How To Lay Composite Decking on Grass

composite decking on grass

There are two ways to lay composite decking on grass. The first method is by building it on the ground level, directly on top of grass and dirt. The second one is building an elevated deck. Each of these options has pros and cons. Building an elevated desk requires more preparation and work, while a ground-level deck is pretty straightforward. However, if you build your deck directly on grass or dirt, it may be more susceptible to damage than having it elevated.

If you happen to decide to build your deck on grass or soil, here are the steps that you should follow. 

decking on grass

Building a Deck on Grass or Soil

  1. The first thing you need to do is mark the area where you will be building the deck. You can use pegs and builder lines to outline the entire space. 
  2. As much as possible, you want to clear the area where you’re building the deck. Remove any plants, rocks, or weeds from the area. Ignoring these steps can damage your deck. 
  3. Next, dig down approximately 50 mm. Make sure to remove any leftover turf. 
  4. Make sure that the ground is even. You can use a tamper to flatten the ground. You may need to move the soil around to flatter the area. 
  5. Next, cover the area with a weed control landscaping fabric. This fabric helps prevent any grass growth, which can damage your deck.
  6. After laying the fabric, cover the area with 40 mm to 50 mm of gravel. Gravel offers protection against water and moisture buildup. Other excellent alternatives are wood chips and stone pebbles.
  7. After finishing the foundation, start measuring and cutting your boards. You can use a pencil to mark the desired lengths. A combination square is also a handy tool that can accurately create lines across the boards. 
  8. Next, you may want to lay down all the materials in the desired area. Doing this will help you determine whether you have enough materials for the job. You will also need to put gaps between the boards for a more accurate layout. 5 mm to 8 mm is an ideal side-to-side board spacing, while at most 3 mm for end-to-end. If you haven’t already, this is the last chance to change your design and layout. 
  9. Start measuring and cutting materials for the frame of the deck. You will need to set up four outer joists. The inner joists depend on the layout and design of the patio. Make sure to follow proper joist spacing. For horizontal boards, the maximum joist spacing should be 450 mm. For diagonal decking boards, joists should be 300 mm apart. The closer the joists are, the more stable the deck will be. 
  10. Assemble the frame. Do this by marking the point where the inner joist and the two outer joists meet. There should be two marks in each corner of two outer joists, having eight in total. This is where you will drill coach screws. 
  11. Drill holes in the marks using a flat wood drill bit, making a countersunk hole, which will make the screw heads sit flush with the surface. Drill the coach screws with a drill driver and tighten them into place.
  12. After having the basic frame of the deck, add the inner joists the same way you add the outer joists. 
  13. Start laying the decking boards using the fastening system that you’ve chosen. Using solid edge decking boards, you’ll likely use nails or screws. If so, make sure to mark them first using a pencil. Then, nail or screw the boards at every joist intersection. If you have grooved decking boards, you’ll be using hidden clips. The first board is installed using a start clip at the house wall, where the boards are firmly set. Then, insert the clips into the grooves and screw them to the joists. Do this for the rest of the decking boards. Tightly secure them in place.


Also, learn how to stop grass from growing under your composite decking.


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