Interior Design

How to Write a Design Rationale Based on the Elements & Principles of Design

October 5, 2017
How to Write a Design Rationale Based on the Elements & Principles of Design (Updated)

How to Write a Design Rationale eBookI’ve put together an in-depth guide on How to Write a Design Rationale, especially dedicated to graduates who are preparing for the Philippine ID board exam. You can read the eBook for free by subscribing to my email list.


As additional help to How to Write a Design Rationale, one of my most visited articles, here’s another helpful way to go about writing a design rationale: Explain what mood or feeling you wish your space to convey, then describe how that particular mood (or moods) has been created in each space of your design using the elements and principles of design.

I learned this from our very first assignment on the online diploma course I’m taking on interior design. The task was to “select three interior spaces that each convey a different message, mood or feeling. Describe how these moods have been created in each space using the elements and principles of design as they have been discussed so far.”

This is what I submitted:

Design Rationale - Elements & Principles of Design 1

Elements of Design

A sense of airiness is mostly derived from the space—a high vaulted ceiling and the generous space between furniture pieces. Space is a luxury, and the wider, the more sophisticated.

The many windows that dress the wall behind the sofa let in generous natural light, which floods the space during the day. When dark, the cove lighting perpendicular to the ceiling beams, accentuates the vaulted ceiling, maintaining the feeling of spaciousness it gives.

The pendant lamp above the mantle, the table lamp behind the 3-seater sofa, and the fire in the firebox give interesting accent lighting at night.

The ombre curtains give away the clear line that divides the white from the blue; the airiness from the sophistication. White visually opens up the space even more, and the blues convey an air of royalty.

The visually sturdy vertical lines of the coffee table legs, the structure of the marble fireplace, the tall windows, and the beams of the ceiling impart a vibe of sophistication.

The golden accents as seen on the coffee table, the base of the table lamp behind the 3-seater sofa, and the inside rim of the pendant lamp above the mantle, add elegance to the space, making it even more sophisticated.

The shape of the structure is almost origami-like. Its details make it interesting. The rigidness of the squares of the space (coffee table and fireplace), although lacking in details, adds class to the space. The curves of the slipper chairs are welcoming, promising to give comfort to those who sit.

The space looks very smooth, sleek and soft: The walls and ceiling look smooth; the polished windows, mantle and coffee table, sleek;  and the fabrics used on the curtains, pillows, cushions, and seats are velvet-like, promising softness and warmth to the touch. The carpet looks like it would give a tingling sensation when walked on barefoot while giving warmth. The sight of flowers ensures that the space smells good and fresh.

The damask patterns on the throw pillows add to the space’s sophistication. They look baroque and valuable. So do the toile de jouy vases on the mantle, seeming to belong to an important collection of porcelain. The grey veins of the white marble stone, as seen on the fireplace, take me back to the classics—when the Greeks and Romans built colossal structures. And the pattern on the back of the slipper chairs, I find sophisticated.

Principles of Design

The placement of seating furniture in this space isn’t very balanced. I’m sure they moved the other slipper chair to face the fireplace in order to not block the view in the photo. An asymmetrical balance would have been achieved if the slipper chairs were beside each other, facing the 3-seater sofa. In the photo, however, the placement of objects creates visual balance.

The distribution of dominant colors though, the whites and blues, are balanced in this space. They are equally distributed in the photo. There’s an invisible line that divides the white from the blue: It starts on the bottom part of the left side of the photo, following the silhouette of the slipper chair, and continues along the carpet onto the coffee table, and onto the cushion seat of the 3-seater sofa and up the leftmost curtain, and turns into a straight diagonal path above the blues of the curtains all the way to the end of the photo. Can you see it?

The softness of the curves as seen on the lamps, mirror, seats, patterns, and windows balance the rigidness and squareness of the rest of the elements in the space.

Rhythm and repetition can be seen in how different shades and tints of blue are paired together. Rhythm and repetition can also be seen in the distribution of flowers, and in the colors, lines, and shapes of the space and structure.

