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 Manor
Adding a room, a second story, or a detached ADU in Manor typically runs $45,000 to $130,000 for a standard room addition, and $90,000 to $220,000 for a new detached ADU. Most projects here take 3 to 7 months from permit to final inspection. If you’re weighing a garage conversion, budget $30,000 to $80,000. Call (877) 610-1318 and we’ll walk the lot with you, check the soil, the HOA rules, and the existing slab, then put a written estimate in your hand.
Manor is not a simple place to build. The Blackland Prairie clay under most of the 78653 zip code moves more than any soil in Travis County, and the homes here are young enough that one mistake in drainage or foundation detailing shows up fast. We know what the inspectors see in ShadowGlen, Whisper Valley, and the older streets off Lexington. That’s why our Home Additions & ADU work in Manor always starts with site conditions, not a glossy brochure.
Why Barrett & Sons Construction Is Manor’s Preferred Home Additions & ADU Company
Tom Barrett founded this company in 1998 and still answers the phone. His sons run the crews. When we say we’ll be on your Manor job site, the people who show up carry the Barrett name, not a subcontractor’s badge from two counties over. That matters in a town like Manor, where you’ll see us at H-E-B or the hardware store on the weekend.
We pull permits on every eligible job in Manor. Every change order, every allowance, every scope adjustment arrives in writing before a single nail moves. That’s not a marketing line. It’s how Tom has run the company for 29 years, and it’s the reason Manor homeowners who got burned by out-of-state outfits call us for the second opinion. The permit inspector works for you, not for me, and we like it that way.
Our Manor customers get a built-in backstop: the 90-Day Done Right Promise, written on every contract. If something isn’t right, one call brings Tom back. No arguing, no fine print. That promise means more on an ADU or room addition than most people realize, because a bad foundation detail or a sloppy tie-in can hide for 60 days before the clay shifts and the drywall cracks.
Our Home Additions & ADU Services in Manor
ADU Design & Permitting
Most Manor ADUs stall at the permitting desk or the HOA review board, not the framing stage. We handle the full design and permitting path: site survey, engineered plans stamped for Blackland Prairie soil conditions, HOA architectural review coordination, and the permit package itself. In ShadowGlen, the HOA wants exterior finishes that match the primary home. In Whisper Valley, the geothermal easements change where you can legally place a structure. We map all of that before you spend money on plans that get rejected.
Garage Conversion ADU
Converting an attached garage into a one-bedroom ADU is the most popular value play we see in Manor, and the price lands between $30,000 and $80,000 depending on whether you’re adding a kitchen, a bathroom, or just a bed and bath. The catch here is the slab. Many Manor garages were poured with a lower elevation than the house slab and without a vapor barrier upgrade in mind. We saw this in a recent Whisper Valley garage conversion where the geothermal lateral lines ran just 18 inches below the garage floor. Hand-exposing those lines before rough-in was the only way to protect the community grid and keep the project code-compliant. We pulled permits, set the subfloor over a moisture barrier, re-routed one loop segment through an engineered change order, and the inspector signed off without a correction. The result was a clean one-bedroom with its own mini-split.
New Detached ADU
A detached ADU on a Manor lot is a bigger commitment: $90,000 to $220,000 is the realistic range, and the site prep matters more than the framing. On Blackland Prairie clay, the new footings must be designed to move with the soil, not fight it. We run soil borings, design the post-tension slab or pier system accordingly, and build drainage that moves water away from both structures. If you’re planning to rent the ADU long-term, we’ll also talk through the utility metering options so the tenant’s usage doesn’t silently inflate your main meter.
Junior ADU & Interior Conversion
A junior ADU, usually carved out of an existing bedroom wing or bonus room, runs far less than a detached build. In Manor’s newer tract homes, we often convert a formal dining room or a front flex space into a 400 to 600 square foot unit with a kitchenette and private entry. The challenge is plumbing: many of these rooms sit on the far side of the slab from the main waste line, so trenching through post-tension cables requires an engineer’s stamped plan before anyone cuts concrete.
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 Manor
We install materials you can look up by name, not mystery brands off a van. In kitchens, we work with KraftMaid and Cambria. On windows, Andersen and Marvin. On roofs, GAF and CertainTeed. For bathroom waterproofing and drainage systems, we standardize on Schluter and Sterling fixtures. If you have a warranty claim on a GAF roof or a Schluter shower system in your Manor home, we can usually source the exact replacement parts locally and get the repair moving faster than a shop that has to order blind.
Common Home Additions & ADU Problems We See in Manor Homes
- Builder warranty voided by unpermitted structural work. Manor’s housing stock is overwhelmingly 2000s to 2020s slab-on-grade construction. The moment you cut into a load-bearing wall or disturb a post-tension cable without an engineer’s stamped plan, the builder’s structural warranty is gone. We handle the engineering and permits so the warranty stays intact.
