How Much Space Between Base and Wall Cabinets

Installing kitchen cabinets would seem, on its face, to be a very simple operation. Unfortunately, it isn’t as simple as it might seem. In a perfect world, all any of us would have to do is set the cabinets in place and install some attachment screws. But that perfect world is assuming that the home those cabinets are being installed into is perfect, with all the floors perfectly level and flat and the walls perfectly plumb. That is rarely the case, forcing whoever is installing those cabinets to make up for any inconsistencies in the way that the home is built.

Base Cabinet Size

While kitchen base and wall cabinets can literally be made to any size one would like, sizes have been standardized over the years, especially the heights of the cabinets and the spacing between the wall cabinets and the countertop. This has been done not only for the purpose of standardized manufacturing, but also to make the cabinets and especially the countertop more ergonomically comfortable for use. A 36” countertop height is considered the perfect height for the average person to work comfortably at, while standing.

Please note that this countertop height means that it is a bit low for tall people and a bit high for short ones. While it would be possible to order or make custom-built cabinets that are taller or shorter to match the height of the home’s occupants, this is rarely done. That would not work out for everyone in the home anyway, as it is unlikely that everyone is tall or short. As those tall and short people typically grow up with standard 36” countertop heights, they are accustomed to it. While it may not be as comfortable for them as custom-built cabinets would be, they can work with it quite well.

Base cabinet depth is also standardized at 24”. This allows for a countertop that is 25” deep. However, some homes are designed with larger counter depth of 25.5” or even as much as 28”. The problem with this is that most kitchens are not large enough to accommodate countertops this deep, without it taking much needed space from the walkway between the countertop and the island.

Islands are more likely to have wider and deeper countertops, with more of an overhang, than countertops mounted to base cabinets that are along the wall. Many times this is done intentionally, providing a serving or eating area at the island.

Wall Cabinet Size & Spacing

The space between the countertop and the wall cabinets is somewhat standardized as well, normally at 18 to 20 inches. What most finish carpenters do is install the wall cabinets 20” above the base cabinets. Since countertops are usually 1-1/2” thick, this leaves a space of 18-1/2” between the countertop and the wall cabinets. That’s high enough to provide a good working space, especially in the case of 12” deep cabinets, while still being low enough that most people can comfortably reach the top shelf of a 30” tall wall cabinet.

It is also possible to buy wall cabinets that are 15” deep. When these are used, it is for the purpose of providing a deep cabinet for storage of serving dishes and platters. A kitchen will normally only have one double wall cabinet that is 15” deep, if it has one at all. The extra cabinet depth makes it more difficult to use the countertop space where it is mounted.

But are all wall cabinets 30” tall? The answer to that question is no. Wall cabinets can actually vary considerably in height; however, 30” is the standard height for a home with an 8’ ceiling height. As the ceiling height goes up, those cabinets could be either 36” tall for a 9’ ceiling height or even 42” tall for a 10’ ceiling height.

Chances are fairly high that you have seen homes which don’t follow this rule of thumb. older homes, which were built before the 1960s are likely to have kitchen wall cabinets that go all the way up to the ceiling. This style was abandoned in more recent times, first replaced by a soffit and more recently leaving the space open. Not only does leaving this space open provide for a lower cabinet manufacturing cost, but it is used by many homemakers as a place to display decorative items.

Base Cabinets

Kitchen cabinets are ordered to fit a specific kitchen layout, either designed by the architect or in the case of a remodel, by a kitchen designer. Homeowners might choose to design their own kitchen cabinet layout; but they are often assisted in this process by sales personnel with training in kitchen design.

The key idea in kitchen design is to maximize storage and countertop space in the kitchen. A minimum of 36” of space is required between the edge of the counter and an opposing counter or island. If the kitchen is being designed for two people to work in at once, this dimension is increased to 47”. That amount of space allows two people to pass, sideways, even with an open oven door.

One big question for many people is whether floor covering should be installed before the cabinets are or afterwards? The old standard, when hardwood flooring was used and later when linoleum flooring was common, was to install the finished floor before installing the base cabinets. However, base cabinets should not be installed over floating wood laminate flooring, carpeting or tile. In those cases, it is best to install the base cabinets directly over the wood subflooring and then install the flooring once the cabinets are installed.

Installing Base Cabinets

Chances are fairly good that the floor will not be perfectly flat and level. Since the cabinets need to be installed perfectly level, with the tops all at the same height, the first part of installing them is to determine the highest point of the floor, along the wall line. To do this, make a mark on the wall, near the floor, and snap a horizontal line at that mark, ensuring that the line is perfectly level. Then measure the distance between the line and the floor at various places. Wherever the measurement is the smallest will be the high point of the floor.

