Removing the soil or grass from below your deck may seem a good idea, but this leads to drainage problems. The grass may eventually die off due to lack of sunlight filtering through the deck, but the remaining topsoil still drains water faster than if you dug out the entire area.Click to see full answer. Besides, do I need to remove grass before building a deck?Although grass removal, cloth barrier and gravel will make it look nicer it is not necessary. Depending on the height of the deck the grass will probably die anyway although I prefer to go ahead and spray grass killer on it. Do make sure you dig up the grass and topsoil where your post will be.Furthermore, can you build decking on grass? If you’re laying your deck straight onto the ground, cover the area with a layer of weed control fabric. Then add 40 mm to 50 mm of gravel on top. Lay the decking on the grass in your decided design and leave the right expansion gaps between boards (5 to 8 mm along the length of timber boards, and 3 mm along the ends). Beside above, how do you kill grass before decking? For organic control that kills existing weeds and prevents most new weeds from growing, add 1 cup of salt to 2 cups of water and pour it over the ground under your deck. Using boiling water is effective at killing existing weeds.How do you prepare the ground for a deck? Preparing Deck Site Checklist Layout the shape of the deck with a hose or string and remove any sod. Ensure there are no underground services in the area where you will be digging. Locate the positions of the piers and footings. Dig the holes for the footings and piers. Prepare the soil with landscaping fabric.