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Three-tier deck and pergola

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A three-tier Merbau timber deck with pergola that is bordered with built-in planter boxes to create a large outdoor entertaining area.





The project


I thought a three-layer deck for my deck and pergola would be nice. I planned the deck to be 9m long, covered by a 6m pergola. The deck consists of three tiers bordered by raised garden beds.


In this design I made, I've staggered down the planter boxes. 




Here's a before photo of the area.




I began the project by constructing the pergola section. It uses a standard construction technique with posts, beams and rafters. I used Merbau laminated 90 x 90mm posts for the three supports, H3-treated Pine 190 x 45mm timber for the beams and H3-treated Pine 140 x 45mm timber for the rafters. The rafters were installed at centres and connected to the beams with Pryda straps.








I ran 4 x 6m H3-treated 140 x 45mm timber bearers to cover the deck width, with approximately 800 - 900mm spacing between each bearer. I also attached a H3-treated 90 x 45mm timber ledger to the house wall. 


The bearers were connected to the concrete slab using Dunnings 130 x 130 x 65 x 5mm M12 brackets and Dunnings 150 x 150 x 75 x 6mm M12 brackets.


The bearers are in and attached to the ground, as well as the ledger attached to the brick, and spaced away from it with 2 x 3mm M12 flat square washers per anchor.




I used Protectadeck flashing on top of the bearers, which was super easy to install using a staple gun. I put three staples in one end, rolled the flashing along the bearer, then at the end I pulled it tight so that there were no creases, and it ran perfectly straight. I then stapled that end down while I applied pressure. After the ends of the flashing were fixed in position, I stapled down the full length every 30cm.


Before installing the joists over the bearers, as a precaution to prevent any shaking in the deck, I used steel brace strapping which is tightened with strapping tensioners. This might be overkill, but it was a quick, easy, cheap job that should remove any sway that may have been there.


After installing the strapping, I fixed the H3-treated 70 x 45mm timber joists into position at 600mm centres with Pryda straps. I used joist hangers to connect the joists to the ledger board.


I also put some drainage gravel over weed mat to prevent it getting shredded by wind over time and for double protection from weeds. 


Here the joists are fully installed over the bearers with some doubling up of supports.




Finally, I laid down the decking boards. I ended up going with the 140 x 21mm x 5.7m Merbau boards with the concealed decking groove. I used the Ekodeck concealed deck fasteners. I am really happy I went with this option as it was really easy and quick to do. In just a few hours I got the main boards in. The most time was spent fitting it around the posts and pipes.




I had then finished the pergola area and highest decking tier. Here’s how it looked.




Next, I began work on the other tiers. The mid-tier is a small section of decking connected to a ledger board on the wall and elevated on adjustable mounting brackets where it extended over the concrete slab. The mid-tier is only slightly lowered below the height of the top tier.


The lower tier is fixed solely to the concrete slab and also uses the same adjustable mounting brackets for the joists. The adjustable brackets were useful in setting the exact heights for the frame.


Due to space limitations in these tiers, I used a single-layer deck frame as opposed to the joist over bearer layout for the higher tier.





Once again, I used the Protectadeck flashing on the framing timbers.




Once the framing was completed, I laid the decking boards.




Next, I finished the side panelling, added LED strips to the side panelling of the first tier and built the raised garden bed for the main deck level using sleepers. I used some pond liner to line the raised garden bed to reduce the time of decay of the sleepers and to prevent moisture and sand from falling through the gaps where the wood isn't perfectly flush.




Here's the completed deck, planter and pergola.




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