so that the car exhaust doesn’t get into the living areas.

    You can find some very descriptive “how-to’s” on air sealing your garage online, for example:

    If you’re using spray foam, then it’s pretty easy to just spray the whole cavity and that will provide your seal. It sounds like you’ve already made the decision to use a vapor barrier, which is fine, but it requires a little more attention. Use a silicone caulk or adhesive around the perimeter of the poly to seal it to the framing. Also be sure to examine for any protrusions such as electrical or piping, and use an expandable foam sealer around these areas. The seal ensures that toxic fumes don’t get into the living areas, and also prevents cold drafts which have a way of getting into even the smallest cracks.

    Hope this helps,

  23. Richard Parker says:

    I do a similar insulated cavity approach, however I also clad the (garage ceiling) perimeter with 1/12 inch SM board, seams taped and edges caulked. I have a heating duct installed into the cavity to heat this space as well as the ducts required for the occupied rooms. I have used this method since 1976 and always have happy customers. Yes I have retrofited other homes where the cavity duct can be installed. If foam insulation is used I have found the need boost the air flow into the occupied space…..a job best left for a heating professional.

  24. Richard Parker says:

    Forgot……taped gyproc must be installed over the SM board…..sorry about that….. the code guys are breaking down my front door :)

  25. Matthew Sachs says:

    Thanks for the comments Richard. That sounds like an excellent approach.


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Matthew Sachs


  • COO of Peak Power since July 2016
  • General Manager of Urbandale Construction (May 2008 – Oct 2014)
  • Vice-Chair R-2000 Renewal Committee
  • Member of Energy Star Technical Advisory Committee
  • Greater Ottawa Homebuilders Green Committee
  • Recipient of Canadian Homebuilder’s Association 2009 R-2000 Builder of the Year Award
  • Participant in Natural Resources Canada’s Technology Roadmap for Sustainable Housing
  • Energy Consultant with Marbek Resource Consultants (Feb 2002 – May 2006)


Peak Power is a Microgrid project development company focused on delivering innovative solutions to offset the most expensive hours of electric demand. We specialize in optimizing the revenue streams from energy storage, advanced building automation, and renewable technologies for customer sited and utility scale projects. Please visit