Building a Sunroom on a Deck: Everything You Need to Do

Giovanni Valle is a licensed architect and LEED-accredited professional and is certified by the National Council of Architectural Registration Boards (NCARB). He is the author and managing editor of various digital publications, including BuilderSpace, Your Own Architect, and Interiors Place.

Sitting out on your deck on a bright morning is one of the best ways to enjoy the outdoor view, but what if you can make the experience even better? A sunroom constructed on your deck ensures you don’t have to worry about flies, freezing temperatures, and other such discomforts while taking in the sights and sounds of your environment.

Building a sunroom on a deck is a challenging but rewarding process that can add value to your home. The process starts with analyzing the deck’s current design and fashioning the right sunroom construction that will fit. You can construct from scratch or purchase aluminum sunroom kits.

The rest of this article will cover all you need to know about building a sunroom on your deck. You’ll learn all you need to do from the design stage to when it’s time to hire a contractor.

What Are Sunrooms?

A sunroom is a structure featuring a lot of glass or plastic built to create a room that lets in plenty of natural light. The designs vary widely, and they are known by other names such as outdoor enclosures, solariums, deck rooms, patio rooms, etc.

Sunrooms allow you to stay closer to the outdoors while you stay shielded away from the elements. This means you can stay outside without worrying about snow, wind, rain, cold, heat, or insects. You get to enjoy the sights and sounds around you while staying as comfortable as someone indoors.

Sunrooms are added after a house is built as an affordable way to create an interior space connected to the outdoors. The best designs of these structures blend into the property seamlessly and won’t look like an afterthought. The structures are built on existing bases like decks and patios and come with opaque roofs to maintain visibility and openness.

You can think of the sunroom as the modern-day solution to decks and porches. Before sunrooms on decks became popular, your relaxation on a deck outside or indoors only lasted as long as the elements or flying insects allowed. The only way to enjoy the outdoors was behind your room or kitchen windows. As technology advanced, designers found a way to solve the problem.

Building sunrooms today is easier because many high-tech and lightweight products in the market can be combined to build the perfect structure. Some of these include:

Low-emission treated glass
Aluminum
Engineered roof panels
Vinyl
Insulated glass
Portable air conditioning and heating devices

What Are the Uses of Sunrooms?

Sunrooms mean different things to different homeowners. The primary aims of bringing in natural light and giving you a comfortable space nearer to nature are not the only reasons people build sunrooms. Other possible uses include the following:

A sanctuary for reading
A yoga or general workout spot at home
Your new home office
A play area for your children
A room for your fishpond or pets like birds
The perfect spot for your house plants

As you’ve seen thus far, the idea of converting your deck to a sunroom sounds great. However, when engaging in any kind of home renovation project, you must first weigh the positives and negatives before you get started. This one is no different.

Pros of Building a Sunroom on Your Deck

You can enjoy the deck all year round. Without a sunroom, you may only enjoy staying out on your deck during the warmer months, and you’ll still even face the abovementioned discomforts. However, by building a fitting sunroom on the deck, you can use the space all year round regardless of how the weather feels outside.
You’ll increase the value of your home. A sunroom is like other home improvement projects that can improve the property’s overall appeal. If you intend to sell the property down the line, it can help you ask for up to 20% more than the average asking price for similar properties.
You can enjoy sunlight in comfort. Going out to the beach to get some sunlight isn’t always realistic. With a sunroom, you can enjoy the sunlight right in the comfort of your home.
You can become more active indoors. Have you always wanted a secluded and comfortable spot for your workout sessions? Your sunroom is the perfect place to sweat out. You no longer have to go down to the local gym or work out in your less airy garage.

Cons of Building a Sunroom on Your Deck

It Requires a Sizable Investment

For all the positives of sunrooms, you still need to spend some money upfront to build them. Sunrooms come in a wide range of configurations and at different price points. Still, it is an investment that you have to think carefully about. How do you intend to use the room? How will it affect the value of your home?

