44x40 Shop Build

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    44x40 Shop Build

    I started This thread three years ago.. and I shelved the idea for a bit, added a 34x10' lean-to on the current shop, and tried to make do but ultimately I finally pulled the trigger this spring when COVID arrived and so did sub-3% interest rates.

    A 34x28 is bigger than a lot of people have, and I've been spoiled in filling it full of crap to the point where I have to clean a bunch and re-arrange to get a second rig inside to work on, and then mostly limit myself to one end or the other at a time - you all know the drill (and the 10 year racer project occupying the official work bay doesn't help)

    I have a 14 year old in the family who will want to drive next year, and given her track record on waking up for school, she'll be driving with a frozen windshield.

    Plus my wife complains about parking outside, too..

    So I'm fixing that.

    I wanted 60x40 like everyone else, but pulled back. I wanted an attic truss, for "free" space, but found out that was as expensive as a second building.

    I downsized to 40x40, thinking that would be a reasonable compromise between "heating way too much space" while still having room for a lift-bay and a non-lift bay without getting frustrated.

    I picked 16' for the walls, but it took a while to settle on that - I had a few factors for it. One, you can put in a 14x14 door and bring in a motorhome, and while I don't have one like that, maybe that'll change - or I'll buy a semi.

    The other was thinking of expansion and what I could do as far as a lean-to or addition. With 16' walls, if I switch from the 5/12 pitch of the main roof to a 4:12, I can get 24' out and still be at 8' of height - or stick with the 5:12 pitch, only go out 12', and still be at 11' walls for a one-car bay with a 9' door.

    I started down the path of a pole-building, and while that's what I'm going to do, I probably should have asked more about sitck built.

    One of the oddities of the pole-building is the outfit I selected does 4' spacing on the trusses.

    One of the things I wanted to add on this building was more solar (I have 6kw on the current shop, last summer's project) - you need to have 3' on either end and the peak for firemen to walk around, so that limits you, and then the truss spacing, so after running some numbers I stretched the shop to 44x40.

    One extra truss lets me add another row of panels.

    With 44x40 and a 5:12 pitch and 2' overhangs, I can get 6 rows of 5-wide on each side, for 60 panels.

    The building runs north south, like my house and my current shop, which means the panels are not facing south, but it also means I can undersize the inverter a little because the east array makes more power in the morning and the west array in the evening - with a big fat broad spot on the curve from 8-10 to 4-6 but never reaching theoretical max.

    My current shop has 12 245w panels on the east, and another 12 on the west. Just under 6kw. I have seen peak production of just a bit over 5kw, and that's only on the peak days.

    I went with a single 14x14 door. A drive-through has appeal, but I live in Montana, and I'm on the plains - the wind blows. Predominantly from the west. We spend a lot of our time in front of the current shop using it as a wind break.

    So I put a single 14x14 door on the east side, to one side. A man door is next to it.
    The west wall has zero openings. The south wall will have a single window (facing away from the road and into my field).
    The north wall has a man door as well - that was originally going to open into the old shop, but circumstances dictated a change for the better.

    So, back in March and April I had to deal with some of the, uh, treasures hidden against the old shop.

    I moved them about and lined them up next to my property line, begging someone to turn me in..

    But along the way, I heard my neighbor beating on his truck one night and wandered over to see what was up and ultimately found out he does concrete and his brother does excavating. Score.

    Relatively recent draft of a proposed layout.

    I did mark out the space on the ground with some tires to mark the corners and the doors and drove some rigs in and out a bit to "see" if I could live with it.

    I had too many people ask if I was putting in a second story, so I've rethought that some and I think I'll add a second floor on the "top" of the diagram (which is the south wall).

    I'm leaning towards the full 40' across. I'm also thinking 8' is the right depth - 4' would be easy, but just a storage area. 6' could be either, but at 8', it might be useful for more than just storing crap.


    The diagonal bay into the SW corner is intended to be the "work bay" - and having a post right there could suck if I hook the loft around the corner.

