# concrete slab vs wooden subfloor for shed build



## Thorbjorn88 (Jan 4, 2018)

I'm planning to build a 16'x24' shed to be my workshop which although not enormous will be a major upgrade to my current 9×7 shed! The plans I purchased show a wooden sub-floor over four 4×6 skids which will be on gravel. Is this sufficient? Or would it be better to just pour a 16×24 slab and bolt the walls straight to that?


----------



## hotbyte (Apr 3, 2010)

My floor is wooden and I've never had issues standing on it long periods of time. I've read often that shops with concrete can cause back aches and often see people using rubber pads.


----------



## drsurfrat (Aug 17, 2020)

I imagine both would work, but being in AZ, I might go with concrete. Makes moving heavy machinery much easier, and it might just be a tiny bit cooler in the heat by holding ground temp a bit longer.
Just my opinion - worth what you paid for it.


----------



## Lazyman (Aug 8, 2014)

I don't think that I would want a shop that big with all of the woodworking machines and materials on skids. I would either do a proper pier and beam foundation or concrete slab. I would use concrete piers if you can. I built a small garden shed about 25 years ago on skids. I didn't have that much weight in it but it eventually sunk into the ground. I had to jack it up and put it on some concrete piers about 7 or 8 years ago. Plus even with pressure treated skids, they may be the first thing to rot and need replacing which would be a PITA.


----------



## prazbotta (May 20, 2020)

If you feel you would ever move the building, I would stick with skids and a wood floor.
If the building will not need to be moved and the budget has room for concrete, I would go that route.

If there is room for concrete in the budget, there may be room for a bigger shop with a wood floor?..... just sayin.


----------



## therealSteveN (Oct 29, 2016)

You should probably check with the local building department for code.

Here even a 24 x whatever, if you built it on a skid (wooden decking) is just a yard barn, storage unit, shed. No permit required.

Now if you put it on a concrete slab, you MUST dig a footer below frost, here it's 4' deep, that gets a paid permit, and 2 inspections, one pre pour, one post. Then 2 inspections when you pour the slab, again one pre, and one post.

All of what Nathan said about a deck, versus a slab is true, probably for all areas of the country. IOW a slab poured building is a permanent build, and using the decking is considered temporary.


----------



## Lazyman (Aug 8, 2014)

Here in the city where I live, almost any structure requires a permit, even a deck, and one that large that has electricity will definitely need inspection so you definitely want to check on that where you live. If you live in tornado alley, they may require it to be well anchored to the ground.


----------



## wapakfred (Jul 29, 2011)

No doubt that wood is more comfortable to the feet, but I would still choose concrete.


----------



## controlfreak (Jun 29, 2019)

I like wood when I drop a tool. I need to expand my shop but it is on the low side so I am trying to decide whether to do slab or dig out a bit.


----------



## bigblockyeti (Sep 9, 2013)

I'm wrapping up my 16' x 22' shed and I chose concrete specifically due to the ability to easily get big machines in and not ever have to worry about what they might weigh. I put PVC conduit in the slab where I know I will put my tablesaw if I ever move my shop in there and another where I'd put my jointer or a large planer. As a point of pride, this is the only thing I had to pay someone to help me with, a wood foundation can be assembled at leisure, concrete waits for no one and the consequences of messing it up have dire ramifications. I don't know what your wall height plans are but there's no such thing as too tall. Per HOA requirements I had to go with an 8/12 roof pitch which I was uncomfortable on initially but fine with as I completed the roof. This roof pitch looks good with 12' walls which allow hanging things out of the way at the joists while still allowing good overhead room. Create a lighting plan as you build or before so you'll have the light you need where you'll be doing work. Anti-fatigue mats are a good idea where you plan on standing for extended periods of time as the concrete will be harder on joints vs. wood. If you're comfortable with the expense, intalling radiant heating tubes beneath aren't too expensive during construction and don't have to ever be used but are very handy should you decide to go that route. I will have only a 1.5T mini-split on mine, again, should I ever go the route of moving my shop in there.


----------



## tvrgeek (Nov 19, 2013)

Build a taller stronger subfloor so you can run your DC and power from below. I have re-arranged my shop a couple of times and new layout avoids cutting up my cement floor. ( saw against the wall, overhead for BS, etc.


