A single-door gate is fairly straightforward, but with a double-door gate, there is a bit more to it. Installing either style correctly is very doable if you know basic carpentry, have someone willing to lend a hand, and access to the right tools. A few tips help, too. Take the time to do it right the first time. You’ll end up with an attractive, serviceable gate that lasts for years.
Even if you have no interest in this project now, it pays to know how to install a level gate on uneven ground.
What You Will Need
To install a freestanding, double-door (or any) gate, you will need:
Materials
- Gate with hardware
- Two posts, typically 4 x 4’s or similar
- Decorative finial caps, optional
- Quik-crete mix, 3 to 4 bags
- Decorative gravel, pavers or flat stones, optional
Tools
- Spirit level
- Post level, optional but very helpful
- Clamps
- Shovel and bar, or a post-hole digger
- Electric saw
- 1 or 2 temporary boards a little longer than gate’s width (whatever you’ve got lying around that’s straight) for bracing
- Primer, paint and brush; drop cloth
- Pencil and tape measure
- Sawhorses or similar temporary support
- Battery-powered hand drill
- Screwdriver (or power drill tips)
- Hose or bucket
Select A Style
First, determine the width for the gate opening. Will just people and pets use the gate, or must wheelbarrows, mowers and propane tanks have to pass through? How about the snow blower or a new HVAC unit? Since my gate spans our primary path to the backyard, it must accommodate all of the above. A 60-inch opening was needed.
Second, determine in which direction the gate will open. If you want it to swing in two directions, you will need fully rotating hinges. Make sure there’s enough clearance when the doors are fully open. We chamfered one post to allow for a wider swing. Slight re-grading may be necessary on uneven ground.
Third, pick an appropriate design. If you’re in an HOA-controlled neighborhood like me, you may need to comply with certain guidelines. In my case, the gate had to be wrought iron or similar metal, no more than 4 feet high and have an “open” design. Since pre-made styles matching these criteria were quite limited, I chose a custom-fabricated gate that is not too ornate.
Select Post Material
Freestanding gates that come without support need two solid posts. An excellent choice is cedar 4 X 4s. Cedar is rot-resistant, beautiful, and easy to work. You could also use pressure-treated wood, “composite” wood, or metal. Anything sold as “deck posts” should suffice for a freestanding gate. The heavier the gate, the more substantial the posts need to be.
Calculate Post Length
First, measure the ground slope from side to side. Using a spirit level set on a board that is long enough to span the gate’s planned opening, rest one end of the board on the (higher) ground where one post will go. Adjust the board until it is level. Holding it there, measure the distance between the board and the ground at the location of the second post. This measurement is the slope, or elevation.
In my case, the difference was 4 inches, so one post needed to be 4 inches longer than the other. If the slope is greater than 4 inches, you may want to regrade the soil line to make it less uneven.
How high should the posts be? This is a matter of personal taste. In my case, I wanted the caps to extend slightly above the doors so the doors would just clear the trim when open. Part of the post gets recessed into the cap, so take that into consideration when measuring height. (This particular cap style contains a solar light.)
Finally, determine the depth of the footers. A rule of thumb is one third the height of the post should be underground. (For a 60-inch post, that would be 20 inches.) Our posts were under that, so we used 18 inch footers.
The posts will sit in holes and get cemented in place. It’s tempting, but don’t skip the Quik-crete. The posts must be rigid enough to handle the weight of the gate in all temperatures without working loose in freeze and thaw cycles.
4 x 4 posts typically come in either 8, 10, or 12 foot lengths. Stores like Home Depot often have warped stock, so ask for assistance and insist on straight pieces. We bought a ten-foot post, cut it in half and then trimmed each to exact length.
Apply the Finish
It’s a good idea to paint your posts (and gate) before you cement them in place. Metal should be primed with a rust-inhibitor such as Rustoleum and finished similarly. Wood can be opaque-stained, latex-painted or left to weather naturally, in which case a rot-resistant wood species like cedar or cypress is best. If you decide to use pressure-treated posts, finish with opaque stain. Some paints perform poorly or not at all on pressure-treated lumber, so check the label.
