The number this whole guide turns on
The USDA Forest Products Laboratory publishes recommended in-service moisture content for wood products by region, and for interior woodwork, flooring, furniture and wood trim the figures are 8 percent average across most of the United States, 6 percent in the dry south-western area, and 11 percent in the damp, warm coastal area, with individual pieces in that coastal zone running 8 to 13 percent. Exterior siding, trim, sheathing and laminated timbers in the same coastal zone are specified at 12 percent average, 9 to 14 percent for individual pieces.
That table is Table 13-2 of the Wood Handbook, publication FPL-GTR-282, in the chapter on drying and control of moisture content by Richard Bergman. Figure 13-1 in the same chapter maps the three zones, and the 11 percent band runs along the Gulf and lower Atlantic coast. Mobile is inside it.
Read the Wood Handbook chapter on moisture content and dimensional change if you want the primary source, and the full Wood Handbook if you want the rest of it.
| Use | Most of the US | Dry south-west | Damp, warm coastal |
|---|---|---|---|
| Interior woodwork, flooring, furniture, trim, average | 8% | 6% | 11% |
| Interior, individual pieces | 6 to 10% | 4 to 9% | 8 to 13% |
| Exterior siding, trim, sheathing, average | 12% | 9% | 12% |
| Exterior, individual pieces | 9 to 14% | 7 to 12% | 9 to 14% |
USDA Forest Products Laboratory, Wood Handbook FPL-GTR-282, Chapter 13, Table 13-2. Major areas are mapped in Figure 13-1 of the same chapter.
What Mobile's climate actually measures
NOAA's 1991 to 2020 climate normals for Mobile Regional Airport give the underlying conditions. Annual precipitation normal is 66.15 inches and annual mean temperature is 67.2 degrees. Monthly precipitation runs from 3.69 inches in October, the driest month, to 7.25 inches in July, the wettest, with nine of the twelve months above 5 inches.
The figure that governs wood, though, is dew point, because dew point states directly how much water the air is carrying. The hourly normals put the mean dew point on 15 January at 39.4 degrees, on 15 April at 54.8, on 15 July at 72.0 and on 15 October at 57.6. That is a 32.6 degree swing between mid-winter and mid-summer. The primary data is at NOAA's US Climate Normals, station Mobile Regional Airport.
| Measure | Value |
|---|---|
| Annual precipitation normal | 66.15 in |
| Wettest month | July, 7.25 in |
| Driest month | October, 3.69 in |
| Annual mean temperature | 67.2 F |
| Mean dew point, 15 January | 39.4 F |
| Mean dew point, 15 July | 72.0 F |
| Seasonal mean dew point swing | 32.6 F |
NOAA National Centers for Environmental Information, 1991 to 2020 Climate Normals, station USW00013894, monthly and hourly datasets.
Air conditioning changes the indoor picture substantially, and the Forest Products Laboratory says so directly: its recommended values are based on measurements in well ventilated buildings without unusual moisture sources and without air conditioning, and in air-conditioned buildings moisture conditions depend largely on the proper sizing of the air-conditioning equipment. So a permanently occupied, correctly conditioned Mobile house sits closer to the national 8 percent figure than an unconditioned one does. A garage, an outdoor kitchen or a coastal rental shut up between guests does not.
Box materials, compared for this climate
| Material | Water tolerance | Flatness | Where it belongs |
|---|---|---|---|
| Cabinet grade plywood | Good; cross-laminated, survives a slow leak | Good, can show grain through paint | Sink bases, dishwasher and icemaker cabinets, exterior walls, vanities, laundry |
| Marine or exterior grade plywood | Excellent; waterproof adhesive, void free | Good | Outdoor cabinetry, and any genuinely wet location |
| MDF | Poor once the seal is breached | Excellent | Painted doors and flat panels where flatness is the priority |
| Particleboard | Poor; swells irreversibly | Good | Interior wall cabinets in conditioned space, on a budget |
| Melamine faced board | Poor at unbanded edges | Good | Closet and garage interiors, if every cut edge is banded and sealed |
| Solid hardwood | Good, but it moves | Moves seasonally | Face frames, door frames and rails, not carcass panels |
Assessment against the conditions above. The governing rule is to specify per location, not per kitchen.
Why solid wood is not a carcass material
This is counter-intuitive and worth stating plainly: a solid hardwood cabinet side would move more than a plywood one, not less. Plywood's veneers are laid at right angles to each other, so the movement of one layer is restrained by the next. A solid panel has no such restraint and moves across its width every season. That is why good cabinetry uses solid wood for face frames, door stiles and rails, where the pieces are narrow, and sheet goods for wide panels.
The sink base, which is where cabinets actually die
If you read nothing else here, read this section. The single most common cabinet failure in coastal Mobile County is a particleboard sink base floor that has been slowly wet. A compression fitting weeps a few drops a week. The water runs to the back corner of the cabinet floor, where nobody ever looks, and finds an unsealed cut edge. The board wicks, swells and softens. Months later a door stops closing properly and somebody finally empties the cabinet.
By that point the cabinet is finished. The swelling is irreversible, the fixings have lost their grip, and in a run of matched cabinets one replacement box is difficult to match. That is how a kitchen that only needed refacing becomes a kitchen that needs replacing.
- Plywood carcass at every sink base, without exception, whatever the rest of the kitchen uses.
- Plywood at the dishwasher cabinet and anywhere an icemaker or filtered water line runs.
- Every cut edge inside the cabinet sealed, especially around plumbing penetrations.