----------



## Knockonit (Nov 5, 2017)

Its Arizona i'd do concrete, especially in the ole pueblo, termites are ugly and since the epa took the sting outta the termite killing stuff, you gotta treat it occassionally to ensure it no get et. 
good luck
rj in az


----------



## CaptainKlutz (Apr 23, 2014)

Were the plans on Pima County/Tucson city pre-approved list?

+1 Check bldg code and permit requirements.
Pima country code used to limit no-permit shed projects to 200sqft and no electrical service. 
They used to be very particular about electrical and below-grade work; both on paper plans and on site. DAMHIK

+1 Likely cheaper to use concrete post/beam, or full concrete slab; once you learn the temp building anchoring rules to prevent loss during min 115mph winds for monsoon storms. Most folks building below 4000ft elevation use slab, as frost line is zero inches; while post depth has to be determined by soil testing?

Best Luck.


----------



## BigAl98 (Jan 29, 2010)

Had a 24×32 pole barn with concrete floor. I lived in northern NJ and working in the winter the concrete was like working/walking on ice….till my propane heater warmed up (after 5 or so hours). Would recomend if you use concrete to put laminate (thicker would be better) over the concrete….garage type rubber/plastic floors also will work well on concrete. I ended up using those 2×2 interlocking matts in the areas I usually worked, but they also impeded clean up, and seemed to attrack dirt and saw dust around.


----------



## LittleBlackDuck (Feb 26, 2016)

I've dropped an egg on both wood and concrete floors and it broke… while, the concrete refused to break, there might be a greater chance of a bounce from wood.

Dropped chisels are more likely to un-blunt on wood and there are more dropped chisels than floors.


----------



## Thorbjorn88 (Jan 4, 2018)

Thanks for the input everyone especially fellow Arizonians. It sounds like concrete is probably the way to go for me.

Has anyone had experience with that epoxy coating they do on concrete? Is that worth doing for a woodshop?


----------



## splintergroup (Jan 20, 2015)

The epoxy coating (or even cheaper concrete paint) is a nice add-on. Sweeping is far easier and if colored (I like light grey), it really can make the shop "brighter". The cheaper paint needs periodic touch up as it is less durable vs. the epoxy.

Downside is it can get very slippery if there is a wet area, but you can get texture added (basically sand) to give it a good all-condition grip plus it still sweeps up nicely.

Working on concrete can have a toll on your back. I've never had the pleasure of working long hours on a wood floor, but A great solution I found for concrete are the large (4'x6') "stall mats" made from ground up tires. They are wonderful in front of the table saw and they stay put. I've seen 1/2" and 3/4" thick versions. A plus is you can run power cords between where two sheets are butted up together (like my TS cord).

I get mine from a local "Tractor Supply" store, they go on sale fairly often.


----------



## controlfreak (Jun 29, 2019)

I hear the "speckled" epoxy or pads make a real challenge to find a dropped screw or nut.


----------



## gdaveg (Aug 1, 2020)

Bldg Dept will want you to build to code since it is habitable and not agricultural use.

If it was my shop would go with concrete slab on grade with a turned down edge footing. Code minimum depth below grade for footings is 12" (or as specified by the local jurisdiction). Likely 2-#4 continuous rebar in the footing will be required.

Look up the local building department online (City of Tucson or Pima County). Read up on new structures and bldg dept requirements, you can set up a meeting with a plans examiner to go over what is required. Do Not try to build without a permit.


----------



## therealSteveN (Oct 29, 2016)

Epoxy coating garage floors absolutely requires following manufacturers instructions, and also you will want to buy at the better/higher priced level of product. BIL did his floors and tried to do it on the cheap (low cost product) it peeled off mostly in less than 6 weeks of cool weather, hadn't really gotten cold yet.

He cleaned off the residual, really did a good prep and used a higher priced product, and those floors were great for the entire time they lived there. His was textured, and even if the cars dripped as snow melted, and made puddles that water never froze, and it wasn't slick. I've seen a few non-textured, that were scary to be on while wet. Of course I've seen a few highly polished straight concrete floors where you could easily slip on a wet spot too.

I guess the "look" it provided wasn't a motivator to me, I still have plain old concrete floors. 

I imagine the building without a permit, when one is necessary is also regulated by the local rules. Here everyone thinks they got away with it, because the building departments don't go out telling you to tear it down, and redo it with permits, and inspections.

They let one of 2 things happen. First if it burns down, behind the scenes insurance companies go and check that kind of stuff if you make a claim. No permit is probably going to be no coverage in event of fire, hurricane, Tornado, etc.

