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Why Choose SEI for Your Home Addition Project
You love your home – and you love the neighborhood you’ve built your life around. But when the space no longer fits your needs, moving doesn’t have to be the solution. At SEI Construction, Inc., we create seamless, thoughtfully designed home additions that allow you to stay exactly where you want to be while gaining the space your lifestyle demands.
From expanding living rooms and creating in-law suites to building a second story or designing a dedicated home office, here’s why homeowners across Central NJ continue to trust us with the homes they love:
Nearly 40 Years of Excellence:
Since 1987, homeowners across Union County and Central NJ have trusted SEI Construction for careful, high-quality additions.
Design-Build Under One Roof:
Our in-house approach unites architects, designers, craftspeople and project managers from concept through completion.
Transparent, Organized Process:
With our proven system and dedicated Project Manager, you’ll know who’s doing what, when – and why.
Respect for Your Home:
We treat your home like ours, from job-site cleanliness and dust control to clear communication and schedule integrity.
Home Addition Services We Offer
Room Additions
A custom room addition gives you the extra square footage your lifestyle demands without disrupting the flow of your home. We design each space to feel intentional, cohesive, and perfectly integrated with your existing layout.
Kitchen Additions/Extensions
A kitchen addition or extension opens up your floor plan, improves functionality, and creates a more spacious, modern gathering space. From expanding your cooking area to adding a breakfast nook or pantry, we tailor every detail to how you live.
Bathroom Additions/Extensions
A bathroom addition enhances convenience, increases home value, and improves daily comfort. Whether it’s a new primary suite bath or an expanded hallway bathroom, we deliver spa-like spaces that blend beautifully with your home.
Sunrooms and Family Rooms
A sunroom or family room addition gives your home a bright, expanded living area perfect for everyday relaxation and entertaining. We design these spaces to feel warm, open, and seamlessly connected to both your home’s interior and your outdoor surroundings.
Second-Story Additions
A second-story addition significantly increases living space without bumping-out your footprint. SEI ensures proper structural planning, code compliance, and architectural harmony so your home looks—and lives – as if it was always meant to be two stories.
Bump-Out Additions
A bump-out adds just the right amount of extra square footage to enhance how you use a specific area of your home – whether that’s expanding a living room, creating a cozy breakfast alcove, or adding space for better storage. It’s a cost-effective way to gain more function and comfort without committing to a full addition.
Our Home Addition Process – From Vision to Reality
Your Addition Project Should Feel Exciting - Not Overwhelming. Here’s How We Make It Happen:
Complimentary Project Consultation:
We start by understanding your frustrations, your dreams, your timeline and budget. We’ll walk your property, talk lifestyle, and explore how space can be optimized.
A Custom Home Addition Proposal & Timeline:
Based on your goals, we prepare a clear proposal and preliminary schedule. If that aligns, we move to design.
Collaborative Home Addition Design & Planning
Working with our trusted specialty-trade professionals, architects and designers, we shape your vision into a detailed plan that aligns design intent and construction feasibility.
Contract & Pre-Construction
Once the plan, timeline and budget are finalized, we meet with you and the trades to align expectations, site logistics, safety, dust control, timeline and communication cadence.
Construction Phase
Your dedicated SEI project manager oversees all aspects – scheduling, trade coordination, quality control, site cleanliness, dust management – to ensure a seamless build.
View Our Home Addition Portfolio
Every addition, kitchen, and bathroom we build is custom-crafted for the home it’s in. We blend modern design with architectural integrity - bringing together structure, style, and details that complement your home’s era and neighborhood.
Here are a few different custom home addition types you’ll find in our project gallery:
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Let a Licensed New Jersey Home Addition Contractor Transform Your Space
We coordinate engineers, inspectors, and specialty trades - from electricians to masons - under a unified project plan.
This eliminates scheduling delays, miscommunication, and mid-project redesigns.
