Outdoor kitchens are not only aesthetically pleasing and a great place for a family get together, but many of them are strong enough to last for years with a little bit of routine maintenance. With many of the appliances and structural materials weighing hundreds of pounds can you really get away with not pouring a foundation for your outdoor kitchen?
An outdoor kitchen needs to be built on a foundation, simple as that. The weight of the outdoor kitchen needs to be supported usually via a steel-reinforced concrete pad. Portable kitchen setups may be placed on existing patios.
This article will discuss if your outdoor kitchen needs a foundation, how thick a concrete slab for an outdoor kitchen should be, the best surface for an outdoor kitchen and the basics of how to lay a concrete slab for an outdoor kitchen.
Does An Outdoor Kitchen Need A Foundation?
The outdoor kitchens can be divided into two sections: portable and permanent. If you have an existing patio, a portable barbeque setup should not require an additional foundation as the patio will be the necessary foundation.
Building an outdoor masonry kitchen could weigh up to 1000-pounds or more and require a strong foundation to withstand its weight and keep it in place. Any builder will stress the importance of a solid foundation when constructing.
Any outdoor kitchen, portable or permanent, requires a solid foundation. Does this foundation require a permit though?
How Thick Should A Concrete Slab Be For An Outdoor Kitchen?
According to Don Vandervort, an experienced builder and remodeler for more than 30-years, a concrete slab for an outdoor kitchen should be a 4-inch-thick slab poured over a 4-to 6-inch deep bed of gravel.
The thicker your slab in inches, the more weight it can support on top of it. There is no harm in making your slab 6-inches thick when you plan to install a heavy masonry kitchen. The compacted bed of gravel is also critical as this provides adequate drainage so that the area directly beneath the slab has support so that it will not crack over time.
What Is The Best Surface For An Outdoor Kitchen?
There are many options to choose from when it comes to the surface of your outdoor kitchen. It isn’t easy to list the best surface. Instead, let us list some of the more popular surface options that many consumers have chosen in the past:
- Natural Stone
- Stainless Steel
The best surface will be the surface that your budget caters to.
How Do You Lay A Concrete Slab For An Outdoor Kitchen?
Many DIY enthusiasts have successfully built concrete foundations for their outdoor kitchens; it is inexpensive and relatively easy to do. By following these easy steps, you will find that it is possible to lay the concrete slab yourself.
Tools You Will Need
- Metal Screed
- Wheelbarrow/Concrete Mixer
- Water Hose
- Wooden Float
- Spirit Level
- Tape Measure
- Timber Saw
- Carpenter Square
- Edging Trowel
- Steel Trowel
- Tamper/Plate Compactor
- Jointing Trowel (Groover)
- Electric Drill
Materials You Will Need
- Quikrete Concrete Bags (Tabel on the bag will indicate how much according to square footage)
- Timber Lengths For Formwork
- Timber Stakes
- Reinforcing Mesh, Reinforcing Bar And Bar Chairs
- Gravel/Road Base
- Clean Water
- FDA & CPSC-Approved PVC Pipes
When you have all the tools and materials ready:
Step 1: Construct The Formwork
- Take the timber lengths, measure them with the tape measure, and mark them with the carpenter’s square.
- Cut it squarely using the timber saw.
- Screw the formwork together with screws using the electric drill so that it is the exact measurement of the slab on the inside.
- The height of the formwork used should equal the thickness of the slab that you are going for and the layer of gravel underneath.
Step 2: Mark The Area That Needs To Be Drugged Out
- Place the formwork on the exact area where you want your slab to be.
- Use the shovel to mark the outside of the formwork, and this will be the area you need to dig out to the correct depth.
Step 3: Excavate The Area
- Move the formwork aside and start digging out the required dimensions of the slab using the mattock and shovel.
- Allow for an extra 4-6-inches of depth for the gravel that goes underneath the slab.
- Place the formwork back in place and use a spirit level to confirm that it is level.
- Use some of the excavated soil to backfill the formwork for added support.
- Take the wooden pegs and hammer them in 3-4 feet intervals.
- Use the electric drill and screw the wooden pegs and formwork together, making sure that the pegs are level or just under the edge of the formwork.
Step 4: Prepare The Slab Bedding
- Place a bed of gravel or road base of approximately 4-6-inches (especially in areas where water drainage could be a problem) and rake it level.
- Use the tamper to tamp it down firmly, let’s say 5-inches of firm bedding.
Step 5: Add The Reinforcing Mesh, Reinforcing Bar And Bar Chairs
- Cut the reinforced mesh out so that it fits inside the formwork-leaving 2-inches between the formwork and the end of the bars so that all of the mesh will be covered in concrete.
- Place the bar chairs underneath the mesh to support it, and they will hold
- it in place in the center of the slab.
- Reinforcement mesh should be at least 1.5-inches from the base and 1.9-inches from the top of the slab.
- Place CPSC (Consumer Product Safety Commission) – FDA (U.S. Food and Drug Administration) approved PVC pipes that will act as a conduit for the relay of utilities from your home inside the slab bedding to be surrounded and fixed inside the concrete with a part of the pipe sticking out.
Step 6: Mix The Concrete
- Throw the concrete into the wheelbarrow or concrete mixer.
- Check the label to see how much water you need to mix in (an 80lb bag will require 2.8 liters of water).
- Mix the concrete and water thoroughly (Excess water ruins good concrete).
Step 7: Place The Slab
- Soak the base with water to minimize moisture loss.
- Start by one edge of the formwork and add the concrete.
- Work your way away from the edge using batches of concrete, spreading the concrete with a shovel, ensuring that all the edges and corners are filled.
- Fill to the top of the framework, using the shovel to tamper down and rid the concrete of any air bubbles.
- Take the metal screed and hold it against the top of the formwork and start moving it from one end to the other, side to side, making the concrete level.
- Fill in any possible low spots as you work to make the surface level.
Step 8: Finish The Slab
- Water will appear on the surface (bleed water), do not do any work on the surface until the water has evaporated.
- When evaporated, the surface should stiffen a little, now is the time to use the wooden float to flatten and remove any ridges from the concrete.
- If you require a very smooth surface, use a steel trowel.
- If you want a textured, non-slip surface, use a wooden float.
Step 9: Edging The Slab
- Use an edging trowel around the whole perimeter of the slab-it will compact the concrete’s edges.
- For larger slabs, use a jointing trowel to provide control joints at intervals of 60-inches by making straight lines of about 1-inches thick in the concrete.
Step 10: Curing The Slab
- Use the water hose and water the surface and edges two times a day for seven days.
- Curing must start the same day, right after the slab is finished.
Step 11: Removing The Framework
- The framework can be removed after 24-hours.
- You can walk on the surface after three days and start assembling your outdoor kitchen after seven days.
By following these easy-to-follow steps, you should have no problem laying a concrete slab for your outdoor kitchen.
When it comes to building an outdoor kitchen, the construction of the foundation is probably the most important part of the whole process. A solid and structurally sound foundation will ensure that your expensive new kitchen will not sink into the ground and devalue your home in the process.
Following the easy steps listed in this article will provide you with guidance for poring a concrete slab yourself.