What a stock house plan does not include

Geotechnical soil report. Where soil is likely to be expansive, compressible or shifting, the building official decides whether to require a soil test [3], but either way it is what the engineer who designs your foundation works from.

Foundation design by a Texas licensed engineer. Texas law requires engineering for a residential slab on expansive soil unless the work meets the IRC requirements as applied where you build [1], and some cities want a seal on every foundation: the North Central Texas Council of Governments' recommended amendments to the 2021 IRC say every foundation shall be designed and sealed by a Texas-registered engineer. [6]

Land survey and site plan. Houston requires a site plan for all buildings constructed in the city limits, showing building lines and setbacks [4], and its residential plan review asks for a survey or a site plan based on one. [5]

Energy code compliance documentation. Houston, for example, wants plans that show prescriptive compliance with the 2021 International Energy Conservation Code or include a REScheck, IC3 or REM/Rate compliance report. [5]

Septic, or OSSF, design where there is no sewer. In Texas a permit and an approved plan are required to build one, and the site is evaluated by a TCEQ licensed site evaluator or a professional engineer. [7]

MEP drawings. Texas law does not require an engineer to draw a private dwelling's plans apart from the expansive soil slab and windstorm carve outs [1], so whether you need them is up to your permit office. They are worth having on a complex house.

The right hand column is the same wording every plan page prints under Not in the drawing set, so what you read here is what you will read before you pay.

A stock plan is drawn before anyone knows your lot, so nobody has designed its foundation for your soil. Check what the listing says about seals before you buy.

Texas does not require an architect for a single-family or two-family house [2], so an unsealed plan is not a problem in itself. What matters is whether your jurisdiction wants a seal to issue the permit. Houston's residential plan review lists an engineer's seal where one is required [5], so ask the permit office which sheets need one.

Outside city limits, Texas law does not require county approval before new home construction begins. In counties that opt in to the state's residential building standards, the builder hires the inspector for at least three inspections. [8] That is not permission to skip the engineering. It just means the consequence arrives later and lands on you rather than on an inspector.

Here, a single build license covers one house at one address. You can have it modified by licensed professionals, give copies to your builder, engineer and permit office for that project, and rebuild at the same address if the house is destroyed. [10]

You cannot build it twice, resell the files, or claim the design as your own. The designer keeps the copyright [10], and US copyright protects the design of a house as embodied in its plans and drawings. [9]

An unlimited build license costs more and covers repeat builds by the original purchaser. The CAD tier here comes with a copyright release so your designer can modify the drawings without coming back to the seller. [11]

All sales are final once the files are released, because files can be copied. [10]

An unlimited build stock license gets you generic drawings you can build more than once. [11]

Commissioning a plan directly from a residential designer gets you drawings drawn for your lot and your jurisdiction, on whatever reuse terms you agree with the designer.

If you are a builder planning to build the same plan more than once in one market, price both before you decide. If you are building one house, the stock plan is the right answer and the thing to budget for is the engineering, not the plan.