Home Additions Designed for the Way New Jersey Lives
From Westfield to Short Hills and across Union, Essex, and Morris County, SEI Construction has been helping homeowners gain the extra space they need without leaving the neighborhoods they love.
Because we’ve spent decades working on Central New Jersey’s most recognizable home styles – Colonials, Cape Cods, Tudors, Dutch Colonials, and split-levels – we know exactly how to design additions that feel natural, proportionate, and true to the original architecture.
Our familiarity with local building nuances, township requirements, and neighborhood character means smoother approvals, smarter planning, and additions that look like they’ve always belonged.
Whether it’s expanding a first floor, building above a garage, or adding a new living space with greater functionality, we ensure every detail aligns with your home’s structure and style.
For homeowners seeking more room without sacrificing curb appeal or craftsmanship, SEI delivers additions that fit seamlessly today and add lasting value for years to come.
Planning Your Home Addition - Frequently Asked Questions (FAQs)
Discover answers to frequently asked questions and get insight from our team of experts.
How much do home additions cost in New Jersey?
The cost of your home addition will depend on the type of addition, square footage, if the space needs to be reconstructed, whether the construction company will build up or out, the materials and products used, and your location in New Jersey. We recommend that our clients visit the The Journal of Light Construction’s Cost vs. Value Guide to get small, mid, and major home addition costs and ROI for their area.
How long does it take for a home addition project to be completed?
Timelines depend on project complexity. Smaller additions may take a few months, while full second-story additions can take longer due to engineering, permits, and structural work. SEI follows a structured project timeline with consistent communication so you always know what’s happening and when.
What does a home addition include?
A home addition adds new livable space to your existing home – either by expanding outward, adding a second story, converting a garage, or building an in-law suite or room extension. At SEI Construction, we handle everything: design, planning, permitting, structural work, utility integrations, finishes, inspections, and the final walkthrough.
Do home additions require permits in New Jersey?
Yes. Most additions – including bump-outs, second stories, structural modifications, and utility upgrades – require permits. SEI handles all permitting, zoning checks, drawings, and inspections to ensure your project meets local codes and passes all approvals.
Can SEI match my home’s existing style and architecture?
Absolutely. Architectural continuity is a core part of the SEI Approach. We match rooflines, siding, trim, materials, windows, and overall style so the new space blends seamlessly with your original structure—no “tacked-on” look.
What types of home additions does SEI Construction, Inc. build?
SEI specializes in family room expansions, kitchen extensions, in-law suites, garage conversions, primary bedroom suites, second-story additions, sunrooms, home office additions, and bump-outs. We tailor each project to your home, lifestyle, and long-term needs.
Will I need to move out during construction?
Most homeowners stay in their homes throughout the project. SEI uses thoughtful planning, controlled work zones, and strict cleanliness standards to minimize disruption.
We also use a professional two-stage dust-filtration system to protect your home during construction:
Coarse pre-filter: Captures larger particles and is replaced after each job.
HEPA filter: A durable secondary filter that captures fine particles and is replaced annually.
Dust removal performance: Our system removes up to 90% of airborne dust, including cement and drywall dust.
If a project involves major structural phases – especially during second-story builds – we’ll discuss temporary adjustments to ensure your safety and comfort.
Why choose SEI Construction, Inc. for a home addition instead of hiring multiple contractors?
SEI offers a true design-build general contractor experience. Instead of managing architects, trades, and inspectors yourself, everything is unified under one team. You get a single point of contact, cohesive design, predictable scheduling, and a smoother, more organized project from concept to completion.
What areas of New Jersey does SEI Construction, Inc. serve for home additions?
We proudly serve Westfield, Scotch Plains, Fanwood, Cranford, Summit, Chatham, Short Hills, New Providence, Plainfield, Clark, Mountainside, and surrounding Central NJ communities. View all service areas.
Top-Rated Home Addition Contractor in New Jersey
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