Custom-Built Sunrooms Designed for Colorado Living

Bright. Comfortable. Built to Last.

At Cillessen Construction Company, we design and build custom sunrooms that let you enjoy the beauty of the outdoors year-round. Whether you’re adding extra living space, creating a cozy spot to relax, or expanding your home’s connection to nature, our sunrooms are crafted for comfort, performance, and lasting value.

Our team brings decades of construction experience and attention to detail to every build. Each project is tailored to your home’s architecture and your lifestyle, so your new space looks seamless and feels like it was always meant to be there.

Why Add a Sunroom to Your Home?

If A sunroom addition is one of the most versatile and rewarding home improvements you can make. It provides:

Additional living space for entertaining, relaxing, or family time
Natural light and energy efficiency through insulated glass and precision engineering
Year-round comfort with advanced climate control and durable materials made for Colorado’s four seasons
Enhanced home value and curb appeal with an elegant, functional addition

Whether you envision a cozy reading room, bright home office, or four-season retreat, Cillessen Construction Company can design a custom solution that perfectly fits your vision.

Our Sunroom Installation Process

At Cillessen Construction Company, we make the process smooth, professional, and transparent from start to finish.

Consultation & Design

We start with a personal consultation to understand your goals, budget, and home layout. Our design team helps you explore options, materials, and layouts to create a sunroom that fits seamlessly with your home’s existing style.

Custom Engineering & Preparation

We partner with Living Spaces Sunrooms to deliver structures engineered for Colorado’s climate. Each sunroom is built for strength, efficiency, and comfort, with our team handling all prep, permits, and code requirements.

Professional Installation

Our skilled crews handle every part of the installation with precision and care. From foundations, framing and roofing to windows, doors, and finishes, we ensure every detail reflects Cillessen’s commitment to craftsmanship and quality.

Final Walkthrough & Warranty

Once your sunroom is complete, we’ll walk through the finished space with you to ensure everything meets your expectations. All projects are backed by our workmanship warranty and product guarantees for long-term peace of mind.

Types of Sunrooms We Build

We offer a full range of custom sunroom styles, including:

Four-Season Sunrooms – Fully insulated and climate-controlled for use in any weather.
Three-Season Sunrooms – Ideal for spring, summer, and fall enjoyment with optional heating or cooling features.
Screen Rooms – Fresh air and outdoor living without the bugs.
Conservatories & Glass Enclosures – Elegant, light-filled spaces with stunning architectural detail.

Not sure which style is right for your home? Our team will help you compare options and select the perfect solution for your needs and budget.

Why Choose Cillessen Construction Company?

As one of Colorado’s most trusted residential construction companies, we combine craftsmanship, innovation, and local expertise to deliver exceptional results.

Decades of home-building and remodeling experience
Locally owned and operated in Colorado
Precision engineering built for Colorado’s climate
Seamless integration with your home’s existing design
Honest communication and transparent pricing
Licensed and insured professionals dedicated to quality

We don’t just build sunrooms — we create spaces that become your favorite part of the home.

