Shimming Cabinets

      Experienced installers share tips for fitting cabinets in place. April 14, 2005

Regarding shimming - does anyone have any tips to increase speed and consistency? We do base units, remodels, toes attached. I need tips for out of square conditions a consistent method of identifying problems in walls and floors and the best way to adjust.

Forum Responses
(Cabinet and Millwork Installation Forum)
From contributor A:
Every situation is different in remodels. When first going to the site its always good to have a level, framing square, and a 6 to 8 straight edge, and if you have a laser it a good thing to use. You should use all of the above to get an idea of what you are dealing with before construction. If a wall has a bad bow in it, have the contractor fix it. If that is not possible you might have to adjust the depths of the units to accommodate the bow. Say you have an 8 wide wall with a bow in the center that pokes out 1. Two things can happen here depending on the situation.

Lets say you have base units 24 deep going on the wall. First, determine if there is any reason to make the units shallower. Do they have to line up with something - if you shim the cabinets off the wall to make a straight line, will it mess anything up? If not, shim the units off the wall and make sure you have plenty of scribe on the back of your counter top to cover the bow in the wall. If there is a finished end make sure to let that end go past the back of the unit so it can be scribed to the wall.

If you have two walls that intersect and they are not at 90 degrees, use your framing square off of the back wall to determine where the back corner of the unit will be on the back wall. This way you can see exactly how much end scribe you will need. On frameless cabinets usually 1 will do the trick. Again, every situation is different.

Check the floor to see how level it is either using a level or the straight edge to see if there are any bad humps or dips. Or if you have a laser but a benchmark on the wall and measure down to see the variations. In this example Im going on the assumption the countertop has to be held at a specific height.

Say you have a floor that drops 1 down over 8- you will now have to shim up the units at the drop and make sure that your base mold is tall enough to scribe to the floor. If the floor rises up 1 you can manufacture the units with 1 less in height in the base so you dont have to cut units down in the field. And once again you will have to shim up the other units and make sure your base mold is tall enough to scribe.

Attached bases are more time consuming and difficult to deal with. In very rare cases you can pre-shim the floor and set the units on them. Usually you have to do one at a time. It is always a good idea to make a shim package, with all kinds of thicknesses, to send to the field. Again, if you put a bench mark on the wall you can see ahead of time how much you will have to shim. Detached bases for long runs of cabinets are faster and easier to deal with. Say you have 4 boxes on a 8 run. Make one long base for all. Just throw down the base, put a level on it and shim it. Screw it to the back wall if you can and use liquid nails to set your units on the base. Once the units are screwed together and to the back wall and the liquid nails dry, it wont go anywhere.

From contributor B:
I see a lot of guys use cedar shingles as shims - if they need an inch, they just stack them up. I dont like this, as the stack can be unstable and shift around as you are working with the cabinets plus cedar is a very soft wood. I keep a basket full of various blocks I have cut from scrap, from 1/8 to 1-1/4 thickness. I slip this in place and then use one nylon break off shim to take up the space I need. For the back of a corner cabinet, for example, I test fit, determine the size of shim I need and then tip the cabinet out and air nail the blocks to the bottom of the cabinet. Then you can move it into place without the shim falling out and fine tune it with shims in the front corners.

From contributor C:
I've started using those composite shims found at most any big box store. There is less shrinkage, they are not as soft, easier to break off, and more consistent than wood. And as said, check out floors and walls right off the bat to get an idea of the lay of the land (as I say) to know what your up against before you start setting.

From contributor D:
With the way that places are built today you have to have loose scribes and base to make anything fit wall to wall or floor to ceiling. If you don't have control of the manufacturing end then you are going to have big problems. I also have gone to larger scribes because the level of quality construction has gotten worse and the only answer is more and more scribe, preferably loose. This way all shimming is done behind the scribe or base and you have a means for a perfect looking fit.

From contributor E:
I cut some hardwood scrap into shims, some with the grain and some against. I always glue them in place and let them dry. The cross-grain ones will snap off clean with a sharp chisel. If I don't want a breakaway shim I'll use the others.

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