24″ sign signpost plans

Parts

Cut list

Kerf 1/8″ included. Every cut runs edge to edge.

Steps

• Tape measure
• Speed square
• Pencil
• Drill/driver
• Clamps
• Safety glasses
• Hearing protection
• Dust mask
• Circular saw and a straight edge (or have the store cut the sheets)
• Miter saw, or circular saw in two passes, for 4×4 posts
• Post-hole digger
• Wheelbarrow and hoe
• Level (2 ft or longer)
• Small foam brushes or a stencil brush
• Painter's tape
• Sander, 120 and 180 grit

Underlined words have a short explanation: hover or tap them. All of them are on the glossary page.

1. 1Before you start

   Read every step once, start to finish, before you buy or cut anything. Each step names the parts it uses by letter; the parts list gives their sizes.

   Set up somewhere flat with good light. A pair of sawhorses with a sheet of plywood on top makes a fine work table.

   Wear safety glasses whenever a tool is running, hearing protection for saws, and a dust mask for sanding and for cutting treated wood or sheet goods. Tie back long hair and loose sleeves. Keep children and pets out of the work area.

   • Tip At the store, pick straight boards: hold each one up to your eye and look down its length. Skip boards that bow, twist or have big knots near the ends.
   • Tip Measure twice, cut once. Most mistakes are a misread tape, not a bad cut.

2. 2Cut and label the parts

   Cut every part on the cut list. Cut the longest parts first: if one goes wrong, it can still become a shorter part.

   To mark a cut, hook your tape on the end of the board, make a small V with its point exactly at the measurement, and draw a square line through the point with a speed square. Put an X on the waste side.

   Cut on the waste side of the line, so the blade's kerf (about 1/8″) comes out of the scrap, not your part. Cut sheets with the good face down when using a circular saw: the blade splinters the top face.

   Write each part's letter in pencil on a face that won't show, and stack the parts by letter.

   Sand the faces before assembly while they're flat and easy to reach: 120 grit, then 180.

   ✓ Lay the parts out and count them against the parts list. Measure a few: if one is off by more than 1/16″, recut it now.

   STOP. Let the saw reach full speed before it touches the wood, keep both hands clear of the blade's path, and never reach under a board you're cutting. Support long boards on both sides of the cut so the blade doesn't pinch.

3. 3Call 811 and check the spot

   At least 3 working days before you dig, call 811 (or use call811.com). It's free. They send people to paint or flag buried gas, electric, water and cable lines near where the sign posts will go.

   Check your property line on your survey or plot plan, and ask your town about setbacks, easements and whether this needs a permit.

   Pick ground that drains: not a low spot where puddles sit after rain, and not over a septic field.

   STOP. Don't dig until the marks are down. Hitting a gas or power line can kill you and is expensive to repair.

4. 4Mark the post holes

   Stand where people will read the sign (the road or the path) and decide where it goes. Keep it on your own land, out of the road right-of-way (often the first 10–15 ft from the pavement; your town knows), and away from corners where it would block a driver's view.

   Drive a stake at each post centre, 18 1/2″ apart. Run a string between them: the sign face will be parallel to it, so aim the string so the sign faces the people reading it.

   The posts stand 51″ above the ground when they are in. On sloping ground, measure that from the ground at the higher post, and dig the other hole deeper so the tops end up level.

   • Tip Spray a cross of marking paint on each stake spot before you pull the stake to dig: the cross shows you the exact centre.

   ✓ The stakes are 18 1/2″ apart, centre to centre, and the string line points the way you want the sign to face.

5. 5Dig the post holes

   Dig 2 holes 10″ wide and 30″ deep with a post-hole digger.

   That depth is 24″ for the post plus 6″ of gravel underneath so water drains away from the post end.

   Make the holes slightly wider at the bottom than the top, like a bell. Frost then can't grip the concrete and lift it.

   Pour 6″ of gravel in each hole and tamp it with the end of a 2×4 or the post itself.

   • Tip Your town knows the frost depth: it's how deep footings must go so winter frost can't push them up. Enter it in the options and the holes will be dug deep enough.

   ✓ Every hole is 30″ deep before the gravel and 24″ deep after it.

6. 6Set the posts plumb

   Stand a post in each hole. Run a string between the end posts at the height you want, to line up the ones in between.

   Hold a level against one face of a post until the bubble is centred: that face is plumb. Then check the face around the corner. Both faces must read plumb.

   Brace each post with two 1×4 or 2×4 boards: screw one end to the post and the other to a stake hammered into the ground, one brace on each of two sides at right angles.

   ✓ Every post is plumb on two faces, in line with the string, and the braces hold it there when you let go.

7. 7Mix the concrete

   You'll use 4 bags of 80 lb concrete mix for the 2 post holes. Mix one or two bags at a time in a wheelbarrow: concrete starts to stiffen in about 30–45 minutes (faster on a hot day), so only mix what you can place right away.

   Pour about 2 quarts of clean water into the wheelbarrow first, then empty one bag on top. (Each 80 lb bag needs about 3 quarts in total.)

   Mix with a hoe or square shovel: pull the dry powder from the corners and bottom into the wet middle and chop through it. Keep going until there are no dry pockets.

   Add the last of the water a cup at a time, mixing between each.

   Get the thickness right. It should look and feel like thick oatmeal or stiff peanut butter. A hoe dragged through leaves ridges that stand up, and a handful squeezed in a gloved hand holds its shape. Too dry: it crumbles and won't stick together, so add a little water. Too wet: it flows flat, water pools on top, and the concrete will be weak and crack. Then add some dry mix from a spare bag.

