Last modified: August 24, 2023

How to Build a Pressure Treated Deck in 6 Steps

How to Build a Pressure Treated Deck in 6 Steps


How to Build a Pressure Treated Deck in 6 Steps

How to Build a Pressure Treated Deck in 6 Steps

Written by Garden Buildings Direct
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Whether it’s around a shed or a summer house, building a deck can be quite a passion project. Though the work is hard, the payoff will be well worth the effort. If you have zero confidence in handling wood, you should consider handing this project over to the professionals. However, if you have some skills in woodworking, this article will help guide you on how to build a pressure treated deck.

Codes and Permits

Before you buy any materials, pay a visit to your local building authorities to learn if you need a building permit. Many neighbourhoods have rules that determine the types of structure you can add to your property. These rules also regulate dimensions, height, structural support, stairways, and railings. It’s essential that you learn about this information before beginning your project.

Building a new deck and deck frame is no easy task. You should go into this project with the mentality that anything and everything can and will go wrong. When problems arise, you must have the patience and aptitude to solve them one by one. Otherwise, you’re just going to give up due to frustration.

It’s guaranteed that you’ll run into several situations where you’ll be forced to solve a significant problem. Doing your research and preparing beforehand will help the project go that much smoother.

If you’re unsure of how to proceed, that’s okay. Take a step back and research the problem at hand. There are plenty of resources out there that can get you out of your rut. You can watch online videos, read books and even find blueprints for your dream deck. The deck footings should be built in your mind before you spend a single pound.

A quick word about freestanding decks

One of the more popular deck types is the kind that is anchored directly to your house with bolts and screws. The one downside to installing an anchored deck is that you’re required to remove the siding from your house – a scary proposition to be sure.

For those who aren’t interested in building an anchored deck, you can build a freestanding deck. Freestanding decks can be beneficial in a number of ways, though they require a bit more work to set up.

Unlike anchored decks, freestanding decks don’t require stripping chunks away from your home. The end of the deck that would normally be anchored to the house would instead rest on additional post footings. Freestanding decks require significant digging and cement work to install properly.

Though it’s more work overall, some people feel more comfortable building a deck that’s separate from their home. An added bonus is that some neighbourhoods don’t require a building permit to construct a freestanding deck. That means you can get started ASAP with nothing holding you back from building your dream deck.

Though freestanding decks are a viable option, this article will only discuss anchored decks.

Gather the proper tools and materials

Just as important as building the deck itself is gathering the proper tools to get the work done. Here is a list of the tools that are typically used to build a deck:

• Drill and bits
• Circular saw
• Carpenter’s square
• Tape measure
• Table saw
• Power mitre saw
• Particle respiration mask
• Shovel and post-hole digger
• Eye protection

• Cement mixer or wheelbarrow
• Carpenter’s level
• Hammer
• Caulk gun
• Wrenches


• Joist hanger nails
• Metal flashing – great if you want to extend the look of, say, a metal greenhouse
• HDG bolts or lag screws, and washers
• Metal Rebar
• Post Bases
• Caulk
• Pre-mixed concrete mix
• Gravel or crushed stone
• Cinder blocks
• Post caps
• Seismic ties
• Cardboard tube concrete forms
• Deck screws or stainless steel or HDG nails
• Joist hangers
• Treated timber decking
Starting with the right tools will ensure that you get the job done in a more efficient manner. Nothing hinders the efficiency of a deck project more than running over to your neighbour’s house to borrow a different tool every time you run into a different problem!

Step 1: Preparation

Now that you’ve researched your local building codes and have the deck blueprint firmly in hand the first step is to prepare the work site.

Use stakes and strings to outline the shape of your deck. Decks that are square or rectangle are often the easiest to measure. Simply measure diagonally from end to end. Each diagonal measurement will have the same dimensions.

Now it’s time to get down and dirty. Remove grass and any other plant life from the area that you have measured, so you have a completely clear workspace. A shovel will get the job done the fastest, but you can use whatever tools you have at your disposal. Take extra care to make the ground as level as you can. Rushing through this step will only cause you issues later on.

Pro tip: laying down a layer of mulch before proceeding any further will repress weeds from springing up from beneath your deck!

Mark where you plan on attaching the ledger board to your house. A ledger board is a structural piece that is mounted to most vertical frames and is a vital component in stabilising your deck to your house.

Ensure that the header board is as level as you can make it and that it’s the proper height. Your header board should be at the same level as your joists. This is where your surface decking will be laid out which is why it’s so important that it’s as level as humanly possible.

