How to Build a Seeded Concrete & Wood Patio Part 1 of 2
A poured concrete patio divided by wood forms is an attractive alternative to a monolithic concrete slab. In addition to its decorative appearance, this type of surface is easier to create, since the permanent forms divide the concrete pour into four equal sections (or more, as desired).
A poured concrete patio divided by wood forms is an attractive alternative to a monolithic concrete slab. In addition to its decorative appearance, this type of surface is easier to create, since the permanent forms divide the concrete pour into four equal sections (or more, as desired). Each section can be poured and finished before moving on to the next, or you can complete all the quadrants in a day. If you choose the latter, you must watch the poured quadrants carefully and finish them at the proper time, so you’ll need a couple of helpers. As an optional addition, this project includes steps for seeding the concrete with small stones, or seeding aggregate, introducing color and texture to the concrete surface.
The form lumber used in the project is brown, pressure-treated 2 x 4s, chosen because it’s more attractive than most green-treated wood. If green is all you can find, you can color the wood with a compatible stain. In any case, use high-quality lumber rated for ground contact, and avoid the type with visible incise marks on the surface, a result of certain forms of treatment. For bolder grid lines, you can use 4 x 4 lumber instead of 2 x 4, joining the form pieces with galvanized spikes.
This four-square patio replaced a small, crumbling slab that had become an eyesore. The new patio combines pressure-treated wood with aggregate to create a natural-looking, durable surface.
This divided concrete patio includes 4"-thick concrete slabs reinforced internally with 6 x 6" 10/10 welded wire mesh. The mesh is supported by 2" wire bolsters to keep it near the middle of the slab interior. The patio, including the forms, is built upon a 6" subbase of compacted gravel. When planning your patio project, consult your local building department to learn about the following requirements:
• Zoning restrictions
• Depth of gravel subbase
• Concrete composition
• Slab thickness and slope
• Internal reinforcement (wire mesh, rebar, etc.)
• Moisture barrier under slab
Adapt the project as shown to meet the local requirements.
From: Complete Guide to Patios & Walkways, 978-1-58923-481-9
How to Build a Seeded Concrete & Wood Patio - Step 1
Prepare the building site by removing any existing building materials, such as for a sidewalk or landing area. If the new patio will abut the house foundation under a patio door, plan to make the height of the finished surface 1 to 3" below the door threshold.
How to Build a Seeded Concrete & Wood Patio - Step 2
Lay out the rough position of the patio using a rope or hose, then mark the exact layout with stakes and mason’s strings. Set the strings for a 1⁄4"-per-ft. downward slope away from the foundation.
How to Build a Seeded Concrete & Wood Patio - Step 3
Remove sod and excavate the project area to a consistent depth using mason’s strings attached to stakes for reference. Mark the excavation depth onto a story pole, and use it to make sure the excavation is a uniform distance from the strings at all points.
How to Build a Seeded Concrete & Wood Patio - Step 4
Create a subbase for the patio by filling the site with an even 3" layer of compactable gravel and tamp the gravel with a hand tamp or rented plate compactor. Add more gravel for a total base thickness of 6" after compaction. Grade the gravel to follow the slope of the layout and tamp thoroughly.
How to Build a Seeded Concrete & Wood Patio - Step 5
Cut pressure-treated 2 x 4 boards to build a permanent frame that outlines the entire patio site. Lay the boards in place using mason’s strings as guides. Fasten the ends together with 21⁄2" galvanized deck screws. Temporarily stake the forms at 2-ft. intervals, set a straight 2 x 4 across the side forms, and set a level on top of the 2 x 4 to check the side forms for level. Tip: Wear gloves and a particle mask when cutting pressure-treated lumber.
How to Build a Seeded Concrete & Wood Patio - Step 6
Cut and install pressure-treated 2 x 4s to divide the square into quadrants; cut one piece full length, and attach two one-half length pieces to it with screws driven toenail style. Drive 4" deck screws partway into the forms every 12" at inside locations. The portions that stick out will act as tie rods between the poured concrete and the permanent forms. Tip: Protect the tops of the permanent forms by covering them with masking tape.
How to Build a Seeded Concrete & Wood Patio - Step 7
Cut reinforcing wire mesh to fit inside each quadrant, leaving 1" clearance on all sides. Mix concrete and pour the quadrants one at a time, starting with the one located farthest from the concrete source. Use a masonry hoe to spread the concrete evenly in the forms.
How to Build a Seeded Concrete & Wood Patio - Step 8
Smooth off the concrete with a straight 2 x 4 screed board that rests on the forms. Settle the concrete by sliding a spade along the inside edges of the forms and rapping the outer edges of the forms with a hammer.
How to Build a Seeded Concrete & Wood Patio - Step 9
Allow bleed water to disappear, and then spread clean seeding aggregate evenly over the surface by hand or with a shovel. Note: if you’re using small aggregate (up to 1" in diameter), spread it out in a single layer; for larger aggregate, maintain a separation between stones that is roughly equal to the size of the stone.
How to Build a Seeded Concrete & Wood Patio - Step 10
Pat the aggregate down with the screed board, then float the surface with a magnesium float until a thin layer of concrete covers the stones. Do not overfloat. If bleed water appears, stop floating and let it dry before completing the step. If you are seeding a large area, cover it with polyethylene sheeting to keep the concrete from hardening too quickly.