Garth Allen Fence Builders wrote this comparison for Allen owners with an alley-loaded garage who want to close off the drive behind the house.
On an Allen alley lot, a swing gate suits a fairly level drive with room inside for the leaves to open, while a sliding gate suits a sloped or short drive with clear fence line beside the opening. A sliding gate across an alley drive must also follow one of the City’s two trash-bin layouts.
Both types can work well. The choice mostly comes down to the geometry of your drive and how the City wants the alley to work on trash day.
How each gate works
A swing gate is usually a pair of leaves hung on heavy posts at each side of the opening, meeting in the middle with a drop rod to hold them closed. Each leaf needs a clear arc to open into.
A sliding gate rolls sideways along the fence. A track gate rides on wheels in a rail across the drive. A cantilever gate hangs from rollers on posts beside the opening and is longer than the opening, so its tail counterbalances it and nothing runs across the drive surface.
Side-by-side comparison
| Factor | Swing gate | Sliding gate |
|---|---|---|
| Space it needs | Clear arc inside the drive for each leaf | Fence line beside the opening, at least the opening width |
| Sloped drive | Leaves can hit the rising slab | Unaffected by slope across the opening (cantilever) |
| Wind | Leaves catch wind like sails when open | Stays parallel to the fence |
| Trash-day layout in Allen | No special City layout | Must use one of two City trash-bin options |
| Automation | Arm or ram openers on each leaf | One opener at the side |
| Typical DFW-area cost | $400–$900 for a double drive gate, manual | Priced per design; automated gates $1,500–$4,000 |
The alley drive problem
Many Allen homes back onto an alley with the garage facing it, so the drive gate sits in the back fence line. Two things make these drives tricky.
Slope. Alley drives often rise from the alley to the garage. An inward-swinging leaf scrapes the slab partway open unless it is hung high, which leaves a gap underneath. A sliding gate moves along the fence instead of across the slope, which is why it is common on steeper drives.
Trash pickup. The City of Allen fence guideline says a sliding gate across a rear-entry alley drive must use one of two City trash-bin pickup design options from its engineering standard details, and the option must be named on the permit. The point is that bins can be set out and collected without the gate in the way. Plan the bin location with the gate, not after it. The Allen permit rules guide covers the rest of the application.
Sight lines. On a lot where the alley meets a street, the City wants 20 ft of clear vision back from the projected curb line. A gate or fence in that triangle has to be held back, which can change where runback space is available.
Posts, clay and wind
A drive gate puts far more load on its posts than a fence panel. A heavy leaf pulls its hinge post toward the opening every time it hangs open, and Houston Black clay, which swells when wet and shrinks when dry, lets an undersized footing drift over a few seasons. That drift is the usual reason a swing gate starts dragging or its latch stops meeting. The sagging gate guide and the clay soil guide explain the fixes.
Allen’s guideline sets 18 in in concrete as the minimum post depth for fences, and gate posts generally go deeper and heavier than that. Wind matters too: the City’s adopted code uses a 105 mph design wind speed, and a solid cedar leaf left open in a storm acts like a sail on its hinges. A sliding gate stays in line with the fence, so it avoids that lever.
When to automate
Both gate types can take an opener. Sliding gates usually take one operator at the side; swing pairs need one per leaf. Any automatic gate needs entrapment protection such as photo eyes and edge sensors, covered in the automatic gate safety guide. See automatic gate installation for power, controls and openers, and gate installation for manual drive gates and walk gates.
A quick way to decide
Lay a straightedge across the drive where the gate will hang. If the slab rises more than a couple of inches inside the leaf arc, lean toward sliding. Then pace the fence line beside the opening: if there is not at least the opening’s width of straight fence free of trees, meters and corners, lean toward swing. If both work, compare how you want trash day to run. For a rough budget, the fence cost guide lists typical gate ranges.