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Shop floor

7K views 29 replies 15 participants last post by  John long 
#1 ·
WARNING! WARNING! Horrible puns ahead!

After a couple of years of having my 40X60 shop with only a dirt floor - I finally did it. Smooth. level. compacted sand, vapour (vapor to our US cousins!) barrier, 5 inch Hi density styrofoam, mesh plus rebar, and then lay in the PEX tubing for hydronic floor heat.

Then last Saturday, 5 and a half inches of 34 MPA concrete, with fibreglass strands mixed in, laid in, and machine finished and polished.

I was just "floored" by the amount of "concrete progress" and "mortarfied" that I hadn't done it sooner!

(I warned you!) :D :D :D :thumbup:
 
#4 ·
Pix of shop floor

Now- just as soon as I can get my pix downsized from the current size to something that will attach, I'll even post 'em!

I had tried - a couple of shots of the floor with the pipes & styro showing (pre-adding re-bar) and a couple of the concrete pumpers etc, and a couple of the finished product

And every single one then said "file too large"
 
#9 ·
I Can't Believe !

Dave, I can't believe you're finishing up MY dream shop. How dare you! With floor heat! Who do you think you are? You ain't right! That was MY idea! Can't believe you're doing this to me! Getting yours finished while mine is still a dream just ain't fair! You stole my plans! Now I guess you're gonna fill it with cool hotrods and stuff! The nerve of some people! YADA,YADA,YADA :thumbup: olnolan
 
#11 ·
heating the floor

Well so far what I am using is - well - nothing.

HOWEVER long range (like maybe next year?) plans call for a small, hi-efficiency natural-gas fired boiler, with pumps, an expansion tank, valves, manifolds to distribute the hot water among the various loops, and manifolds to collect the cooler return water for it go back into the boiler. Valves to regulate how much hot water goes through each loop, etc. An Air/water separator is crucial.

The system is full of a 50/50 mix of Prestone automotive anti-freeze and water, and pressure-tested to 175 lb BEFORE I poured the concrete - leaks are never a good plan INSIDE the slab!
 
#13 ·
Verrrrry nice! Now if you lived in Ca. you could use solar to heat that water...but then you wouldn't need the heat...never mind, it's early and I just ain't the brightest shop light in that shop this early.....I'll be up next January to help with the latest project. :D
 
#14 ·
Looks Great!

Does the floor have expansion joints or whatever you call them between the different segments? Or does having floor heat do away w/that?

And how did you (or did you even need to) 'grade' the slab for drainage, or is there a central drain, or? I know I will need to because it's outside.

Reason I ask, is I'd like to someday redo the shop's surrounding slab, and am obviously clueless.

Thanks.
 
#15 ·
you did it right.

I wish I had done the pex for radiant heat for my 40 X 60 shop on the working end. I have big woodstove and I was using the backhoe bucket or 2 load of firewood each day. And it would just thaw you out a little bit. I was spending the winters working in sunny Calif and forgot what 40 below was like up here. I don't know if it is efficient enough but some people have used solar heat on the cloudy Oregon coast to heat water to 70 degrees then a heat exchanger to bring the floor loop temp higher.
 
#16 ·
I have the system up and working in my 40X60 shop. I use propane since we do not have natural gas available. Next fall, I hope to add solar panels to heat the water and use the propane as a back up. When I installed the system, we designed for the addition. We will install a reservoir to collect/hold the heated water from the panels for night time. It gets a little involved to drain the panels back into the reservoir at night so the panels do not freeze and to send it back to the panels the next day when the panel temp gets above the reservoir temp. I had this system in Utah and the panels work most every day, even with cloud cover and -15F outside temp. This winter, the thermostat has been set at 55* and I have been working in my shirt sleeves and the feet never get cold!! So far, I have burned 240 gal of propane. Not bad for heating 2400 sq feet and the heat has been on since mid Oct. Of course the mountains of North Carolina are not Canada in the winter time.

By the way, you did elevate the PEC to be in the middle of the slab thickness didn't you?

Trees
 
#17 ·
Elevating the PEX

Yes we "lifted it" - the placing crew was VERY good - they had a "hook" that they used to lift the mesh-pex-rebar "sandwich" and poured concrete around it, let the mesh settle back onto the wet concrete, then let go and poured the rest of the concrete. The pex is approx 2" above the styro base everywhere now.

We put "Zip strips" into the concrete - they are thin plastic strips that function much like a cut through (but without cutting the Pex!) as "crackstops"

Because its indoors, we eventually decided not to use any expansion joints, but I DID leave a 1/2" gap around the edges. I did that by placing a half-inch thick border of styro 6 inches high above the styro "floor" to create a thermal "break" so that when I heat the floor, I am not heating the foundation as well. Ditto the need for a break between the shop floor and the approach slabs - I'm not trying to heat the whole world, and don't need the approach slabs in front of each door to be show and ice-free - I just want a warm floor!

