Building a perfect picket fence
by Al Kupchella
I have received so many compliments on this fence that I decided to share the experience. I'm sure you have seen those plastic fences that are getting so popular. Call me old-fashioned, but to me they just look, well…plastic! I wanted an economical, perfect, white wooden picket fence. I have a privacy fence around the side and back of my yard, and I wanted the picket fence to be of the same style in a scaled-down version.
Making your own fence from "scratch" allows you to perfectly customize it to your yard. Here's how to do it!
Laying out the fenceposts...
I employed several tricks to get the posts in the correct positions. Of course, I wanted them to be linedup straight, at the proper height and have holes for the cross rails perfectly placed.
First, put up a temporary post about two feet beyond each end of the intended fence line and string a mason's line between them. These temporary posts can be 6 ft 2x4s that are poked into the ground a little and supported with some scraps and stakes. Of course the ground underneath the mason's line won't be level or even linear. Move the mason's line up or down, and grade the ground a little until the mason's line represents the tops of the fence posts you will be installing. If you are building a long fence, or the ground rolls up and down too much for a linear fence, you will have use more than two temporary posts.
Next, figure how many fence posts you will need with the assumption that they should be spaced a maximum of 8 ft on center. I needed 9 posts evenly spaced at about 7 feet. Mark the ground with stakes to indicate where to dig the postholes. Mark the location of the mason's line on the temporary poles, remove the mason's line, and leave the temporary posts in place.
Dig the postholes...
If you have ever dug a hole in New England you know we have lots of rocks, so getting the posts in exactly the right place can be challenging. So I dug my postholes, making sure they stayed aligned with my masonry line, but I didn't worry too much if a big rock altered my spacing a little. Since I wasn't constrained by commercial fencing dimensions, any variations between the posts would be rendered invisible later.
I also didn't worry about the precise depth of the holes; I just made them as deep as I could with my clamshell posthole digger and an occasional assist from a big steel pike.
Making the posts...
Make your posts out of pressure-treated 4x4s. I used 8 ft lengths, but don't shorten them until later. Figure how high from the top of the posts you want the center of the rails to be (mine are10” and 32”) and drill two holes through each post for the round tenons you will have at the end of each rail. To drill the holes I used a self-feeding 1-3/4 inch bit in a drill press. But with the posts being wet, this was a little more than my drill press could handle, so I removed the self-feeding screw from the drill bit. The drill press also didn't have quite enough stroke length to drill the holes all of the way through, so I finished the last © inch of the holes from the other side by drilling a 1 inch hole then enlarging it with a piloted trimming bit in a router. (Note from NH: This procedure can also be done with a 3/8 or 1/2" portable drill if you don't own a drill press.)
Next, drop a couple of small stones into each posthole. Use the posts like a pile driver into the bottom of each hole to be sure they each have a stable bottom. Now put your mason's line back in place, put the posts in the post holes UPSIDE DOWN, and mark the length of the posts according to the mason's line. Number the posts, so that you don't get them mixed up. Then cut all of the posts to length.
Installing the rails...
To get the rails to fit well, and still keep the whole thing straight, install the posts one at a time, starting at one end. Using the mason's line between the temporary posts, a level, and some wood scraps and stakes – get the first post where you want it. Then fill the hole around the post with some potato-sized rocks pounded into place and about a half bag of concrete. Fill to within 2 inches of the top, leaving room for a little dirt after painting.
Now get the second post in position so you can measure the length of the rails for the first section. The rails should be 3" longer than the space between the posts. Cut two rails to length from 8 ft. 2x3, (I didn't use pressure treated, since I would be painting them and they wouldn't be in contact with the ground) and finish the ends with round tenons. The tenons don't have to be perfect. I rough cut them with a circular saw set at 45 degrees, chiseled off the rough cut from the end, and then rounded the tenons off with a drawknife (graphic right). It's handy to have a scrap of wood with a 1-3/4" hole in it to use as a gage as you shape these tenons.
Put these two rails in place between the first and second post, get the second post positioned just right (using the mason's line, a level, wood scraps and stakes), then fill the hole with rocks and concrete, pounding the rocks in tight.
Repeat this procedure one section at a time for the rest of the fence, cutting the rails to length, putting tenons on the ends of the rails, installing rails and setting the next post. I wound up with the spacing between my posts varying from about 6.5 feet to 7.5 feet.
The rails at this point are going to be loose and can be rotated about their horizontal axis. Now is a good time to put a coat of primer on the rails. I used a heavy coat of linseed oil followed (after drying) by an oil-based primer. You might as well prime the posts at this time too. After priming, you can secure the rails by driving a 3 inch galvanized screw into the posts through the tenons.
Making the pickets...
