top of page

Guidelines for Looking at Online House Plans

Updated: Jul 3, 2023

Wait! Before you buy that set of House plans you found online...

We hear it time and time again, a potential client spent a not-insignificant amount of money on a set of plans for a house they liked online and dropped them off at the building department thinking they would have an approved permit in a couple of weeks' time. But that is never how this story ends. So, in an effort to try and help potential clients before they pull the trigger on expensive online plans, we have outlined some basic guidelines for looking at online house plans below.

I doubt it has escaped anyone's notice that in California, regulations tend to be so complicated that even those tasked with enforcing them often need to take a second (or third) look. This is as equally true of our building codes as anything else in this state. When we submit a set of drawings for a residential project, not only are there floor plans, elevations, and pretty renderings like that drawing set you were looking at online, but there are also:

  • A full architectural package - Code analysis and project overview on the cover sheet, applicable code notes for the agency reviewing the plans, building sections and details, ventilation calculations (and other WUI requirements), stormwater management calculations, a site plan showing everything your permitting agency (AHJ - 'Authority Having Jurisdiction') specifically requires to understand the safety, access/egress of the property, and that zoning code has been met, and much more depending on the agency.

  • A full structural engineering package - Foundation, roof, and framing drawings, details, and calculations, coordinated with the architectural plans and the truss calculations (if applicable)

  • A set of *climate zone & building orientation specific* energy calculations that assess the overall energy budget of the home, assign insulation values and window glazing efficiency, photovoltaic array sizing, etc. that have been coordinated with the architectural and structural drawings (all that insulation requires careful consideration in wall thickness and roof design)

  • Electrical layouts for outlets and lighting along with required notes on the energy efficiency requirements of those lights

  • Plumbing layouts for all the fixtures in the project along with water conservation requirements for each fixture type.

  • Truss design and calculations - provided by the anticipated provider/manufacturer of the trusses and coordinated by the structural engineer.

  • Additional design requirements for customizations our clients request like radiant (in-floor) heating, gray water systems, steam showers, etc. - all of these will require additional code analysis, drawings, details, notes throughout, and coordination with other project components

  • Plan Check Responses - A critical part of every project. Once you submit it to the AHJ, they will come back with comments and questions to clarify concerns that they have about the project and how it is compliant with building and zoning codes. Some anonymous designer online is unlikely to answer those questions and they are not going to change their generic plans to accommodate what your AHJ is requesting without an additional fee. You will need a design professional capable of altering the plans as required - and having someone local who is familiar with the local agencies and also comfortable pushing back on requirements they don't agree with can be the difference between a project that gets approved and one that dies in plan review.

  • Additional consultants that can be required for difficult locations:

    • Soils Analysis & Report

    • Civil Engineering if there is complex earthwork or grading required

    • Landscape Architect for communities with strict CC&Rs or WUI Regulations

    • Storm Water Design for designated areas

So, when you buy a set of plans online, at a minimum, you should expect to engage someone to produce and coordinate each of the items above that are not included in the plan set and to also bring them up to the current code (which is updated every 3 years). This will likely include:

  • A Structural Engineer - It is unlikely that the plan set will come with foundation, roof, and framing drawings that are compliant with the current code cycle and your site's constraints (soil conditions, wind loads, seismic design, etc.). Some plan sets may come with drawings designed per the residential code's Conventional Construction requirements, but even these should be verified with your site-specific requirements.

  • An Energy Consultant - The California Energy code is a complicated beast and there is very specific software that must be used to produce the calculations your AHJ is looking for, as well as specific online project registrations that must be completed. While yes, there are ways of doing things 'prescriptively', it does not actually save money because the requirements are more generic and may result in over-designed systems with little to no room for project-specific modifications.

  • A Truss Manufacturer (if the roof design calls for trusses) - While this is commonly handled by contractors, most AHJs now require the truss layouts and calculations to be submitted with the initial plan review and they must be coordinated with the structural design. Those roof loads translate directly to foundation sizing and detailing and a whole host of other points of coordination that will hold up a plan review or cause construction delays if not completed early on.

  • Someone to Coordinate Plan Review - This is someone who can answer questions and modify the original plan set as needed to get through the plan review. If you can do this through PDF mark-ups or some other strategy, more power to you, but just be prepared to tackle this common sticking point if/when it is not covered by the original home designer. The designer may offer this service at an additional hourly rate, but reach out in advance to ask what their fee and turnaround times look like.

So, what do we recommend instead?

Moving from a vacant lot filled with dreams to reality can be done in an infinite number of ways. Some options will be faster, some will be cheaper, and some will be higher quality - lay out your project goals early on and stick to them.

  • In our experience, new homeowners that are the happiest when all is said and done had the highest degree of input throughout the design process, and design professionals who could answer their questions thoroughly and keep them informed every step of the process (and it is a long, complicated process, there's no sugar coating that fact, and it will be no matter which path you choose).

  • These homeowners tend to use online plans as a framework for starting the project. When they called for a proposal, they sent a couple of links to plans they liked and specified what they wanted to customize, and what they did and did not like. This makes it very quick for us to put together a proposal because the project is no longer completely open-ended - we have an idea of size and level of complexity.

    • No money needed to be spent on plans to get to this point, just an emailed link.

  • Some very diligent homeowners have elected to pay for the simplest drawing package available on their favorite online plans to use for preliminary pricing.

    • This is an investment we can support. If you are looking to get a ballpark construction cost (and design costs), spending a few hundred dollars on a PDF copy of the plans to send out to contractors and design professionals for preliminary estimates to inform your budget is a wise investment.

Ideally, our clients spend enough time looking at plans and exteriors to know what they do and do not want. They use their time comparing the infinite options as an exercise in making efficient and expedient decisions for when it comes time to sit down with their chosen design professional and contractor(s). From here, we can efficiently proceed through the conceptual design phase and get to a design sign-off before proceeding with engaging the required consultants and putting together the permitting package. This, in our experience, is the most reliable way to get from point A to B, even if it is not as easy or cheap as point and click. Buildings are an investment, and taking shortcuts in the beginning almost always leads to delays and headaches later in the construction process or years down the road.

We hope this information has been useful in your project planning and perhaps has even saved you from spending money on unnecessary plans that will only complicate and extend the overall process.


ADU - Accessory Dwelling Unit, sometimes referred to as an In-laws Unit or a Mother-in-law Cottage, etc.

AHJ - Authority Having Jurisdiction - the government agency or building department that will issue your building permit

CC&Rs - Covenants, Conditions & Restrictions are limits and rules placed on a group of homes or condominium complexes by a builder, developer, neighborhood association, or homeowners association.

WUI - Wildland Urban Interface, sometimes referred to as the Very High Fire Severity Zone, is the area in or around a city that is adjacent to open space or forested areas that are prone to wildfires. These areas are specially designated and have strict building regulations that must be followed on all new construction.


bottom of page