Privacy Is Often an Issue

The average sunroom is typically made of large glass panes to allow for as much natural light as possible. However, you’ll have to think of balancing this with relaxing in a spot that is too exposed. If you’ve never had any issues with having your neighbors see what you’re up to while out on the deck, this shouldn’t be a problem.

However, if privacy is paramount for you, you’ll need to invest in blinds and curtains. Using coated glass in the construction is also a good idea, but this will permanently limit the amount of natural light you’ll get in the space.

You May Experience Buyer’s Remorse

It’s not uncommon to find homeowners missing their deck (as it was earlier) after installing a sunroom on it. You may also not like how the sunroom looks on your deck, even after doing your best with the design. Spending adequate time with the design prototype and possibly seeing live samples can help you avoid this.

Your Property Taxes Might Increase

An investment like building a sunroom will most likely bump up your property taxes. However, you should also consider that the investment returns around 51-92% of the cost. So, compare the potential numbers before you get started with the project. Expert contractors can help with the calculations.

Types of Decks for Sunroom Construction

The different types of decks that are commonly converted to sunrooms include the following:

Wraparound decks: These are typically elevated and built at the same height as the house’s entrance. The deck may be covered or left bare and may also cross the entire front of the property.
Covered decks: These are plain decks with covering attached to a property. The covering can be complete or partial.
Attached decks: These decks are arguably the most fitting for sunroom installation. The decks are attached to the side or back of a home and are typically slightly elevated. The construction often features steps leading downwards into the yard.

Different Sunroom Designs for Decks

There are different sunroom designs to go with when you’re thinking about converting your deck:

The studio design: Also known as a shed, this sunroom design features a single-pitch roof sloping away from the property. The walls are typically made of glass.
The glass design: In this design, the sunroom is almost wholly made of glass. The roof is typically made of polycarbonate, but it’s not uncommon to find people with roofs also made of glass—especially those that want the sunroom to host their houseplants.
The three-season design: This popular sunroom design focuses on giving you a relaxing spot for most of the year, except for the winter months. The design doesn’t include much insulation bar, the one built into the door between the sunroom and your home. So, you won’t be able to relax in the sunroom in the winter, but you don’t have to worry about frosty air coming in through the sunroom door.
The gable design: The roof is the main focus of this design. A support beam holds up two roof panels, but the walls are still made of glass and screen paneling.
The four-season design: As you’ve guessed from the name, this design is geared to give you a comfortable sunroom all year round. It’s often the costliest as the design includes insulation, HVAC for heating and cooling, energy-efficient walls and roofs, etc. It is designed to be a full extension of your home.

Which of these designs should you go for when converting your deck to a sunroom? It will come down to how you envision the sunroom. If you see it as an integral home extension, investing in a four-season sunroom design makes sense.

On the other hand, if you live in an area where the winter doesn’t bite very hard, a three-season design will work. If you want a space to hang your pet parrots and keep your houseplants that you’ll step out to occasionally, any of the less comprehensive designs will work.

However, your choice still needs to be ratified by a professional. As you’ll see further down this article, many considerations go into choosing the design for a sunroom that will be built on an existing deck.

What to Do When Building a Sunroom on a Deck

When thinking about building a sunroom on a deck, you should first remember that not all decks are designed to support the weight of a sunroom structure. The frame, roof, and windows are relatively heavy, and the overall weight will increase in the winter if you get a lot of snow in your area.

Therefore, before you consider installing a sunroom on your deck, you must ensure it can support everything. Check your pier size and the weight they can support. Usually, standard deck piers are not designed to carry the extra load. You’ll most likely need to add additional support.

The contractor will also check the amount of weight the pier can support in relation to the soil pressure. They will also check other parts of your deck, including the supporting posts, joists, and beams. You’ll also need to construct a roof that connects to your existing roof. This is another part of the process that a professional should do.

What Happens During a Deck Evaluation?

When you call in a contractor to inspect your deck in readiness for conversion to a sunroom, there are a few things they’ll check:

The deck materials: This covers what the deck is made of and its current condition. They’ll check to see which of the materials can be incorporated into the new sunroom.
The deck attachment: The contractor will look at how the deck is attached to your home to see if the connection is solid enough to carry the sunroom installation.
The deck foundation: You can’t build a sunroom for your deck without a solid foundation. It is arguably the most important factor checked during the evaluation process.

