How To Extend a Concrete Patio with a Wood Deck

Patios are a great place to entertain on summer evenings and can hold your grill and maybe a couple of deck chairs. However, a cold slab of concrete isn’t the most attractive solution and they typically aren’t big enough to enjoy properly.

You can extend a concrete patio with a wood deck and we are going to show you how. In this step by step guide we will cover the tools and materials needed for the project and take you by the hand to explore every step along the way.

This DIY project isn’t as difficult as you may think. You can even start today! Let’s learn how.

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Best Reasons to Extend Your Patio

Many homeowners are dissatisfied with their current patio, but for many different reasons. Here are the top explanations for adding on a wood deck extension.

Not enough room. Most patios are small and don’t offer enough space to properly entertain guests.
Not aesthetically pleasing. A bland slab of concrete isn’t something many homeowners want to look at when they head outside.
Cracked or damaged slab. Covering and extending a patio can help hide cracks, chipping or water stain damage.
Hard to keep clean. Not everyone has access to a concrete power washer. Wood decks can be easier to maintain than concrete.
Patio surface is too low. Some patios have a significant drop from the door threshold to the top of the slab. A deck extension can correct this.

Tools Needed For Deck Extension

You will need a host of tools to complete the project. Depending on your yard, current slab condition and other factors, your list may vary. The essentials, though, are listed here.

Circular saw
Power driver or handheld drill
Hammer drill
Masonry drill bits
Bubble level
Chalk line
Miter saw
Shovel
Trowel
Mixing buckets
Hammer
Screwdrivers
Measuring tape
Marker/pencil

Materials Needed for Deck Extension Project

Aside from the tools you need to have on hand, you will also need some materials to work with. Again, your list may vary slightly depending on your specific needs, but the basic list will include:

Decking material (pressure treated lumber, composite decking, etc.)
Flashing tape
PVC trim (for spacers)
Treated 2x4s
Plastic shims
Concrete pier blocks
Concrete screws

Step-by-Step Guide: Extending a Concrete Patio with a Wood Deck

Now that you have the tools and materials needed, it is time to start building your new patio extension. The following guide will take you through the entire process for covering and extending a concrete patio with a wood deck.

We do take a few assumptions, though. For example, we assume you already have the plans and measurements for your new patio space. Since different situations will require different measurements, there isn’t a one size fits all approach. Use the following guide to help you understand the process and then adapt it to your needs.

Step 1: Draw Your Layout

You need to get out the measuring tape and chalk line here. A marker won’t hurt either. The first step is one of the slowest, but the most important. Take your plan and place it down in the real world.

The first decision to make is to decide if your boards will run parallel or perpendicular to both the house and each other. Most patios will have the decking run perpendicular to the house and parallel to one another.

Use chalk lines to snap a line on the patio surface where the support beams will go. You can then use the marker to mark where your sleepers need to be placed to allow for drainage and airflow.

You will also want to include any areas for different board usage, steps, through-posts for railings or other additional items.

Step 2: Level the Patio

Before you start doing anything else you need to ensure that your current patio is level. They can sink or warp over time with the weather and erosion, and this needs to be corrected.

Using a self-leveling concrete compound you can fill any dips or slants to make a nice level patio once again. You can also use standard concrete mix, but this will take longer to cure. Another factor to consider is water runoff.

You may wish to add a slight pitch from the house side of the patio to the yard side so water and rain can run off without pooling underneath your lumber.

Once you have the patio level, pitched or sloped and cured, you are ready to start the next step, moving out into the yard.

Step 3: Placing Pier Blocks

Now that you have the visual idea of your project on the concrete slab, it is time to look into the yard itself. You want to follow the joint lines into the yard and place pier blocks as needed. Each block will support the joist lumber and will need to be shimmed and sized appropriately.

Start by placing the pier blocks directly on the ground where they need to go. Double check your measurements, keeping your joist spacing in mind. Once you have a row or two, grab the shovel, it is time to dig.

Start by cutting the sod around the block so you know what to remove. Your first few will be slower but you will get faster as you go on. After the block is traced, remove the block and then shovel out the side and dirt where it stood.

You want to dig deep enough to keep the top of the block even with the surface of the patio. Measure out from the top of the slab to the top of the pier block. Remember to keep the slope and pitch in mind as you extend further and further out.

Using a bubble level will help you maintain the proper depth, but the measuring tape will get you started with placement and angle.

