Building a garage

[Junior437t]

I am finally making headway on a garage. I am building it 32'x48'. I have been trying to build it for about 3 years, (get most of my lumber sawed and someone would buy it). It started rough. I hired 2 young men to help me pour the footer. I told them to be here at 8:00 Wednesday morning, the concrete truck would be here. The truck showed up but not the help. 4 yards of concrete and only me and my wife. Luckily my mother and an uncle showed up and helped. A friend of mine is a pretty good block layer and he told me he would lay up my corners for a case of beer, (seemed cheap enough). Held the beer back until late in the day. He helped me a couple evenings and we got the block done. Ordered my trusses from Lowes, told the to call the day before delivery. I got home Friday evening and they had dumped them in the yard, a week early. Had to jack them up and put blocks under them and got them covered. Ordered my furnace. It is supposed to be delivered Tuesday or Wednesday next week. I looked at Taylor stoves and Classic and Aqua. I settled on one called "Free Heat Machine". Heard some bad about Aqua, the Taylor dealer never seemed to have time to talk to me when I went to his shop. The one I ordered seems to be about equal to the others, except better warranty. Now I have a couple questions. I am going to set it up for radiant heat in garage floor. What size stone should I use under cement, 4 inches thick? I have heard I should use larger stone (#3) and I have heard I should use smaller (#57). Next question, I think I want to build a cupola for ventilation. I saw an article years ago that talked about the proportions of building a cupola so that it would look right. Does anyone know what proportions should be used? I searched and the only thing I have found on the internet is 1" of cuplola for 1' of roof. I wonder about the height. I thought I could buy 4 shutters and frame it up. I know this is pretty long winded but starting to get "happy" about garage. Will try to post some pics later.

[Daren]

Been there, looking at a concrete truck, and up and down the road for my "buddies". Good idea with the beer payment, been there too (cutting in a patio door, did all the work myself and had cans to pick up when the beer/buddies were gone). I think I can help wth the stone question, it doesn't matter. You want to insulate between the base and the slab, as long as you get good compaction (I am not familiar with the size number you used). Get the cheapest rock you can get, compact well , and spend the money on insulation. The earth is a HUGE heat sink, isolate your space from it and just heat the garage.

[Junior437t]

The number 57 stone is about the size of my thumbnail and the number 3 is about the size of a small egg. I am plannig to put 1/2 styrofoam insulation under the entire slab. I have read comment that said only insulate in 8 feet from the wall and I have heard insulate under it all. I am planning to insulate under it all.

[bitternut]

I put 2" thick styrofoam under all the concrete in my barn floor. Barn is unheated and floor never sweats with sudden temperature changes. Floor is holding up great and would do it again.

[UNCLEBUCK]

I have never heard of using stone underneath a 4" poured slab but only sand and then vibrated for compaction before the pour . Wont little stones keep on settling and eventually crack your slab ? Maybe I have read this wrong . I insulated my whole floor with 1 " blueboard styrofoam and even then I had to tiptoe over it when pouring . Do you have rebar and expansion joints planned ? Might want to consider one expansion joint somewhere , actually 2 expansion joints , shouldnt make a pour longer than 30 foot max without a control joint or it going to crack and also tell the cement plant to put in air when they mix it to prevent the slab from cracking if the building ever gets below freezing if you go away on vacation . Good luck and I hope you enjoy your project ok !

[Furby]

3/8" pea gravel is becoming the common replacement for compacted sand. It's faster and eaier to use and you don't need to compact it.
It's use is just like sand to level off and fill low spots.
When using the foam under concrete, make sure you get the higher density foam, F250, it holds up better then the F150 foam.

Two things, I hope you are pouring the floor before putting up the walls?
How tall of walls are you planning?

[UNCLEBUCK]

I had to ask my old dad the retired concrete guy and he said pea rock was excellent , shows what I know but he did say atleast have one expansion joint on the 48 foot run at half way and would advise rebar at 2 foot both directions or mesh but then he said things might be different down south in warmer climates . Good luck Junior , Furby u da"man  ;D

[Furby]

Nope!
Learned that myself last summer.......from my concrete guy. ;D
Did some digging to double check the info because I always was told compacted sand.
The pea gravel really is MUCH easier to use.