During the evaluation process, the contractor will assess your deck’s dimensions covering the distance from it to your main roof, the length, and the width. The data will help them determine the best sunroom size and style to recommend for you.

Assessing Your Deck’s Foundation

As we mentioned above, sunroom construction won’t start unless you have a suitable foundation. It should be strong enough to hold the materials required to construct a sunroom.

The piers and footers currently on your deck can’t do the job alone. You’ll most likely need extra joists and new beams for extra strength, but these will still need to stand on the perfect foundation for the project.

The main types of foundations often recommended by contractors are covered below.

The Crawl Space Foundation

This type of sunroom foundation is generally the most expensive but has advantages. Firstly, it ensures you have enough space underneath the sunroom to hold your insulation, ductwork, plumbing, and wiring required in the design.

Therefore, it’s a top option when you’re going with a four-season sunroom design where the structure will be a comfortable extension of your home.

The Concrete Slab Foundation

You can count on a concrete slab supporting all kinds of sunrooms. So, contractors may recommend removing the deck floor if it isn’t strong enough to build a concrete foundation for your sunroom. This option is popular because you can count on it to be strong enough to hold all kinds of sunrooms. Secondly, it’s affordable.

However, concrete should only be an option if your sunroom will be at the same grade level as the rest of your home’s structure. You should remember that plumbing, electrical, and heating must be installed before the foundation is built. A concrete foundation will also make your sunroom colder in the winter. Therefore, you should have plans for heating if you choose to go with it.

The Current Deck Foundation

If your existing deck is very sound, you can use it as the foundation of your sunroom. Again, the contractor should be the judge of whether your existing deck is structurally sound or not.

Not all decks are designed to be solid enough to act as a foundation. A solid-looking deck structure that can support up to a dozen people relaxing on it may give way when it has to carry the glass walls and polycarbonate structures of a sunroom.

If your existing deck can’t be used as a foundation, the contractor will strengthen it with piers and joists. Alternatively, they can recommend prefabricated structures and sunroom kits matching the existing deck’s strength.

Adhering to Building Codes When Adding a Sunroom to Your Deck

Building a sunroom on your deck is regarded as remodeling, so your local laws may have some recommendations on what to do. Check to see what permits you have to get to adhere to the building codes in your area. Qualified contractors will know what permits you need, but you can also check your local council offices or research online to see what to expect in your area.

The process of getting a permit for such a project will vary from place to place and will depend a lot on local laws. In many cases, you’ll have to fill out an application form at your municipality offices and then wait for the officials to visit your home before they give you the permit.

Government officials may return at the project’s end for another round of checks and approval. If you choose to work with qualified contractors, chances are, they’ll take care of the permits for you or at least guide you on what to do.

Designing and Building a Sunroom on a Deck

When it comes to designing a sunroom deck, there are no limits. Work in all the functions you’d like to see in the room and consider how you want the project to look when you’re done. Would you like a classic screen paneling or an all-glass appearance? Once you have these points squared off, bring it all together in line with the dimensions of your deck.

If you are working with a contractor, all you need to do is communicate your wishes, and they’ll present you with renders and design samples. You may also get pictures of live construction completed elsewhere that can be replicated on your deck.

When designing the overall structure, don’t forget to consider elements like the following:

Your choice of flooring: Just like any other flooring in your home, you must consider what kind of flooring works best for how you intend to use your sunroom. You can choose between carpeting, tiles, or hardwood.
The window situation: Sunrooms should allow lots of sunlight in, but you’d still want to stay in control of the light and your privacy. Curtains and blinds are typically the go-to options, but you may also treat the windows, especially with one-way window films and other such technology.
The interior décor: You may need to outfit your sunroom with furniture, carpets, and maybe some electronics. Again, this depends on how you intend to use your new sunroom space. For example, you won’t need cushions for relaxing if you intend to use the sunroom as an exercise spot and a room for your house plants.