Now you have a lot of pickets to cut! I used 1x3 for the pickets (not pressure treated), and I wanted the spaces between them to be about the same size as the pickets themselves, so each picket would account for about 5 inches of fence. Divide the length of your fence (in inches) by 5 (or whatever is the sum of your picket width and the gap size you would like) and you get a good estimate of the number of pickets needed. Keeping in mind that you will still be adding caps onto the posts, and that your pickets shouldn't touch the ground, decide how long you want your pickets to be. All of the pickets should be the same length (you can shorten some later if needed) so you can cut them all to length now.
I wanted the shapes on the tops of the pickets to be very uniform, so I rough-cut them with a jig saw and finished them with a piloted bit in a router, following a pattern piece. To do this, first I carefully laid out and cut my pattern piece out of one of the pickets. I used the pattern piece to trace the shape onto each picket with a pencil. Then I cut them all a bit oversized with a jigsaw.
Next I used the pattern piece to guide the router. To do that I put a couple of box nails (skinny nails with heads) through my pattern piece. I trimmed them so they stuck out about a © inch and sharpened the points. Then I nailed the pattern piece to the top of my workbench with the sharpened nails sticking up. (You might have guessed that I don't worry about having a pretty top on my workbench.) Then I pushed one of the rough-cut pieces onto the pattern piece (the nail points being used to keep the pattern picket and the unfinished picket from shifting around.) Then I clamped the pair of them to the table for good measure, and used a router with a piloted trimming bit to make the rough cut piece match the pattern piece.
Prime all the pickets BEFORE installation...
Once you have all of your pickets finished, you should prime them all over before installation. This takes forever with a paint brush (which is how I did it). But this is a great application for a timesaving tip. Use a piece of PVC pipe with a sufficient ID for a picket to fit inside, a little longer than your picket, and with an end cap on one end. Support the pipe somehow. Put a picket in, and fill the pipe with primer. Pull the picket out (it will have way too much primer on it). Stand it up in a paint roller tray, and use a squeegee or stiff brush to wipe down the excess primer into the tray. Lean the picket someplace to dry, or you could staple the picket onto a wire like a clothesline. (It's nice to have a helper with this, since you are going to have primer all over your hands or gloves.) You will need about as much clothesline (or wall space) as the length of your fence. You could also just lean them against your fence if you put something on the ground under them.
Spacing and Attaching the Pickets...
Now you have perfect pickets ready to hang on your rails, but the real key to making your fence look great is to get the spacing just right. You want all of the spaces to look exactly the same including the spaces between the posts and the adjacent pickets. To do this, I made a spreadsheet using Microsoft Excel. On the spreadsheet, you enter the width of your pickets and the width you would like to use for the gaps between the pickets. For each section of the fence you enter the space between the posts. The spreadsheet tells you how may pickets to use in each section, figuring out the gaps between pickets a little larger or smaller than the gaps you specified. You stretch out a tape measure along the top rail and make a mark for the edge of each picket. It gives you the distance from a post to the edge of each picket, so you don't have to measure the gap directly, and you don't accumulate an error that would all show up in the gap between the last picket and the post. The actual gaps in each section are a little different, but to the eye they look identical.
There are two versions depending on which version of Excel you have...
Setting rail height
Determine how high above the rail you want the top of your pickets to be. Cut a scrap of wood to that length, then use the marks you made on the rail and the block of wood to place the pickets. Use galvanized screws or an air nailer and attach all of the pickets to the top rail. Use a level to get each picket vertical as you attach each one to the bottom rail.
Using post caps to dress up your fence
You can buy these, but they are wicked expensive, and they aren't that hard to make. I used PT 2x6 and made all cuts on a table saw. Set the blade at an angle, and set the rip fence at a distance so that you can rip the 2x6 as shown. (The image shows an end-view of the 2x6. The diagonal line is the saw cut.) Then flip the 2x6 over and cut the other side. The result will be a 2x6 with a cross section that is nearly triangular.
Now you can cut the 2x6 into 5-1/2 inch lengths. These pieces still need 2 more angled cuts. However, they are too small to just run them through the table saw by hand. Attach them to another 2x6 (at least 3 ft long) with screws. Make sure your saw won't hit the screws. You can make both cuts without re-attaching your pieces.
To make the caps look nice, you will want to add 4 little pieces of molding around the top of the post, under the caps. I cut these molding pieces on a miter saw and attached them to the underside of the caps with a brad nailer and primed them before putting them on the posts. Your 4x4 posts won't be exactly 3-1/2 inches, or square. You can trim the posts with a hand plane to get the caps to fit on. Attach the caps to the posts with galvanized screws or nails from the top.
Now paint the whole thing!
If you are lucky like me and you have a "green thumb" in the family, and you can delegate the task of planting flowers along the fence.