[Don P]

We just had a radiant slab put in the house we're doing, pea gravel, radiant barrier (foil with 2 layers of bubbles), 6x6 welded wire mesh, the tubing is zip tied to the mesh, then fibermesh concrete. We're told its best to put in joints on 12'x12' sections (that gets pushed alot) these guys put in none and no sealer afterwards...and we have cracks  :

[Engineer]

I just did the same thing, Don: 3/4" dia. crushed stone (I hit it with a big plate compactor after I put it in), radiant barrier, 6x6 mesh, 1/2" tubing zip tied to the mesh, then fibermesh concrete.  I used these little tiny nylon fibers instead of the polypropylene, and it finished out smooth as glass.  The poly fibers are like porcupine quills, can't get a good finish on them for anything.   It got put in a basement that already had a deck on it, no sealer and 4 months later, not a crack in sight.  It stayed really wet for the first several weeks.

[Furby]

The big plus for using rock under a slab is if planned ahead, it can also be used for radon venting. While it doesn't matter as much in an out building, there is a bigger and bigger pust to install radon vents in homes.

[Quartlow]

I don't knownothing about radient heat or radon vents but around here we use 617 under concrete. its about the size of 57's and goes down to dust. In other words if it falls through a 57 screen it goes in that pile, realy chokes in tight. Run a vibratory plate or roller over it and it will get almost ike concrete itself

[Don P]

I know how we all hate pics, I got this one out from a few weeks ago. The concrete guys used a pumper, the man outside the window has wireless joystick control back to it. He has a horn button to let the concrete truck driver know when to spin and stop.
One thing to keep in mind if you use the radiant barrier...the thermometer in the hole was reading 150F that foil will warm you thru and thru  :D Have some shades handy too! On the upside you don't have to turn for an even tan  ;D.



The walls are precast, insulated, crane set, on a pea gravel trench...that was a new one for me. I've been told that crusher run can "bridge" and leave voids in the fill. I've never used 617, is it different, maybe more flowable? I know those guys can do more things with a simple rock than I can imagine.

We rolled the tubing out in the pasture a few days ahead of time to let it relax in the sun, that helps it uncoil and lay easier.

[Don_Papenburg]

I am doing my garage now .   Poly film over the earth , then 2" 25psi extruded poly insulboard, 6x6 ww mesh on each end then streach the 1/2"PEX tube out and ty rap to wire use the wire as a spaceing gauge .  I run mine at 6" space ,that way there is less thermal stripeing and I can run a lower water temp.     Then I put 6x6 ww mesh over the whole foor tyrap the tubes to that ,for straight even runs.           Then I used no.4 rebar on 24" center grid use the plastic chairs to hold the bar up .  (on sale at menards this week for .09  each ) . pour the 8" concrete, smooth and finaly I will have a garage floor after ten years of dirt.

I would use atleast 1 1/2" exp  25 psi     1/2" cracks to easily

Bend the pex slowly and carefully on the 6" returns.

[Junior437t]

I am planning to use 6x6 mesh for reinforcement. As it is right now, I am trying to locate some help to help me pour it, to try to get it done before the walls. The ceiling will be a little over 10 feet. 3 1/2 rows of block and then 8' material on top of that. I have called several concrete finishers and the earliest I have been able to get anyone to commit to is March 2006. Not many good finishers around here so they are really busy. I have never run a power trowel but I am thinking of trying, if I can get enough help to get it spread. I figure it will be poured in 4 sections, 16x24 each. Not so much to try to finish alone.

[Don_Papenburg]

!6 x 24 is a LOT to finnish alone .  Make sure you get help. With ten foot ceilings are you planing to bring in heavy equipment to work on ? If so I would use rebar on at least 2' grids.   Try to find a power screed also . I think more important than a power trowel.  run it over the pour a couple of times .

[isawlogs]

 Junior
I did my shop last year and did the power trowel for the first time on my floor . As soon as you can stand on it go for it ..  there are two sets of trowels that come with it . It aint all that hard to do I did a good job on mine , it is almost shiny .. You might need to put some water on it at one point , but all and all the trowelling aint that hard . On your third pour you will have the hang of it ..  ;)