Concrete base for sawmill

[jrokusek]

I'm tired of screwing around and having my homemade sawmill sitting on railroad ties and having them move, sink, heave, etc.   I took 2 days off next week and want to form up and pour an oversized concrete sidewalk for the sawmill to sit on.  I was thinking of bolting 6"x6" green treated timbers to the concrete and bolting the sawmill bed to the timbers.

How thick should I make the concrete?  I'm wondering if the standard sidewalk thickness of 4" is a bit too thin.  Should I use a 2x6 for forms (5.5") or can I get by with 4" or so?  I'm just a hobbyist so it won't be used daily....if that makes any difference.

Jim

[beenthere]

I can only think that you will want to account for frost heaving below that slab. Beiing in SD, seems that will be the major problem. Are you going to make it a floating slab? such that it moves in one piece on the movement of frozen ground beneath? 

I'd think piers (concrete or treated wood) with ends down below frost line, with timbers on the piers would be a better choice. What is the choice of other construction in your area?

[jrokusek]

Floating slab was what I was thinking.  A few pieces of rebar tied together were in the plans....probably would have helped had I told you that piece of info!   :

I was thinking piers too at one time.  I could use the railroad ties I have and put the nice timbers on top.  Also have a tractor with a post-hole digger to make digging MUCH easier.  However, I kinda want the concrete slab to keep things lower to the ground and more stable than if on piers.  Either way would work fine though.

Around here a floating slab is no big deal as long as you use mesh or rebar and it's backfilled propperly. 

[Weekend_Sawyer]

 I put in a real nice pad for my mill. It is 32 x 24. about 11 yards of concrete. I really liked it. I poured it 4" thick and had it floating with no problems. I prepared the ground underneath with my skid steer and it was very well compacted.  It was nice to have enough area to turn the skid steer around on, stack boards or park a truck to off load onto. The mill was along the high side so slabs could be pushed off and allowed to pile up on the slope.

I traded that pice of property to my brother who now has his garadge on that pad and I have my mill set up in my back yard in the dirt. It is compacted fill but I still have to level the mill alot more. I am going to pour another slab someday and will make it the same size and put a roof over it.

Jon

[Haytrader]

Jim,

In consideration of the cost of concrete and all the labor involved, and the possibility that you may at some time have the same issue as Jon, I would consider stiffening the frame on your mill.  Angle iron, while strong, can allow a lot of twist. How about adding a frame of 2x6 rectangular tubeing under the angle iron. Box the ends and add a couple cross members with the same tubeing. This would make it very stiff and may solve the original problem.
It looks like you are set up in an urban setting. (looked in your gallery) An electric power source would sure be quieter.  ;)

[Tom]

However you decide to place it, I would be concerned with the ability to clean out from beneath it.  I have sawed on my portable mills that have ample room beneath them and still  get sawdust and trash buildup beneath the bed that is difficult to remove.   Openings should be a must. Perhaps the idea of using a power washer or garden hose will help in the design.  The slab will definitely make it easier to level, but piers might make it easier to clean.  Maybe combine both.

[jrokusek]

Jim,

In consideration of the cost of concrete and all the labor involved, and the possibility that you may at some time have the same issue as Jon, I would consider stiffening the frame on your mill.  Angle iron, while strong, can allow a lot of twist. How about adding a frame of 2x6 rectangular tubeing under the angle iron. Box the ends and add a couple cross members with the same tubeing. This would make it very stiff and may solve the original problem.
It looks like you are set up in an urban setting. (looked in your gallery) An electric power source would sure be quieter.  ;)

I've been thinking about that.  There's more to this story than meets the eye, however.  My wife and I are considering buying a new house.  In the Sioux Falls area the housing market is still quite good.  I'm fairly sure I can get a lot in town where I want it and may be my own contractor and then subcontract most stuff out to others.  I looked at what a house costs to build and realized that contractors make about 20% off the cost of the actual house.  ANYWAY, I think I have my wife almost talked into letting me cut enough wood for the trim, moulding and flooring.  If I can do that I can buy a Woodmaster Moulder/Planer and it will probably come close to paying for itself.  HOWEVER, I need to get some boards made in the very near future.  I don't necessarily need to cut everything right now, just enough to show my sweetie that this crazy idea is indeed possible. 

The pad is meant to be semi-permanent.  I can use it for the sawmill for the time being and later use it for a stack of lumber to air dry.  It's only about 1.25 yards of concrete anyway.  It won't take up much room....I have right under 400 acres to work with so I'm not concerned about room.  The second part of this is that I may upgrade to a commercial sawmill of some sort in the future so I'm not sure how much work, time or cash I want to put into this one right now.  I'm researching the idea of an urban logging/sawmill operation so I'd need something a bit more reliable if I take the plunge.  I really just need what I have to be more functional.