Step 4: Placing Joist Boards and Extensions

Now that you have your support system in place you need to start laying the joist boards. The treated 2x4s will be your sleepers and joists for this project and you can use PVC cut to size for spacers and even shims.

The screws for your sleepers should go into the concrete at least an inch, so make sure your concrete screws are long enough to get the job done. You will be drilling a lot of holes into the slab on this step. Go slow, measure often and replace your drill bit as needed (about every 40 – 50 holes).

You want your sleepers to follow the slope of your patio, but any sunken or raised areas will quickly become apparent. Start by laying the sleeper board directly on the slab and looking for the biggest gap between board and concrete.

Drill your first screw here. You want to add shims to support and raise the low spots. After every few boards, measure and check for level in both directions (across the joist boards and along them).

The goal is to add the spacers so the board is off of the concrete, but secure. This will allow for water and rain to run off of the concrete slab without being stopped by the sleeper boards. It also allows air flow to help evaporate any left over moisture which can cause rot or mold under your deck.

When you get to the edge of the patio you may need to rip a joist board (cutting along the length) to use as spacers and wedges to extend out to the pier blocks. Continue extending the joists through the pier blocks using smaller and smaller shims until the final one is in place.

Now, your project is about halfway complete and you should have a solid joist and support system for your deck. Double check that all sleepers and joists are level, even and properly attached to the patio.

Step 5: Flashing Tape

Now that you have your support system laid down you need to protect it. Flashing tape along the tops of the joist boards. This will prevent standing moisture and help prevent rot, decay and mold.

Flash the entire board top on all of the joist boards/sleepers until your entire patio area is completed. It will take some time, but this important step could add years of use to your decking.

Step 6: Add Decking Material

The final step is now here and you can unbox your decking and start laying it down. You will use the same installation method here as you would with a normal deck. You can use hidden fasteners, decking screws, nails, etc.

Follow your decking products suggested installation method and always measure before each cut. Place and set the decking before attaching and check for level and evenness along the way.

Once the decking is done you only need to add fascia to the ends to cover the joists and sleepers. PVC fascia is inexpensive and can be painted. Many composite decking brands also offer exact-match fascia boards for use, or you can use pressure treated lumber here, too.

Step 7: Enjoy

Once the project is complete, you want to clean the new patio surface and put away all your materials, tools and equipment. It is crucial to clean the entire space so you can see any errors, scratches or damage before you stop for the day.

Once the patio is clean, you are done. Move the barbecue grill and patio furniture back to its new home and enjoy your summer on your new patio.

Other Patio Options

A sleeper system is essentially joist boards placed between a hard surface like concrete and the decking on top. It allows for easier installation, repairs and cleaning. It also allows for drainage and airflow to help protect your investment from odors, rot and decay.

However, if you don’t want to go this route, there are other options to consider. Perhaps your patio is large enough but just doesn’t look good. Or, you don’t want to mess with lumber and decking materials. Here are some other ideas to consider for your patio project.

Pavers. You can use a sand mix to place pavers directly over the concrete patio. This will give you a new look and feel without costing a fortune. Most pavers are inexpensive and you can generally expect a weekend project to cost about $4 to $5 per square foot.
Outdoor carpeting. Rugs, carpets and throws also help cover unsightly concrete while adding protection from heat retention and a hard surface to walk on. With carpet you have several installation methods, but rugs are the most common use.
Staining the concrete. You can pick up a few gallons of concrete stain and sealer and spend the weekend painting instead of drilling. This offers a more temporary solution as you will need to stain and seal every couple of years, though.
Resurface concrete. Using concrete resurfacer may be the fastest permanent solution. This will cover cracks, damage and help you relevel your patio, but it will still be concrete.
Ceramic tile. Concrete patios make an excellent base system for laying outdoor tile. You can get as simple or creative as you want and rejuvenate the entire space in a couple of days.
Locking deck tiles. Give your patio a new look of wood (or other material) with quick to install locking tiles. These floating floor style tiles can give you a patio uplift in a few hours.

Conclusion

Concrete patios are common backyard accessories for water drainage and entertainment spaces. However, they tend to be too small or not very pleasing to the eye. Deck extensions with a wood deck is one of the most popular solutions.

With a wood deck extension you can transform your patio into a backyard deck and add space for all of your furniture and grilling supplies in the process. This how to extend a concrete patio with a wood deck guide showed you how easy the task can be. Enjoy your new backyard!