    Otherwise, when you have toolboxes and/or workbenches along the wall, an 8' ceiling for that edge isn't a big deal, and even coming out 8' - there's still plenty of room to open the hood.

    North (bottom) wall is adjacent to the old shop. The man door will be about 24 or 25' from the SW corner - I need that wall space for steel storage. I get the stuff delivered and they drop it in the driveway - so open the door, drag it inside, and rack it.

    The bandsaw sits on the other side of the man door, so after you take down a stick of tubing, you can just walk it down the wall to cut it. The grinder and drill make sense in the same "dirty corner" as well - though I think I need to move the parts washer and/or blaster - to keep the washer from the sparks at least.

    With stairs to go up, that might make a nice place to hide the mill/lathe under. I could even see a curtain.

    Not shown - back in along those stairs, and I plan to hang my hardtop from the ceiling.

    I'm not sure I'll be able to get two vehicles end to end in the "lift bay" but it's a nice thought.


      A few more details before we get to the dirt work.

      I wanted a bathroom, but didn't hear back from the State on whether I could or not - conflicting opinions on whether it would be an additional bathroom, and I'd need a bigger tank AND a bigger drainfield.

      Plus there was some concern if I had enough drop or not.

      So.. fine.

      I did get water run to the shop - 200' of hose to fill the camper or wash a rig had me towing the camper to the well head, and dragging extension cords over to use the pressure washer. No more.

      We ran a 1" water line to the NW corner of the building, 6-7' below grade.

      We also trenched from the house to the shop, and I put in a 1" gas line (just in case), along with 2" conduit for 200A service, 1" conduit for the ethernet, and an extra 2" just for fun (perhaps some coax for more ham antennas..).

      Side bar - I wound up upgrading the house service to 400/320A from the previous 200A. Partly because I wanted to backfeed more solar, but then also since I'm producing power, I want to try heating the shop with (free, I hope) electricity.

      In any case.. they got serious about the dirt work in August.

      Dug out an 18" mono

      Then eventually framed it up

      shot gravel, and compacted

      You may notice it doesn't share a wall with the old shop.

      The builder informed me it would cost more if I built right against the old shop (or even a few feet away), because they couldn't use their lift to do the high walls - they wanted 8' of clear space around the building.

      I wanted it against the old shop, so I would have room enough to still drive around my drainfield. But 8' would cost me that, so if I had to space it 8', I opted for 12 or 14'. I actually decided on 14', but after we found out the septic line didn't run parallel to the old shop (sorta parallel, but not) things changed again.

      The new shop isn't square to the old - we turned it slightly, and the gap between buildings is more like 12' or 13' on the "front" end and 14-15' on the back (west).

      I've been calling it my bonus room - next year's project will be to box it in, and I'll have a long 1-car garage sandwiched between the two - among other things, so I only have to brave the -20F wind tunnel once to go from the house into the old shop, then stay indoors.

      Everyone talks about how nice radiant floor heat is.

      We'll see.

      I goofed on my measurements - well, I was right, but I failed to account for the mono. In the end, I had 8-10 pieces left over, as I had planned (for damage) but also an extra FOURTY because of the mono-slab. D'oh.

      These are R-10 panels.

      Panels went down one night, and I got 3 or 4 of the 7 tubing runs in that night, and finished the next.

      Then I hauled a TON of rebar and the guys got to work. 2x2 grid of #4 rebar, 60kpsi plus the mono. We also used rebar in the bonus-room slab later, and my wife wanted a new patio and a few other bits and I have 28 pieces left over that I think the other neighbor will need when he pours a floor in the 30x40 shop you see across the road.

      A few things on this last picture.

      Not enough bracing. Not enough stakes. Had some challenges with the pour.

      We eventually put 2" foam around the perimeter, down 24". I had lobbied for making the forms +2" per side and putting the foam in, but my neighbor had a different idea (he's since re-thought that). Putting the foam in would have helped distribute the load across the forms better, and we wouldn't have had to dig out the "footings" afterwards to place it.

