Custom Home Building & Renovation Blog | Sims Luxury Builders.

What Your Builder Needs Most from Your Interior Designer

Written by Marie Sims | 7.27.2026

Our most successful projects are the ones with an experienced, organized, and talented interior designer on board. We are definitely a custom builder who sings the praises of incredible interior designers we’ve worked with in the past because they make such a demonstrable difference in how smoothly the custom home process can move. And that’s not just true for us as the custom builder. A strong interior designer improves the entire custom home journey for the architect, the homeowner, and even the trades as well!

This blog post explores key deliverables that your builder will need from your interior designer throughout the custom home architectural design and construction phases. The best interior designers do not have to be pressed for these materials at every step along the way; they have a clear internal process and timeline for both producing them (or collaborating with the architect to produce them) AND for delivering them to the custom builder.

1. Organized Documentation of Selections

Before sharing the concrete deliverables with you, it’s important to point out that the best interior designers are organized and thorough in both their process for making selections with their clients and delivering those selections to the custom builder. When both the interior designer and custom builder approach the project with a high degree of organization, attention to detail, initiative, and professionalism, construction moves quickly, and fewer balls are dropped along the way.

2. Conceptual Interior Design Package

It is incredibly helpful to receive a multi-page PDF document that illustrates the overall design concept for the home. We have seen this document called a variety of names, including “vision board,” “north star packet,” “design concept board,” etc. It is composed of inspiration images, material photos, colors, textiles, fixtures, and other design details that make up the design visions for each major space in the home. For us as the custom builder, it also helps us to create a preliminary budget that more accurately reflects the level of materials and finishes that will be going into the home.

Before actual selections are made, this conceptual design package provides direction and vision to everyone involved, from the architect as they finish developing plans for the home, to the interior design team as they begin sourcing options for finish selections, to the builder as they communicate needs to the trades and build a thorough construction budget.

3. Finish Interior Design Package

Once selections begin being finalized, the interior designer should have a digital repository to document everything in an organized and comprehensive manner. Every selection for every space should be documented accurately in this document, and approvals should be noted as soon as they are obtained. This digital reference of all finishes ensures the builder and all trades can reference all material specs, installation details, and additional notes, which will reduce errors and miscommunication throughout the project.

4. Ceiling and Soffit Plan

This deliverable (often called a Reflected Ceiling Plan) will be supplied by either the architect or the interior designer, depending on which partner has it included in their scope. In this deliverable, the designer provides all actionable details that will be needed by the custom builder, including varying ceiling heights (dropped ceilings, trays, coffered details, beams, etc.), material specifications, lighting locations, and HVAC locations.

5. Electrical & Switch Plans

Either the architect or interior designer needs to supply a thorough, thoughtfully designed electrical plan to the builder well before the framing stage is complete. This plan should include fixture placement locations (recessed cans, chandeliers, pendants, sconces, under-cabinet lighting, and exterior fixtures) along with switch locations and details about which lighting is included on each switch. The electrical plan should properly incorporate all lighting layers, including task, ambient, and accent lighting, and should specify which will necessitate dimmer switches. Dimmers are used more and more in our custom homes to allow for greater flexibility and mood-setting.

Also needed on the electrical plan are locations for all outlets. Interior designers are especially good at considering a variety of lifestyle needs for outlets, like ideal locations for Christmas tree/décor outlets, hidden charging stations in drawers, floor outlets in open-concept living rooms, conspicuous outlets in backsplashes, etc.

Overall, the electrical plan should reflect how the homeowners are going to be living in and using various spaces and should thoughtfully anticipate the natural flow and movement throughout the home.

Wondering if you need a lighting designer for your custom home? Find out here.

6. Plumbing Fixture Schedule

You’ll notice that some deliverables in this list may be produced by either the architect or interior designer (depending on whose scope it’s under), but this plumbing fixture schedule will only be coming from the interior designer. They should include details like room/location, vendor, item number and name, item image, finish, size, exact location details, and installation notes. For wall-mounted fixtures, they should always specify the installation heights. This level of detail and organization ends up saving a lot of time and money by preventing costly misunderstandings, mistakes, or changes mid-construction.

7. Custom Millwork Drawings

This deliverable may be produced by either the architect or interior designer (depending on whose scope it’s under). Either way, the interior designer will be intimately involved in finalizing the custom millwork drawings. The goal here is to provide FULL drawings and elevations for built-ins, closets, banquettes, and vanities, so nothing is “interpreted” on site but instead executed exactly according to the drawings.

Closet and storage customization is a hugely important part of every custom home, so interior designers and homeowners will collaborate very closely to determine the unique needs of the family and incorporate those into the drawings. From walk-in pantries and linen closets to seasonal storage and built-in mudrooms, custom solutions should be planned early and thoughtfully.

Curious what makes a truly well-functioning custom home? Visit our previous blog post here.

8. Tile Layout and Transition Plans

Tile layouts should include both the direction and pattern for every single space where tile is to be installed. In addition, the interior design team will want to thoughtfully dictate how they would like transitions to adjacent materials to be handled. In high-end luxury homes, they will often weigh in on where exactly they want grout lines to fall, in addition to basic decisions like grout color and thickness. For more information on how to avoid common tile mistakes, visit our previous blog post here.

9. Meeting Agendas & Follow-Ups

Everyone involved in a high-end custom homebuilding endeavor wants clarity, thoroughness, and accuracy. This speeds up the process and prevents costly mistakes. As a result, it is always a good idea for interior designers to provide a meeting agenda and follow-up notes for every design meeting. The meeting agenda should include the overall purpose of the meeting and outline the major decisions that need to be made. As conversations stray throughout the meeting, these agendas help get everyone back on track quickly. Notes and timely follow-ups ensure nothing falls through the cracks and action items are accomplished in a timely manner. This communication shows next-level professionalism and makes a world of difference in a custom home project.

In summary, experienced and organized interior designers not only bring vision and creativity to a custom home project but also provide critical organization, documentation, and communication that benefit everyone involved, from the builder and architect to the trades and homeowner. This is especially true when these key deliverables are supplied throughout the project, ultimately helping to minimize errors, streamline decision-making, and keep construction on track.