The pic's in my gallery are right after I finished it.  I brought it into the city to tweak it, paint it and test it.  The thing got lots of looks from curious neighbors!!  Right now it's about 75 miles away from me.  Sure was lots more fun when it was in my driveway!

[thecfarm]

I suppose you know to have a good gravel base and compact this down.I  had to level a place off for my mill.I only put round pre- made cement pads to put it on.Has not moved.The gravel is about 2 feet deep where the mill is.I would go with the 2x6 rectangle tubing too.That is what is under my 4x4 angle iron.

[jrokusek]

I went ahead and poured the pad.  Now I remember why I haven't poured concrete for over a decade!  It was only 1.25 yards, but man am I tired!  Scraped the dirt, dug it in, put down gravel and compacted it, formed it, poured it and finished it all in about a day.  Would have gone faster if I didn't have to fiddle with the tractor to get it running and keep it running.  Dimensions:  44" wide, 5" thick and 20' long.

BEFORE




AFTER

[beenthere]

jr
That looks good. At least it will keep the weeds down. and be much easier to keep level and more fun to saw..

[fivedogs]

i'm going to build something  similiar very soon  did you put in any footers  iwas wondering if i need to i live in upstate n.y. and it gets cold up here

[jrokusek]

Nope, no footers.  Gets DanG cold here too but I figure sidewalks hold up OK so this should too.  I did use three pieces of 1/2" rebar in it just for good measure.  I used these goofy little plastic rebar "chairs" to elevate them off the base.....I'd recommend using something a little better like a rock or a half of a brick.  I was trying to get fancy, but they were mostly just a pain in the rear end. 

[bedway]

nice slab, let us know how it works for your purpose,,,bedway

[dail_h]

   Reckon why he went to all that trouble to pour a slab for the mill,an then didn't pour it under the mill?????
   WE REALLY GOTTA GET A RUNNING FOR COVER SMILEY

[jrokusek]

Awwwww dangit.....I knew I was going to screw something up   :D

[Furby]

Better try again. ;)

[Gary_C]

That's the trouble with pouring concrete, as soon as you are done, the screw-ups start showing up.  :( :(

Sometimes they come with advice on how you should have done it.  :D :D :D

[jrokusek]

Well, I guess I can update this thread now.  I bolted 6"x6" green-treated timbers to the concrete, and then bolted my mill to the timers.  I guess I should have known that the treated timbers from the BORG are only treated for the first half-inch to an inch or so.  Oh well.

Anyway, I bolted everything together, leveled and shimmed a few spots, and then adjusted everything on the mill that can possibly be adjusted.  This homemade mill now cuts incredibly well!  I can't wait to get more logs - this is fun.  I cut some 7' Elm slabs and got lots of sawdust in my teeth 'cause I was smiling so much!

Jim

[Furby]

 8) 8) 8) 8) 8)

[logwalker]

I didn't know that John Deere made sawmills. Ain't she purty? Joe

[Handy Andy]

  Regarding your statements about building your own house, in my career of 25 years as a builder, I might have made 20% once.  Normally it is less than 10% by the time I pay the property taxes etc.  If you are talking to subcontractors, they will talk up building your own, as they charge owner-builders more than their steady contractors.  They call them "once in a lifetime customers".  The subs like framers and plumbers are really ripping us off here.  All the regulations that get passed restricting who can do work in your city results in higher prices by the ones that are allowed to do the work.  Now, if you could frame your own house and do the plumbing, wiring, painting, installing woodwork and flooring, build your own cabinets and tops, you can save money.

[WDH]

Nice pad.  I need to do something similar.  I store my LT15 in a shed.  I skid it out with the tractor, set it up (on the dirt), and saw.  When done, I skid it back into the shed.  I need a pad like yours to set it up on.  That would make set-up a snap.

[mike_van]

For the guy that doesn't want to spend the $$$$ for concrete, or stand on it all day, I don't know why a wood pad wouldn't work. If you layed [or half buried] PT 6x6's  flat on 2 ft centers, sawed out your own deck & screwed it down, put a coat of Thompsons [or similar] once & awhile?   I needed a sidewalk in front of my sugarhouse to stay out of the mud - 4 ft x 16 ft - I did the same thing with PT 4x4's, screwed  2x6's to them, 7 years ago, it's still there & working fine. I ran out of PT 2x6's part way, so I used some oak & maple I had - They'll all cup a little when the summer sun beats on them, but it sure beat buying the concrete [or mixing it] under the mill  you'd have to watch out welding on it.

