How to Lay Out Your Deck & Footings

Creating your own deck can be a big project, as there are many different steps you need to take – especially when it comes to planning. 

One of the first things you need to do before you can build your own deck is to lay out the frame and basically decide where everything is going to go. This includes your deck’s perimeter, as well as any posts and beams you hope to add. 

Laying Out a Deck Perimiter

Because this is such a huge and important task, it can be intimidating. That’s why I am sharing this handy guide so you know what you need to do and when. Hopefully, yo can learn from my many years building decks.

This is my how-to guide for your deck framing layout. Check it out, and I hope you find it useful! 

Step One: Prep Your Deck Site

Before you start laying out your deck’s framing, you first need to get your deck site cleaned up and prepared. This can be a big task and can take a while to complete, depending on how much debris you need to move away from the site where you want to put your deck. 

Once you have decided on the area where you want to put your deck (often attached to your house by the back door or a free-standing deck elsewhere in your yard), it’s time to start clearing away the debris. Remove any plants, rocks, and rake the ground until you are left with a clear work site. 

You also need to inspect the grade of the land. It’s very unlikely that the ground you will be building your deck from will be exactly flat, so you need to fill in any holes that could cause water to build up around the foundation of your decking. 

However, before any digging is started, you need to check where any pipes and lines could be lurking under the ground. This includes piping for your utilities like water and gas, sewer lines, communication and electrical lines, and more. 

First, call 811 or your local utility locator. It may feel like a waste of time, but this will save you hours of stress and thousands of dollars if you accidentally cut a pipe.

Call before you start digging on your property.

A few quick questions, and then they will send someone out to locate any utilities that could be located around your yard where you plan to build your deck.

They will mark the ground and leave flags to show where exactly the lines or pipes run.

Then you will know if it’s safe to dig your deck footings. Or if you need to adjust your footing locations where there is a conflict.

Step Two: Start Marking Out Your Deck Perimeter 

Once your site is ready, it’s time to start marking out the perimeter of your deck. 

If your deck is going to be up against the side of a building, like your house, then you first need to mark where the edge will be on that wall. Give yourself an extra inch or two for any additional finishing materials, like fascia or handrails. 

Make a mark where the frame will be, and then make another mark at the foundation. Use a level to measure where that mark will be. There, you will hammer in your first stake – and repeat this step for where else your decking will come up against your house. 

After that, it’s time to make your corner stake. 

Measure out how far you want your deck to be, and then add an additional foot to that length. Then, move the stake over another foot so that when the string is tied up, you have the flexibility to adjust the square of your decking. Do this process for all the corners of your deck, then tie them together with your string. 

Once the front string is done, add slide strings to the outline and tie them to the stake placed at your house. The loop should be able to move side to side so you can adjust it. Pull the strings tight, and your deck framing layout will start to take shape. 

For a smaller deck it is easier to lay 2 straight boards on the ground along the edges of your proposed deck. With them intersecting at a outside corner of the deck. A single screw will hold them together while you adjust them for squaring.

Builders Tip
Squaring a Deck with 2x4 and a Tape

Now, you need to make sure that your deck layout is square to the house. To do this, most builders use the 3,4,5 method or the 6,8,10 method for larger decks. 

What you need to do is measure six feet from the edge of your deck (or the stake that represents it) and mark the house.

Then, follow the string line that represents the edge of the deck frame and mark the string eight feet away from the house.

Using a tape measure, measure that the length between these two marks is ten feet long. If it isn’t, adjust the sliding string until it is so. 

This will ensure that the side of your deck’s frame is exactly at a 90 degrees angle from the house. Repeat this process for your other corner to ensure the deck is exactly square. 

Step Three: Mark Your Beam Locations

This step is super easy – all you have to do is go along the string line that represents the frame perimeter of your deck and make a stake wherever you want to put a beam. 

Having your perimeter in place makes this step incredibly easy as you can just go along the perimeter, placing stakes at the right measurements, then use more string to attach each beam stake with their opposite on the other side of your deck. 

Once your beams are located using the string (make sure to pull them so they are tight) it’s time to mark your deck’s footing locations. 

Step Four: Mark Your Footing Locations

To start marking out your footing locations, you first need to check with the plans of your deck to see how far the first post is from the edge of the deck frame. Some decks use cantilevers to extend the deck over the footing posts, so it’s important to keep this in mind. 

Once you are sure of how far back your post will be, mark it on the beam line (make sure you are marking the center of the post, not the edge) and then extend that mark down to mark the ground beneath it with a bit of spray paint. 

Keep measuring back the beam line until you have all your footing posts located on the ground. Make sure you avoid any obstacles (like utility lines) and that you keep to the measurements set out on your deck plans. 

Repeat this step for all of your beams, so you have the center of all of your footing locations clearly marked on the ground. 

Once you have marked the center of your footing locations, it’s time to locate the perimeter of each footing post. This will show you where your post hole needs to go and where you need to dig. 

So, take something that is exactly the diameter of the hole you need to dig out. For example, if your concrete footings are 12 inches in diameter, you will need something round with a diameter of 12 inches to use as a pattern to mark out your footing holes.

A popular way and what I often us is forming (sono) tubes as they come in a variety of sizes. They are easy to line up with the center mark of your posts, and you can easily spray the perimeter either inside or outside the tube. 

If you can’t find a forming tube that fits your needs, you can just use your measuring tape to measure out the diameter. Center it to the mark on your beam line, and spray accordingly.

Do the same in the other direction until you can paint a circle yourself. This method is a little less accurate but if you are careful and patient, you shouldn’t have any trouble, and it will be enough to get the job done. 

Repeat this process for each of your footing locations, and this will show you the ground you need to dig out for each footing post. The next step then will be to start digging – but that means moving onto the next process entirely of creating your new decking! 

Final Thoughts

And that’s it! 

After you have marked your footing post locations on the ground with some spray paint, you will have finally completed your deck framing layout.

You will have the perimeter marked out with string and squared off, your beams will also be marked via string, and the foot postings will be sprayed on the ground in the correct positions. Once all this is done, you are ready to start installing your decking! 

The key to success when laying out your deck’s framing is to have the plans at hand, so you have all the measurements ready to mark the positions.

You can’t lay a deck without knowing the distance between each beam and foot post. So, make sure your plans are completed and accurate before you start laying out the frame on the ground. 

I hope this guide has helped you out, and good luck with your deck project!

Ryan Nickel

A Red Seal carpenter, passionate about building decks to be enjoyed.

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