Emphasis is definitely given to the seating area, which comprises of the 3-seater sofa, slipper chairs and coffee table. The blues visually advance, inviting guests to take a seat. At night, though, seeing where the lamps are placed, I’d say emphasis would be on the beautifully vaulted ceiling, on the 3-seater sofa lit by the table lamp behind it, and on the fireplace, lit by the live fire in it, and the pendant lamp above the mantle.

Part of the seating area being the emphasis of the space has to do with the proportion and scale of the furniture pieces. They seem a little grand in comparison to the background, but their grandness not only balances the high ceiling very well, but they add to the sophistication of the space.

I find this sophisticated lounge to be harmonious. The whites and blues are well distributed and give a feeling of relaxation and calmness. The placement of furniture pieces makes it a place ideal for conversation, the placement of lamps creates interesting highlights when dark, and the tall curtains and high vaulted ceiling give an air of grandiosity, successfully achieving sophistication and airiness in the space, sprinkled with golds and interesting accents.

Design Rationale - Elements & Principles of Design 2

Elements of Design

The space is intimidating—square with a high ceiling. If this space were a person, it would be a tall, dark, handsome and a neat, relaxed, yet hard-working man.

The vertical lines of the tall windows give the space a whiff of grandiosity. The horizontal lines formed by the bricks on the wall give a sense of calmness. The longer beams on the ceiling lead the eye out the window, to a green view, adding more to the calm feel of this office.

The shapes of the tables are square, giving off a serious feel to the space. I like how the designer added subtle hints of femininity—the curves of the chairs, the spindle legs of the long table, the half-circles of the windows, and, obviously, the glass-blown ornaments hanging from the ceiling.

The colors are very masculine—dark and muted—terracotta, beige, browns and black, with a sprinkle of gold (the brass lamp).

The office’s texture is cold—the metals of the furniture legs, the brass lamp, the windows, and the glass. Even the long table looks cold, yet it’s smooth. The brick-clad wall adds roughness to the space. Definitely very masculine—like a rough man who’s soft at heart.

Men’s inclination to being more (physically) natural than women is reflected on the source of light in the office—sunlight let in by the tall windows.

The patterns in this office are basic and square—the brick wall and the geometric pattern formed by the orientation of the floorboards—with a touch of femininity: the damask pattern on the wallpaper (on the wall where the windows are) and the glass-blown ornaments.

Principles of Design

There is a sense of balance in the space. The long table is weighed out by the two desks by the brick wall, and the office chairs around the table are laid out equally. The structure looks very balanced—the stone wall, tall windows, and massive table give a sense of stability—just as all men should.

Rhythm and repetition can be seen in the squares of the room—the ceiling beams, the tables, the windows, and the chairs. A neutral color scheme is applied throughout, consisting of black, browns and beige.

The glass-blown ornaments hung from the ceiling are definitely the focal point of this office. They contrast the masculinity of the space, adding a tinge of femininity to it.

The proportion of the large furniture pieces outweigh the grandness of the space, creating a harmonious design overall.

Design Rationale - Elements & Principles of Design 3

Elements of Design

The square space in this living room provides a blank canvas for the décor. Its squareness makes it easy to play with the placement of furniture pieces, and the narrowness of the space allows for extra decoration.

The space between furniture pieces is wide, adding to the light feel of the space.

The lamps are placed in the corners of the room, lighting up every nook at night, while the wide windows let in generous natural light during the day, making the space feel light and bright while saturating the bright colors that make this living room so playful—aqua, fuchsia and yellow.

The shades of brown in this space add warmth to the room, along with the beige area rug and golden accents. The greenery adds a tinge of refreshment and rejuvenation, on a white background that lets the light bounce throughout the room.

There’s a play of different lines in this space—vertical, horizontal and diagonal, with the diagonal lines dominant, creating a sense of movement and playfulness. They give a sense of busyness to the space, too.