#2 being if nothing ever happens, some day, maybe way in the future, you go to sell, and whoever is doing the title search will come across a little bomb the county put in a file and recorded it. No selling it, until you do whatever fix, penance, tear down, or whatever was determined to be needed on your permitless build to satisfy the county, plus the cost of a building permit, inspections, and likely a fine of equal value. Then you can sell it.

Building inspectors, at least in my experience, are pretty regular guys. BUT if you try to mess with them, they can make a build really hard. My suggestion is always involve them, and try to make it as pleasant as you can. It seems to be the best way to get it done.


----------



## CaptainKlutz (Apr 23, 2014)

> Has anyone had experience with that epoxy coating they do on concrete? Is that worth doing for a woodshop? - Thorbjorn88


Yes a little?

- Can not put coating on fresh concrete. It needs to age at least month, or longer. So you have time to research and think about it.

- Humidity levels in Arizona are low enough, don't need a coating to prevent moisture permeation or retention in the concrete. Especially if you lay down vapor barrier required by code.

- Unsealed concrete pores can hold sawdust. If you just want to make floor easier to clean, and reduce staining from machine oil spills; a clear sealer is cheaper/simpler solution.

- Shop carefully, and read installation guides. Installation is usually more than mix this 2 part goop and slop it on floor evenly. Different brand epoxy has specific requirements to have 'lifetime' adhesion. Some want a freshly ground surface with minimum roughness even on a new surface?

- If choose a high gloss floor coating, need to use diffuse light sources overhead. Direct light sources create annoying glare. Nothing worse, than walking into a show garage with glossy light colored floor, and strips of LED lights overhead; and all you want is sunglasses so you can see across the room.

Last but not least:

- Epoxy surfaces are slicker than banana peels when they get wet. Some folks use them purdy colored plastic flakes to add some texture and grip. But those same flakes make it IMPOSSIBLE to find any hardware that routinely drops on floor and rolls away to hide. If you want grip in walkway areas, floor epoxy folks sell fine sand. I prefer a solid color floor, and recommend you avoid any grey tones if you drop hardware like this Klutz. 
BTW - Red/Burgundy colors are great as they don't show blood stains when you get injured!

Bottom line: Not a fan, but they can be really cool looking in a fancy work shop. Can say that when the floor is covered with saw dust or shavings, can't tell if floor has epoxy coating or not? So only YOUR opinion is the one that matters!

Best Luck.


----------



## kelvancra (May 4, 2010)

My shop is on concrete. Over that I am laying the 1" x 4' x 6' horse mats. They TOTALLY change the nature of the concrete floors.

The mats isolate the floor from the shop atmosphere. A plus since mine does not have the HUGE advantage of insulation under the concrete (a must for dealing with cold, but a plus for heat, until it becomes the flywheel).

I've had shops with wooden floors and I'll take concrete and the horse pads every day, when it comes to foot comfort.

Too, the occasional tool drop is not a big calamity with the floor covered in rubber.

Presently, I only have about 10 mats. I plan on adding at least that many more.

Ten, which covered 240 square feet, ran $400.00 and were worth every penny. I'll have about a grand in, but I can spend two or three times as long in the shop without feeling like my feet have been beaten.


----------



## Knockonit (Nov 5, 2017)

in my original shop we had the two part epoxy coating, and it was great, damage was minimal but when it did get damaged was a booger to repair.
\

I opted in my new shop 1100 sq ft t use a epoxy paint, gave it two heavy coats, and so far moving in draggin tools with stuck wheels, and broken wheels, no major scratches or gouges, and holding up well, with move mostly done, i see minor scuffs, but nothing major, and as easy as it is to recoat if needed, and cheaper and faster than the two part, which i was gonna use, but ran out of time.
Rj in az


----------



## northwoodsman (Feb 22, 2008)

About a year ago there was a thread on pretty much the same subject I believe. The poster got a lot of input but it was always too late. Instead of asking for advice on what he should do and researching it, he had either already taken action and then when it didn't work out was asking how to fix it, or he had already purchased the materials and could not take them back. It was a mess and extremely frustrating to follow. I think every mistake that could have been made was, and his cost more than doubled. Get the proper permits, follow codes and best practices. You most likely aren't always going to live in the same place and a couple of years from now you may need to sell it and move. You want it to increase the property value not decrease it. Also think what may make a home underneath it, or in it. I'd go with concrete.


----------