[jrokusek]

Actually, for me, forming and pouring the concrete was faster.  Not that I'm against saving a few bucks or anything  ;)

I had the mill on 4 railroad ties and the frost and freezing temps would move the RR ties quite a bit.  This just turned out to be a bit easier for me.  Concrete was $124.52 delivered to me. 

[WDH]

Mike,

A good idea.  I might do that since the foundation deck could be portable if I wanted to move my sawing location.

[solodan]

I have thought about building an elevated deck on a slight grade, and then  digging a 3 sided pit and leaving an access on the downhill side, then using that heavy duty expanded metal decking you see at ski resorts, so the saw dust can fall through into the pit. The pit would still have to be cleaned out every so often, but not as often as sawing on grade. ??? maybe I could conveyor the sawdust out to a sawdust burner. ???

[kelLOGg]

Did something dumb 10 years go when I put RR crossties for the base of the mill. Now they are rotting. I am considering 3 options:

1. dig up the rotting ties and replace with concrete
2. drill 12" (approx) dia holes where the legs are and fill with concrete
3. excavate a bed and fill with concrete for the entire mill to rest on. (about 29' long)
 I will have a concrete company do the work due to the amt of concrete involved. Access is limited to the ends of the shed due to the rollway on one side and trees on the other. I want to keep cost down but minimize the labor I have to do. I am leaning to option 1 but I want FFer's comments

[doc henderson]

cheapest and easiest might be the hole in the ground with concrete.  you can throw in the cardboard sono tube if your soil will not hold.  could even do the quick-rete bags if you want it fast and simple.  a small pad of concrete (2x2) under the tires may help them last, or they can be taken off and stored inside. I only tow/move mine about once a year.

[VB-Milling]

How are option 1 and option 2 different?  Not sure I'm understanding.  It seems to me if you go with option 1, you are 90% of the way to option 2.  Maybe I'm missing something.  ???

[kelLOGg]

In option 1 the rotting ties are about 4 or 5 ft long and span the width of the mill (plus about a foot on each side)
In option 2 a 12" dia hole would be drilled where the legs contact the ground and then filled with concrete. Drilling would go through the rotting ties and down maybe 18" to 24".

[WDH]

You deserve a nice set up.  You have worked hard.  I would pour the pad and enjoy how much better that will make things for you.  

[doc henderson]

I agree the pad is the best/nicest option.  if that does not fit your budget, you can do the sono tube footings, and pour a slab over them later.  i think if the mill is all that will roll on the slab, then a 4 inch reinforced slab should be enough.

[doc henderson]

a 5 x30 foot 4 inch slab is under 2 yards of concrete.  that costs about 210 bucks here.  I would add wire mesh or even the roll wire that is 5 feet wide.  i still like having the footing under where the most pressure will be under the feet.  if you hire it done, it will add to the cost, but be a better finish if you are unfamiliar with concrete placement.

[VB-Milling]

I would also agree the pad is the best option. Hired out, it could be formed and poured in a day and its done.

If you're like me (stubborn and cheap), it can be formed and poured in sections with welded wire fabric as doc said and rebar doweling between pours.  The sections give you built in control joints so nothing needs to be cut afterwards.

I broke my patio up this way into 7 pours over a few weekends.  Each pour was roughly 100 sqft.  Totaled about 360 80lb bags mixed in a drum mixer.  My wife and I did it with occasional help from a friend.  Mostly helping to dump bags into the mixer.

If you did two pours, each 5 x15ft, I think it could be very manageable.  If you're not familiar with concrete finishing, I wouldn't worry about it.  You could mix it a little dry to avoid pooling water, screed the top with a straight 2x4 and give it a throwaway push broom finish.

[kelLOGg]

Thanks for the encouragement to pour a pad. I am seriously considering it. And thanks to WDH for the kind supporting comments. 

So, 4" thick with wire and rebar is the recommendation?

[Magicman]

There would be no way to control any shift in position with multiple support pads.  Yes, pour a single pad with a moisture barrier beneath the wire. 

[Ventryjr]

 

 

I did concrete piers with railroad ties crossing them.  Then hemlock 8x8s on top.  Haven't been thru winter yet. So we will see. The idea is the posts are below the frost line so they won't move. 

[doc henderson]

most walks and driveways are 4 inch.  if you were going to drive a dump truck loaded on it then I would go 6 inches.  just increase the concrete cost by 50%.  the labor would be the same as you only finish the top.  if you pour a pad, still best to put some circular footing under the pressure points down to the frost depth.

[PoginyHill]

A pad of any thickness would do better with a 2-3"+ base of crushed rock or gravel compacted. If it's a wet area, add a daylight drain if your slope allows to keep water from collecting under the slab.

