Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
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AfterFast, Reliable Home Additions & ADU Across Friendswood
Adding square footage to a Friendswood home usually costs between $45,000 and $130,000 for a room addition, while a complete detached ADU runs $90,000 to $220,000. The right number for your house depends on what you’re building, whether flood-elevation work gets triggered, and how deep the foundation has to go in Beaumont clay. At Barrett & Sons Construction, we walk every Friendswood Roofing and addition job with a FEMA flood-zone map in hand before we quote anything, because a surprise regulatory stop mid-project costs more than any material upgrade ever will. Call (877) 610-1318 and we’ll come out, look at your lot, and give you a straight answer.
Why Barrett & Sons Construction Is Friendswood’s Preferred Home Additions & ADU Company
Our name goes on the truck and our crews answer to Tom Barrett, who founded this company in 1998 and still shows up on most job sites in Friendswood with his sons running the work. That’s not a franchise model. It means the person who signs your contract is the same person you’ll see at the lumberyard on FM 528, and the same person who picks up the phone when you call with a question three weeks after the job is done.
Friendswood homeowners have already been through enough with contractors who quoted one price and handed over another bill. We do it differently: every scope, every allowance, every price change arrives as a written change order before work happens. No surprise invoices at the end. The permit inspector works for you, not for me. That’s why we pull permits and get inspections signed on every eligible job, including every ADU we build in Friendswood.
We also stand behind finished work with a written 90-Day Done Right Promise. If something isn’t done right, one call brings Tom back. We’ve built enough additions in the 77546 and 77549 zip codes to know which streets sit in the AE flood zone and which don’t, and we’ll tell you upfront if your project is heading toward the 50% substantial improvement threshold before you’ve spent a dollar on design. Call (877) 610-1318 and we’ll give you a free estimate you can actually plan around.
Our Home Additions & ADU Services in Friendswood
ADU Design & Permitting in Friendswood
Most Friendswood ADU projects start with a site visit to determine whether the lot can support a second structure without triggering floodplain complications or exceeding the city’s impervious-cover limits. We handle the design, the FEMA flood-zone review, the city submittal package, and every inspection from rough-in to final. Our Home Additions & ADU team has built accessory dwellings on Friendswood lots where the primary home was flooded in Harvey and rebuilt, which means we know how to design around the elevation and drainage rules that trip up out-of-area contractors.
Garage Conversion ADU in Friendswood
Converting an attached garage into a rental unit or an in-law suite typically runs $30,000 to $80,000 in Friendswood, depending on whether the existing slab is high enough to meet current floodplain requirements and how much new plumbing the floor plan demands. On many older 77546 ranch homes, the garage slab sits lower than the main house, which means the conversion may need slab-raising or fill work before framing starts. We’ll tell you on the first visit whether your garage conversion is straightforward or whether a flood-zone review changes the math.
New Detached ADU in Friendswood
A new detached ADU in Friendswood generally lands between $90,000 and $220,000, with site prep and foundation work often accounting for the biggest swing in price. Friendswood’s expansive Beaumont clay swells and shrinks with seasonal wet-dry cycles, so we engineer foundations that won’t move with it. We build detached ADUs to post-Harvey elevated-slab or pier-and-beam standards where the lot and flood map call for it, and we pull every permit and pass every inspection before you cut the ribbon.
Junior ADU & Interior Conversion in Friendswood
A junior ADU conversion inside an existing Friendswood home typically costs between $30,000 and $80,000, depending on whether we’re carving a bedroom suite out of existing space or adding a small kitchenette to a first-floor wing. Interior conversions are often the fastest path to multi-generational living because they stay within the existing footprint and usually don’t touch the foundation. We’ve done these in the established neighborhoods around Clear Creek tributaries where the housing stock is older slab-on-grade ranch construction, and we know how to route plumbing and electrical-and Windows & Doors - Friendswood installations-through those layouts without tearing up more floor than necessary.
What happens when you call
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A real person answersNo phone trees - you reach a local pro.
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You get an upfront price rangeHonest numbers before anyone is dispatched.
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A background-checked tech heads outLicensed & insured, dispatched right away.
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You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in Friendswood
We stock and install premium materials you can look up, not mystery brands off a van. For Friendswood addition and ADU work, that means Techo-Bloc and Cambridge Pavers for any driveway, walkway, or patio surface tied to the project, and Quikrete for engineered slab pours where the clay needs a stable base. When you pick a brand with a published spec sheet, you know what you’re paying for before the first nail goes in. We keep local material suppliers on speed dial for Friendswood jobs so lead times don’t stretch out longer than the build itself.
