How to Attach Deck Posts – EP 2

This article is about how to attach deck posts to concrete. When building an entrance deck it is important to understand what are the proper techniques to attach posts to the base surface. Generally speaking this diy project can be done in more ways, according to the type of the deck material: if we speak of a wooden deck, then the posts have to be attached on the deck frame by using long lag screws and shims to make sure the post is plumb; on the other hand if we speak of a concrete surface we have to install post anchors before installing it.

This step by step guide will help you choose the best materials and tools, in order to build an entrance deck with a professional look, but you have to take into consideration several aspects before starting the deck construction. On the market there are a lot of types of posts, but the most common ones are the 4×4 ones. In addition, it would be wise to buy posts which have been treated against wood decay or moisture. Before starting such a project pay attention to your local codes. It is essential to know and understand the requirements you have to meet before starting your diy project.

Before attaching post anchors and deck posts, you have to make a complete plan, as to know from the very beginning what you have to do. Without a proper plan, your project can turn in a total fiasco as you don’t know in any moment what would be the next step. As to attach posts in a professional manner, you have to use proper tools: a circular saw, a drill machinery with hammering function and a planer. In addition, you have to know several basic carpentry techniques, as to get the job done properly. See all my Premium Plans in the Shop.

Made from this plan

In order to attach deck posts, you need the following:

Materials

• 4×4 posts
• post anchor hardware
• wood lag screws
• wood primer

Tools

• Level, rubber hammer
• Hammer, measuring tape
• Circular saw, drill bits
• Clamps, drill machine
• Electric screw driver with torque control
• Framing square
• Carpenter pencil

Tips

• Read safety and disclaimer pages
• Select with great care the wood posts, otherwise the railing would look bad
• Use a good drill machine with torque control
• Before fastening the posts, make sure they are plumb

Related

• Episode 1: Deck Plans
• Episode 2: Anchor Deck Posts
• Episode 3: Building Deck Railings
• Episode 4: Deck Stair Railings

 Preparing entrance deck for installing post anchors

Entrance Deck

Before starting the project, you have to make sure the base surface is level, by removing all irregularities. In addition, you have to use a vacuum cleaner or broom to remove the dust, as to ensure you can install post anchors properly.

Smart tip: before purchasing posts and materials for deck railings, you have to use a tape measurement, as to be able to draw a complete plan. Therefore, you should get accustomed to the fact that proper balusters and railings must follow certain regulation.

Measuring deck to install deck hardware

Afterwards, the first thing you should do is to set the layout of the post anchors. Consequently, use a tape measure to get the dimension from the wall up to the post anchor.

Smart tip: when measuring this distance, you have to make sure the tape measure is perpendicular on the wall, as to get the exact length.

Using tape measurement to install post hardware

Next, use the tape measurement to set the post anchor on the opposite side of the deck entrance. You have to remember that you have to position it at the same distance from the wall, as you have done with the first post anchor.

Smart tip: make sure the both post anchors are positioned symmetrically, otherwise you won’t be able to build the balusters properly. In addition, remember that you have to install the post anchors on the concrete floor, by using several screws. Consequently, make sure you will be able to drill the holes on the edges, without damaging the concrete.

Marking where to make drill holes

After you have positioned the two post anchors properly, you have to use a carpentry pencil to mark the places where you will drill the holes in concrete.

Smart tip: use a good pencil, as to mark properly the spots, otherwise you won’t know where to drill the holes.

Installing post anchors

Aligning deck post anchors

In addition, to make sure the posts will be perfectly aligned each other, you could use a straight piece of  timber (in our case we used a metal stud, but you can try with anything which is perfectly straight).

Remember that before drilling the holes, you have to make sure the post anchors are aligned each other, but also with your house. Therefore, pay attention to our guidelines, as to get the job right from the very first time.

Smart tip: use a level, as to make sure the base surface  is perfectly level, otherwise your posts won’t be plumb. Pay attention to these steps before starting the actual project.

Enlarging drill hole

After you have set the layout of the post anchors, you can start drilling in concrete. Consequently, you should use a good drill machinery with hammering function and several drill bits. We will insert plastic anchors in concrete, as to fix the lag screws.

Smart tip: first choose the lag screws (at least 3” long), then the plastic anchors and last the proper drill bit. If the needed size of the drill bit is greater than #8, you could first drill a hole with a smaller bit and then enlarge it to the required size, with a larger drill bit.

Installing anchors in concrete

Next, after you have drilled the holes, it is time to install the plastic anchors in the concrete deck. Consequently, push them gently in the holes and then tap them with a hammer (we recommend you to use a mallet, as not to damage the plastic anchors).

Smart tip: make sure the end of the plastic anchors is aligned with the concrete surface, otherwise you won’t be able to install the post anchors properly.

Fastening deck hardware to concrete

Last but not least, use a wrench key to drive in the lag bots. In order to fix properly the post anchors, you have to fasten each one with at least 4 lag bolts. Consequently, drive in the screws by moving the key clockwise, until the post anchors are fixed firmly.