Good to Know: The chemicals in pressure-treated lumber can seriously inhibit or kill susceptible plants. I had this happen with roses on pressure-treated fencing. If you want vines or flowers to climb your posts, consider a different option.
Oil-based paint holds up better than latex, but it requires mineral spirits for cleanup and takes much longer to dry. If you opt for latex be sure to apply multiple coats and follow directions closely for the longest-lasting results. Personally I’m not thrilled with latex, but I hate the mess of applying oil-based products. I went with latex. We will see how it holds up.
TIP: Grille work or balustrades are easier to paint if you lay it horizontally on raised supports. The height saves your knees and more flat surfaces mean fewer drips. If you set up in the garage, you can paint in comfort and shade. Drying will be faster too.
I used a spray-on metal primer followed by three brushed-on coats of Rustoleum. Even if you don’t plan to paint the upper posts, paint the footer section as a precaution against rot. Don’t forget the hardware unless it’s stainless.
Measure Twice
Temporarily lay everything “in position” on the garage floor or lawn. Mark off the footers. Note where hinges and latches fall, and allow a small gap between doors. When everything is square, measure from center to center of each post. This will be the distance apart your post holes must be.
As noted earlier if your mounting spot is not perfectly level, each post will have a different above-ground measurement. In my case, 35 inches on the upside vs. 39 inches on the downside of the slope.
If you’re using end caps or finials, try them out. Check to ensure the doors will clear the trim. (Mainly an issue with curved-top gates.) Don’t neglect to check out the details now; it will be too late once the posts are cemented in place.
Dig Your Holes
Mark one post center on the ground. Dig a hole 8 to 12 inches in diameter around the center mark and however deep your footer will be — in our case, 18 inches. Pry out any rocks. If you hit anything truly immovable you will have to move the hole. If that happens, the second hole must shift with it, so it pays to dig as you go. You never know when you could run into a problem. Use your hands to excavate the dirt out; it’s faster and easier than a shovel.
Measuring from the center of the first hole, locate the center of the second hole. Dig the second hole in its entirety before you cement in the first post. Again, this is a precaution in case you hit rock.
Both holes should measure the same depth. Width is less critical. You need wiggle room, but not so much that you need a lot of Quik-crete. Set the posts in the holes and level them across their tops. (If they are off slightly, just fudge the hole depths.)
After squaring them up with levels to both each other and the path, brace them with boards and clamps. A twisted post will create mounting headaches, so make sure both are facing straight ahead.
TIP: Buy or borrow a post level. This hinged tool straps onto any upright and makes quick work of squaring a post in three dimensions at once. Combined with a regular spirit level spanning the two posts, you get perfect alignment.
Slowly pour Quik-crete into the first hole, wetting it per bag instructions. Clamps and braces are essential to prevent shifting. Allow to set up overnight. (In case of rain, a tarp will protect it adequately.) Do the same with the second hole the next day.
IMPORTANT: Repositioning is impossible once the Quik-crete is in. If one post moves even a small amount, the whole thing will skew out of alignment. The wider the gate, the worse the skew will be.
Prepare the path
If desired, regrade the ground or add pavers where the gate will sit. We chose to extend a short gravel-and-flagstone walk so we didn’t have to mow around the posts, and to visually connect the area with an adjacent flower bed.
Mount the doors
Finally, enlist a helper to mount the gate onto the posts. Use a level to locate (and double-check) where the hinges go. Be sure you position it with the latch (or lock) on the correct side!
With one person holding a door, the other can attach the hinges and bolts. Mount the other door. Finally, affix the caps or finials if using.
Voila!
You’re done! The doors and latches should align and work smoothly. If they are slightly off, you can try shimming the hinges on one side with metal washers for a better fit.
So there you have it. Our gate works well and the 4-inch slope is hardly noticeable. No matter what style or size gate you decide on, the principles outlined here apply. Go for it, you can do it!
