Raised Access Flooring in workshop

[Alan Lightstone]

Wow, much more to consider then I had expected.

The plan had been to move the equipment into the workshop with a single pallet jack +/- an overhead bridge crane. Once in place, I don't imagine them moving.

Are their systems/materials that can handle larger masses? Are smaller tiles with more supports a sufficient solution?

Really only 4-5 heavy pieces of equipment. Only two above 1000 lbs. I think 1150 lbs max, but unclear how many points of support under those. I had thought of placing them on 4x4's so that they could be moved, if needed, in the future easily with a pallet jack. That would clearly spread out the loads over large contact area.

[Mike Kreinhop]

Alan, everything you want to do is possible and likely easy to accomplish with adequate planning and research. Just make sure the flooring components are rated for the load, or can be augmented as required, the flooring is properly installed and secured, and you have a plan to move and secure the equipment. If I didn't do this as much as I do, I would contract out the moving and placement of the equipment to make sure it was done correctly and safely.

[Greg R Bradley]

Am I missing something here? My present garage floor is concrete slab that a number of years after installation I had an epoxy coating put on. This is my present workshop. I've never noted any issues of moisture resulting from anything sitting on the floor. And the epoxy coating looks like new. Isn't this what these coatings are made for?

Is this different if a raised access floor is sitting above it? Or is there not an issue.

I understood that you were building a shop. I also understood that you had moisture coming through other slabs and were concerned about the new one.
IF you have moisture coming through a slab from below, even epoxy or polyurethane will not stop the moisture movement as the higher pressure water will find a way even lifting the bond from paint to cement. Air conditioning or dehumidifiers can create a problem since you are lowering the vapor pressure above the paint.

I have one building that used to be a shop. We blasted the floor and used two part poly floor sealer before moving in. It was fine for 20 years until that building was converted to a warehouse and air conditioned. Now you can see damage where the ground is occasionally moist underneath after a heavy rainy winter.

I do think we might have a slightly different problem as it is very possible to drop the inside humidity into single digits at times.

To put it simply: IF you have moisture coming up through a slab, you aren't likely to successfully stop it permanently with a coating. Lowering the humidity in the space above will make it fail sooner.

[Brian Tymchak]

Aside from the loading aspects, when I worked in data centers early in my career, my knees and feet took a beating. Maybe things have changed over the last 20 years but back then walking on those data center floors all day was like working on concrete all day.

[Bill McNiel]

Bill, the house is already built, so I can't put any barrier or gravel under the slab.

Alan-
4" of gravel and a vapor barrier have been standard under slabs for a long time throughout the country. It is highly probable that this is the existing condition, especially in a wet state like Florida. But I could be very wrong. Have you experienced any signs of moisture transmission?

Just trying to save you some money - Bill

[Alan Lightstone]

Alan-
4" of gravel and a vapor barrier have been standard under slabs for a long time throughout the country. It is highly probable that this is the existing condition, especially in a wet state like Florida. But I could be very wrong. Have you experienced any signs of moisture transmission?

Just trying to save you some money - Bill

Bill:

Thanks, I very much appreciate the advice. I'm just closing on the house this week, so I don't know if there are any issues of moisture transmission. Hopefully not.

I'll have to ask the architects if there is a vapor barrier under the slab. Hopefully yes.

[BOB LLAMA]

My architects had a really intriguing idea for the floor in my workshop. I've decided that I want the dust collection ducting to run under a false floor in the workshop. Don't need the rehash to over/under debate, this is how I've decided to do things.

I was originally going to go with 2x10 or 2x12 floor joists, with plywood over them, screwed to the joists. Vapor barriers over concrete, etc...

They suggested I go with a raised access floor system. Not sure how many people have had experience with them, but they are commercially used in data centers, car show displays, etc...

Having to just put in the supports every 600mm or 24" and allowing the ducting to go diagonally seems to solve many problems.

Anyone with experience with these? Suggestions?

This will be in coastal Florida, so humidity is 4000 percent, although the workshop will be climate controlled, but not all the time.

