Building an Outdoor Kitchen: Laying the Foundation

Laying the foundation for an outdoor kitchen begins with preparing the site. An external kitchen is a small structure that has its own foundations and roof. It is located a short distance from the main house. Preparing the site starts with clearing bushes, grass, termite nests and rubbish. You'll also have to cut down any trees on the proposed site. Next, make sure that the ground conditions are suitable for construction; for example, avoid laying foundations on weak, sandy soil. Locate any nearby or underground pipes for plumbing and electricity before digging up the trenches. You may accidentally damage a hidden utility connection if you start digging without doing any prior site investigation. Digging the trenches and laying the concrete beds and footings should be a small job for an experienced builder. Once you clear the site, you can begin setting out the foundations.

Step 1 – Scarify/Dig Up the Site

Sprinkle water on the site if the ground is hard. This will loosen up the soil and make it easy for you to dig. Scarify or dig up the soil at an average depth of 150mm within the boundaries. Use a sharp pick to dig up the ground. Since the building area of an outdoor kitchen is often smaller than 36 square metres, one person can finish the job within 4 hours. You can dig manually or you can use a scarifying machine. With a scarifying machine, you will finish the job much quicker.

Step 2 – Level the Site

Take a rake and level up the site. You can also use a shovel to level up the site. Push the soil to positions that need to be filled up. Fill up holes and spread the soil evenly to achieve a flat surface. Break up large soil lumps and remove roots, including any large stones, old bricks and pavers.

Step 3 – Moisturize and Compact the Soil

Rent a soil compactor from a construction service provider. Sprinkle water on the prepared surface. Rev up the compactor engine and move the compactor over the surface. Flatten the soil so that the wet soil particles stick together to form a firm surface. Move the compactor from one end of the site to the other. Repeat the process many times until the soil hardens. Take a soil sample to the nearest soil laboratory to test its compacted density. Check that you have compacted the soil to the required maximum ASHHTO density of 95 percent or more.

Step 4 – Mark the Foundation Lines

Take a setting-out rope, foundation plan, tape measure, white washer, hammer and pegs to the site. Spread out the foundation plan for reference. Insert pegs at all corners around the external perimeter of the imaginary building. Connect the pegs with a setting-out rope. Mark the external perimeter with a white washer. Proceed to peg and mark the internal perimeter of the foundations until you have completed all the foundations. Use the dimensions on the plan to mark the foundation width and length. Half-brick foundations are 500 to 600mm wide and one-brick foundations are 600 to 800mm wide.

Step 5 – Excavate Trenches

Dig the trenches within the marked lines using a sharp pick. Dig to an average depth of 1.50m, but the depth can be less or more than 1.50m depending on the ground condition and height of the building. Use a shovel to take out the soil.