Common Home Additions & ADU Problems We See in Friendswood Homes
- Floodplain triggers on older homes. A 1970s brick ranch in 77546 that flooded during Hurricane Harvey can cross the 50% substantial improvement threshold mid-project, which legally halts work until the structure is elevated to the new Base Flood Elevation. We check this on day one so it never surprises you at week six.
- Slab movement from expansive clay. Friendswood sits on Beaumont clay that swells in wet seasons and shrinks in dry ones, causing the slab cracks and foundation movement we see on nearly every older ranch home. Any addition has to be designed from the ground up to resist that movement, not just cover it.
- Moisture intrusion behind existing cladding. Summer heat and near-100% humidity after rain storms accelerate wood rot and fastener corrosion on homes that were dried-in too quickly after Harvey repairs. Before we tie a new addition into an existing wall, we check what’s behind the siding so you’re not paying to frame over rot.
- Utility service sizing that wasn’t built for more square footage. Many 1960s-1980s Friendswood homes have 100-amp or smaller electrical panels that can’t absorb the load of a new ADU kitchenette, mini-split, or laundry stack. We’ll check panel capacity and service line condition as part of the estimate, and we’ll put the panel upgrade in writing before work starts if the design calls for it.
Pricing for Home Additions & ADU in Friendswood, TX
Room additions in Friendswood run $45,000 to $130,000 depending on square footage, foundation complexity, and whether flood-elevation work is required. A garage conversion ADU runs $30,000 to $80,000, a junior ADU or interior conversion $30,000 to $80,000, and a new detached ADU $90,000 to $220,000. The biggest cost drivers here are floodplain triggers, Beaumont clay foundation engineering, and the condition of the existing structure where the new work ties in. We give every Friendswood homeowner a written line-item quote, not a phone estimate. Call (877) 610-1318 to schedule a free estimate and we’ll put your exact numbers on paper before you commit to anything.
We Also Serve Cities Near Friendswood
Barrett & Sons runs crews to Friendswood every week, and we also cover Webster, Pearland, League City, and Alvin for larger additions and ADU builds. If you’re on the edge of Friendswood or just over the city line, call us anyway. We also handle Kitchen Remodeling in Friendswood and Bathroom Remodeling in Friendswood for homeowners who want to fold those rooms into a bigger whole-home plan.
Serving Friendswood, TX - Our Local Coverage Area
We’re based in the Friendswood service area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
FAQs - Home Additions & ADU in Friendswood
A room addition in Friendswood typically costs $45,000 to $130,000, while a garage conversion runs $30,000 to $80,000 and a new detached ADU runs $90,000 to $220,000. The flood zone review, foundation depth, and condition of your existing home are the three biggest swing factors. Call (877) 610-1318 for an exact quote, and we’ll put every number in writing before you sign anything.
Yes, we pull permits and get inspections signed on every eligible job, including every ADU, room addition, and garage conversion we build in Friendswood. The permit inspector works for you, and we want his signature on the job just as much as you do. No addition leaves our crews without the final inspection passed.
If your Friendswood home sits in the AE flood zone and your addition crosses 50% of the structure’s assessed value, the project legally triggers mandatory elevation to the new Base Flood Elevation before work can proceed. We review the FEMA flood map and the city’s adopted freeboard requirements at the first site visit so you never get surprised mid-job. Sometimes a smaller addition designed to stay under the threshold is the smarter play, and we’ll walk you through that math honestly.
No. Every scope, every allowance, and every price change at Barrett & Sons arrives as a written change order before work happens. If we hit a condition inside a wall or under a slab that changes the plan, you’ll see the number on paper and approve it before a single nail moves. The allowance that isn’t on paper is a surprise waiting for a date, and we don’t work that way.
A typical room addition takes 10 to 16 weeks from permit to final inspection, a garage conversion 8 to 14 weeks, and a new detached ADU 6 to 10 months depending on foundation work and city review timelines. Flood-elevation work extends the schedule, but we give you a written timeline at contract signing and we stick to it. Call (877) 610-1318 and we’ll tell you exactly what to expect for your specific street and lot.
Written by Tom Barrett, Owner at Barrett & Sons Construction, serving Friendswood and surrounding communities.
Ready to talk about your addition or ADU? Call (877) 610-1318 today. We’ll come out to your Friendswood home, walk the lot with you, and put a free written estimate in your hand before you decide anything. If you have a written estimate from another contractor, bring it. We’ll give you a free second opinion and tell you straight if their numbers hold water.