BEFORE YOU START

• Before you get into it there are a few important things you need to know. While you don’t actually need a building permit, you will have to adhere to building regulations, so you’ll need to get a Licensed Building Practitioner (LBP), to draw up some plans to help you make sure you’re doing it right, and you’re using the correct materials.
   
• When drawing up your plans with your LBP, there are a few things to consider.
  
  - You want to make the beam high enough so it doesn’t obscure your view from inside.
  - You want to build it so it’s in keeping with the overall style of your house.
  - And if you think you might want to put a roof on your pergola, then it’ll need to be under 20 square meters, and you’ll need to design it with a fall, so water can run off it.

• Once you’ve got a plan just take it into Mitre 10, and the guys in the Drive Thru can help you out with selecting the right materials, and a trailer or delivery if you need.

INSTALLING THE POSTS

• Using the measurements on the plan you’ve had drawn up, run a line parallel to the house and determine the position of your posts.
   
• If your design has a corner post, then also run a string line 90° square to the house to help determine its correct position.
   
• If your pergola will be over an existing deck you will need to decide if you are installing the posts either through the deck or on the outside of the deck. Either way you will need to install the posts into a concrete footing.
   
• If you’re placing a post through the deck, you’ll need to remove some decking boards so you can dig a hole into the ground.

• Dig your hole 600mm deep, place a brick into the bottom of the hole, and insert your post.
   
• Mix concrete, fill the hole, and let it dry for 24 hours.
   
• Repeat for each freestanding post, as per your plan.
   
• Don’t cut posts to height yet.
   
• If you’re attaching a post to the side of your house, you’ll need to establish its correct height, and cut it to length before installing – as you don’t want to damage the side of your house when cutting it to length. Wait until you’ve installed the ribbon plate to the house, from here you’ll be able to determine its exact height.

• Determine the height of your ribbon plate from your plans.
   
• Measure and cut ribbon plate to length.
   
• Place a level line along the side of the house indicating the position of the bottom of your ribbon plate.
   
• Determine the position of your studs in the wall, and mark the centre of them on the weatherboards – this is where you’ll be fixing the ribbon plate to the house. Look out for lines of nail holes on the side of the house – this is where your studs will be.

• Measure the distance of the stud marks, and transfer these measurements onto your ribbon plate.
   
• Mark the position of your rafters onto the ribbon plate. Determine the width distance between each rafter, and mark the centre of each on your ribbon plate. If any of the rafter positions are exactly the same as your stud positions, you may need to adjust the position of your rafters to accommodate the fixings that will attach the ribbon plate to the studs on the house.
   
• Now mark the width of each rafter onto the ribbon plate. In this case we’ll be attaching them to the ribbon plate using a rebate – this will create a stronger, tidier looking join. Using a circular saw create a rebate 10mm deep to accommodate each rafter on the ribbon plate.

• Attach 12KN metal straps to the back of the ribbon plate, centered behind the position of your rafters – these will give the join some extra strength, and will be hidden once complete.
   
• If you’re not going to create a rebate, then you’ll need to use a couple of metal brackets to attach your rafters to the ribbon plate.
   
• Predrill the ribbon plate at the stud marks. Mark the center of the ribbon plate at your stud positions. Drill a 13mm hole to accommodate 12mm coach screws. As per my plans, my coach screws need to be no more than 1m apart.
   
• Attach 20mm (min. thickness) packers at the back of the ribbon behind each hole and drill through the packer. This is to set the ribbon plate out from the side of the house, so water can drain past.

• As per council water-tightness regulations, attach a neoprene washer around the hole at the back of the packers.
   
• Attach ribbon plate to side of house using 12mm diameter coach screws. Sit the ribbon plate on some nails to hold it in place. Firstly drill a 10mm hole through the existing holes on the ribbon plate, and into the cladding. Then fix the ribbon plate to the house with the 12mm coach screws. Drive them through the ribbon plate, into the stud. (I’m using 150 x 12mm coach screw, as I have a 45mm ribbon plate, 20mm packer, 40mm weather board and 50mm into my framing)
   
• Ensure you keep the ribbon plate to the level line on the side of the house.

DETERMINING BEAM & POST HEIGHT

• Now we’re going to determine the height of the post that we’re attaching to the side of our house.
   
• Draw a level line from the top of the ribbon plate, along the side of your house, and mark your 5° fall measurement as per your plan.
   
• Measure the distance at the point your post is to be placed. Now measure down the height of your beam – this will be the height of your posts.
   
• Cut the post that’s going to be attached to the side of the house to the correct height.

• Any post attached to the house will need 20mm packers and neoprene washers – just like the ribbon plate.
   
• Drill a 13mm hole through both post and packer.

• Position the post, and drill a 10mm hole through into the cladding. Attach the post with the coach screws.
   
• Cut the remaining posts to height, ensuring they’re level with each other.
   
• If the width of your beam is skinnier than your posts then place this measurement on the top of the posts, and cut a 45° degree on this mark. This will make for a tidy job and will prevent water from sitting on it.
   
• Lightly plane the edges with a block plane.
   
• Prime any exposed timber on top of the posts

INSTALLING THE BEAM

• Measure the length of your beam. Determine this by measuring the distance from the outside of your posts. If any overhang is required, add this to your measurement.
   
• Cut your beam.
   
• Mark out the position of the rafters. To determine their position on the beam, transfer the position of the rebates from your ribbon plate onto the beam.
   
• If your pergola has a 5° fall, then your rafters will need to be cut to 5°. This will mean the depth of your rafter will be slightly longer than if it were a square cut – so to get this correct measurement onto your beam, just cut an offcut of your rather to 5° and use it to mark your rafters on the beam, so you know the exact length to rebate out of the beam.

• Prime the timber exposed by the rebate.
   
• In this case we’re attaching the beam with a 12mm galvanized threaded rod through the beam, and into the top of the posts. Attaching them this way will give you a tidier look. However, you can also use a Bowmac plate fixed to the outside of the beam and posts.
   
• Mark the position of your posts onto the beam.
   
• Drill through the beam. You’ll need a drill extension, and a 16mm spade bit.

• Mark the center of your posts, and use a 16mm spade bit, drilling down as far as the bit will allow. Ensure all the dust is removed from the hole.
   
• Cut threaded rods to length (width of beam + depth of hole + room for nut and washer). Attach a washer and a nut to the top of the rods.
   
• Fill holes in posts with glue using a High Performance Epoxy Anchoring System, suitable for both timber and concrete. This will securely hold our rods in place.
   
• Lift beam into place, fill the holes in the beams with the glue, and insert rods through the beams, into the posts. Clamp the beam into place, and allow the glue to set overnight.

INSTALLING THE RAFTERS

• Determine the length of your rafters. Either measure the distance between your two points, or hold up an over-length rafter and simply mark it to length. Now cut your rafters to length. It’s a good idea to measure each rafter individually, in case your house is uneven.
   
• Pre-drill 2 x 5mm holes through the beam to accommodate 150mm bugle screws - these will attach the rafters to the beam.
   
• Attach the rafter to the beam.
   
• Attach the other end of the rafter to the ribbon plate with 75mm 10 gauge galvanized screws, skewed through the rafter into the ribbon plate.
   
• Nail the 12KN metal straps onto the top of the rafters using at least 6 product nails.

INSTALLING THE PURLINS

• Refer to your plan to determine the spacing of your purlins. Use a chalk line to mark exactly where they’ll sit over the top of your rafter.
   
• Cut and fix the purlins to the rafters.