How to Build a Walk-through Garden Pergola

Materials list

Before building this pergola……..
Check with your local Authority to see if any Building permits, permissions or conditions are required.

Check with the utility companies to make sure the area is clear of underground gas, water, electrical lines etc.

Find out the depth of the frost line in your area and if applicable check to see if the footings require any special consideration. Usually the bottom of the footings should be below the frost line to prevent movement.

Note: To see how Tim built this pergolaA structure with open wood-framed roofs, often latticed and supported by regularly spaced posts or columns, and covered by climbing plants such as vines or roses, shading a walk or passageway. Pergolas are distinguished from “arbors,” which are less extensive in extent and structure. go comments.

Tools required
carpenter’s hammer    carpenter’s square    carpenter’s pencil    measuring tape    handsaw	adjustable spanner    builder’s string line    power saw    electric drill	12mm (1/2″) drill bit    bucket or hose    spade    wheelbarrow

A bit about the lumber 

The lumberAny of the framing wood. used in this project needs to be suitable for exterior use and the posts need to be suitable for inground application. The local lumber yard will be able to advise you on the most suitable lumber for the job.

The lumber sizes referred to in this project are the nominal sizes. The nominal sizeThe rough-sawn size of a piece of lumber. Before the lumber is surfaced, planed or dressed. The nominal size is usually greater than the actual dimension. e.g. 100x50 (2 x 4) actually equals 90x45 (1 1/2" x 3 1/2"). is the size of the lumber before it is dressedSurfaced; planed; smooth; even surface; gauged. or seasoned. This is the size generally referred to when purchasing from the lumber yard. The actual (or dressed) size of the lumber will be less than the nominal size. For example, a piece of 100×50 (2×4) lumber when dressed may be 90×45 (1 1/2″x 3 1/2″) actual sizeThe finished (dressed) size as opposed to the nominal size of a piece of wood.. Please make necessary allowances.

Materials list

Posts: 100×100 (4×4) – 4 pieces at 3000mm (10ft)
Beams: 200×50 (2×8) – 2 pieces at 4200mm (14ft)
Rafters: 75×50 (2×3) – 8 pieces at 1800mm (6ft). Up size to 100×50 (2×4) or even 150×50 (2×6) if a bulkier look is preferred
Bolts: 12mm (1/2″) galvanizedCovered with a protective coating of zinc. carriage boltsAre round headed bolts with square shoulders that resist rotation when located or driven into place. They can be called coach bolts or carriage bolts depending on which part of the world you live in. The head end of the bolt does not need a washer, but the other end of the bolt (the nut end) usually does. 120mm (5″) long – 8 of
Nails: 90mm (3 1/2″) galvanized – 1kg (2.5 lb) of
ConcreteA mixture of sand, gravel, water and cement which hardens to a stone like condition when dry.: As needed
Batter boardsProfiles;Horizontal boards attached level to stakes, used to mark out the boundary of a construction and establish the levels and building line. and stakes: 5 meters (16ft) of 50×50 (2×2) – 8 meters (26ft) of 100×25 (1×4) throw-away low grade woodTimber, lumber. The hard fibrous lignified substance under the bark of trees.

Instructions: Steps 1 to 3:

Step 1: Familiarize yourself
Familiarize yourself with the plans and instructions and read the “Before building this pergola” notes in the previous page.

Step 2: Location
Determine the location of the pergola. Mark out the position by placing a peg in the ground at each corner forming a rectangleFour-sided figure with four right angles. 3600mm (12ft) long x 1000mm (44″) wide. The pegs also mark the outside corners of the posts.

Step 3: SetHow much the teeth are angled out on a circular saw blade. out
Make a temporary framework structure at each corner consisting of horizontalParallel to the horizon, flat, level. boards (batter boards) attached level to stakes. The batter boards are used to establish the levels and the building lineThe outline of a building. (boundary / perimeterboundary.) of the pergola.

3a) Cut 8 stakes 600 (2ft) long, out of 50×50 (2×2) stock. Cut a point at one end of each stake so they can be easily hammered into the ground.

3b) Position the stakes as shown in the diagram and hammer them firmly into the ground. The stakes should be at least 600 (2ft) away from the building line to allow room to dig the corner footingA base (in or on the ground) that will support the structure. holes.

3c) Make a level mark on all eight stakes beginning approx 150 (6″) above ground level, at the corner where the ground is the highest (if the ground is sloping). Use a long straight edge and a carpenters level to transfer the level mark from stake to stake.

3d) Once a level line has been established and marked on all eight stakes, proceed nailing 100×25 (1×4) batter boards to the stakes, so that the top of the batter boards are flushBeing even with. with the level lines marked on the stakes.

3e) Run a taut string line from batter boardA piece of sawn, or dressed lumber of greater width than thickness. Usually 19mm (3/4") to 38mm (1 1/2") thick and 75mm (3") or more wide. to batter board, passing directly over the pegs and tie the ends to nails hammered half way in to the tops of the batter boards. This will now show the approximate building line and perimeter of the pergola, but more exact measurements are needed.

3d) Check that the distance between the string line at point AA and BB and the distance between DD and CC are equal. If not, make any necessary adjustments by moving the string line along the batter board and adjust the nails accordingly. The distance between AA and CC and the distance between BB and DD, also need to be equal. Make any necessary adjustments.

Once the perimeters are parallelBeing of equal distance from each other at all points., the diagonals need to be measured to ensure that the building line is square.

