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Addition to existing structure builders in Ashburn

Avatar for 3D Design Space
3D Design Space
6435 Lincolnia Road
5.00(
16
)
Approved Pro
3D Design Space
6435 Lincolnia Road
5.00(
16
)
Approved Pro
Customers say: Quality work
33 years of experience
Free onsite estimate

3D Design Space was established in 1992 Specializing in Additions, Major Renovations, Bathroom, Kitchen, Basement, Garage Remodels, design, and architectural services in Northern Virginia. Quality customer service and workmanship is a number one priority of 3D Design Space. We are fully insured and licensed.

"An amazing, super nice guy to work with...great communication and design ideas. I've never seen someone (and his crew) work so hard to complete a job! I would hire again in a heartbeat."

Melissa E on July 2015

3D Design Space was established in 1992 Specializing in Additions, Major Renovations, Bathroom, Kitchen, Basement, Garage Remodels, design, and architectural services in Northern Virginia. Quality customer service and workmanship is a number one priority of 3D Design Space. We are fully insured and licensed.

"An amazing, super nice guy to work with...great communication and design ideas. I've never seen someone (and his crew) work so hard to complete a job! I would hire again in a heartbeat."

Melissa E on July 2015


Moses Housing LLC
2753 Sutton Rd
4.94(
8
)
Approved Pro
Moses Housing LLC
2753 Sutton Rd
4.94(
8
)
Approved Pro
Customers say: Quick response
Recommended by 100% of Angi customers
Recommended by 100% of HomeAdvisor customers
5 years of experience

We are committed to excellence in every aspect of our business. We uphold a standard of integrity bound by fairness, honesty, and personal responsibility. Our distinction is the quality of service we bring to our customers. Accurate knowledge of our trade combined with ability is what makes us true professionals. Above all, we are watchful of our customers' interests and make their concerns the basis of our business.

"They replaced my beaten wooden deck with a new composite one. The price was more than fair after shopping around. What I liked from the experience was the cleanliness and speed. Everything we agreed on they did in timely manner."

Charlie H on October 2023

We are committed to excellence in every aspect of our business. We uphold a standard of integrity bound by fairness, honesty, and personal responsibility. Our distinction is the quality of service we bring to our customers. Accurate knowledge of our trade combined with ability is what makes us true professionals. Above all, we are watchful of our customers' interests and make their concerns the basis of our business.

"They replaced my beaten wooden deck with a new composite one. The price was more than fair after shopping around. What I liked from the experience was the cleanliness and speed. Everything we agreed on they did in timely manner."

Charlie H on October 2023


HW Mechanical and Remodeling
65 Richland Rd
New on HomeAdvisorNew on Angi
Approved Pro
HW Mechanical and Remodeling
65 Richland Rd
New on AngiNew on HomeAdvisor
Approved Pro
15 years of experience
Free onsite estimate

We take great pride in our experience, expertise, quality, and customer service that we provide to meet the consumers' needs. It is our mission to provide excellent workmanship and complete customer satisfaction from start to completion of a project. To understand the needs and expectations of our customers, we take great care to work and communicate with every customer in a professional manner. Our reputation is based on service, safety, and quality, regardless of how large or small the job.

We take great pride in our experience, expertise, quality, and customer service that we provide to meet the consumers' needs. It is our mission to provide excellent workmanship and complete customer satisfaction from start to completion of a project. To understand the needs and expectations of our customers, we take great care to work and communicate with every customer in a professional manner. Our reputation is based on service, safety, and quality, regardless of how large or small the job.


Avatar for Alltecs, LLC
Alltecs, LLC
1800 Diagonal Rd Ste 600
3.96(
13
)
Approved Pro
Alltecs, LLC
1800 Diagonal Rd Ste 600
3.96(
13
)
Approved Pro
Customers say: Terrific value
19 local quotes requested
10 years of experience

At Alltecs, we are a leading minority-owned construction firm dedicated to delivering exceptional residential and commercial construction services throughout the DC area. With a strong commitment to professionalism, integrity, quality, and service, we have established ourselves as a trusted name in the industry. Our company was founded with a vision to provide top-notch construction solutions that exceed our clients' expectations. We understand that every project is unique, and our team of skilled professionals brings a wealth of expertise and experience to every endeavor. From concept to completion, we strive for excellence and ensure that each project is executed with meticulous attention to detail.

"I purchased a property that needed a full remodel. I contacted Alltecs and they were very accommodating & professional. My home is so beautiful & luxurious. Few delays due to permitting & material delivery, however Alltecs always communicated during the process. Although, the delays were a frustrating process Alltecs pulled through & I’m so happy with the final results! Thanks Again! I would definitely recommend this company."