Various shapes are sprinkled throughout the space—triangles, circles, and squares. This space is definitely a circus of shapes; playful and whimsical.

The plush area rug promises warmth and comfort. There’s a lot of play with texture—softness, smoothness, and warmth of the rug, throw pillows and blanket, sofa and curtains juxtaposed by hardness and sharp edges of the furniture, coldness of the glass and metal of the side table, and the sting of the cactus, topped with a fresh and natural texture to the polished room by the plants.

The various patterns in this living room add a lot of playfulness—black and white stripes, colorful scalloped pattern on one of the throw pillows, the subtle diamonds of the rug, the Navajo printed chair and the Mediterranean star on the floor pillow.

Principles of Design

There is a sense of balance between the femininity and masculinity of the elements of the room. The white background balances the colorful décor, and there’s a balance between the non-patterned and patterned elements as well.

I see rhythm and repetition through the recurring use of the colors fuchsia, turquoise and yellow, and the greens and magenta of the plants. Stripes are repeated throughout the space through the throw pillows. Diagonal lines are everywhere—on the Navajo print, on almost all furniture legs, on the area rug, and on the star pattern on the floor pillow.

With all the play between patterns, lines, and color, the living room is visually busy. To me, what stands out, or in other words, the emphasis in this room would be the jungle of plants at the far end.

The proportions of the various furniture pieces are also very playful and contrasting. Take the floor pillow and the aqua 3-seater sofa, for example.

This living room is definitely harmonious. The bright colors can’t help but make you happy and smile. Femininity and masculinity are balanced—the colors being feminine, and the bronze accents and wood being masculine. The furniture range from retro to Mediterranean to contemporary. The play of colors, lines, style, proportion, patterns, and shapes balance everything out, making it a harmonious living room.

I hope these have been helpful to you. In case you’re wondering, I got a mark of 10/10. Good luck to you all! ♡



  • Reply CatValiente August 22, 2014 at 9:14 am

    Hi, this is really helpful! Thank you for sharing. 🙂

  • Reply Sue Foster February 2, 2015 at 10:04 am

    Hi Jennifer, I found your assignment one really inspiring and reading through it has really given me a head start for my own first assignment with the Interior Design Institute.
    I have completed my first assignment and now look forward to assignment two. A great challenge living in NZ finding styles going back to 19th century. I look forward to hearing your tips n tricks again.

  • Reply Enas March 6, 2016 at 4:39 pm

    can you but more for all your ASSIGNMENT it is benefit for me and help me beacuse i study diploma in interior design online course and i need help for writing my assignment and can you tell which course your study by online .

  • Reply Teodora October 11, 2016 at 5:21 pm

    Did you have any background before taking the online diploma course ? As I see from your assignment it looks like you already had knowledge in the field before beginning , as would not be able at this point to describe my rooms in such detailed and comprehensive way.

    • Reply Jen Cederstam October 21, 2016 at 11:32 am

      Hi Tedi,

      Yes, I did have a 4-year bachelor degree in Interior Design. But that only helped with the design and decor vocabulary. It would help to tap into poetic writing, and try to put yourself in your readers’ shoes, kinda like describing the surroundings of a blind person and make it more ‘alive’ for them. 🙂

  • Reply Larni December 3, 2016 at 5:55 pm

    Thank you I only just started my course and I was struggling finding a way to write that first assignment! Finding this helped figuring out how they would like it written out!

  • Reply Lillie Mallia January 25, 2017 at 7:00 am

    Hi Jen, Yes I thank you too! I just recently started the course andI found reading your material very helpful. I will follow your tips, Thank you.Lillie

  • Reply saif khalid March 30, 2017 at 8:26 pm

    This was something i was searching for online for sometime now. you made it really easy to understand the elements and principles of design.
    thank you for sharing.

    • Reply Jen Cederstam December 3, 2017 at 9:34 am

      Saif, I’m so glad you found it useful! 🙂

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