After years of working with numerous clients, interior designers Michael Smith and Mary Cook have seen many of the same design mistakes over and over.
The Los Angeles-based Smith, whom the Obamas appointed to redecorate the residential quarters of the White House, is the author of five decorating books, including his latest, ''The Curated House.'' Cook is president of Chicago-based Mary Cook Associates and author of ''The Art of Space: The Seven Fundamentals That Guarantee Great Interior Design.''
The award-winning pros revealed decorating mistakes that drive them crazy and shared insider tips and tricks for creating a harmonious room design. In addition to the designers' pet peeves, we've added a few of our own:
Mistake No. 1
Ignoring scale and proportion
Cook: Scale and proportion are the holy grail of design. Scale is the size of things, and proportion is the relationship of those sizes to one another and the room as a whole. That is probably the biggest issue we end up fixing.
The way American homes are built today, with open floor plans and volume ceilings, you have to integrate good scale and proportion into all the layers of your design, starting with the backgrounds and ending with the last accessory. Americans get seduced by large, expansive spaces, but without good proportion in those spaces, they will lack harmony and impact. Managing volume space is intimidating and where I see people struggle the most.
Smith: This is a really, really terrible one. To have a 9-foot sofa in a small room can be kind of treacherous. Make sure furniture decor has similar scale. It's all about scale, proportion, measuring, being conscious of the overall plan. People buy things in isolation and don't think of how they work together.
Mistake No. 2
Neglecting the function of a room
Smith: People get trapped in the way things should feel and less focused on the way things should function. Making a dining room into a dining library gives it function. You could make the living room a study or put a TV in it so you could actually use it. Think of how much furniture you need. What's the best way to have it be functional in a great way? If it's in groups, define it.
Cook: You have to know how you want the room to function. Are you going to entertain there, dine there? Do you have a large family, is it just the two of you? Drill down into how you want the space to function. As you assemble and select the pieces of furniture, think about selecting pieces that will enhance the way you will live in the room. Think about multifunction and multitasking as you design your rooms. Chances are your rooms will function differently at different times of day and different times of the year.
Lifestyle trends are a great indicator of how the function in our home designs will evolve. Working from home, entertaining, multigenerational living, family gathering spaces, and technology are a few of the big drivers right now. Keep flexibility in mind. Rooms with layouts that can be moved around to accommodate last-minute gatherings, guests or different chapters of life will allow you to live better in your home.
Mistake No. 3
Overdoing a theme room
Smith: Look at your world and your life, and look at what is personal to you. If you're living in an apartment, you need to stick with a narrative that's personal to you. To be influenced by a magazine and, say, a Swedish theme, unless it resonates with you, it seems kind of odd and influenced.
Mistake No. 4
Using inadequate lighting
Cook: Lighting is a very key ingredient. You have to think about the color of light, the quantity of light, and where to place it. You have to think about light at various times of the day and various times of the year. The best way to design your lighting for success is in layers with as many of those layers as possible to be switched separately and on dimmers. So now you can adjust your lighting for whatever kind of mood you want.
We just designed and installed a model home for Toll Brothers called Trotters Glen in Olney, Md. The lighting is done in multiple layers, with recessed cans in the ceiling on dimmers for overall general lighting, chandeliers and pendants to highlight a dining table or kitchen island, and table lamps to help light within seating groups.
In two-story foyers or staircases, we will often use clusters or groupings of fixtures together to add impact at the right scale.
In the dining room, we've integrated chandeliers or pairs of chandeliers to light the space and add decorative interest.
Table lamps are next to the living room sofa or on a night stand in the bedrooms.
Mistake No. 5
Buying poor-quality furniture
Smith: Avoid spending too much on one thing. Be judicious with your budget and buy things that are going to last. People buy very badly made furniture and fabric. Instead, buy a beautiful dining table, well-made upholstery. It's almost like dressing for success.
Mistake No. 6
Not testing paint colors
Smith: Avoid too much intense color. Make sure you mix colors and try them out. It's always good to do a swatch.
Cook: Color is your biggest cost-to-impact ratio. Color has the ability to do so much. Add formality with a glossy white, add sophistication with rich jewel tones, start a trend with something bold and different. But remember that color is one of many layers.
I just overheard a woman at one of my model home grand openings tell her friend: ''This is the room that they changed/repainted the color in. It used to be hot pink, and they repainted it this softer shade.''
Actually, she had walked through the room when it was just painted and none of the other layers were in. When she returned to the fully furnished room, she thought the color had changed. In fact, it was the impact of the color with and without the other layers that changed. Sometimes color comes off very strong at first, but once it's all together, it's perfect. So don't panic at first.
Mistake No. 7
Placing all living room furniture against the walls
Move the furniture inward to create a warm, intimate seating arrangement for conversation. This is particularly important for entertaining in large, open-concept homes. The furniture should be arranged to allow for guests and family to circulate through the space. A large area rug can unify the furnishings.
Mistake No. 8
Going overboard on accessories and art
Cook: Accessories and art will bring your composition into perfect harmony, but you have to be very careful not to clutter. You have to constantly do scale-and-proportion checks on yourself as you compose your art and accessories. They are the final layer that will oftentimes be what brings your composition into perfect harmony.
Mistake No. 9
Overlooking the focal point in a room
A prominent item like a fireplace, artwork, or mirror can serve as a eye-catching focal point for any space.
''With strong background design and interesting architectural elements contributing to the composition, your art and accessories won't have to work too hard,'' Cook points out in her book. ''They can make the contribution they're supposed to make and not have to carry too much of the overall design on their own.''
Mistake No. 10
Making everything matchy-matchy
It's tempting to buy the coordinated, ready-made furnishings on the furniture showroom floor. Try mixing accessories with ready-made pieces from the store to add character to a room.
It takes time, sometimes years, to achieve a warm overall feel, but the result is a home that is as unique as the people living in it.
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