- A removable panel or an accessible route to the trap, so the first leak can be reached.
- A drip tray or a sealed liner in the sink base, which costs very little and buys a lot of warning.
- The underside of the cabinet sealed, not just the visible interior.
Doors and panels: where movement shows
A five-piece door is built to move. The centre panel floats in a groove in the frame precisely so it can expand and contract without splitting the frame. What that means in practice is that in a dry January the panel shrinks slightly and withdraws from the frame groove, exposing a hairline of previously hidden material at the shoulder.
On a stained door that line is invisible, because the stain was applied before assembly and the newly exposed wood matches. On a painted door it is visible, because the paint film was applied after assembly and has been cut at the shoulder. That is not a defect and it is not a failure of workmanship. It is the panel doing exactly what it was designed to do, and on this coast it does more of it than in most of the country. The painted versus stained guide covers the trade-off.
The ways around it are all legitimate. A slab door has no panel joint. An MDF five-piece door moves very little. A stained finish hides the line. Or a species from the lower half of the movement table, which the wood species guide ranks using the federal coefficients.
Finish, and the edges nobody seals
A finish is a moisture barrier before it is a colour. That is why the sealing of end grain matters more than the sheen of the topcoat. End grain absorbs moisture many times faster than face grain, so an unsealed end grain edge is a straw into the middle of the panel.
The edges that get missed are always the same ones: the back edges of a face frame, the cut edges inside a carcass where a hole has been drilled for plumbing, the underside of a cabinet bottom, and the bottom edge of a door where it was trimmed to fit. None of those is visible, which is exactly why they are skipped, and each one is a direct path into the material.
The other practical finish issue here is flash-off. A coating cures by releasing solvent or water into the surrounding air, and air already carrying a 72 degree dew point accepts less. That lengthens the time between coats in summer, and recoating too early traps solvent in a film that stays soft for months. The painting and refinishing page goes through the schedule.
Hardware and salt
Inland around Mobile and Saraland, hardware finish is an aesthetic decision. On bay-adjacent sites in Daphne and Fairhope, and down at Gulf Shores, it is a durability decision. Salt attacks any breach in a plated surface, and plating on a cabinet pull is thin by design. Solid stainless and solid brass corrode at the surface rather than through, which is why they are the coastal default.
This matters more for hinges and drawer slides than for pulls. A tarnished pull is cosmetic. A seized slide or a hinge that has lost its adjustment is a functional failure, and it is the one that ends up costing money. The hardware page covers selection.
Formaldehyde and composite panels
Composite wood products sold in the United States, which includes the plywood, MDF and particleboard used in cabinetry, are covered by federal formaldehyde emission standards under TSCA Title VI. Those rules apply in Alabama exactly as they do everywhere else. The EPA publishes the standards at formaldehyde emission standards for composite wood products. If a quote names the panel product, asking about the compliance label is entirely reasonable, and cabinet-grade material from a reputable supplier carries it.
Acclimation, and why it is not a delay tactic
Cabinet stock leaves the kiln at 6 to 8 percent moisture content and the recommended in-service figure here is 11 percent. That gap has to close somewhere, and there are only two places it can: in a controlled space before the cabinets are installed, or in your kitchen afterwards.
The first is better for obvious reasons. A cabinet that has stabilised before its doors are hung and its reveals are set will hold those reveals. A cabinet that is installed straight off the truck does its moving after installation, which is when a reveal that was even on day one stops being even by the following season.
There is a practical corollary that applies to new construction and to major renovations. Drying plaster, fresh screed and wet trades all put a great deal of moisture into a building, and the Wood Handbook is explicit that interior finish should go in after the building has dried down rather than before. Installing cabinets into a house that is still giving off construction moisture puts them into an environment well above the 11 percent figure, and they will shrink back when the building finally dries.
Ventilation inside cabinets, which almost nobody specifies
A cabinet is a small sealed volume. In a climate with 66.15 inches of annual rainfall and a mean July dew point of 72.0 degrees, sealed volumes against exterior walls are where mildew starts, and it starts out of sight.
The fixes are trivial and cost nothing at build time. Leave a ventilation gap behind the carcass rather than pushing it tight to the wall. Avoid a fully sealed, fully lined interior on any cabinet against an exterior wall. On a closet, a pantry or a cupboard housing equipment, consider a louvred door, which is the one door style that exists specifically to let air through. And do not fit an airtight seal to a cupboard that does not need one.
This matters most in the places people think about least: a closet against an outside wall, a pantry in an unheated corner, a bench seat with enclosed storage under it, and anything in a garage or on a covered patio. In those locations the air is not being conditioned at all, which is the assumption the federal 11 percent figure is based on.
The Gulf Coast specification, on one page
- Plywood at every sink base, dishwasher cabinet, icemaker run and any cabinet against an exterior wall.
- MDF for painted doors and wide flat panels, where flatness matters and water does not reach.
- Solid hardwood for face frames, door stiles and rails, never for wide carcass panels.
- Marine or exterior grade plywood for anything outside, including covered patios.
- Every cut edge sealed, including the ones inside the cabinet and underneath it.
- Species with lower tangential movement wherever a panel has to be wide.
- Solid stainless or solid brass hardware on bay-adjacent and coastal properties.
- A finish schedule that respects flash-off time in summer rather than rushing the recoat.
That list is the difference between cabinetry built for this coast and cabinetry built to a national average specification and shipped here. None of it is expensive at build time and all of it is impossible to retrofit. See the custom cabinets page for how it goes together, or start a measured quote at contact.