      I forgot - why the mono slab? Among other things, the single door screwed me on doing the pour afterwards - we would have needed a pumper truck, so I was convinced to pour the mono-slab first, rather than set poles and pour it later. Why would we need the pumper? The radiant heat makes it hard to wheel-barrow the mud, or back the concrete truck inside like you otherwise would.

      One thing that I didn't anticipate, and everyone else might watch out for - the price for my building, originally with 16' walls (with 20'+ posts I presume) with posts set in holes drilled in the ground with concrete went UP in price when they switched to "just" 16' posts and added the floor mount brackets.

      No discount for shorter posts, no discount for no hole drilling, just an added cost for the brackets.

      7 runs of 1/2" oxygen barrier pex. I bought 3000' of the stuff. I needed 1760 for the main shop, and while I was at it, we put heat in the bonus room floor, so another 400' was needed there - so 2150' would have done it, but that assumes zero waste and perfect length runs - so 3000' it was.

      I'm thinking of putting the rest in the approach and toy with ice-melt later.

      The 2 2" conduits (4 total) are for the main shop floor - two are the out, two the returns. I wanted something to bunch them up and hold them in place for the pour.

      The four 1" conduit elbows are for the heat in the "bonus room" - I thought 1/2" pex would go into the 3/4" conduit, and it did, but not the elbow.

      I have two manifolds - one is a 7(x2) and one is a 2x2. They'll both be in the shop. The bonus room won't be heated this year (it won't even be a room).

      On the end by the door, I put another group of 2" conduit for the ice melt expansion.

      The 14x14 door will have a 5' wall section to the right of it, which is where these conduits are. A nice little spot for a heat exchanger.

      Also visible on the right side of that trench, is a run of 1" PEX to feed the (eventual) manifold for the nice melt. I figured I might as well run it in the slab that's already heated so I wouldn't have to worry about heat loss.

      There's also a run of 1" conduit in there. I ran it around three sides of the building - I will stuff my 1/2" pex water lines in there later to run water around the shop, but mostly in the floor - rather than (entirely) in the walls.

      I plan on water on the short wall by the door, and on the two southern corners.

      No drain the shop, so these will be mostly outdoor water fixures.

      I am thinking when we pour the approach, of putting a "wash basin" / trough below this corner with a drain pipe running south out into the field.

      I'm also thinking of an on-demand water heater for a hot spicket.

      I'll put an in-door water faucet too in at least one spot - I just need to be careful what I do with it. Fill a water jug. Pressure wash the floor before pushing the water out..



        They did wind up coming at it from three sides.

        The mini-ex had to come in to hold the wall - but underneath still bowed out and was later chipped away.

        And you can see some of the overall bow in the wall here.

        The builder wanted a lip in the edge of the pad for the skirt board to rest down/in, so we wound up cutting a new straight edge later and chipping out the overage.

        Things didn't go as smoothly as you'd hope - the wall tried to blow out, the other walls bowed, the new power screed they had bought for the job wasn't assembled right, the extra help didn't show up, the 48" power trowel should have been a 36..

        But all in all, it worked out.

        Couple of low spots..

        I kept water on it for a week or so.

        My youngest decided to dance in the "rain" and got soaked having fun.

        Then a week later, the "bonus room" was poured. I decided to only insulate the slab to the 28' mark where the original shop ended, not the extra 10' of lean-to I had added. The lean-to isn't insulated. This way, the bonus room will have two insulated (R-21 for the old shop, that or better on the new) walls already in place - just need to add the rear wall, a roof, and a garage door..

        Because the new shop is a little bigger and wound up sitting "in front" of the old one a little, we wound up with about 2' of concrete "in front" of the bonus room. I put 2" foam to cut the two sections of concrete, and ran a single loop of PEX in the little itty bitty approach.

        Then the forms were pulled from the main shop and the foam installed on the perimeter

        In a week, they're supposed to come put the building up on the 40x44 pad to the left.