REVIEWS

Amy Burry ★★★★★ 8 months ago
We used Cillessen Construction to replace our siding, gutters, paint the house and add/replace egress windows in the basement. They were great through the whole process. The salesman, Devan, was great and the crews doing the installation … More were great and on time when they were supposed to be there. Everything was done in a timely manner. Will definitely be using them again if any further construction needs arise.
Cathy Jarnagin ★★★★★ 3 months ago
Our roof needed to be replaced due to hail damage. We were very impressed with the attention to customer service and project details. Devon helped us through the insurance claim process and made himself available to meet the insurance adjuster … More at the house to walk him through the damage. The subcontractors on the project (roofers and gutter installers) were professional, on time, picked up after themselves, and the work was of good quality. We would highly recommend Cillessen Construction.
randi harmon ★★★★★ a month ago
I had water damage with a skylight from all the recent rain. I had heard of Devon Larussi from a friend who had used Cillessen Construction.
Devon came over and repaired my skylight leakage and also discovered a leak in my swamp cooler … More drip line. He took care of that also.
Very professional and extremely responsive. I highly recommend Cillessen Construction.
Jeffrey Broetzman ★★★★★ 9 months ago
We had Cillessen Construction repair and replace our roof last week and were very happy with our experience. Devon and Austin were outstanding in their knowledge and advice which proved to be accurate. Thankfully they found that we had … More issues with the structural integrity and venting of our roof which became apparent to us as soon as the shingles were lifted. The work team was amazing, well organized, polite and considerate of our needs. At the end of the job everything was cleaned up, left tidy and any nails, etc. were picked up diligently. It is without hesitation that we would recommend Cillessen Construction, as it was a pleasure to deal with such a professional, knowledgeable and ethical company.
Lacey Zubricky ★★★★★ 3 years ago
Cillessen Construction saved our house purchase! The inspection on a home we were trying to buy showed the roof was in very bad condition. The seller did not want to come down on the purchase price, but Nic was able to work with the seller … More and their insurance company to get a new roof covered under their policy. They made the whole process very streamlined for us!
David Luker ★★★★★ 3 years ago
Devon with Cillessen Construction, the general contractor for our roof, stucco repair, and window installation project, provided professional services beyond anything I expected or have ever seen from a construction company. He was knowledgeable … More without arrogance, quick to communicate our thoughts with his crews as well as return our inquiries, and always arrived with a positive attitude, which help us through the jitters of a new phase of work. Cillessen had the resources to respond quickly and efficiently to any developing needs. For example, my wife and I realized we were in over our heads when it came to paint color selection. Within the day, Devon had us in contact with a color consultant, who was the best. The Cellessen work quality was top-notch.
Daniel Ronish ★★★★★ 3 years ago
Nic Law responded to my call immediately and came over asap. He has helped us significantly thru this whole crazy process. His professionalism is unmatched and always very efficient. The worker dudes that Cillessen uses are also very professional … More and do extremely quality work. They cleaned up their roof replacement and left no debris in my yard or surrounding area. We are extremely happy with the whole Cillessen team, starting and ending with Nic Law. We most certainly Will continue to refer others to your well established professional company and I’m positive they too will be just as satisfied customers as we are.
Brittany Lozano ★★★★★ 3 years ago
Nic Law was absolutely wonderful to work with! As real estate agents, my partner Blanche and I are always on the lookout for contractors that are dependable, trustworthy, responsive, informative and ones we can count on to meet our tight … More deadlines. Nic met those conditions to a "T"! He was extremely helpful to our sellers by inspecting the roof ASAP, then being informative and answering any questions they had. He met the insurance adjuster at the home so he could help point out damage and then scheduled the work in a timely manner before we closed on the property. He was very responsive by returning phone calls and text messages. It's important to us that our vendors make our clients happy and Nic did an excellent job leaving a smile on our client's face, and therefore ours!
Jennie Done ★★★★★ 6 years ago
Due to the hailstorm in July, I needed a new roof, some window replacements, and other minor repairs. I had a great experience overall with Cillessen. The roofers were fantastic! They did a very professional job and were super fast (7:30 … More am start and finished at 1:45 pm). The foreman (Roberto?) introduced himself to my neighbors and even did a huge personal favor for me and didn't want to take any money. The window replacement took longer than anticipated but Terrence was excellent and took really good care of my project. His customer service skills were a highlight. He worked diligently with my insurance company and was able to get some valuable upgrades for me. I was happy with my Cillessen experience.
Melissa Wilson ★★★★★ 5 years ago
I was referred to Cillessen Construction Company and could not be happier. The insurance process is really complicated and Devon was able to really guide me and my husband through it. Now I have a fantastic roof, and zero complaints. Devon … More was communicative, responsive, professional and treated me like family. Somehow he was even able to get the repairs my carrier wasn't going to pay for PAID almost like magic. I would highly recommend this fantastic team and will absolutely make sure they get my business forever. If you are ever looking for a great team, with good people just ask for Devon and you will not regret it.
Blanche Boren ★★★★★ 3 years ago
As a realtor, when I am getting a client through a transaction, whether they’re buying or selling, time is of the essence! That’s why Nic Law is my “go-to” guy for roofing. He has saved my clients time and money, without sacrificing quality … More or service! Need a roofer? I have the perfect guy in mind that I highly recommend! (Thank you Nic for everything!)
Kyle Henning ★★★★★ 5 years ago
Devon and Cillessen are awesome. I'm an insurance agent and have used them personally and referred them to my clients. They're always very timely and professional, but beyond that they do great work. They specifically work very … More well with insurance companies and adjusters to make sure claims are taken care of properly. Would highly recommend them to anyone needing inspections, roof, or exterior work.

Areas We Serve

Cillessen Construction Company proudly designs and installs custom sunrooms throughout the greater Denver metro area and beyond, including:

Denver
Highlands Ranch
Wheat Ridge
Castle Rock
Centennial
Colorado Springs
Boulder
Surrounding communities

If you’re looking for a trusted sunroom contractor near you, our team is ready to help bring your vision to life.

Contact Us

Frequently Asked Questions

What is a sunroom?

A sunroom is a bright, glass-enclosed living space that brings the outdoors in while keeping you comfortable year-round. It can be attached directly to your home as an extension of your living area or built as a standalone retreat.

Unlike standard patios or decks, sunrooms can be fully insulated and designed for year round use. At Cillessen Construction Company, we design and build custom sunrooms engineered for Colorado’s climate, giving you a relaxing, light-filled space to enjoy in every season.

What’s the difference between a three-season and four-season sunroom?

A three-season sunroom is ideal for use in spring, summer, and fall, providing protection from wind and rain but without full thermal insulation. A four-season sunroom is built with insulated glass and framing that allows for heating and cooling, making it usable all year long. Most Colorado homeowners choose four-season sunrooms to get the most out of their investment.

Are sunrooms energy efficient?

Yes. Especially when built with modern insulated materials. Our partnership with Living Spaces Sunrooms ensures each structure includes energy-efficient glass, thermal-insulated framing systems, and tight seals to maintain comfort through Colorado’s cold winters and hot summers. These features make our sunroom additions both beautiful and efficient.

Do I need a building permit for a sunroom?

Yes, most sunroom projects in Colorado require a building permit to ensure compliance with local codes and structural safety standards. The good news is that Cillessen Construction Company handles the entire permitting process for you, including engineering, site preparation, and inspections. This ensures your new space meets all Denver-area and state requirements.

How long does it take to build a sunroom?

On average, a sunroom installation takes 6–10 weeks from start to finish, depending on the complexity of the project and permit timing. Cillessen manages every phase, from design and engineering to construction and finishing, so your new space is completed efficiently and with minimal disruption to your home.

What types of sunroom designs do you offer?

We offer fully customizable sunroom designs, including cathedral-style rooms, studio sunrooms, conservatories, and patio enclosures. Each is tailored to your home’s architecture and your personal style. Whether you want a sleek modern space or a cozy traditional design, Cillessen Construction Company will build a sunroom that blends seamlessly with your home.

Do you offer warranties on your sunroom installations?

Yes. All of our sunroom installations are backed by manufacturer and workmanship warranties for peace of mind. Our partnership with Living Spaces Sunrooms ensures you receive industry-leading quality and protection, so your investment lasts for decades.