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My New Shop: A Radiant Slab    

When I started designing my new shop I thought of all the shops I’ve hated working in and what I wanted to avoid: poor electrical outlets, terrible lighting, inefficient heating (always having cold feet), inefficient cooling (bugs everywhere in the summer because all the doors had to be open)… More than anything, I wanted a comfortable environment, no matter the season or time of year, someplace I could work enjoyably into my 70s and—if I’m lucky—beyond. That’s why I chose to install a radiant floor.

I’ll never recover the investment I made in the radiant slab, at least not economically. As one friend suggested, I could have installed a propane heater, turned the thermostat to 70, and never spent nearly as much on propane as I did on that radiant slab!

But having spent three years working in my new shop, I think every dime I spent was well worth it. I never get overheated because the primary heat radiates up from the floor, heating my feet first, rather than from the ceiling and heating my head first!

It doesn’t cost a fortune to heat the slab—I set the thermostat to 60 degrees and my electrical bill goes up about $65.00/month from December through March. I generate mountains of wood and sawdust waste in my shop—especially milling logs and turning bowls, which is one reason I installed a woodstove—to burn up the waste and the mistakes. But I use the woodstove to bump the temperature up, which takes only a few minutes. Trust me, it’s a heavenly place.

Comments/Discussion

15 Responses to “My New Shop: A Radiant Slab    ”

  1. Bob Barnett

    Radiant heat is a great way of going in certain areas of the county. It is efficient and safe in a dusty environment. What did you do about the bugs and having the doors and windows open in the summer? My previous shop (part of my garage) wasn’t heated or cooled so my working time was limited and uncomfortable. But the main problem was rust from the moisture. I built a new detached shop, it is fully air conditioned with lots of dust collection and NO rusting tools. I can only imagine and dream about a utility bill that low.

    Reply
    • Gary Katz

      Bob,
      I have screens on all the windows. I made a 4′ wide screen door for the front of the shop. And I installed Phantom screens on the pair of French doors out the back of the shop, so I can ventilate the whole shop pretty quickly and not worry about bugs getting in, which is very nice when you work out there in the evenings during the summer. There are mosquitoes along the river, though not so many up at the shop, but the screen keep all of them, and the other flying critters, out. Sometimes I think about building a set of four screen doors for the roll-up door, too. But you gotta learn when to draw the line!!!

      I use the radiant system for about 4-5 months, and set the thermostat to about 55 degrees, then fire up the wood stove to bring the shop up to 65, which is very comfortable to work in when your feet are warm. Boy I owe that to Rick Arnold. The humidity in the shop is usually very low, around 30 percent and lower, though in summer it goes up to about 50%, which is probably far lower than where you live. It doesn’t get humid on the west coast. Imagine that!
      Gary

      Reply
  2. David Pugh

    Gary: Congratulations on another wonderful article. Good for you to build such a great space. You deserve all the best because that is what you bring to us. Good luck on using it way beyond your seventies.

    Reply
    • Gary Katz

      Thanks David. I figure someone else (I imagine another woodworker/carpenter hopefully living here after me) will certainly appreciate all the effort I went to on the shop (and everything else!).
      Gary

      Reply
  3. Jay Rhind

    When I built my shop I had both radiant heat and a Modine heater installed.
    I’f I have a project that will take several days I crank up the radiant. If I will be in the shop briefly I just turn up the t-stat and have the forced hot air heat the shop.

    Reply
    • Gary Katz

      John,
      I installed a ducted air conditioning unit, though I’ve used it only once or twice, during video shoots in August/September when it’s over 100 degrees here. But otherwise, I never turn it on. I insulated the 2×4 walls with closed cell foam and used Zip R-panels with 1″ rigid foam for exterior sheathing. Rather than venting the attic, I sprayed open cell foam against the roof sheathing. The insulation works wonderfully. During the summers here, it always cools down below 70 degrees at night–I’m right on the Applegate River. There have been a few nights where it stays in the low 70’s, but even then, if I open the shop early in the morning–along with the roll-up door, and turn on all my fans, I can cool the place down, then I shut all the doors. Even when it gets up to 100 degrees, the shop stays extremely comfortable. Same with my house, though last year I did put a mini-split into the house.
      Gary

      Reply
  4. John L

    I really enjoyed the video, but was really interested in the dust collection idea about the ducts under the slab. I’m guessing it’s 4″ PVC, but was wondering if you can give more detail especially the layout.

