William Giakoumatos

President

For more than 25 Years, William Giakoumatos has helped homeowners make informed decisions about protecting and improving their homes. As President of American Custom Contractors, he oversees company operations, quality standards, customer experience, and the technical accuracy of the educational resources published on the company’s website.

Since joining the family business, William has worked closely with homeowners throughout Maryland, Washington, DC, Northern Virginia, West Virginia, and Pennsylvania, helping them navigate roof replacements, storm damage restoration, siding projects, window replacements, and exterior renovations.

His approach is simple: provide honest recommendations, explain every option clearly, and help homeowners choose the solution that’s best for their home.

Areas of Expertise

William regularly advises homeowners and oversees projects involving:

Professional Experience

Throughout his career, William has helped guide thousands of exterior remodeling projects, with a focus on craftsmanship, communication, and long-term value.

His responsibilities include:

Certifications & Industry Knowledge

American Custom Contractors maintains relationships and certifications with many of the industry’s leading manufacturers.

William works closely with products and installation systems from companies and organizations including:

Industry Involvement

William believes that continuous education is essential to delivering exceptional workmanship and trusted guidance to homeowners. He has organized specialized training with the Slate Roofing Contractors Association to ensure our team is equipped with the highest level of installation knowledge and craftsmanship. He also coordinates ongoing education with our manufacturing partners to keep both our sales and installation teams current on the latest products, installation standards, and best practices, while leading the company’s insurance restoration training initiatives.

To ensure American Custom Contractors remains at the forefront of the industry, William regularly stays current through:

Community Involvement

American Custom Contractors has proudly served homeowners since 1972, and William believes giving back to the communities the company serves is just as important as delivering quality workmanship. He has led organization involvement with Habitat for Humanity and the Owens Corning’s Roof Deployment Project.

What my Customers Say

courtney pattee

Potomac, MD •

Siding, Trim, Windows •

Google

American Custom Contractors was amazing from the word “go”! First, William went above and beyond in helping get an insurance claim approved for new siding and were so thorough and patient with our adjuster. When we got the approval for coverage and decided we wanted to add on new windows, Chris and William really worked with us on the options and got the price to something we felt comfortable with. We got all new Climatech windows and went with Alside Ascend siding (in Sterling Grey) because we liked the wider planks and additional insulation. Chris took lots of care and time explaining the options for us, with zero pressure. Once the contract was signed they kept us well informed of the timing and double and triple checked the scope of work. For the windows they built 13 custom windows within a couple weeks of order, and they were installed within 2 days of work – no complaints at all. Delivery of the materials for the siding was easy and thoughtful and they worked hard to keep access to at least part of our garage and driveway. As soon as the work started you could tell they were professionals and took pride in their work – they kept the site clean each day and got the insulation up swiftly. The team showed up bright and early each day and worked ALL day – shockingly so – to get the work done quickly. Whenever they had a question about a design decision they stopped and asked for our input and offered their expert experience. Everything turned out better than we could have expected and they stuck to the budget. Once the siding was all done they painted our brick to match the siding and put a fresh coat of paint on our garage doors. They were incredibly meticulous. Our neighbors were obviously jealous of the quality of the work since they had just had their siding replaced weeks prior and didn’t see the same work ethic. We are SO pleased with the results. Frank (our project lead) came by repeatedly to check on quality and progress. Cesar and his team are obviously the best siding installers this side of the Mississippi. I would not hesitate for a second to recommend American Custom Contractors!!

Christian Fenimore

Germantown, MD •

Roofing, Gutters •

Google

American Custom Contractors installed a brand new SLATE roof at our house. This was a very big job with many custom features as we have many dormers and other non-traditional features. Blase, the coordinator on-site, Aaron the production manager, Gabriel the install team-lead and everyone else were meticulous from the planning phase all the way through to the end. The whole job, however, would not have been possible without the many on-site visits and in-depth analysis and support from William, the owner. For all aspects of the job, they deserve 5*****.

Nav N

ACC installed our roof over 10 years ago. Their team was superb and installed a quality roof with no problems. I recently called to have my roof inspected to make sure everything was working well. Subsequently, I received a telephone call from Dimiti who co-owns ACC with his brother, William. I had met both brothers when our roof was being installed. About an hour after I spoke with Dimitri, his top technician Blase called and came over the following day to inspect our roof. I can say that this level of response combined with positive attitude and quality installations speaks volumes of their commitment to customer satisfaction. I am very satisfied and would highly recommend this company.

Ernest T

Dunn Loring, VA •

Roofing, Siding •

Yelp

I hired American Customer Contractors to replace my roof and siding. They walked me through every stage of the project. William was fantastic in helping me choose colors and designs. Blaze was my project manager. His communication throughout the project kept me informed from start to finish. American Custom Contractors changed the look of the outside of my house from a retro 1980’s look to a modern home. My next door neighbor replaced her roof and siding a year earlier. She had problems with her contractor and a very envious of the quality of work of American Custom Contractors. She wished that she had hired them.

Connect with William

To learn more about American Custom Contractors or request an estimate, visit our Contact Us page. You can also connect with William on LinkedIn.

Editorial Role

William reviews educational content published by American Custom Contractors for technical accuracy and consistency with current industry practices.

Content may be reviewed for:

Roofing systems
Siding installation
Window replacement
Storm damage restoration
Exterior remodeling
Manufacturer recommendations
Product comparisons
Homeowner maintenance guidance

Articles reviewed by William display a “Reviewed by William Giakoumatos” attribution and are updated as industry standards, products, or best practices evolve.