Smart tip: make sure you don’t apply too much pressure, otherwise you risk damaging the lag screws.

Cutting deck posts

Deck post anchors

After you have driven in the 4 lag screws, the post anchor should be fixed firmly, but in the same time it should be level and plumb. Before installing the wooden posts, you have to check again if the post anchors are fixed properly and will be able to support the wooden post for a long period of time. This is a heavy duty post anchor which I prefer to other products, because of the wide base. In this manner, you can pour screed and tile the deck without damaging the wooden posts.

Deck Posts

For this project we have chosen 4×4 posts, treated against wood decay and moisture. In addition, we bought decorative posts, as we considered they will fit better the design of the house.

Smart tip: when selecting the deck posts, make sure you buy only the best ones, without cracks or scratches, as to get a nice appearance. In addition, you can notice in the image, that the post has a nice model carved in the wood.

Marking cutting line on deck posts

Next, we have to cut the post as to fit our needs and tastes. Usually deck posts are about 50” long, but we needed them to be of 42”. Consequently, use a tape measurement, as to mark 8” (or the length you want to cut), starting from the base of the deck post.

Smart tip: as to make sure you cut exactly the length you want, use the tape measurement along the edge of the deck post. Mark the spot with a carpentry pencil.

Using a l-square to mark the post

Next, use an L-shaped square to draw a guideline on the deck posts. Use again a good carpentry pencil, as to make sure the mark is highly visible.

Smart tip: mark the cut line on all faces of the deck post, as to make a professional cut. Remember that this will be the base of the post, which will be installed in the anchor hardware, so make sure it is perfectly squared off.

Cutting deck posts

Next, we have to cut the deck post to the desired length. Consequently, we could use several tools: a circular saw or a carpentry chainsaw. There are both useful power tools, but we recommend you to use a good circular, as a diy-er will get easier a proper cut.

Smart tip: make sure the bottom of the post is squared off, so that it can seat securely in the post anchor. In addition, cut the post exactly over the drawn line.

Adjusting deck post with a planner

Next, we have to adjust the base of the post as to fit in the anchor. In most of the cases, you don’t have to do this operation, but it is good to know the exact technique for other projects.

Consequently, mark on the post the depth of the post anchors, as to know the length on which you have to use the planner. The planner should be used on all faces of the posts, as to get a symmetric output. In addition, you have to measure the inside dimensions of the post anchor, as to know how much you have to shave from the post.

Deck Post after using a planner

After we have used the planer several times on each face of the post, we got the result you can see in the image. It is far from being perfect, but it is a solid starting point.

Smart tip: when using the planner, make sure you don’t go over the drawn line, otherwise you won’t get a professional result.

Adjusting Deck Post to fit in hardware

As to level off the post, we also used a block plane over the whole surface. Use safety gloves, as to protect your hands while you are using the hand tool. From our experience, we can assure you that the possible injuries are quite painful, so it is better to be safe than sorry. More details on How to anchor post to concrete.

Smart tip: use the block plane alternatively on each side of the deck post, until you get the desired result. Removing the protective coat from the wooden posts is no desirable, but that was the only solution to make them fit into the anchors. I built this deck 10 years ago and I can assure you it is still alive and kicking.

Attaching deck post

Applying primer on deck post

Before attaching the post in the anchor hardware, we have to apply a protective coat of primer over the wooden post. Consequently, use a brush and apply one or two coats of primer over the exposed post, according to the manufacturers instructions.

Smart tip: before installing the post in the post anchor, we have to wait for the primer to get dry. In addition, make sure the primer is resistant to water and moisture, as it will be exposed to bad conditions.

Using a level to ensure the deck post is plumb

Next, set the post in the anchor, making sure there is no space between the anchor and the bottom of the deck post. Attaching the deck post is a very important operation, as it will influence directly the look of the railings and balusters.

Smart tip: use a level to make sure the post is plumb in all directions. If you work by yourself, you should brace the post in two directions.

Pre-drilling deck post

Next, after you ensured the deck post is locked firmly into position, you have to use a  drill machinery with torque control, to make several holes in the post. Remember that the holes must be made with drill bits smaller than the size of the lag screws, otherwise you won’t be able to secure the post.

Smart tip: for unexperienced diy-ers is safer to mark the spots, remove the post from anchors and drill the holes.

Using a wrench key to drive screws

The last step of our project is to secure the post by driving in the lag bolts. Consequently, use a key wrench to insert the screws in the wooden posts. Remember that you don’t have to apply too much force, as you risk damaging both the posts and the screws.

Attaching Deck Post

Smart tip: Install the first screw on a side of the post anchor and the next one on the opposite side of it, as to distribute evenly the force, otherwise you might get a post which is not plumb. Check the full Concrete Deck Series.

Thank you for reading our article on how to attach deck posts to concrete, and we recommend you to check out the rest of our projects regarding deck, posts and railings.

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