    Reply
    • Gary Katz

      John,
      I used 6″ PVC for the under-slab dust collection. I was told afterward that I should have run 7″, but the system works extremely well (more on that in minute). I drew the whole shop in Sketchup, placed each of the tools I owned and tools that I planned to buy, then located dust collection and in-slab outlets (110 & 220) near each location. There are four main dust control ports: One exclusively for the table saw which remains open all the time; one for the joiner; one for the planer (each of those tools has a gate valve which is easy to operate with my foot). When I use my Woodmaster, I plug it into the unused port at the planer, where I installed a vertical Y. There’s also a dust control outlet at the bandsaw, again with an inverted Y, so that I can plug in my spindle sander, scroll saw and drill press if needed (never done that yet!). After the shop was built, I ran a duct high on the wall between the shop and the utility room. That duct runs straight to my lathe.

      I have a 2hp Oneida cyclone system with wireless remote controls at four locations in the shop. I removed the filter bag and the fine particles (and a lot of conditioned air) go directly out the exterior wall. Those particles are so small there is no sign of them outside, except when I forget to empty the cyclone can–then chips collect on the ground outside the shop. During the winter, when I have the wood stove running, I have to open a window or the dust collector will suck smoke out of the stove! But with the radiant floor and stove going, I never notice any discomfort from having a window open. I did run a 3 in. make up air line to the wood stove, but that apparently wasn’t big enough. When that dust collector comes on, it moves a LOT of air. When I’m using one of my floor tools, I can tell if I forgot to turn on the dust collector (you can barely hear it in the shop because it’s in the utility room with my compressor)–if ANY wood chips or sawdust appear at the jointer or planer, the dust collector isn’t on. Period.
      Gary

      Reply
  5. Norm Yeager

    Nice shop Gary,
    How did the contractor put the final finish on the slab ? The video shows a couple guys with hand floats along the edges. I’m thinking they were just fine tuning where a power trowel would eventually finish. If power trowel was it walk behind or riders ? On the bigger jobs I’ve done of 10,000 sq. ft or more rider trowels were the equipment of choice. The subs called it “burning the slab” because they seldom got on those slabs until you could walk across them and barely leave a mark. They’d finish the slab in both directions and when they were done the slab was like glass. All together different world than the countless basement floors I’ve finished by hand. On huge pours the concrete was placed and leveled with a laser screed. They could unload a truck every 3 minutes. Every time that screed reached out it could level one yard.

    Reply
  6. Emanuel Silva

    Gary & Scott,
    Nice job and great video. Your articles are always helpful for all of us in the trades.

    Thanks again
    Emanuel

    Reply
  7. Joe Dunn

    Gary:
    I have learned a phenomenal amount from your videos, shows, and your website. Thank you. I really, really hate to criticize other’s work but I have installed hydronic floors since 1988 (almost always in conjunction with ground source heat pumps) and want to very respectfully share 3 observations. First, in the industry’s infancy, Stadler, (now Viega) in an attempt to make hydronic more cost competitive with other systems, recommended a 12″ o.c. placement for tubing. Big mistake. Tubing material represents a minor cost of these projects. The correct method is 6″ o.c. for the field and 3″ o.c. on walls with large door or window areas. Second, Stadler advocated 300′ circuits, which your contractor has intelligently reduced to 250′. Even that is too long. Optimal is 200′. The shorter runs mean a lower “Delta T” between leaving and returning water temps and is far more efficient, because the shorter run means higher retuning water temp which meas lower “Delta T” at the heat source and therefore more system efficiency. Third, Manifolds are too few and too close together. Look at the spot where they leave and return to manifolds. The tubes are almost touching each other. Again tubing and manifold costs are relatively minor % of total project expenses.

    Reply
  8. Joe Selgrade 6w8

    Hi Gary,

    Very professional work from all involved trades.

    Williamson has grown by another dorm with the work being done by a contractor who builds custom homes in PA.

    I guess you heard we are now Williamson Free College of the Trades!

    We had 3 shop instructors leave the school for various reasons:

    Carpentry (deceased), Masonry ( Ex Marine super Mason because the Carp. teacher was his buddy and this past week, Machine Shop instructor (deceased after 30 years)

    Keep moving!

    Joe

    Reply
    • Gary Katz

      Joe,
      I deeply feel the loss that Williamson has suffered. I was lucky to have met Ken. He took me up in his Piper Cub once and–in a moment of pure foolishness–he handed the stick to me (but he wasn’t stupid, he kept his hands and feet gently on the controls). I’m sorry that Dan has left, too, and that the machine shop instructor has passed away, too. A very tough year for a very good school. But the school will survive, and “Williamson College of the Trades” will continue to graduate student who are ready, willing, and able to work. These days, that is saying a lot.
      Gary

      Reply

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