Do you mean MDF? It's because of moisture - swelling of the wood. The best way to avoid this is to seal all the edges as well as the two sides. Now that it's absorbed moisture - dry them out before sealing.

Sorry yes it is MDF. I am having issues with cabinets and the mfg is saying it is due to water damage and I believe it is excessive humidity because we live in a hot humid coastal area. Sigh! I included a photo to show what is going on.

The issue: high humidity and neglect

May I ask what kind of neglect? The cabinet is not on the floor and I dust it. It is in the garage and came pre-made. So I am not sure what I could have done differently. Appreciate your help and advice

Please, post some pictures of the cabinets in their entirety, being sure to include the surrounding area. And who’s the manufacturer? How long have you had them? If they’re not sitting on the floor, what are they sitting on? You know, the basics.

Is your garage climate controlled?

Neglect: not opened for 9 months.

It's common with MDF materials when they used in garages or basements without periodic ventilation. The moisture and humidity will make them swell and delaminate and eventually destroy them.

I appreciate your honestly. I had no idea. I trusted the person selling me these cabinets and installed them. They were 8,000. They have only been up 7 years. The manufacturer has a lifetime warranty and said it was water damage. I am pretty anal. We put down shelf protector and everything is stored in original containers and then those are stored in a plastic tub in case of leaks. A friend checks the house 1 time a month and flushes my toilets etc. But other than opening the garage once a month there was no additional opening or closing. It is a PT residence and the sales person also knew that. I am in my 70s now. The original sales person/installer is out of business. I contacted the manufacturer who said when I sent the photos it was water damage. There is a hose bib on the same wall but we drain it and turn the water off when we leave. No water has ever touched those cabinets! a couple of the interior hinges have rusted! Only in one cabinet. Nothing leaked but I am wondering if vapor are emitted plus heat plus humidity could cause a chemical reaction. Rather than help me figure out the cause, have someone make the repairs Which I already agreed to pay for their reply “water damage no warranty”! I am not sure at this point what to do. It is so disheartening. .

From your picture it looks like particleboard rather than MDF, which is even more prone to picking up humidity from the atmosphere and degrading like this. If you've had a lot of 90% humidity/90 degree weather that kind of damage isn't particularly surprising. Because the material itself is falling apart repair isn't really an option, you need to replace the failing parts, preferably with plywood or solid wood. If you replace the cabinets go with plywood bodies and solid wood doors, or even plastic in this location.

Yes, it is water damage, but from humidity in the air, not liquid water.

I appreciate your assistance. I was told it was MDF. I requested that someone assess it and yes replace the pieces. They must know This was not the right product for the location yet sold it to me anyway. They did work in the house no issues. The installation itself was fine. It would not surprise me that they were sold a bill of goods by the manufacturer. I think if they were still in business they would have worked with me. They retired. I have never dealt with a manufacturer that does not work with a customer. Always a first I guess.

I took more photos. You all have been wonderful! See what you think. This is part of the wall system. It is hung on the wall with space above and space below. In most cases the interior cabinets are fine but one there is an issue. nothing was left open no leaking in a second container and even shelf liner. wondering how those lower hinges got this way. The only thing that makes sense is vapors and humidity and heat reacting. Keyes hanging higher up same issue. There is slight spacing between the cabinet doors I would assume for ventilation. The hinge that is okay is on the top of the same cabinet. And I am noticing pitting on the handles exterior on a number of the cabinets. I am just trying to give as much information but I know difficult without being on site. There is a hose and a hose bib we make sure we do not let water touch the cabinets and we blow the lines out below we leave for the season and every time we use the hose we make sure all the water is out. There are no water marks anywhere on the cabinets just the separation and the rust or whatever it is.

It is moisture - from the humidity in the air. I have Gladiator cabinets in my garages. They are metal.

They sound expensive and no direct exposure to water. I'd challenge the manufacturer again. Can you get just replacement doors?