How to Build a Deck on a Hillside

Decking your home is one of the most common renovations, but it can be challenging to decide where to place decks. A deck addition on a hillside may sound like an impossible feat, but it’s possible with the correct planning and construction techniques!  

Whether you’re looking for a new deck or just exploring options, this post will help you navigate your way through building in challenging terrain. The first thing to do is find out what kind of soil conditions are under your property. This information will be essential when choosing which type of foundation system will work best for you.

How to Build a Deck on a Hillside

For instance, if there is a high water table condition under the ground, you need to have some form of drainage from your house to a low point where you can divert the water or add a french drain. This post is about how to build a deck on a hillside.

Step to Follow on How to Build a Deck on a Hillside

Step One: Know Your Site

Before you start any deck-building project, you need to understand the site conditions. This includes knowing about the sun exposure wonder if your deck will receive morning or afternoon shade, knowing how much weight your hillside can hold, and understanding potential drainage issues in certain areas of your land.

A good builder will know all of the possible problems and tell you about them and what can be done before any materials even hit the ground. A good builder will also be able to give you potential solutions, should any problems arise.

Step Two: Plan, the Deck

After you know about your site condition and understand what materials can be used in certain areas, start planning for your deck. For example, you will need to work out where the supports will go, if there is room for railings around the edge, what sort of stairs should you consider, and how will they be secured to the land.

You must ensure that your deck meets all the legal building requirements for your area, not just in terms of safety but also local codes. If you are unsure about anything, then check with your local authorities before committing to the building.

Step Three: Build the Deck

Once you have the plan and know what materials to use, it’s time to start building. You will need a builder or contractor who has experience working on hillsides and is aware of all safety protocols. Once the crew starts work, you can expect things to move quickly, so stay out of their way and let them do their job.

Building Deck on Hillside Slope

Once the deck has been built, you will want to think about how to keep it looking its best after it is built. Maintaining a deck on a hillside may be more complex than other decks but even if you don’t use your deck regularly, take the time to sweep out any leaves and debris to prevent mold from developing.

Step Four: Dealing with Drainage Issues

One of the biggest issues you might have if you’re building a deck on a hillside is drainage. Not only do you have to worry about water flow from your deck, but also rain runoff and snowmelt. So your first step should be to look at what sort of grading work has been done for your site.

If you’re dealing with a severe grade, you’ll need to install special drainage features below the deck or consider building a raised deck instead. If you want to find out more about how to build a deck on a hillside, keep reading.

Step Five: Sourcing Quality Materials

If you are building a deck on a hillside, the chances are that you have specific structural challenges in mind. The best way to ensure success with your project is to choose quality materials for the job. Be sure that all of your supports, beams, piers, and other elements will be able to handle the weight expected.

One of the most popular materials for deck supports is treated lumber. Since it has been pressure treated, you can expect it to last a long time and hold up even with heavy foot traffic. However, when it comes to materials for stairs, railings, and any other long-term part of your deck plan, spend a little extra money.

You Can Check It Out to Build a Four Season Room on a Deck

Step Six: Planning for Stairs

If you are building a deck on a hillside, the chances are that you’ll want to build stairs to provide access. Stairs can be built out of almost any material, but treated lumber is often a practical choice due to its rot and insect damage resistance. Another important aspect of steps is the rise and run of the steps.

Example of Hillside Deck Stair

You can either build them one at a time until you have the right measurements or use a stair calculator to work out all of your dimensions before construction. The most important thing about your stairs is that they are safe and provide easy access to your deck. If you’re not sure what sort of measurements should be used, check with your local codes.

Step Seven: Designing a Rail System

If you’re planning on building stairs that meet with your deck, you’ll need to consider ways to attach the two. In some cases, all of the stairs and the deck will be flush and self-supporting. In other cases, you may want to consider attaching a handrail or railing system from one level to another.

If you are attaching a railing system to your deck, make sure that the construction is solid and can handle even heavier loads when people are standing on it. Always plan to ensure that all of your stairs and railings are safe.

Step Eight: Finishing Touches

Once your deck is finished, you can add all of the finishing touches that will help it become a full-time feature in your home. For example, if you’re building a deck on a hillside, chances are there’s at least one spot where dirt and grass constantly build up.

Clean the Deck Area for Finishing Touches

You can use pavers or deck blocks to keep debris at bay and prevent it from causing damage to your stairs. Another finishing touch you might want to consider is adding some seating onto the deck. You can use a patio chair or even build out a bench if you have the space. This will help in how to build a deck on a hillside.

Step Nine: Enjoy Your Deck

Once your deck is finished, it should be able to stand up to the weather and provide you with plenty of beautiful views. Be sure that all of your railings are safe, solid, and can do their job correctly even in harsh weather conditions. It’s best to use treated lumber for any long-term part of the build. 

You can also consider using resin or even concrete to ensure that your stairs are strong and will last a long time. Finally, remember the golden rule when building decks on hillsides: regardless of how you build it, make sure that there is at least one safe way up and down from the deck.

Frequently Asked Questions

How Much Does It Cost to Build a 20×20 Deck?

A 20×20 deck can cost anywhere from $8,000 to $25,000, depending on the type of materials used. The best way to determine how much a 20×20 deck will cost is by calculating the square footage of your home and multiplying it by $1,500. For example:

If you have a 3,500 square foot home, then you will need to spend about $17,500 for a 20×20 deck.

Do You Need Planning Permission for Decking on Slope?

If you are thinking of decking on a slope, there is no need to worry about planning permission. However, if you have an established building on the site or the property where you want to build your deck, then planning permission is required.

What Is the Maximum Slope for a Deck?

The maximum slope for a deck is 12 inches per foot. You can also add this to your design: Include steps or ramp sections at the corners of the deck so that people have an easier time getting up and down from the area.

What Is the Cheapest Way to Build a Deck?

A deck is a structure built on or outside a building. It is generally one level and has posts that are made from wood, metal, or concrete. The cheapest way to build a deck would be to purchase the materials needed and hire someone who can do the work for you.

Another way would be to find free plans online that you can use as guidelines for your project. This will allow you to save money on the cost of the materials but still have it done by professionals.

How Far Apart Should Deck Joists Be?

The distance between the joists depends on the span of the deck. If you have a smaller deck, it is likely that they will be closer together than if you have a larger deck. However, if you are building a very large deck, there should be more space between them so that they don’t sag or buckle.


The deck you build on a hillside can be beautiful and functional. Here are some tips to help make the process easier, safer, and more enjoyable for everyone involved! -Have an experienced contractor design your deck project with landscape considerations in mind.

Ask them about their experience working on sites that are difficult or unusual, like hillsides. They’ll have plenty of ideas on how to get it done right, which will save you time & money down the road. For example, the article has been a good guide on how to build a deck on a hillside.

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