Then when we (OK - my son did this part all himself) sprayed the "cure & seal" on the fresh floor, it dissolved the styro border. After the requisite 28 days, I will then go and caulk that "gap" so that little nuts, bolts, Carb jets etc, etc can't escape.

No drains and it's all dead flat level, set with laser levels, checked on a one-foot square grid as the placers and finishers worked.
 
#18 ·
Sounds like you and your crew knew what you were doing!!! You are going to have a lot of visitors during the winter when they learn how cozy you are when the system is up and running. I put a big French drain in the middle of my shop because I like to mop up the dirty floor on occasion and I want to wash vehicles inside during the winter. It also takes care of the wet, drippy vehicles that I bring in, especially in the winter.

Trees
 
#19 ·
Nice floor. How many loops did you use, and how long per? I had three at 160+ ft per and the return was quite cool. Since I was using a conventional water heater it was pretty hard on the system. A boiler would have handled it easily.

I will be building a 30x60 or close in a year and will be heating the floor. It is such a great way to go.

I will consider your thermal barrier too. I heated the whole pad, glued 2" foam around the perimeter, but I could tell I was wasting heat. It was nise that the garage door never froze to the pad, but that extra bit of concrete outside was probably costing me a lot in wasted heat.
 
#20 · (Edited)
shop floor

I have 3 zones - one used 7 loops, one used 3 and one used 4

All together there is about a half mile of PEX in there! (just over 2600 feet total!) The longest loop is 180 feet, the shortest is about 110. (hence the need for ball valves to "balance" things)

I posted a site in another section of HR.com about where to get info on laying it out.

Bottom line - you want 6 inches apart around the perimeter, and then a foot apart for the rest.

My son and I laid it all out and installed all the pex while trying to keep the lengths of all the loops as constant as possible

We also had to make allowances for my two 4-post hoists, so we had to mock up the hoists and mark the styro, then measure and make an accurate "map" for where the posts will be installed in a few weeks.

If U want the sites for how to lay it all out, I can dig 'em up & include them in here, or you can PM me
 
#22 ·
Dave57210 said:
We also had to make allowances for my two 4-post hoists, so we had to mock up the hoists and mark the styro, then measure and make an accurate "map" for where the posts will be installed in a few weeks.

If U want the sites for how to lay it all out, I can dig 'em up & include them in here, or you can PM me
You can see where the post bases will end up, you sure were meticulous in your layout.

If you have some links that would be appreciated. I'll bookmark tham for future use.

Cheers
 
#23 ·
Great job!

What is the r factor of the foam you used?

When you get ready to run the system, cut the glycol back to 30 %, you will still have adequate freeze protection and have a higher heat transfer efficiency.
Check out Munchkin boilers.
Taco makes a good circuit setter for the money.
Make sure your expansion tank is for glycol and not for potable water
 
#24 ·
shop floor layouts

The sites I relied on for info on laying out the PEX tubing were:

http://www.houseneeds.com/shop/HeatingProducts/heatu/heatinguniversity.asp

http://www.radiantcompany.com/manual/Manual-Edition8.pdf

http://www.pages.drexel.edu/~mvj22/AED1/A5/hydronic.htm

I can't recall the exact R-factor of the styro I put in the floor, but it was 5 inches of Hi-Density (closed cell) styro, which I purchased at a local supplier of hydronic heating components. I remember that I looked up what the code called for (which turned out to be an R-factor of "whatever", which translated to four inches for this climate zone) and went 25% better. (I have an annoying tendency to over-build everything I do) :D

Then a bunch more research into "which type and brand of PEX is best" for this use - so far as I can tell, they are ALL good, but some are even better, although price is not a guide. The most expensive brand is not well-regarded by local installers. One brand kept coming up as "best", and I was told that it is NOT the red or white stuff, but is orange, so I went with that one. Add in a couple of bags (1,000 in each bag) of zip ties so you can attach the PEX to the mesh and/or rebar and allow at least 3 full days of messing around to get the layout exact - after you pour the concrete there are no second chances! :nono:

Fill 'em with anti-freeze/water mix, and start installing the couplings on the ends. When you have all the "cold" ends plugged and sealed, hit the "wearm ends" with 175 psi air and wait 5 - 10 minutes for any possible leaks to appear. No leaks? Good! Release the pressure, cap the hot end of THAT loop, and move on to the next one. If you DO find a leak (I didn't) then replace that whole loop! You do NOT want to have joints inside your concrete slab! :nono: (At least, I don't!)
 
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