Alternative to poured concrete for machine shop floor

Hi all,

I'm just talking to my partner about a machine shop that we will, one day, build. Together with a friend we have a couple of small metal lathes, a grinder, a belt sander, a pillar drill and the usual suspects. We are likely to expand this to include a big mill and a larger metal lathe.

Traditionally, workshop floors have been poured concrete. This makes a very stable, high-mass surface that machines can be bolted to - reducing vibration (particularly when coupled with high-density rubber pads for machinery feet) and making it easy to level. Due to the embodied energy in concrete, as well as restrictions that are likely to be placed on the use of high-energy materials by the planning office (we are hoping to build using a piece of legislation that requires a very low-impact development), we would like to seek an alternative to this.

My initial thoughts are that re-using hardcore/urbanite could create a heavy, stable floor, but that there would need to be some filler to bind it together. I wonder if a cob mixture could be used, although that may suffer due to moisture in the ground if the drainage wasn't perfect.

I welcome any suggestions or relevant experience.

TIA

many years ago I think it was in populate mechanics they had a big DIY story that showed how they made a solid concrete floor first they put down a layer of crushed stone then used bags of Portland spread out, a rototiller to mix it all up and a hose to wet it all .

A lot of national guard armories (back in the day when every little town had a national guard and each of them had some tanks) used to have floors made of dimensional lumber "on end" so you were looking at the tightly-packed and glued-together ends of a bunch of 2x4s (or whatever) when you looked down at it. They could run tanks in and out of there all month and then when it was time for the New Year's Eve ball (or whatever community event) they could run a power sander over it and it became a nice wooden dance floor.

That would work -- but it's expensive unless you mill your own lumber from your own trees.

I recently saw a YouTube video (can't now find it) where a guy did his blacksmith shop floor with six-inch-long rounds of roundwood (heavy pole or small log size)  set in sand and tamped down like cobblestones or pavers.  I don't think that would be quite stable enough for machine shop anchoring and it looked very labor intensive.  But my wild idea is to meld it with the national guard armory notion and set longer lengths (couple of feet maybe) of tightly-arranged bigger logs (as big as available) on end in a suitable excavation, filling the interstices with tamped-in sand for stability.

Edited to add the video, which someone (thanks, Jordan!) found for me.  I forgot that the guy used a froe to turn the rounds into blocks, which makes a lot of sense but is way more laborious:



However, in my experience one of the chief benefits of a concrete shop floor is that when some tiny spring or e-ring or machine screw goes flying, you can freeze and listen for the *ping* where it hits the concrete, then just wander over there and pick it up again.  Having worked in dirt and gravel floored shops where tiny flying parts are lost forever, I don't like the idea of sandy lacunae (cracks) between the hardwood parts of my shop floor.  It would be a great floor but not a perfect one for this reason if for no other.

bruce Fine wrote:many years ago I think it was in populate mechanics they had a big DIY story that showed how they made a solid concrete floor first they put down a layer of crushed stone then used bags of Portland spread out, a rototiller to mix it all up and a hose to wet it all .

I went looking for this and did not find it (old magazines are poorly represented on the Internet, and these search terms aren't highly unique) but what I did find may be just as good.  How about a 1949 cooperative extension bulletin that includes several pages of instruction and photos for making "Roto-Tilled Concrete Floors"?

Hard-Surfaced Floors For Farm Buildings

And that's just one of nine alternatives suggested to the traditional concrete floor.  Could be that one of the others is also useful here, I haven't had time to peruse yet.

bruce Fine wrote:many years ago I think it was in populate mechanics they had a big DIY story that showed how they made a solid concrete floor first they put down a layer of crushed stone then used bags of Portland spread out, a rototiller to mix it all up and a hose to wet it all .

A friend of mine did his shop floor like that 7 or 8 years ago and it worked, and is holding up, great.

Dan Boone wrote:

bruce Fine wrote:many years ago I think it was in populate mechanics they had a big DIY story that showed how they made a solid concrete floor first they put down a layer of crushed stone then used bags of Portland spread out, a rototiller to mix it all up and a hose to wet it all .

I went looking for this and did not find it (old magazines are poorly represented on the Internet, and these search terms aren't highly unique) but what I did find may be just as good.  How about a 1949 cooperative extension bulletin that includes several pages of instruction and photos for making "Roto-Tilled Concrete Floors"?

Hard-Surfaced Floors For Farm Buildings

And that's just one of nine alternatives suggested to the traditional concrete floor.  Could be that one of the others is also useful here, I haven't had time to peruse yet.

Just downloaded that.  Thanks for posting it.

Dan Boone wrote:A lot of national guard armories (back in the day when every little town had a national guard and each of them had some tanks) used to have floors made of dimensional lumber "on end" so you were looking at the tightly-packed and glued-together ends of a bunch of 2x4s (or whatever) when you looked down at it. They could run tanks in and out of there all month and then when it was time for the New Year's Eve ball (or whatever community event) they could run a power sander over it and it became a nice wooden dance floor.

That would work -- but it's expensive unless you mill your own lumber from your own trees.

