Pics or a better description of the cabinets would be helpful. You should be able to reinforce them. How is a little hard to say without seeing what you have.

 

Sure, Mark.

If you look under my name on the far left side, there's a link in blue text called View Lucifugen's Album, or something like that. That's where I posted all the pictures related, because it was way easier.

If there's another picture that should be taken, just describe it and I'll post it.

Thanks for your response!

 

You could add some wood corner blocking to the inside corners for stabilization. Inexpensive and can be glued in place. As far as the outsides you could reface with new laminate providing the existing laminate hasn't come loose from the substrate. If the laminate has come loose apply some heat to melt the glue and apply pressure to reattach.....fairly inexpensive. You could trim the corners with wood to spruce them up and hide laminate edges. Laminate can be edged seamed to make invisible (almost) joints but takes a little skill. This work would be labor intensive but you indicated that is your preference.

 

Glued corner blocks. THAT's a fix I can do! :smile:

There's no way I could edge seam laminate, but thanks for mentioning the possibility. The issue isn't really the laminate coming loose from the substrate, because the substrate isn't much thicker than the laminate. I like the idea of replacing some pieces of laminate/substrate with sturdier wood, but if new side material increased the size of the gap of the joints between the face frames, how could I hide that in the middle of a run of cabinets? Making new face frames (bad), or installing fillers (less bad)...would wood putty crack when the cabinets are loaded? Maybe the solution is as simple as paintable caulk??

 

Glued corner blocks. THAT's a fix I can do! :smile:

There's no way I could edge seam laminate, but thanks for mentioning the possibility. The issue isn't really the laminate coming loose from the substrate, because the substrate isn't much thicker than the laminate. I like the idea of replacing some pieces of laminate/substrate with sturdier wood, but if new side material increased the size of the gap of the joints between the face frames, how could I hide that in the middle of a run of cabinets? Making new face frames (bad), or installing fillers (less bad)...would wood putty crack when the cabinets are loaded? Maybe the solution is as simple as paintable caulk??

Usually the cabinets are attached to each other by screwing the face frames or bodies together. Will these be painted? You could add a wood filler. Durhams Rock Hard Water Putty is good stuff. You could also use a 2 part epoxy....Minwax is good. You can sand either product smooth. Cabinets should not sag when loaded.....if they do then something is wrong e.g. the cabinets themselves or the wall attachment or they have been loaded with things they were never intended to hold.
Besides wood corner cleats you could add under supports to the shelves if they sag.

 

Use glue, screws (#6) and staples (long glue coated ones fired from a gun) to repair & rebuild. Since you are having to spend time to rebuild them, I'd add some structure. Use non trim wood like; 1x3, 1x4, etc to build a basic frame for them. Use PT for the bottom boxes. I'd spring for soft close hinges and slides.