Nakita G on January 2022

At Alltecs, we are a leading minority-owned construction firm dedicated to delivering exceptional residential and commercial construction services throughout the DC area. With a strong commitment to professionalism, integrity, quality, and service, we have established ourselves as a trusted name in the industry. Our company was founded with a vision to provide top-notch construction solutions that exceed our clients' expectations. We understand that every project is unique, and our team of skilled professionals brings a wealth of expertise and experience to every endeavor. From concept to completion, we strive for excellence and ensure that each project is executed with meticulous attention to detail.

"I purchased a property that needed a full remodel. I contacted Alltecs and they were very accommodating & professional. My home is so beautiful & luxurious. Few delays due to permitting & material delivery, however Alltecs always communicated during the process. Although, the delays were a frustrating process Alltecs pulled through & I’m so happy with the final results! Thanks Again! I would definitely recommend this company."

Nakita G on January 2022


Avatar for Q3 Designs LLC
Q3 Designs LLC
410 Course St
4.83(
3
)
Approved Pro
Q3 Designs LLC
410 Course St
4.83(
3
)
Approved Pro
Customers say: Terrific value
Recommended by 100% of Angi customers
Recommended by 100% of HomeAdvisor customers
13 local quotes requested

We are committed to excellence in every aspect of our business. We uphold a standard of integrity bound by fairness, honesty and personal responsibility. Our distinction is the quality of service we bring to our customers. Accurate knowledge of our trade combined with ability is what makes us true professionals. Above all, we are watchful of our customers interests, and make their concerns the basis of our business.

"I had Q3 Design complete a home addition project for me. They did tremendous work. From the moment I contacted them they showed high expertise and professionalism. They managed it all, from design, permit applications and inspections, to devoting meticulous attention to complete the project successfully on time and with the highest industry standards and materials. Their price is very fair and their work ethics is highly commendable and reliable. My family and I can't be happier with the end results. We'll contact them for sure again for any new home improvements."

Julio H on July 2023

We are committed to excellence in every aspect of our business. We uphold a standard of integrity bound by fairness, honesty and personal responsibility. Our distinction is the quality of service we bring to our customers. Accurate knowledge of our trade combined with ability is what makes us true professionals. Above all, we are watchful of our customers interests, and make their concerns the basis of our business.

"I had Q3 Design complete a home addition project for me. They did tremendous work. From the moment I contacted them they showed high expertise and professionalism. They managed it all, from design, permit applications and inspections, to devoting meticulous attention to complete the project successfully on time and with the highest industry standards and materials. Their price is very fair and their work ethics is highly commendable and reliable. My family and I can't be happier with the end results. We'll contact them for sure again for any new home improvements."

Julio H on July 2023


Avatar for Best Homes
Best Homes
233 Morrisons Road
4.64(
176
)
Approved Pro
Best Homes
233 Morrisons Road
4.64(
176
)
Approved Pro
Customers say: True professional
Recommended by 92% of Angi customers
Recommended by 92% of HomeAdvisor customers
55 local quotes requested

Here at Best Homes, our company is based on the belief that our customers' needs are of the utmost importance. Our team is committed to meeting those needs. We welcome the opportunity to earn your trust and deliver you the best service. Please call today for a quote and thank you for doing so.

"We had an exceptional experience with Johnathan, Jeffry, and their team. Their professionalism, friendliness, and expertise stood out from the start to the finish of our basement project. The process was smooth, transparent, and free of surprises, with clear cost and material outlines. We appreciated their flexibility in allowing us to choose different materials and only charging the price difference. When we added more work mid-project, they were accommodating and maintained high-quality workmanship. They provided a wide selection of cabinets, flooring, tiles, mirrors, and bathroom faucets. The project was completed on time and within budget. We are thrilled with the results and plan to work with them again. Everyone who has seen our basement loves it! Overall, we highly recommend their services."

Sammaad S on February 2025

Here at Best Homes, our company is based on the belief that our customers' needs are of the utmost importance. Our team is committed to meeting those needs. We welcome the opportunity to earn your trust and deliver you the best service. Please call today for a quote and thank you for doing so.

"We had an exceptional experience with Johnathan, Jeffry, and their team. Their professionalism, friendliness, and expertise stood out from the start to the finish of our basement project. The process was smooth, transparent, and free of surprises, with clear cost and material outlines. We appreciated their flexibility in allowing us to choose different materials and only charging the price difference. When we added more work mid-project, they were accommodating and maintained high-quality workmanship. They provided a wide selection of cabinets, flooring, tiles, mirrors, and bathroom faucets. The project was completed on time and within budget. We are thrilled with the results and plan to work with them again. Everyone who has seen our basement loves it! Overall, we highly recommend their services."