- Foundation heave at the new-to-old transition. On Blackland Prairie clay, a new room addition without upgraded perimeter drainage acts like a dam. Water collects at the junction of old slab and new footings, the clay swells, and within two or three wet seasons you see cracking at the transition. We design drainage before we pour.
- HOA rejection on sunroom and patio enclosure finishes. ShadowGlen and other master-planned Manor communities enforce strict exterior finish packages. A sunroom that doesn’t match the approved roof pitch, trim profile, or window style gets rejected at architectural review, sometimes before permits are even filed. We pull the HOA approval checklist before drafting plans.
- Geothermal easement conflicts in Whisper Valley. Whisper Valley lots run on a community geothermal grid with buried ground-source heat pump loops and pre-run conduit. Any detached ADU, room addition, or garage conversion on those lots must work around those easements. Standard utility trenching in neighboring ShadowGlen or Pflugerville doesn’t face this constraint at all.
Pricing for Home Additions & ADU in Manor, TX
Here are the ranges we quote most often in Manor, based on current local material and labor costs:
| Project Type | Typical Manor Range |
|---|---|
| Garage Conversion ADU | $30,000 - $80,000 |
| Room Addition | $45,000 - $130,000 |
| New Detached ADU | $90,000 - $220,000 |
What moves the number is site prep, not square footage alone. A room addition on a flat, well-drained lot in ShadowGlen costs less than the same addition on a sloped Whisper Valley lot with geothermal loops to protect. Kitchen and bath finishes swing the interior budget by $15,000 to $40,000 depending on whether you want builder-grade or Cambria counters and Schluter waterproofing. Call (877) 610-1318 and we’ll give you a written line-item estimate, not a phone number with no name behind it.
We Also Serve Cities Near Manor
We run crews in Manor every week and take projects in Hornsby Bend, Pflugerville, Elgin, and Wells Branch. If you’re just outside city limits on a county lot off FM 973 or Cameron Road, Tom will still come walk the property and give you a straight answer. Call (877) 610-1318.
Serving Manor, TX - Our Local Coverage Area
We’re based in the Manor 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 Manor
Yes, if the addition cuts into a load-bearing wall or post-tension cable without an engineer’s stamped plan and a permit. ShadowGlen’s HOA also requires architectural review before permits are filed, and unapproved exterior changes can trigger a separate violation. The safe path is engineered plans, HOA sign-off, and a permit, which we handle start to finish. Call (877) 610-1318 and we’ll check your home’s specific warranty language before you commit to anything.
Yes. Every Whisper Valley lot has buried ground-source heat pump loops and pre-run conduit with legal easements that limit excavation depth and placement. A detached ADU must be sited outside those easements, and any trenching near them requires hand-exposure and sometimes engineered re-routing. This is a constraint ShadowGlen and Pflugerville builders never deal with, and we map it during the very first site visit. Call (877) 610-1318 for a free lot walk and a straight answer on your specific parcel.
Because the Blackland Prairie clay under Manor swells and shrinks with every wet and dry cycle, and a new patio room’s footings concentrate water at the old slab’s edge if you skip the drainage plan. Within two or three seasons, you’ll see cracking at the transition. We design perimeter drainage and grade the connection so water moves away from both the old foundation and the new one. Call (877) 610-1318 and we’ll show you exactly what’s needed on your lot.
Usually no, if the conversion adds a kitchen or a separate entry. Most Manor HOAs, including ShadowGlen, treat any exterior change or second living unit as a full architectural review item, and the city permit office wants to see that HOA sign-off before issuing permits. We prepare both packages in parallel so the review doesn’t stall the job. Call (877) 610-1318 and we’ll pull the exact HOA checklist for your subdivision.
Plan on $90,000 to $220,000 for a detached ADU in Manor, with the lower end being a simple one-bedroom and the upper end including a full kitchen, in-unit laundry, and higher-end finishes. Rental-grade fixtures and Schluter waterproofing keep maintenance costs down. We’ll also talk through sub-metering so the tenant’s utilities don’t land on your bill. Call (877) 610-1318 for a line-item estimate based on your lot’s actual conditions.
If you’re anywhere in Manor and weighing an ADU, a room addition, or a second story, call (877) 610-1318. We’ll walk the lot, check the soil, the HOA rules, and the slab, and give you a written estimate you can hold us to. The price you see in writing is the price you’ll pay. That’s how Tom Barrett has run things since 1998, and how his sons run things in Manor today.
Written by Tom Barrett, Owner at Barrett & Sons Construction, serving Manor with permits pulled and promises kept.