Also, how to drill holes to allow ducting to pass through seems more difficult with these than just with plywood? Anyone drilled through these before? (I'm thinking a router and a template). These come in a variety of materials. Most have galvanized metal on the underside. Some are pretty finished surfaces on top, some have composite wood, some have calcium sulphate, among others.

Alan,

It has been many years. There is not much information online about people using raised access flooring in their woodshops. Did you eventually install this?

[Bill Dufour]

When the they remodelled the Berkeley public library they did some work on the floor framing. the night before the books were to be put on the shelves the architect had a fit. He realized they shelves were line loads not spread out. He had to order in steel plates to span between floor beams under each line of shelves. Other wise they would have gone through the floor deck.
Bill D

[Alan Lightstone]

Wow!! A blast from the past.

So yes indeed, I did have a raised access floor installed. I found a company based out of Orlando that installed many of these. I found out that you can buy used ones for a fraction of new, so I took that route. Really couldn't care less how it looked, and with a little cleanup it looks just fine.

Watching installation was fascinating. They just glue steel support posts the floor under each of the four corners of each tile (which is a sandwich of steel, cement, and steel. The supports aren't screwed into the concrete floor, just glued on. Then the tiles all screw down with screws. You use a suction cup to raise each tile if needed (heavy, but not a huge deal with the suction cups).

The floor can hold up insane amounts of weight. All of my commercial equipment is supported with no issues whatsoever.

They cut a number of holes for me with a concrete grinder (if that's the right term), and horizontal, portable bandsaw. I've cut a few holes since then with a grinder.

I have lots of 6" Nordfab ducting underneath it, so essentially all of my long runs of DC ducting are under the floor, with me not tripping on them. I love that.
IMG_1221.jpg
There can be some minor issues with locating holes for ducting if a machine is sitting partially on a tile (which then can't be lifted unless you move the machine. I found a little prior planning before placing machinery solved all that.

Electrical runs under the tiles too, making that far easier and less expensive than dealing with that on a ceiling or on the walls.

I chose 18" of height for the supports and floor. I have 17 foot ceilings, so that still left me with 15-1/2 foot ceilings which is way more than needed (wish those were lower, but that's what the house had).

Oh, and no moisture issues now for 5 years.

[BOB LLAMA]

Glad to hear that it has worked well for you! Finding used hasn't been easy up here in Ontario, but I'm still looking!

Did you watch the full install? I read that they glue down the supports, let it set, then come back and screw it down. Are there no fasteners at all holding down the supports? Did you try to heed any of the advice in this thread, or just let the contractors do what they do? Mostly asking about perimeter bracing here.

I plan to run ducting and electrical in the RAF. I have a core drill capable of doing 10" holes, so locating them and planning where the holes are shouldn't be a problem, as long as I plan accordingly!

My biggest concern is about concentrations of weight. I've got a wide belt sander that is 2T+. I've already made changes to my plan to reduce the area of RAF in my shop so that this machine sits on concrete, and not the RAF. All other machines are under 1T. Big slabs of wood could bring that number up again. Weight ratings listed online for RAF seem to be hit or miss, but I've found some that say they are rated for 3000lbs, maybe higher if I recall. So overall weight shouldn't be an issue, but all these machines are on feet, which concentrates the weight down to a much smaller point. Was this something that you considered at all? It was mentioned earlier in this thread that steel sub-structures have been built to carry the weight down, but I've also read about just heavier duty custom panels where the feet meet the floor.

With these heavy machines, I don't foresee vibrations being an issue, but have you experienced any?


I was originally thinking my whole shop would be RAF, a big rectangle. Now I've reduced that to a square, leaving space in front and in behind the RAF. But as I plan out this shop, all my duct runs and electrical, run in an F shape, so I can accomplish what I want by running a 2ft a section along one wall, with 2 legs off that into the middle of my shop.

I think it's time I contact a professional haha. I just like to answers all my questions before reaching out, so I can consider all my options. I appreciate your advice here. Information on this topic is hard to come by, your thread has helped me immensely already.

[Alan Lightstone]

Glad to hear that it has worked well for you! Finding used hasn't been easy up here in Ontario, but I'm still looking!

