Apron, Slope and Plantings at the Door

The concrete apron in front of a garage door must slope away from the door at roughly 1/8 inch per foot, and the driveway must keep falling from there. If it does not, water reaches the bottom seal, wicks under the door and starts the rust that eats the bottom section first. The apron, the grade and the plantings are one system, and they are planned together before any concrete is poured. The planning logic here is the same one used for any residential landscape project, and a guide such as landscape planning for homeowners walks through site reading, water and plant selection by function before anything is ordered.

Why must the apron and the driveway slope away from the door?

A garage floor sits at or slightly above the surrounding grade, and the apron is the transition between the two. The building code that most U.S. jurisdictions adopt, the International Residential Code, requires the garage floor to be above the outside grade and the driveway to fall away from the building. The practical number on the apron is 1/8 inch per foot, about 1 percent. A 20 foot apron drops about 2.5 inches from the door to the driveway.

That slope does three jobs. It carries rain and snowmelt away from the bottom seal. It keeps the seal from sitting in a puddle, which is what turns a rubber gasket into a stiff, cracked strip. And it keeps the slab under the door from freezing and heaving in a climate with freeze and thaw cycles.

A flat apron, or one that falls back toward the door, sends water to the worst possible place. The bottom seal is the lowest point of the door, and the bottom section is the first panel to rust. Standing water at the seal also freezes into a lip of ice that the door has to break every morning.

The fix is not a new driveway. A mudjacking or polyurethane foam lift can raise a settled slab and restore the fall. A shallow trench drain across the apron, tied to a daylight outlet or a dry well, catches what the slope cannot move. Both are concrete work, and both are cheaper than replacing a bottom section and its seal every few years.

How close may plantings and trees sit to the door and its track?

Keep the soil and the mulch at least 6 inches below the bottom of the door, and keep the finished grade below the slab. A bed that is built up against the door frame holds moisture against the wood or steel and gives termites a bridge. The same rule applies to the side jambs: soil piled against them is a slow leak.

For the track, leave 18 to 24 inches of clear space on each side of the door opening. The vertical track, the hinges and the rollers need that room to move, and a shrub pressed against the track bends it out of line. A bent track makes the door bind, and a binding door is a service call.

For trees, the limit is the root zone, not the branch spread. A tree planted within 10 feet of the door will send roots under the apron and the slab. Roots lift slabs, crack aprons and open the joints that let water in. Small ornamental trees and shrubs with fibrous roots are the safer choice near a garage; large shade trees belong 15 feet or more away.

Plantings also decide how the door reads from the street. A bed of low, mounded plants along the apron softens the concrete edge and frames the opening. Tall plants at the corners of the door pull the eye up and make the door look smaller than it is.

What does the door plane contribute to how a house reads from the street?

A two car garage door is often 16 feet wide and 7 to 8 feet tall, which makes it the largest single plane on the front elevation. On many houses it is larger than the front window and the entry combined. That plane sets the scale for everything around it.

A door that matches the siding color recedes, and the entry becomes the focus. A door in a contrasting color becomes the focus itself. Neither is wrong; the point is that the choice is made, not inherited from whatever the builder installed.

The apron and the plantings are part of that plane. A wide, bare slab in front of a door reads as a parking pad. The same slab with a defined edge, a low bed and a clear path to the entry reads as an approach. The concrete is not decoration; it is the ground the door sits on, and it is visible from the street every day.

What should a household fix first when the approach looks tired?

Fix water first. A tired approach is usually a wet approach, and everything else is cosmetic until the drainage is right.

Start with the seal. Close the door and look for daylight under the bottom seal. A seal that is flattened, cracked or missing lets water and air in, and it is a homeowner job on most doors. Replace it before spending anything on plants or paint.

Next, check the slope. A 4 foot level on the apron tells the story. If the bubble shows a fall toward the door, or no fall at all, the concrete is the problem. A trench drain or a slab lift comes before new plantings, because a bed planted in a puddle will not survive.

Then clear the track. Pull mulch and soil back from the jambs and the vertical track. Look for rust at the bottom of the track and at the bottom bracket. Rust there means water has been sitting, and the drainage work is not finished.

Last, the plantings. Once the water moves away from the door, a low bed along the apron and a small tree set back from the slab will hold the grade and finish the elevation. The order matters: water, seal, track, plants.

Where the homeowner stops

Springs, cables and drums are never a homeowner job. The torsion spring above the door stores enough energy to break a bone, and the cables and drums hold that energy in place. A door that is out of balance, or a track that has been bent by a shrub, is a call to a technician. The homeowner can replace a bottom seal, clear the track of soil, adjust the photo eye and test the safety reversal every month. That is the line.

What the standards say

The installation instructions that come with the door and the opener govern the specific clearances, and they vary by manufacturer. ANSI/DASMA 102 covers the standard sizes and the dimensional conventions for sectional doors. UL 325 covers the entrapment protection on the operator, including the photo eye and the edge sensor. The IRC covers the floor elevation and the driveway slope. Read those three before pouring concrete or planting a tree, because the concrete and the roots are the parts that are expensive to move.