Using Sunroom Kits on Your Deck

Sunroom kits offer you an excellent method of building a sunroom on your deck without any wholesale changes to the current structure or the overall design of your home. You won’t need to demolish your current foundation, as this is a temporary modification for your home.

Even though these kits are not permanent, you may still need to get approval before installing them in your home. You’ll need to confirm with your municipality office as well.

When you buy a sunroom kit, you’ll get frames (usually aluminum) that are strong enough to cope with the demands you’ll exert on an average sunroom. The packaging includes all the hardware needed to set up the kit. The lightweight frame is designed to attach seamlessly to the exterior of your home.

Should you use sunroom kits on your deck instead of going with a bespoke construction? It will come down to your unique needs. If you want a four-season sunroom with everything from sofas to your office table and entertainment systems, sunroom kits may not be ideal. You should seek professional advice before spending money on them.

How Much Does It Cost to Build a Sunroom on a Deck?

As you’ve probably deduced from this piece thus far, sunroom prices vary widely. The total cost of the construction can be as low as $5,000 and go as high as $50,000.

It’s not uncommon to find people spending well beyond that upper boundary. It all depends on how you envision the room and how deep you’re willing to go into your pockets to get the job done. For example, a sophisticated four-season room will cost much more than a plane glass sunroom built using kits.

You can get an average sunroom kit for between $100 and $300 per square foot. Even with kits, you can still spend tens of thousands if your project requires pouring cement, attaching fence posts to the house of your wall, digging footers, etc.

Other Factors That Affect the Cost of a Sunroom

Apart from the type of sunroom you’ve chosen, other factors that can determine how much you’ll pay for your sunroom include:

Your zip code: If you live in a high-demand city, you should expect to pay an amount that is considerably more expensive than someone else in a rural area where the cost of living—and, by extension, the labor rate—is lower.
The sunroom’s energy rating: You can use many high-tech energy-saving products when setting up your sunroom, but they can add to the costs significantly.
Type of finishing: If you choose vinyl flooring, you won’t spend as much as someone who chose stone or natural hardwood flooring.
Your deck’s location: If you have your deck on clear, solid ground, the construction process will likely be cheaper than when the deck is in between other structures or in a position where the soil underneath can’t support the construction without any changes.

Choosing the Right Sunroom Contractor

Your choice of sunroom contractor will determine if you can bring your ideas to life or if you’ll waste your investment. This is why you should spend enough time finding the perfect one for the job. Here are some questions you should ask contractors during your selection process:

Are they insured and licensed? You should never work with contractors that are not insured and licensed. If they are not licensed, you could run into legal trouble during inspections, and uninsured companies have unprotected workers. You’re exposing yourself to lawsuits if something goes wrong during the project. Check for a General Liability Certificate.
Who is responsible for the permits? The contractors you’re considering should know the local building codes and the permits you’ll need for the project. Some will also have no problems securing the necessary authorizations for the project. Find out who’s responsible for this part of the project.
Is there a portfolio? The best contractors to look at for this project have built a sunroom on a deck multiple times. They should also have no problems with sharing their past work with you. Look through the projects to see if the construction process appeals to you and if it aligns with the scope of work you’re about to hire them for.
What’s the project timeline? You should have an idea of how long the project will take. This will allow you to create a schedule that works for you. It’s easier to mark X number of weeks in your calendar as to how long you’ll have to endure the noise generated by the construction process. You should also know how many hours the construction will take per day.
What’s the estimate for the project? You should have a ballpark figure of what the sunroom project you have in mind will cost. This way, you can weed out contractors with estimates that are too far off your budget and the average prices quoted by other contractors.

Conclusion

Building a sunroom on your deck is an excellent way to get more out of your home and get closer to the outdoors. You can choose to go the DIY route using sunroom kits—especially if your deck has a strong foundation.

For decks not equipped to handle the rigors of carrying a sunroom, you should hire a contractor to get the job done to avoid wasting your resources. When it’s time to hire one, don’t rush through the screening process. This project can cost tens of thousands of dollars, so you must get it right.