Do this by measuring the distance between AA and DD and the distance between BB and CC (the diagonals). Make any necessary adjustments to ensure the diagonals are equal and if adjustments are required, re-check the parallels again, since altering the diagonals will also change the parallels.

When the building lines are parallel and the diagonals are equal, the building line is then square. You now have a level, square building line to work from.

Instructions continued: Steps 4 to 7:

Step 4: Dig the holes
Mark the centersCrs; O.C; Term used for spacing; The measurement of spacing for studs, rafters, and joists in a building from the center of one member to the center of the next. for the four holes which will be (50mm (2″) in from the building line (string line) at the corners.
Take down the string line and dig the four postsee PILE holes, 350mm (14″) square and 600mm (24″) deep. They will need to be deeper if in a frost prone area. See notes in page one.

When the holes are dug, replace the string line. (The string outlines the outside faces of the posts.)

Step 5: Mix and pour the concrete
Make a mix of concrete in a wheelbarrow at a ratio of 3 gravel, 2 sand and 1 cementA powdery type substance made from a mixture of earths materials such as limestone and shale, which is sintered (cause to become solid mass by heating without melting), ground, and mixed with small amounts of calcium sulphate and calcium carbonate. Cement is activated by water and when mixed with gravel and sand, forms concrete.. Add clean water and mix to a uniform consistency until wet enough to fill around the posts, yet stiff enough to hold the posts upright without the need of supports or braces. Of course you will need a wind free day.

Carefully shovel some concrete into the bottom of each hole before placing the posts. (Minimum 75mm (3″))

Step 6: Stand the posts
This step will require two people.
Have one person position a post verticalPlumb, upright. into one of the holes and next to (but not quite touching) the building lines (string lines) where they meet at the corners.

Check the post is vertical by holding a plumbVertical; Upright. level against two adjacent sides of the post. The other person can then proceed to shovel concrete around the post to within 50mm (2″) from the top of the hole. Repeat this action until all four posts are concreted in place.

Confirm again that all posts are vertical and leave to set.

A couple of days later

Step 7: TrimThe finish materials in a building, such as narrow boards applied around openings (window trim, door trim) and vertical corner battens. the tops of the posts 
Trim the top off one of the posts 2200mm (88″) from the ground. (Remember from the materials list that all posts are slightly over length.)

Note: Keeping the top of the pergola as low as possible gives the appearance of a wider opening and less elongated look. However, if you prefer a higher pergola – Then do it.

Measure down from the top of the trimmed post to the building line (string line) and transfer that measurement to the other three posts. This gives a level mark at the top of the posts.

Trim the other three posts.

On the outer side of each post mark a horizontal line 200mm (8″) down from the top.
Cut along the mark with a power saw to a depth of 50mm (2″) i.e. the thickness of the beamA supporting member.. Do this to all four posts.

Next – Scribe a vertical mark 50mm (2″) in from the outer site of each post from the top, down 200mm (8″). Cut down that mark with a sharp handsaw. See fig.2

Safety first
When using a power saw make sure you have firm footing.
Erect a scaffold if necessary.
Wear safety goggles and earmuffs.

Instructions continued: Steps 8 to 11:

Step 8: The beams 
Cut two 200×50 (2×8) beams at 4200mm (14ft) long, tapering the cuts in 30 degrees off squareA line across the face of a piece of wood (at right angles to the length) is a square line. A line deviating from the square line is off square. Off-square refers to how many degrees the off square line is in relation to the square line. For example, a line at a 5 degrees angle to the square line, is 5 degrees off square. at the ends. (See fig. 3.)

On the top edge of each beam measure in 300mm (12″) and then another 50mm (2″) from the ends and mark square.
Make notches in between the two marks (50mm (2″)apart) by running a series of saw cuts 25mm (1″) deep and then by cleaning out with a chisel.(See fig.3.)

Make similar notches along the tops of the beams at 500mm (20″) centers/O.C. In all a total of 8 notches spread evenly along each beam.

Step 9: The rafters
Cut eight 75×50 (2×3) rafters 1600mm (64″) long, tapering the cut in 30 degrees off square at each end.

Note: If you prefer a more bulkier look, then up size the rafters to 100×50 (2×4) or even 150×50 (2×6).

Make two notches 50mm (2″) wide and 25mm (1″) deep on the bottom side of each rafterStructural member of a roof that supports the roof load and runs from the ridge to the top of the side walls. in the same manner as described in Step 8 and to the dimensionsAny of the three linear measurements, length, breadth and depth. as shown in fig.4.

Step 10: Place the beams
Sit the two beams in the rebates at the tops of the posts. Align the beams so that each end overhangs the posts 350mm (14″) and that the notches line up flush with the outsides of the posts. See fig.5.

Drill and boltA metal rod that has a head on one end and threads on the other and is used to fasten together lumber. The most common bolts used or referred to in projects within this website are coach/carriage bolts and hex bolts. beams to posts using 12mm (1/2″) galvanized carriage bolts and washers.

Step 11: Place the rafters 
LAST AND LEAST. Place the rafters on top of the beams so the notches on the underside of the rafters line up with the notches on the top side of the beams. Tap the rafters into place and nailA short nail with a large flat head used for securing roofing felt, plasterboard, sheet metal to wood etc. down through the top of the rafter into the beam with 90mm (3 1/2″) galvanized nails. See fig.6.

That’s the lot. Have fun 🙂