Modular Construction Drawings

In a previous post, I emphasized the importance of carefully reviewing your modular and general contracting specifications and notes. In this post I discuss the importance of reviewing your modular construction drawings.

How to Avoid Mistakes in Your Modular Construction Drawings

The need to review your modular construction drawings with the same attention to detail you give to your modular specifications is of course because your modular dealer and contractors will build your home according to these drawings. This includes each page of the floor plans, electrical plans, foundation plans, basement layout, garage and porch plans, etc., as well as any accompanying notes.

A modular manufacturer's construction drawings of the first floor of a two-story home with notes
When reviewing your modular construction drawings, keep in mind that someone may have unintentionally made a mistake and that you share responsibility for verifying their accuracy

When reviewing your modular construction drawings, keep in mind that however hard everyone has worked to get every detail right, someone may have unintentionally made a mistake. This is especially true if you select a custom designed plan, since each draft submitted to the manufacturer will likely contain a lot of hand written changes and notes. Sometimes the plans and changes will be easy to interpret and easy to complete, and the resulting modular construction drawings will look just as you anticipated. Other times the plans and changes will be difficult to interpret and impossible to complete exactly as you imagined. After all, your initial modular construction drawings were probably not drawn with a professional CAD program. If your plans were drawn by hand, several of their features – for example, room dimensions, closet sizes, and window spacing – may change significantly when they are drawn to scale. This makes it critical that you look at these types of details closely. In short, you must share responsibility for verifying the accuracy of all aspects of your order, including your modular construction drawings.

A Checklist for Your Modular Construction Drawings


  • Shape & size of each room
  • Location & length of each wall
  • Location and size of each closet
  • Size and type of stairs
  • Location and direction of all flooring seams (where carpet, vinyl, wood, and/or tile come together)

Exterior Elevation

  • Decorative features: window & door mantles, reverse gables, window trim, dental molding
  • Aesthetic appearance: window & door spacing; symmetry on each side of house


  • Location and size of each passageway
  • Location and size of each marriage wall opening
  • Location of each cathedral ceiling
  • Type of supports for each cathedral ceiling
  • Location of each HVAC chase
  • Size and type of each dormer & “fake rake”

Doors and Windows

  • Location, size, & swing of each door
  • Location & size of each window
  • Number of front door sidelites
  • Which side of each slider opens

Kitchen and Bathrooms

  • Size of each kitchen wall & base cabinet
  • Location of each kitchen cabinet drawer
  • Location, type, & size of special kitchen & bath cabinetry (lazy susans, oven cabinets, etc.)
  • Size of each bathroom vanity
  • Location of each bathroom vanity drawer
  • Location and size of each appliance – always verify the size of the actual appliances you select
  • Typical sizes – the first dimension is side-to-side, while the second is front-to-back
    • Stove opening (30″), (24″)
    • Dishwasher opening (24″), (24″)
    • Refrigerator opening (36″), (33″) – refrigerators vary in size, especially side-by-side  models
    • Kitchen Sink Cabinet (36″), (24″)
    • Washer opening (27″), (27″)
    • Dryer opening (27″), (27″)
  • The following come in a variety of sizes – be sure you know which size you are getting
    • Kitchen Cabinets
    • Cook-tops
    • Double Ovens
    • Microwaves
    • Bathroom Vanities
    • Showers
    • Garden Tubs
    • Whirlpool Tubs
  • Swing of appliance doors

Plumbing, Electrical, and Heat

  • Location of plumbing & electrical runs to the second floor of unfinished capes
  • Location of each phone & TV jack
  • Location of each electrical switch
  • Location of each electrical receptacle
  • Location of each switched receptacle
  • Location & type of each light
  • Location of special wiring, such as ceiling fans
  • Location of each thermostat
  • Location of the door chime bell and transformer
  • Location of the electrical drop (panel box)
  • Location of smoke detectors
  • Location of plumbing access panels
  • Location of each heating baseboard unit and covers


  • Orientation of plan
  • Dimensions of plan
  • Location of a walkout bay & other bump-out
  • Location of each fireplace
  • Basement

Location of the Following Items in Relation to House Windows and Exterior Doors

  • Fireplaces, decks, porches, garages, etc.;  bulkhead, windows, stairs, heating system (including power vent or flue), water heater, fuel tank (including fill and vent pipe), washer & dryer, heating ducts, future rooms, etc.
  • Location of septic or sewer line penetration, water supply line penetration, exterior frost-free faucets, overhead waste and vent pipes, heating and cooling ducts, sump pump, central vacuum unit
  • Location of circuit breaker panel and electric meter (outside and adjacent to breaker panel)
  • Location of kneewall/walkout windows and doors, drive under garage overhead doors


  • Sunlight and views: consider which sides of your home will be bathed in sunlight in the morning, afternoon, and evening; locate some windows where you have the best views
  • Furniture placement in each room: think about your L-shaped sofa and television table, your queen size bed and two large dressers, your dining room table and hutch
  • Traffic patterns: if you will always enter the basement from the kitchen, ensure the swing of the door makes this easy
  • Electrical needs (lights, receptacles, switches, appliances, controls, etc.): if you will have an end table with a lamp on each side of your long couch, place a receptacle on each side
  • Windows and doors: refer to the modular manufacturer’s schedule that comes with your plans
  • Notes: read closely the information contained in each note on each page of the plans
  • Contractor input:  review your modular plans with your contractors, since they will be completing your home

For more information about verifying the accuracy of your modular construction drawings, see Designing a Modular Home, Modular Home Specifications and Features, and The General Contractor’s Responsibilities for Building a Modular Home in my book The Modular Home