        Then I have more fun to finish it..


          A few spec/notes.

          The insulation under the slab is R-10. The PEX really does just walk into the nubs.
          The nubs end up consuming 1" worth of concrete to fill in the voids. We put 5" of concrete on top of that on the main shop, 4" on the bonus room.

          I have a 23kw electric boiler. 95A current draw.
          I am thinking of buying a couple of suspended forced air electric heaters too - so I could keep the slab at 40 or 50deg, and use the forced air as needed to warm it up a bit more.

          I said I should have gone stick after going mono-slab - well, to finish the interior, I have to just about frame it out anyways. The one good thing is I can avoid thermal-bridging. The posts are 8' or 10' apart (end walls are 8', long walls are 10') and 4.5x5.5. I can frame out 2x4 walls and the 2x4 won't reach the outside, so less thermal bridging.

          I'm going with Corbond in the walls - vapor barrier and good insulation all in one. 3" minimum for R-21. I'm mulling over going to 4" - it looks like it could be a 9 year back back, while the extra inch to go from 4-5 is at least 12 years.

          R-50 in the ceiling. Ceiling will be steel liners, because of the 4' spacing you can't hang sheetrock.

          Walls will be 'rocked with 5/8 for the fire barrier over the foam.

          I may find some 3' sections of steel siding/roofing and do an interior wainscot.


            Sweet looking start, very jealous of the radiant heat.

            Did I miss what part of the world your in? Temps?

            Also, sounds like you need to take that neighbor a few cases of beer and have him trench a loop around the property to throw a few hundred feet or pipe in for geo-thermal. A simple pump would keep that pad heated that low. I realize thats over simplifying it but ... if you've gone that far
            America is all about speed, hot nasty bad ass speed.
            -Elenore Roosevelt


              Where did you get those R10 panels from?
              Im about to do a 4000sqft floor and those look pretty cool


                Originally posted by Austin View Post
                Sweet looking start, very jealous of the radiant heat.

                Did I miss what part of the world your in? Temps?

                Also, sounds like you need to take that neighbor a few cases of beer and have him trench a loop around the property to throw a few hundred feet or pipe in for geo-thermal. A simple pump would keep that pad heated that low. I realize thats over simplifying it but ... if you've gone that far
                I'm in Helena, MT - where it gets cold.

                Dang! I had been researching Air to Water heat pumps because the high cost of geo-thermal put me off with the need to drill - or trench, but now you have me rethinking that as a possibility in the future.

                I do have some land I could cut the trenches into for horizontal loops. Hmmm.

                Too bad the budget is shot for a while.

                Thank you for the good idea.


                  Originally posted by Baconator View Post
                  Where did you get those R10 panels from?
                  Im about to do a 4000sqft floor and those look pretty cool
                  Home Depot

                  Looks like the cost is $15 now for 8 sq ft. or $60 for 4x8 equivalent, while the 4x8 R-10 Foamular is $45.

                  I think the Amvic panels were a little cheaper when I ordered them.

                  Free shipping, which was nice. They're not heavy, but I had 7 pallets delivered. I hauled one stack of left over 20 panels into town for my mom to think about doing radiant in an out building - they had a tendency to try to fly out of the pickup above 35mph, even when bundled together.

                  I might've been better off with more insulation under the slab - perhaps a run of 2" blue board, then this stuff for R-20 under the slab.

                  The Amvic panels did make installing the tubing easy - just bend over and walk it in.

                  I previously installed insulation and PEX in my mom's 30x30 about 20 years ago. I think the insulation value was less, and it was a mostly flat board with some stiffening ridges. The tubing went in with staples into the foam. Harder to get the spacing right and to keep it neat.

                  There is a down side to putting the tubing so far into the slab - heat response won't be great, but if you're just going to maintain a constant temperature, probably not a big deal.

                  On the plus side, I have 5" of concrete above the tubing, so I can still set anchors without too much fear, as long as I don't go down past 5"