Attaching Cabinet Backs for Strength
Will a quarter-inch cabinet back, stapled to the carcass, keep the rest of the cabinet attached to the wall? Cabinetmakers discuss. March 25, 2007
I recently moved and went to work at another cabinet shop. I've been impressed with the overall look and quality of cabinet they produce here. They definitely put a lot of effort into producing truly custom designed, well planned cabinetry. I've learned a lot from them.
However, they do one thing that I do question. They do not use a 3/4" nailer on upper cabinets (wall cabinets). They only staple on the back (lots of staples). The box is attached to the wall with a normal 3" screw through the 1/4" back but the back is only held in place by staples and melamine glue (melamine or pre-fin interiors).
I am not accustomed to this. I am accustomed to building cabinets that conform to AWI standards, putting a 3/4 nailer in the top and bottom of each wall cabinet. I am looking for advice on whether this is safe from other cabinetmakers. Does anyone else do this?
From contributor R:
Wow. I wouldn't trust that either. I use full 3/4" backs on uppers, not just the nailers.
From contributor G:
Wow indeed. I think they are asking for trouble because someday one of those cabinets will let loose. It's also true that a 1/4" plant-on back takes up less room inside the cabinet, so they may be thinking that this is a benefit for the customer, saving 3/4" space in a 12 or 14 inch cabinet.
So don't address the issue with your employer as an issue of ethics (i.e. how can you be so cheap?) but one of safety and liability. The advantage to the customer is probably outweighed by the risk to your employer. Ignore the cost issue - that's not your job. Cabinets are going to be abused and hanging on the wall for many a year. Lots can go wrong.
From contributor F:
So, there you have the two extremes. On one hand, full 3/4" back on a wall cabinetů definately strong, but cabinets can be made strong enough without being made so heavy. On the other hand, just a glued and stapled 1/4" back. I will give them credit for the glue but I think it is still very weak compared to cabinets that integrate a 3/4" nailer along with a 1/4" back.
After a certain California earthquake that disrupted the world series baseball game, I had the opportunity to bid on some earthquake repair jobs and I saw several houses with the upper cabinet boxes crumpled up on the floor while their cabinet backs were still very strongly fastened to the wall studs all by themselves. I even saw some with the nailer and the backs being the only thing still on the wall. This is because the nailer wasn't fastened to the top shelf.
So, 1/4" backs are fine and keep the cabinet light. Be sure to screw down through the top shelf of the cabinet and into the nailer. Cabinets that were built like that (including ones I had made) were fine after the quake. Even if you use a full 3/4" back, it must be fastened other than just stapled or nailed straight through if it is melamine.
From contributor A:
I assumed the melamine boys out there in cabinet land used 5/8" backs and sides. We always use 1/2" ply. When the material is too dear or not available, we occasionally use 1/4" and glue and staple a 1/4" nailer top and bottom on the outside of the back.
From contributor J:
In the frozen country to your north, the standard back for melamine boxes is a full back of 1/2" thickness. I've seen only one failure since 1978 with this type of construction, mind you we don't get any earthquakes.
From contributor B:
Rather than suggest they are doing something wrong, why don't you ask your boss about it? Maybe they have a good reason, such as having conducted some testing and found their design adequate. Say something like "Hey boss, I see that a lot of other cabinetmakers add a nailer or use thicker backs. Is that overkill or do our installers add something to our cabinets to ensure they stay put?"
From contributor P:
I staple on 1/2" melamine backs, and then add screws on the top of the back. Never had one fail.
From contributor G:
And then if the backs were 1/4" Baltic birch, that would probably be strong enough, and we have done cabinets like this occasionally when there were some severe clearance problems. If you are using the big headed screws, that will help to keep the screw from pulling through the 1/4" ply... but wouldn't help keep the back to the cabinet.
From contributor W:
Never ever would we rely on that to hold the cabinet up. The installers must do something else to help hold them upů?
From contributor M:
I agree with contributor B. As long as my name didn't go on the cabinets I wouldn't worry about it. I would hold my breath and look away when I walked through the kitchen, though. I'll stick to my 1/2 backs.
From contributor O:
We staple our backs, no glue, with a 3/4 nailer. I'd be willing to bet that leaving out the glue and adding the nailer would be just as cost effective but make them much safer.
From contributor H:
We use 1/2" melamine backs with 3/4" hardwood nailer in the top of the cabinet. Nailer is attached to back and top. You have to work there long enough and do a good enough job for the boss to respect your opinion or you are wasting your time. He's not going to change his operation because of something a newbie says. If he did, no one would know what the system is.
From contributor R:
Contributor F, full 3/4" backs is a little overkill. We actually do it more for the fact that we have a small shop, and no room to order in a lot of different sizes. Being small, the cost difference isn't significant between our method and using 3/4" or 1/2" nailers and 1/4" back. If we did a higher volume (which ultimately is my goal), it certainly would make sense if you save a few dollars per cabinet, but we would also likely have a larger shop to store the different sizes.
I would never trust a 1/4" nailer, whether they're screwed, glued, nailed or double stick taped, and whether it's solid wood, plywood, melamine or MDF. If I were in your situation, I would approach it from the liability standpoint, and that it may not conform to AWI standards. If, as contributor T suggests above, they don't have any respect for the newbie yet, stating such a concern could earn that respect.
From contributor K:
We use 3/4 ply backs with blind dado - no worries. I have built miles with 1/4 let in a full dado with 1/2 nailers. I have honestly been called to look at 2 jobs in 15 years where the wall cabinets were laying on the floor, both times the 1/4 backs were still screwed to the wall with staples sticking out that used to be in the cabinet - not a pretty sight, and a potential lawsuit for anyone involved.
From the original questioner:
Many thanks. I have covered my rump by suggesting a more durable alternative, but as could be predicted, tradition trumps logic. I shall do as St. Peter did to his readers, "be submissive to your masters with all respect, not only to those who are good and gentle, but also to those who are unreasonable."
And for the record, I have never seen a melamine glue (what is used here for backs) that actually bonds pre-finished to any substrate. It pulls off rather easily even after curing for a day or two. Money better spent on a nailer or, at least, on a good insurance policy.