[kelLOGg]

Still planning. Is it a good idea to install any support system (pad, piers, e.g.) under the sawmill trailer tires? Seems to me that since they are soft and flexible they don't provide firm support when sawing, so why bother? Omitting such support would make the forms for pouring concrete a little simpler.

[doc henderson]

it is always dangerous asking for advice with things like pouring concrete.  even my buddy Eddie who has done it for 40 years, will waffle on certain "rules" for no apparent reason.  so the piers could be a mixed blessing.  can transmit forces on the pad down to solid ground below the frost line, and make everything more solid.  If the whole pas settles, the concrete may crack there.  If you have a 3,000 pound log on a 1,000 pound mill, that is 2 tons, and divided that into the square inches of surface on the pad.  many jack have what seems to be a 2 x 4 inch foot (prob. more)  if there are 6 of these jacks supporting the mill, then 6 x 8 is all the weight on 48 sq. inches or 83 pounds per sq. inch.  you could also put a chunk of wood under each jack say 12 x 12 and now you spread out the forces and reduce to 4.6 pounds per sq. inch.  if you will be dropping and scooting large logs, this will impart some dynamic forces as well in addition to the static force.  you have all kinds of options.  you can form a slab that is 4 inches in the interior, with a 6 inch thick edge for a foot reinforced with rebar like a beam or mass footing.  a simple 4 inch slab with some wire roll mesh in it is much better than what you currently have.  I have what you have at this point.  If you have well compacted soil, you can dig the holes for the footings, and pour it all in one pour.  it is only time and money. ;)

[doc henderson]

On the tires, unless they are suspended off the ground, then they are sharing part of the weight.  my jacks and tires are all in line,  I am liking the thicker edge with rebar along the edge better and better,  I think that is what I would do.

[2308500]

4 piers dug down 3 feet below grade  and 6 inch pad with rebar and wire mesh. overkill.....maybe...maybe not

 

[thecfarm]

overkill? you will never know.  ;)
overkill has made me feel better about a build many times.  ;D

[kelLOGg]

It is finally done. 4 x 27 with 2 x 4 for the tires and 4" thick. Packed gravel beneath all - but no rebar. My concrete guy said it wasn't necessary. Hope he's right. Good bunch of guys to watch work. I told them it was the first time I had watched people work. While it cures I will be getting my 1st cataract surgery.



 

 

 

 

[TimW]

No rebar?  I think your concrete guy is wrong.  Guess you won't be handling any huge logs.  I do hope I am wrong.
hugs,  Brandi

[kelLOGg]

32" dia is the max. Usually less than 16'. Fingers crossed. I guess what I failed to emphasize to him is that logs "fall" several inches when they are turned.

[230Dforme]

They didn't want to unload, carry, cut
or tie the rebar

[doc henderson]

no option now but to wait and see.  I only use the plastic fiber when nothing else will work.  keep us in the loop!  thanks.  I used it in my pool floor under vinyl and in the 1.5 inch slab over plywood and trusses in my shop with floor heat, and it has done well.

I would put some relief cuts as it is long and skinny and will crack, even if you had put mesh and rebar in it.  

[TimW]

32" dia is the max. Usually less than 16'. Fingers crossed. I guess what I failed to emphasize to him is that logs "fall" several inches when they are turned.

Oh, okay.  Not too big.   When I load a huge 36 incher 20 feet 3 inches with the loader arms, if it rolls too fast on the bunks to the back stops, my whole mill moves, then settles back down with a thunk.  Think water shifting back and forth in a dog's water bowl.
All bets are off if you accidently drop a log while sitting it down on the bunks.
hugs,  Brandi

[kelLOGg]

I roll logs onto the mill over ramps from the rollway. The only "thunk" I get is when rotating to a new face.

[bannerd]

Something that works pretty well is a ruble trench.  Have a backhoe come in and dig below the frost lines and then fill it with number 2 stone or number 1 stone.  Make sure he or she runs a drainage pipe at the bottom as the cold water/ice will absorb thermal the deeper it creeps.  It needs to run out at some point.  Compact it (not much to compact with stone) and when that is done, pour the concrete slab on top of that.

[kelLOGg]

The pad has been in use a couple of months now and it has held up well, so far. I have had several 25" x 17' pine on it so far so good.



 

 

[esarratt]

I can only think that you will want to account for frost heaving below that slab.

Well said.

[DaleK]

Maybe went a bit overboard with mine but I went 2' high by 32" wide by 26' long, put some boulders in for fill but there's still 4.5 yards in it and some rebar. Backfilled it about halfway and left the notches for adjustable log decks. Put 10 adjustable deck blocks in the concrete so I can adjust it some if it doesn't settle evenly, I thought they might be weak but I found some with 2500 lb capacity, had a 24"x18' elm on it and it held up nicely