Cleats as in French cleats? That's been around for a long time. I've got a cabinet out on the porch hung on cleats, works great.

Do we lose some cabinet space when using the cleat system to hang the cabinets? Can the cleats be made of particle board?

The cleats have to be strong. No particle board. Lose a fraction of an inch depth. No big deal.

My cabinet maker said they use cleats made of particle board only. Should we be concerned about the safety and durability of the cleats since our kitchen cabinets will be made of solid maple wood, including the doors?

I’ve never heard of making cleats from particle board. Sure you didn’t mishear?

Very unlikely your cabinets are being entirely made from solid maple. Maple plywood boxes, maybe.

“French cleats” are usually either solid wood, or high-grade plywood, or metal. See this article for example - note the plywood has 8 layers, it is high-grade stuff.

https://homefixated.com/french-cleats-and-how-to-use-them-secure-cabinet-hanging/

The cleat surfaces are angled, 30 to 45 degrees, and that angle plus the cabinet’s weight keeps the cabinet secure from being pulled away from the wall. Don’t need screws. But the cleat material has to be strong. If the angle surface breaks off, the cabinet will not be secure.

Particle board and MDF are much weaker than those materials, so not used for French cleats. If the cabinet is lightweight, then it might work . . . but why? It’s not like cabinetmakers don’t have actual wood available.

Now, maybe what your cabinet maker has in mind is not actually a “cleat”, but simply a 1/2” or 5/8” strip of material, cut at 90 degrees, screwed level to the wall. That strip positions the cabinet level - what actually supports and holds the cabinet to the wall are screws through the cabinet back into the wall studs (not merely into the 1/2” strip). .

Particle board or MDF could work there. No angle that needs to hold, the strip is simply filling the space between cabinet back and wall, so being a weaker material is not a problem. The screws are doing all of the work anyway.

If that is what they mean by “cleat”, then fine . . . I guess . . . but honestly if I told a cabinetmaker I wanted actual French cleats of solid wood or high-grade plywood, not particle board, and he REFUSED, I’d drop him and find a different cabinet maker. Unless he had a super convincing reason.

It is a totally reasonable request, won’t cost him any more (he’ll have plenty of plywood offcut left from building the boxes), and, you know, one of you is paying for the job and it isn’t him.

Particle board, as is the stuff made of crumbly particles? That's supposed to be your cleat? Nuh-uh, nope. He was already skimping out with that 5/8 gap, french cleats should be at least 3/4. Using particle board on top of that is not good. The cleats in my porch might be a bit much, but they are inch thick solid wood.

What's the reason for why he won't use solid wood or plywood? "I don't do that" is NOT a valid reason. Is there anything in your contract about this?

I've used French cleats to hang some large and heavy decorative items on the wall......mine are metal. I didn't know they could be made from wood.

We used French cleats to hang 2 large and heavy framed prints. Ikea uses a rail system to hang kitchen cabinets that are metal.

Hanging rail

@beesneeds. I checked the contract, there is no mention of cleats but on the blueprints, there is a note, "cabinet cleats: 8 feet & 4 feet". After I researched on how the cleat system works for hanging kitchen cabinets, I asked them what materials they are made of. They told me they have used the particle board cleats for over 5 years, there has been no issue and they are not going to change it.

For the best response, you need to find out from the cabinetmaker exactly what this "cleat system" is, then describe it here.

5 years is not a very long time.

If the "cleats" are just merely to position the cabinets, then screws into studs do the actual holding of cabinets to wall - i.e. not angled "French cleats" - and they warranty the cabinets not sagging the slightest bit for life including all damage resulting from failure, then . . . okay I guess.

Still, I think it is weird they are so inflexible. Is this a big shop, small shop, God's gift to cabinetmakers, what? Do you have to use this shop? Sorry, my hackles are going up.

For clarification, the cleats are made as an extension of the side panels of the cabinet box, about 3/4” wide, with the same material as the box, and the cabinets will be screwed to a horizontal board (which I assume it's cut at 45°) on the wall. It appears to be different from the French cleats.

Particle board has virtually no structural strength. The dfference in cost between particle board and plywood for cleats is negligible.

Does that mean the cabinet box is particle board?

You said the cleat or whatever they are using to hanging the cabinet is particle board; you also said the cleat or whatever is an extension of the box side and the same material as the box.

I wonder if the cabinets are going to be screwed to the ”cleat” instead of hung on them? If that‘s the case no 45 angle would be needed, they would just be screwed to the studs and then cabinets could be attached anywhere along this line instead of having to use only stud locations. Strange for contractor to be so insistent on particle board on so small an amount of material.

It's an extension of the side of the box itself? Do you happen to have photos of all of this going on?