Sammaad S on February 2025


U.S. Builders, Inc.
22831 Silverbrook Center Drive, Suite 100
4.92(
16
)
Approved Pro
U.S. Builders, Inc.
22831 Silverbrook Center Drive, Suite 100
4.92(
16
)
Approved Pro
Customers say: Quality work
Recommended by 93% of Angi customers
Recommended by 93% of HomeAdvisor customers
25 years of experience

U.S. Builders is led by a German-trained architect who considers high craftsmanship, careful attention to detail and client satisfaction a paramount of his business. With more than 30 years of trade general construction experience, U.S. Builders serves residential and commercial clients in Washington DC and Northern Virginia, focusing on quality, design and value. U.S. Builders handles each phase of your custom home building or remodeling project, coordinating timing and workflow to ensure a timely completion. Services include roof and gutters (replacement and repair), windows,doors, powder rooms, elegant custom baths, in-law suites, master bedrooms, kitchen updates, fireplaces, bars, decks, garages, additions, finishing basements & attics or re-designing any interior or exterior space. Please visit our website and contact us to learn about the variety of options available for your project within your time and budget.

"I would HIGHLY recommend US builders for any home remodeling project. I saw the quality of their work when they did a total kitchen remodel for my neighbor. The quality was top notch so I hired them to repair the outside and inside of my home when a car, traveling at a high rate of speed crashed into the front of our home. Workmanship is superb, they arrive on time, have the skills and resources to do the job, and they clean up at the end of every day. They same workers were at the job site start to finish, they could easily problem solve unique issues. They repaired and painted drywall, put on new siding and new windows, replaced ceramic tile in the foyer, and "sistered" support beams around the stairwell. PLUS they worked seamlessly with the insurance company!!!!"

mark d on May 2024

U.S. Builders is led by a German-trained architect who considers high craftsmanship, careful attention to detail and client satisfaction a paramount of his business. With more than 30 years of trade general construction experience, U.S. Builders serves residential and commercial clients in Washington DC and Northern Virginia, focusing on quality, design and value. U.S. Builders handles each phase of your custom home building or remodeling project, coordinating timing and workflow to ensure a timely completion. Services include roof and gutters (replacement and repair), windows,doors, powder rooms, elegant custom baths, in-law suites, master bedrooms, kitchen updates, fireplaces, bars, decks, garages, additions, finishing basements & attics or re-designing any interior or exterior space. Please visit our website and contact us to learn about the variety of options available for your project within your time and budget.

"I would HIGHLY recommend US builders for any home remodeling project. I saw the quality of their work when they did a total kitchen remodel for my neighbor. The quality was top notch so I hired them to repair the outside and inside of my home when a car, traveling at a high rate of speed crashed into the front of our home. Workmanship is superb, they arrive on time, have the skills and resources to do the job, and they clean up at the end of every day. They same workers were at the job site start to finish, they could easily problem solve unique issues. They repaired and painted drywall, put on new siding and new windows, replaced ceramic tile in the foyer, and "sistered" support beams around the stairwell. PLUS they worked seamlessly with the insurance company!!!!"

mark d on May 2024


Avatar for 3DF, LLC
3DF, LLC
11630 Mediterranean Ct
4.63(
8
)
Approved Pro
3DF, LLC
11630 Mediterranean Ct
4.63(
8
)
Approved Pro
Customers say: True professional
Recommended by 100% of Angi customers
Recommended by 100% of HomeAdvisor customers
40 years of experience

3DF LLC is a locally owned and operated company serving the Reston, VA area and surrounding communities. 3DF, LLC is a full service design & builder of your dream home and living environment. We can help expand your existing structure for you and your family to enjoy for years. Professional craftsmanship, reasonable rates, and friendly customer service. Call us now!

"Could not be happier with Jim's work. Remodeled master bath, kitchen, replaced front door, plus several other smaller tasks. Easy to work with. Has a talented eye for style and design. Kept me informed throughout the process. Has experience with the design board in my town (Reston). Never up-charged. I've recommended him to several neighbors already."

Brian B on August 2024

3DF LLC is a locally owned and operated company serving the Reston, VA area and surrounding communities. 3DF, LLC is a full service design & builder of your dream home and living environment. We can help expand your existing structure for you and your family to enjoy for years. Professional craftsmanship, reasonable rates, and friendly customer service. Call us now!

"Could not be happier with Jim's work. Remodeled master bath, kitchen, replaced front door, plus several other smaller tasks. Easy to work with. Has a talented eye for style and design. Kept me informed throughout the process. Has experience with the design board in my town (Reston). Never up-charged. I've recommended him to several neighbors already."