From that point on the floor, measure up 34-1/2” and 73-1/2”. The lower dimension is the height for the tops of the base cabinets, while the upper one is the height of the bottom of the wall cabinets. Snap level horizontal lines around the kitchen, at these dimensions, wherever cabinets will be installed. Do not worry about the height above the floor, other than at the high point. Rather, make sure that the line is level, so that the cabinets will be level.

Also find the locations of the studs and make a vertical mark at each stud that goes from below the 34-1/2” line to above the 73-1/2” line. These vertical lines can either be aligned left-right or center on the studs, as the woodworker prefers. Just make sure they are consistent and that everyone working on the cabinets knows how they are marked.

It is always best to start by installing a corner cabinet. The manufacturer may provide instructions, delineating any spacing between the cabinet and the wall. If so, be sure to maintain this spacing. As for height, many of the base cabinets will probably have to be shimmed, in order to bring them up to the line snapped at 34-1/2”. Maintaining this height is of supreme importance.

Set the corner base cabinet in place and shim it to bring it up to height and to space it out from the wall, if needed. Shims against the wall must be located at the studs. If there is to be another cabinet set beside the corner cabinet, allow the shim to stick out, so that the adjacent cabinet can sit on it also. Then drill through the mounting rail on the back cabinet, as well as the shims. Attach the base unit to the studs in the wall with 2-1/2” screw. There should be at least two screws going through the back of the cabinet into each of the studs.

Once the cabinet is installed, install doors and drawers, ensuring that they fit and that they have clearance to open and close.

Each additional base cabinet is aligned with those that are already installed, tight up against them. Ideally, it should look like one continuous cabinet, once the installation is finished. So the next cabinet will align with the corner cabinet, as well as with the 34-1/2” height line. It should be level with the top of the corner cabinet and flush in the front. Continue mounting cabinets, ensuring their alignment, until all the base cabinets are installed.

In order to tighten up the space between the cabinets, it is normal to screw the cabinets together, wing through the side wall of one cabinet, just behind the face frame, into the adjacent one. Since the side walls of the cabinets are normally made of ¾” thick plywood, 1-1/4” screws should be used for this.

Before installing the toe kick, make a final check of cabinet alignment. It may also be necessary to trim off any shims sticking out below the front of the cabinets. The toe kick is attached to the side panels of each cabinet, in the proper area. Use finish nails to attach it.

If there is a gap between the back of the base cabinets and the wall, it is a good idea to fill the space between the back of the cabinet and the wall with expandable urethane foam. Allow it to set, then trim it off flush with the top of the cabinets. This will keep caulking from falling down into that space when the backsplash is caulked.

Installing Wall Cabinets

Unlike base cabinets it’s rarely necessary to shim wall cabinets. Even so, it is important to keep the front frames of the cabinets and the height perfectly aligned, just as with the base cabinets. This may require a bit of shimming at times, if the wall is wavy. In that case, it would actually be better to mount thin strips on the wall for the cabinets to mount to. However, in cases where that is done, a filler strip or molding will need to be nail to the wall, just below the cabinets, to hide the gap between the cabinets and the wall.

Temporarily attach a ledger board to the wall, with the top of the board aligned with the 73-1/2” line. This will be used for the back edge of the cabinets to set on, while it is being hung.

If the cabinets already have doors, shelves and drawers installed, it is a good idea to remove them while hanging the cabinets. This will make the cabinets lighter and easier to handle. Even so, it’s a good idea to have an assistant to hold the cabinets in place while the hole are drilled and screw installed.

Start with the corner cabinet, as with the base cabinets. Set the cabinet on the ledger strip and check to see that it is plumb and level in both directions. If necessary, shim behind the cabinet, in line with the studs to make the cabinet plumb. Then drill two clearance holes through the back of the cabinet or through the mounting strips installed into the back of the cabinet (if the back is ¼” thick). Attach the cabinet to the wall with 2-1/2” long cabinet screw.

Working from that cabinet, set the next cabinet in place, sitting on the ledger line. Clamp the two cabinets together, aligning the face frames. If necessary, shim the cabinet as the corner cabinet was, and then holes and screw it to the wall. Each stud should have two screws into it and it is best if each wall cabinet is attached to at least two studs. However, some wall cabinets may be too narrow to attach to two studs.

As with the base cabinets, it’s a good idea to screw the cabinets together, just behind the face frame. This will help eliminate any gap between the cabinets, giving them a uniform appearance.

Reinstall shelves, doors and drawers, making sure that they are properly aligned and function smoothly without hitting anything. On cabinets where molding is provided, the molding should not be installed until the cabinets are fully installed. This might include crown molding at the top of the cabinets. The molding will not come from the factory pre-cut, but will need to be cut to fit on site.