   • Tip More water makes concrete easier to push around and much weaker. Resist the urge.
   • Tip Rinse the wheelbarrow, hoe and shovel before the concrete sets on them. Don't wash concrete into drains or onto the lawn: let leftovers harden in a scrap box and throw them out.
   • Tip Buy one more bag than you need. Running out halfway through a pour is the most common mistake.

   ✓ Even grey colour throughout, no dry powder, no puddles of water on top; a ridge made with the hoe stands up.

   STOP. Wet concrete is caustic and burns skin. Wear waterproof gloves, safety glasses, long sleeves and long pants. Open bags slowly and wear a dust mask: the dust has silica. Rinse any concrete off your skin right away.

8. 8Fill the holes

   Shovel concrete into each hole around the post. Every 6″ or so, poke it hard with a stick or a piece of rebar to work out air pockets.

   Fill to about 1″ above the ground and shape the top into a little mound with a trowel, sloping away from the post so rain runs off.

   Check plumb again on both faces while it's still wet, and adjust the braces if needed.

   ✓ Posts are still plumb and in line after the concrete is in.

9. 9Let the concrete cure

   Concrete hardens by reacting with water, not by drying out, so keep the concrete around the sign posts damp for the first 7 days: mist it with a hose morning and evening, or cover it with plastic sheeting held down at the edges.

   Keep it from freezing for the first week. Don't pour when it's below 40°F (5°C) or frost is forecast in the next two days. On hot days, pour in the early morning and shade it.

   You can walk on it or remove braces after 1–2 days. Wait 3 days before putting real weight on it. It reaches full strength in about 4 weeks.

   ✓ The surface is hard and grey-white when dry, with no powder when you rub it.

10. 10Make the sign board

    The board is one 24″ × 18″ piece of MDO plywood: exterior plywood with a smooth paper face made for painted signs.

    Cut it with a circular saw against a clamped straight edge, best face DOWN: the blade lifts splinters on the top face, so the face you keep goes underneath.

    The edges are plywood and soak up water. Fill any gaps in the edge layers with exterior wood filler, let it dry, and sand it flush. Round the corners slightly with sandpaper.

    • Tip Prime the back and every edge as well as the front. Water gets in wherever paint is missing.

    ✓ The board is 24″ × 18″, corners square (the diagonals match).

11. 11Paint the board and the lettering

    Brush on one coat of exterior primer everywhere: front, back and edges. When it is dry, sand lightly with 220 grit, wipe off the dust, and brush on two coats of the background colour, letting each dry as the can says.

    Lay out the lettering in pencil. Draw the lettering area, 14″ wide × 13 1/2″ tall, centred on the board (the frame will cover the rest). Inside it draw 2 baselines for letters 4″ tall, with 2″ between lines. Your text takes about 10″ of height, so start the top line 1 3/4″ down from the top of the area to centre it.

    Lay the stencils for each line out on a table first and measure the whole line. Mark the board's centre, then start the line half that width to the left of it, so each line is centred.

    Tape each stencil flat with painter's tape, its bottom on the baseline. Dip a stencil brush or foam dauber, blot nearly all the paint off on a paper towel, and dab straight down. Lift the stencil straight up. Too much paint creeps under the stencil and blurs the letter, so build up two thin coats rather than one thick one.

    • Tip Practise one word on a scrap of primed board first.
    • Tip A sign shop can cut vinyl letters to your text; they go straight onto the dry painted board instead of stencilling.

    ✓ From 10 ft away the lines look straight, the letters sit on their baselines and the gaps between letters look even.

12. 12Add the frame

    Prime and paint the frame pieces first. The top and bottom rails (C) run the full 24″ width; the stiles (D) fit between them, 15″ long.

    Lay the board face up. Set the rails along the top and bottom edges and the stiles at the ends, all flush with the board edges. Clamp them.

    Turn the board over carefully and drive 1 1/4″ screws through the board into the frame from the back, every 6″ all the way round. The screws stay hidden on the back.

    • Tip 1 1/4″ screws through 3/4″ board go 1/2″ into the 3/4″ frame. Check the length before driving: a longer screw comes out the front.

    ✓ The frame is flush with the board edges all round and no screw tips poke through the front.

13. 13Mount the board

    Measure 30″ up from the ground at each post and mark it: that is the board bottom. Check the two marks with a level on a straight board; if the ground slopes, use the higher mark and move the other to match.

    Screw a scrap block to each post with its top at the mark, as a ledge to rest the board on. Set the board on the ledges, 1″ past the outside of each post, and clamp it.

    Fix it with four 3″ screws through the board into each post, in a line down the post centre, keeping them inside the lettering margin. Predrill each hole and countersink it so the screw heads sit just below the surface. Fill the holes with exterior wood filler, sand, and touch up the paint.

    Remove the ledge blocks.

    • Tip Press a post cap onto each post top and fix it with the nails or screws supplied. It keeps rain out of the end grain, the part of a post that rots first.

    ✓ A level on the top edge reads level, the gaps past each post match, and the board doesn't move when you push it.

14. 14Finish

    Ease every sharp edge and corner with 120-grit sandpaper so nobody gets a splinter.

    Sand all over with 180 grit, always along the grain (the direction the wood fibres run). Scratches across the grain show through stain.

    Wipe off the dust with a barely damp rag and let it dry.

    Outdoors, use an exterior finish: a penetrating deck oil or exterior stain, or primer and exterior paint. Leave cedar bare to weather silver if you like. If it holds soil for food plants, leave the inside unfinished.

    Let it dry for the time on the can before using it.

    • Tip Try your finish on a scrap of the same wood first: stain looks different on every board.