Brian B on August 2024


Apollo Builders, LLC
PO Box 322
4.84(
22
)
Approved Pro
Apollo Builders, LLC
PO Box 322
4.84(
22
)
Approved Pro
Customers say: Quick response
Recommended by 95% of Angi customers
Recommended by 95% of HomeAdvisor customers
10 local quotes requested

An Award Winning Firm with experience in most any style, Apollo Builders, LLC, coordinates the building process from inception to completion and provides valuable critical overview of each phase. From architectural design to vigilant, uncompromising start-to-finish construction management, an Apollo bears the unmistakable stamp of superior craftsmanship and meticulous care. We hope that you will take time to meet with Apollo Builders, LLC, today.

"With so many scams these days, it is hard to trust people. You can 100 percent trust Scott and his team. From the beginning of the process, Scott and his team surpassed my very high expectations. Scottâ s communication is clear and prompt. His prices are reasonable and payment method is easy. His experience working in the county facilitated getting permits approved. His team of contractors are professional, clean and timely. I appreciated that Scott himself managed my construction. When I wanted to change something, Scott would tell me the implications and then, if I still wanted to go forward, worked with me to make that change happen. When we discovered some unfortunate surprise inside the walls of my house or something went wrong (eg. New window delivered broken), Scott and his team made it right every time. Scottâ s honesty, flexibility, and professional expertise made working with him and his team a sincere pleasure. My experience was so good, I am saving money for my next project with Apollo!"

Ebony T on December 2023

An Award Winning Firm with experience in most any style, Apollo Builders, LLC, coordinates the building process from inception to completion and provides valuable critical overview of each phase. From architectural design to vigilant, uncompromising start-to-finish construction management, an Apollo bears the unmistakable stamp of superior craftsmanship and meticulous care. We hope that you will take time to meet with Apollo Builders, LLC, today.

"With so many scams these days, it is hard to trust people. You can 100 percent trust Scott and his team. From the beginning of the process, Scott and his team surpassed my very high expectations. Scottâ s communication is clear and prompt. His prices are reasonable and payment method is easy. His experience working in the county facilitated getting permits approved. His team of contractors are professional, clean and timely. I appreciated that Scott himself managed my construction. When I wanted to change something, Scott would tell me the implications and then, if I still wanted to go forward, worked with me to make that change happen. When we discovered some unfortunate surprise inside the walls of my house or something went wrong (eg. New window delivered broken), Scott and his team made it right every time. Scottâ s honesty, flexibility, and professional expertise made working with him and his team a sincere pleasure. My experience was so good, I am saving money for my next project with Apollo!"

Ebony T on December 2023


Avatar for District Renovations LLC
District Renovations LLC
1336 Spring Hill Rd
4.88(
13
)
Approved Pro
District Renovations LLC
1336 Spring Hill Rd
4.88(
13
)
Approved Pro
Customers say: Terrific value
Recommended by 92% of Angi customers
Recommended by 92% of HomeAdvisor customers
54 local quotes requested

Here at District Renovations LLC, we pride our company on reliability, great communication, integrity, and quality work. We strongly believe in giving our absolute best in all of our projects no matter how big or small. We are experts in our trade and will always keep you educated on your particular task or project. We look forward to earning your business!

"I'm so happy with the work Alex, Kevin and the team did! Alex provided quotes, and high quality work in a very timely manner. The details are really beautiful, and I am especially pleased with the quality of cabinetry, painting, and most of all the beveling on the quartz counters! I had three bathrooms done and the painting jobs were crisp and the cabinetry is elegant. Alex gives very honest opinions on options and details."

Adriana M on March 2025

Here at District Renovations LLC, we pride our company on reliability, great communication, integrity, and quality work. We strongly believe in giving our absolute best in all of our projects no matter how big or small. We are experts in our trade and will always keep you educated on your particular task or project. We look forward to earning your business!

"I'm so happy with the work Alex, Kevin and the team did! Alex provided quotes, and high quality work in a very timely manner. The details are really beautiful, and I am especially pleased with the quality of cabinetry, painting, and most of all the beveling on the quartz counters! I had three bathrooms done and the painting jobs were crisp and the cabinetry is elegant. Alex gives very honest opinions on options and details."

Adriana M on March 2025

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Addition to existing structure building services FAQs

How far you can push a room depends on the structure you choose. A cantilevered bump-out can extend 24 inches before building codes require its own footing or foundation. Anything longer needs engineered support and a permit. Check local codes or consult with a structural professional before finalizing plans to ensure your design remains safe and compliant.

Most bump-outs are completed within one to four weeks, even with minimal electrical, plumbing, or HVAC work. Their compact size means less demolition, simpler inspections, and fewer weather-related delays compared to a full-scale addition. Your contractor can provide a more precise timeline once they have determined the scope, materials, and permit schedule, but plan on having the extra square footage ready in approximately a month.

The homeowners guide to addition to existing structure building services
From average costs to expert advice, get all the answers you need to get your job done.
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