Did you watch the full install? I read that they glue down the supports, let it set, then come back and screw it down. Are there no fasteners at all holding down the supports? Did you try to heed any of the advice in this thread, or just let the contractors do what they do? Mostly asking about perimeter bracing here.

I plan to run ducting and electrical in the RAF. I have a core drill capable of doing 10" holes, so locating them and planning where the holes are shouldn't be a problem, as long as I plan accordingly!

My biggest concern is about concentrations of weight. I've got a wide belt sander that is 2T+. I've already made changes to my plan to reduce the area of RAF in my shop so that this machine sits on concrete, and not the RAF. All other machines are under 1T. Big slabs of wood could bring that number up again. Weight ratings listed online for RAF seem to be hit or miss, but I've found some that say they are rated for 3000lbs, maybe higher if I recall. So overall weight shouldn't be an issue, but all these machines are on feet, which concentrates the weight down to a much smaller point. Was this something that you considered at all? It was mentioned earlier in this thread that steel sub-structures have been built to carry the weight down, but I've also read about just heavier duty custom panels where the feet meet the floor.

With these heavy machines, I don't foresee vibrations being an issue, but have you experienced any?


I was originally thinking my whole shop would be RAF, a big rectangle. Now I've reduced that to a square, leaving space in front and in behind the RAF. But as I plan out this shop, all my duct runs and electrical, run in an F shape, so I can accomplish what I want by running a 2ft a section along one wall, with 2 legs off that into the middle of my shop.

I think it's time I contact a professional haha. I just like to answers all my questions before reaching out, so I can consider all my options. I appreciate your advice here. Information on this topic is hard to come by, your thread has helped me immensely already.

I did watch the full install. And yes, the supports are just glued down. The installers, who do this every day, insisted that screws were not necessary. Five years later, I have not seen a single loose support or tile, so I have no reason to suspect they were incorrect.

The heaviest machine I have is my 27" wide-belt sander, but I have a number of heavy machines on the floor. It may be that the particular tiles I chose can easily support their weight (those steel/cement/steel sandwich tiles). There certainly are tiles that are more decorative, and likely less supportive.

You could place any machine on wood supports to spread the weight out. I initially placed my bandsaw on two 4x4's so that I could move it for final placement with my pallet jack. You could certainly do something like that to spread out the weight. You definitely want to think about tile placement in regards to the ability to lift a tile next to a machine to put ducting/electricity through it, and potentially have access later.

Vibrations have no issue at all.

Time to get a professional. Though they didn't scout out my floor before installation. I just gave them square footage, and spoke about machines, holes for ducting, and weight.

I sing the praises of my raised access floor anytime anyone asks about it. I love not having ducting hanging from the ceiling going down to my machines, or tripping on the floor over them. It's great.

[mike stenson]

The machines we load onto these floors are heavier than most woodworking machines per sq/ft. Things like tape robots are highly sensitive to vibrations and movement. IME, these flooring systems, properly installed, are rock solid.

[BOB LLAMA]

Thank you Alan for your insight, and your update 5 years later.

[George Yetka]

Whats the math to determine the size and length ductwork you could drop into a 24" grid?

The grid system breaks down to do this. I had to put 10' lengths of copper below one a few weeks ago. They are made up of stands glued or anchored to the floor and hollow tube stock that is about 3/4x3/4 in 2' and 4' increments(maybe longer).

The tiles are a bit heavy made of steel and about 2" thick(not solid) they cut them with circular saws/grinders. A hole saw or jig saw can cut them.

As for weight I roll CRAC units at 2000 lbs quite often

[Tom Bender]

Seems like you could just add support legs anywhere you have an extreme load. No need to addd wood on top of the floor.

No doubt the floor has a safety factor in the rating. You might decide to use that (carefully) when moving machinery. Or you could put in temporary extra supports underneath. Or you could use something on top to spread the load.

Cutting holes will compromise the rating for cut tiles.

If you do only part of the floor will you have a big step up in your shop? That sounds like a deal breaker.