24″ sign roofed 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
• Jigsaw or circular saw for the gable angles
• Tin snips
• Utility knife with hooked blades
• Hammer
• Chalk line
• 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 3/4″ 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.

    ✓ 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. 14Cut the gable ends

    The roof sits on two gable ends: flat pieces of plywood shaped like a house front, a 3 1/2″ band with a triangle on top. The roof slope is 8 in 12: the roof rises 8″ for every 12″ it runs sideways.

    On each 24″ × 11 1/2″ piece, mark the centre of the top edge: that is the peak. Mark both sides 3 1/2″ up from the bottom. Draw straight lines from those marks to the peak and cut along them with a jigsaw or circular saw.

    Clamp the two pieces together and sand the edges so they match exactly.

    ✓ Each gable end is 24″ wide at the bottom and 11 1/2″ to the peak, and the two match when stacked.

15. 15Fix the gable ends and roof panels

    Hold a gable end (E) against the front faces of the posts, its bottom edge 1/4″ above the board and its ends flush with the board ends. Drive three 2 1/2″ screws into each post. Fix the second one the same way on the back faces of the posts.

    Each roof panel (F) is 18 1/8″ up the slope by 10 7/8″ front to back. Set the first one on the sloped edges of both gables with 3″ hanging past the gables at the front, the back and the low edge. That overhang keeps rain off the board.

    Predrill and drive 1 5/8″ screws down into the gable edges every 6″. Then fit the second panel, lapping its top edge over the end of the first at the peak, and screw it the same way.

    ✓ The panels meet tight at the peak, with the same overhang front, back and at each side.

    STOP. Lift the panels from a stepladder set on firm level ground, with a helper. Don't lean the ladder on the posts.

16. 16Drip edge and underlayment

    How a roof keeps water out: it is layers that overlap like the feathers on a bird. Every upper layer laps OVER the one below it, never under, so water running downhill always flows over a joint instead of into it. From the wood up the layers are: the roof deck you just fastened, drip edge on the edges, underlayment, and shingles on top.

    Drip edge is a bent metal strip shaped like an L with a little kick at the bottom. You need 1 10′ piece. Cut it with tin snips. Along the eaves (the low edges, 21 13/16″ in all) nail it on now, straight onto the deck, with the bent lip hanging down over the edge. Water coming off the shingles drips off that lip, clear of the wood. Use 7/8″ roofing nails every 12″, high on the flat part. Overlap pieces 2″.

    Underlayment is a roll of water-resistant felt or synthetic sheet: the second line of defence under the shingles. Unroll the first row along the eave so it laps over the drip edge you just nailed. Each row above overlaps the row below by 4″ (most rolls have a printed line to follow).

    Pull it flat with no wrinkles and fasten it with roofing nails every 12″ near the top edge, where the next row will cover them. Lap the top row 6″ over the peak onto the other side, then do the other slope the same way so it laps back over the first.

    Now nail drip edge along the rake edges (the sloped side edges), this time ON TOP of the underlayment. Start at the bottom so each higher piece laps over the lower one. The one rule to remember: drip edge goes under the underlayment at the eaves and over it everywhere else.

    • Tip Snip the vertical flange where eave and rake pieces meet at a corner and fold it around, so the corner is closed.
    • Tip Synthetic underlayment is lighter, doesn't tear and is less slippery than felt. Either works.

    ✓ Run your hand up the roof from the bottom: you never catch the edge of a layer. No bare wood shows anywhere, and every drip edge lip hangs straight.

    STOP. Do this with the roof at a comfortable height if you can (before the post goes up, or with a stable stepladder). Don't lean a ladder against the finished sign.

17. 17Shingle the roof

    A 3-tab asphalt shingle is a 12″ × 36″ strip. The top half gets covered by the next row; the bottom half is split by two slots into three "tabs" and is the part you see. The black sealant strip across the middle glues the row above down once the sun warms it.

    Starter strip: cut the tabs off a row of shingles with a utility knife (cut from the back against a straight edge; the shingle snaps along the cut). Nail the strip along the eave, sealant strip at the bottom edge, hanging 3/8″ past the drip edge. It gives the first real row something to stick to and fills in behind its slots.

    First row: lay full shingles right on top of the starter strip, bottom edges flush, starting at one rake edge and hanging 3/8″ past it. Four 7/8″ roofing nails per shingle, in a line just below the sealant strip: one 1″ in from each end and one above each slot. Drive them flush. A nail that is crooked or sunk into the surface leaks; pull it and nail beside it.

    Every row after that shows 5″ (the "exposure"). Snap a chalk line 5″ above the bottom of the previous row so the rows stay straight. Shift each row sideways by half a tab: start row 2 with 6″ cut off the first shingle, row 3 with 12″ off, and so on, then start over. That way the slots never line up and water that runs through a slot lands on solid shingle below.

    Ridge cap: cut shingles into three 12″ squares at the slots and trim the top corners at a slight angle. Warm each one in the sun so it bends without cracking, fold it over the peak, and nail 2 nails, 1″ in from each side, just below the sealant strip. Start at the end away from the prevailing wind and lap each piece over the last, 5″ showing, along the 10 7/8″ ridge. Seal the nails on the last piece with a dab of roofing cement.

    Trim anything that hangs past the rake edges to 3/8″ past the drip edge, cutting from the top with the hooked blade.

    • Tip Shingle on a mild day (50–80°F). Cold shingles crack when bent; very hot ones scuff under your knees.
    • Tip 1 bundle covers the roof with waste for the cuts. A bundle is 33 sq ft and weighs about 65 lb: carry it on your shoulder, never by the wrapper.
    • Tip The short 7/8″ nails grip the 3/4″ roof deck without poking through where you would see the tips from below.

    ✓ The rows run parallel to the eave, every slot sits over the middle of a solid tab in the row below, and no nail heads show except under the last cap.

18. 18Finish

    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.