Next, label the area where your footing posts will be set. Footing posts are often regulated by the rules and regulations set by your local building authorities.

Step 2: Installing the Ledger

As we’ve discussed, the ledger is a vital component that helps to connect and stabilise your deck against your house. Ledger boards are typically 2 x 10 or 2 x 12.

Now, carefully remove the siding where the header board will be placed and place flashing (sheets made of stainless steel, copper or vinyl) under the areas that you have opened up. Once you’ve completed this step, bring the flashing down along the side of the house and cover the bottom of the ledger board. Flashing prevents moisture from entering the areas that you have opened up.

Now install the ledger board over the flashing with screws. Use caulk to seal the ledger as an added layer of defence against moisture.

Step 3: Install the Posts and Footings

The next step involves installing the vertical posts. Vertical posts are vital to your deck because they act as the backbone of the beam.

Vertical posts require that you do a bit of digging so they can stand up from the ground. This aspect can get a bit tricky because the depth of the hole must be to the exact specifications indicated by your local building authorities.

Once the hole has been dug, fill it with wet concrete and install your posts (typically 6 x 6 or 4 x 4). Be mindful of the regulated height. It may be easier to install the posts and then to cut them down to the required height once you’re finished.

Step 4: Installing the Support Beams

It’s typical to need one or more horizontal beams when constructing your deck. Beams are vital for the support of the structure. Specifically, they support the joists (a long length of steel or timber that supports part of a building or structure). You’ll find in many cases that the deck joists do most of the heavy lifting.

Pay extra attention to your deck plans. There are various types of beams and posts, and each has their own configuration. If you’re careless, you might end up purchasing the wrong type and you’ll either lose out on money or waste time as you go back to the proper material. Whatever configuration you require, get it right the first time to avoid the ensuing headache.

Keep in mind that heavier decks will require two or more beams to support the heavier weight whereas smaller decks typically just need one.

Step 5: Installing the Joists

Joists serve as one of the most vital components of maintaining the integrity of your deck. There are two types of joists that you will need to complete your project – interior joists and rim joists. The interior joists must be spaced around 12″ or 16″ apart from each other. Your rim joists will serve as the outside edge of the deck itself.

Typically, you can get away with using galvanised fasteners to secure your joists in place. However, the chemicals within pressure treated wood can corrode them away thus compromising the integrity of the entire structure.

To avoid this issue use fasteners and metal connectors that are resistant to corrosion. This also applies to nails, screws and other hardware. The proper spacing of joists and the dimension of the pressurised wood are dictated by the local building authorities.

On another note, the size of your deck will significantly determine the dimensions of the lumber used. For example, larger decks often require 2 x 10 or 2 x 12 lumber whereas smaller decks only need 2 x 6 lumber. If you aren’t sure of what you’re doing, consult a professional.

Step 6: Setting the Deck

If you take a step back from your deck, it should look like what you imagined in your head before you began to work. Of course, if it doesn’t, you may have to reevaluate what you’ve done up to that point.

The next step is to lay down your pressure treated decking boards. It’s most common for decking boards to be attached to the joists via nails or screws. This is one way of doing it, but if you’re looking for a more aesthetic appeal, you can opt for a bracket system that allows you to nail down your pre-treated timber decking without visible signs of a screw or nail.

Pro tip: Space out the decking boards in a uniform manner. Not only does this make your deck more pleasing to look at, but it also stops trash and other debris from falling between the boards.

Final Step

Depending on how you construct your deck, you may or may not have to regard these final steps. As mentioned before, if your deck is a certain height you may be required to insert railings and a stairway. In most cases, building codes will require that you add these components for the sake of safety. Railings and stairways are entities within themselves when it comes to installation. If you’re unsure how to install these components, you’re encouraged to consult a professional.

At this point, you’re all finished! How to build a deck is a question where the answer is no longer required. You can clean up and enjoy your brand new deck. With the use of pressure treated wooden decking, you won’t have to worry about maintenance for decades to come. As a final step, you can choose to add stain and sealer if you feel inclined though it’s recommended that you wait several weeks as you wait for the lumber in your deck to dry out.

Featured image credit: joe warden / Flickr
In Post Image credit: JamesDeMers / Pixabay

There you have it – how to build a pressure-treated deck for outside your greenhouse, summerhouse, shed or log cabin. Sit back and relax by adding some furniture and enjoy those long evenings looking out over your garden!

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