I recently saw a YouTube video (can't now find it) where a guy did his blacksmith shop floor with six-inch-long rounds of roundwood (heavy pole or small log size)  set in sand and tamped down like cobblestones or pavers.  I don't think that would be quite stable enough for machine shop anchoring and it looked very labor intensive.  But my wild idea is to meld it with the national guard armory notion and set longer lengths (couple of feet maybe) of tightly-arranged bigger logs (as big as available) on end in a suitable excavation, filling the interstices with tamped-in sand for stability.

However, in my experience one of the chief benefits of a concrete shop floor is that when some tiny spring or e-ring or machine screw goes flying, you can freeze and listen for the *ping* where it hits the concrete, then just wander over there and pick it up again.  Having worked in dirt and gravel floored shops where tiny flying parts are lost forever, I don't like the idea of sandy lacunae between the hardwood parts of my shop floor.  It would be a great floor but not a perfect one for this reason if for no other.

https://permies.com/t/166641/Unlimited-supply-odd-square-ish#1308289  Is a related thread with my post including that video about the blacksmith shop. I too have heard of the end grain wood brick floor in heavy industry. The upside is if you drop a tool, or a heavy piece of work, there's a chance the floor gets a dent, and the item survives unharmed. You could remove damaged/stained/oil soaked blocks and replace them. It would be a great use of salvaged wood, where you might have short or random lengths/widths, but maybe a consistent size/thickness to make the bricks easy to lay in rows.

You might also consider a hybrid, of concrete pads for larger machines that really would benefit, and wood brick, or clay brick in between, to have less concrete in total. You could always take up some bricks and place a new concrete pad for a new machine. Large machines don't tend to get shifted around much, they arrive, sit in one place, and leave.

If you are trying to avoid the high energy input into concrete, then stay away from Portland Cement, that is the component of concrete that has the high energy input!

I have been involved with the issue of reducing energy waste since about 1970.
One thing I have learnt is that sometimes it is best to use the best product or equipment for a job, because its not going to fail or it saves an inordinate amount of human labour.
I give a few examples;
- using river rocks as foundations instead of concrete. What is the embedded energy in collecting rocks from a river and carting them to the site.
  What damage occurs to the river by the removal of the rocks
- Using an excavator instead of hand digging foundation trenches. I think using mechanical equipment at times can be justified.
- Power tools over hand tools, I built a house using only hand tools.  I wont do it again!
I have seen a mechanical workshop with a wooden floor and large machines were set onto blocks of poured concrete which matched the footprint of the machine, I think that is a clever and good use of the most suitable materials for the job.
So there are rectangles of concrete under each machine.
Just something to think about.

Many thanks for all the replies. My thoughts surrounding concrete extend to Portland Cement, as John points out in the post above. I may stretch to using much smaller pads for the tools that really require them but I'd like a more general solution that avoids the need for any concrete.

Another thought that I had was the use of lime in place of OPC, where it was necessary. I worry that the curing time would be enormous, however, and that it just wouldn't have the necessary strength.

As for the end-grain blocks approach: I too have heard about this and it sounds great, albeit very expensive and time-consuming. I'm less concerned about the time factor. Something that I did worry about with this method was how easy/possible it would be to bolt machinery into the floor; I support using steel plates that fix into 4 or more blocks, and bolt to the machine, might be a solution.

Many thanks for your thoughts

Here is a modern floor example
Michigan State University - Wooden Machine Shop Floor

John C Daley wrote:
I have been involved with the issue of reducing energy waste since about 1970.
One thing I have learnt is that sometimes it is best to use the best product or equipment for a job, because its not going to fail or it saves an inordinate amount of human labour.
I give a few examples;
- using river rocks as foundations instead of concrete. What is the embedded energy in collecting rocks from a river and carting them to the site.
  What damage occurs to the river by the removal of the rocks
- Using an excavator instead of hand digging foundation trenches. I think using mechanical equipment at times can be justified.
- Power tools over hand tools, I built a house using only hand tools.  I wont do it again!

This is important. I think people sometimes approach projects/life with hard rules about what is allowed, and forget to take into account the balancing impact that these decisions have on people. "People care" is an important principle in permaculture and written into the original Handbook by Mollison.

Appropriate use of fossil fuel technologies is absolutely compatible with permaculture principles. The key is working out what is appropriate.

In this case, it is quite easy to argue that a concrete floor is appropriate - it is an ideal surface in many ways, incredibly durable, and it will last the life of the building. It is not at all comparable with eg single use plastics, because the life of the building is so long.

bruce Fine wrote:many years ago I think it was in populate mechanics they had a big DIY story that showed how they made a solid concrete floor first they put down a layer of crushed stone then used bags of Portland spread out, a rototiller to mix it all up and a hose to wet it all .

Dan Boone wrote:instruction and photos for making "Roto-Tilled Concrete Floors"?

Very cool. I'm going to try that for my shop. I've got a tiller, truck/trailer to go pick up the right sand at a place fairly close and I've got a water tank on a trailer and the tank has 50 gallon marks that I can easily subdivide into 10 gallon marks or even 5. I can get creek rock pretty cheap but I'd probably get the proper rock from the same place I can get the sand.

The tiller tines ought to be nice and shiny by the time the floor's done.

I am keen to see how the Roto tilled floor works out.