About Us

Home Improvement Contractors Quad Cities

Established in 2001, Mainstream Home Improvement has consistently been a top contractor in the Quad Cities area, offering exceptional services in windows, gutters, roofing, siding, and beyond. Under the guidance of owner Spencer Sierra, our team has consistently executed a vision of excellence for over two decades, ensuring the highest quality workmanship in every project. Our skilled staff, premium products, and transparent estimates ensure that our home improvement services provide complete peace of mind. Reach out to our team today to explore our financing options and schedule a consultation to discuss your home renovation requirements.

Our Vision Statement

At Mainstream Home Improvement, our vision is to make the home renovation process simple, easy, and stress-free for our clients by providing quality products at affordable prices and guaranteed workmanship. Our success is built upon forging meaningful relationships with past, present, and future customers in the Quad Cities area.

We are Licensed and Insured Contractor

At Mainstream Home Improvement, we recognize the critical importance of having the proper licensing and insurance in place as a professional home improvement contractor. This ensures that our customers are protected from liability and can trust that their project is being handled by a reliable and accountable team. To provide complete peace of mind, we are more than happy to provide a copy of our insurance and any applicable licensing at the time of contract signing. By choosing Mainstream Home Improvement for your project, you can rest assured that you are partnering with a responsible and trustworthy company that prioritizes your safety and satisfaction above all else.

Meet Our Team!

At Mainstream Home Improvement, customer service and expert results are our number one priority. When you work with our experienced and friendly team, you can guarantee that we’ll treat your home project like our own. From start to finish, our team works directly with clients to discover their wants and needs for renovating their property. Whether you’re looking to upgrade your roof or install energy-efficient windows, our professionals will work with homeowners to set their budget, choose finishing touches on products, and ensure every area of their project is completed at the highest quality. Reach out by calling our office at 309.762.6244, and we’ll set you up with a free consultation to discuss your project needs.

Spencer Sierra

Spencer was born in Silvis and has spent his whole life here in the Quad Cities. He started Mainstream Home Improvement in 2001. Spencer has been married to his lovely wife, Betsy, since January of 2001. They have two daughters, Rosemary and Ruby. Spencer is passionate about his Catholic faith. He is a devoted parishioner and attends mass daily. In addition to his faith, Spencer enjoys spending time with his family, reading, and listening to the Rolling Stones. His weakness is Whitey’s Ice Cream. He enjoys the Vanilla Oreo shake, slightly melted. (Please don’t try and bribe him because you’ll win.) Spencer’s motto is that he wants to be a great company, period. Not just a great Home Improvement Company.

Marci Boswell

Marci was born and raised in the Quad Cities area and attended High School at Alleman. She studied at Illinois State University. She has been with Mainstream Home Improvement since the first day back in 2001. She most enjoys spending time with her family. She can be found working on projects around her house with her husband Aaron. She is also very active in her son Braydan’s life. Braydan is a great swimmer and Marci loves to watch him. Most of Marci’s family lives in the area and she is grateful for that so she can spend as much time with them as possible. Marci is always cheerful on the phone and eager to help you out when you call Mainstream.

Steve Milbrandt

Steve was born and raised in a small rural community in SE North Dakota. He attended kindergarten through grade 12 with the same 55 classmates. He has been married for 42 years to his lovely wife, Penny. Together they have 2 daughters and 1 very precious grandson. Steve has served customers at Mainstream Home Improvement for over 15 years. He has several more years of experience in the home improvement field, in sales and management. He was also a window manufacturers rep for a major window company.
Steve is passionate about history and identifies as a big WWII buff. He has lived in the same small town of 255 residents just outside of the Quad Cities, for the past 18 years. He and his family enjoy the outdoors and Steve likes to throw a pole in the water anytime it’s not too cold.

You are in good hands with Steve Milbrandt.

Meet Our Team

spencer sierra

Spencer Sierra

Spencer was born in Silvis and has spent his whole life here in the Quad Cities. He started Mainstream Home Improvement in 2001. Spencer has been married to his lovely wife, Betsy, since January of 2001. They have two daughters, Rosemary and Ruby. Spencer is passionate about his Catholic faith. He is a devoted parishioner and attends mass daily. In addition to his faith, Spencer enjoys spending time with his family, reading, and listening to the Rolling Stones. His weakness is Whitey’s Ice Cream. He enjoys the Vanilla Oreo shake, slightly melted. (Please don’t try and bribe him because you’ll win.) Spencer’s motto is that he wants to be a great company, period. Not just a great Home Improvement Company.

marci boswell

Marci Boswell

Marci was born and raised in the Quad Cities area and attended High School at Alleman. She studied at Illinois State University. She has been with Mainstream Home Improvement since the first day back in 2001. She most enjoys spending time with her family. She can be found working on projects around her house with her husband Aaron. She is also very active in her son Braydan’s life. Braydan is a great swimmer and Marci loves to watch him. Most of Marci’s family lives in the area and she is grateful for that so she can spend as much time with them as possible. Marci is always cheerful on the phone and eager to help you out when you call Mainstream.

steve milbrandt

Steve Milbrandt

Steve was born and raised in a small rural community in SE North Dakota. He attended kindergarten through grade 12 with the same 55 classmates. He has been married for 42 years to his lovely wife, Penny. Together they have 2 daughters and 1 very precious grandson. Steve has served customers at Mainstream Home Improvement for over 15 years. He has several more years of experience in the home improvement field, in sales and management. He was also a window manufacturers rep for a major window company.
Steve is passionate about history and identifies as a big WWII buff. He has lived in the same small town of 255 residents just outside of the Quad Cities, for the past 18 years. He and his family enjoy the outdoors and Steve likes to throw a pole in the water anytime it’s not too cold.

You are in good hands with Steve Milbrandt.

Choose Mainstream Home Improvement in the Quad Cities

Choosing Mainstream Home Improvement over a large corporate contractor based in another city offers numerous advantages to homeowners. As a local company staffed by local professionals, we understand the unique needs and preferences of our community. Our local office allows us to provide personalized service, ensuring that when you call us, you’ll be greeted by a live person who is ready to assist you. Our strong local reputation is built on years of investment in our community, fostering trust and reliability with every project we undertake. We take pride in the many glowing testimonials from our past customers, which serve as a testament to the exceptional work we deliver. By partnering with Mainstream Home Improvement, you can be confident that you are choosing a dedicated, community-focused company that genuinely cares about the success of your project and your satisfaction as a homeowner.

Our Awards & Achievements

In our 20+ years of business, we are proud to have been awarded for several achievements in the Quad Cities area. On top of these awards, we continue to uphold our industry memberships and charitable contributions to our local communities year after year. Here is an updated list of our most recent awards and reoccurring recognitions.

Awards
  • Better Business Bureau Integrity Award
  • Keeping Rock Island Beautiful Award – Recycling Shingles Program
  • SCORE’s Small Business of the Year Award
  • Owens® Corning Preferred Contractor
  • Featured in the Quad Cities Business Journal Top 40
Memberships
  • Better Business Bureau
  • Chamber of Commerce
  • The Quad Cities Homebuilder’s Association
Charitable Contributions
  • Children’s Therapy Center of the Quad Cities
  • Newspapers In Education
  • Muscular Dystrophy
  • Area Schools
  • Area Churches
  • Birdies for Charity
  • Arrowhead Ranch
  • Boy Scouts and Girls Scouts of the Quad Cities
  • Area Sporting Teams
  • The Quad Cities Marathon