How To Paint Foam Crown Molding: DIY Techniques, Tips & Tricks!

One of the smartest ways to add tasteful décor and depth to a room, crown molding is a subtle alternative to many of the over-the-top embellishments some people fill their homes with. For years, moldings have been made almost exclusively from wood, resulting in a process that requires very detailed calculations, expensive tools, and woodworking skill. Foam, on the other hand, represents a newer, simpler, more cost-effective alternative that can give you the same look as wood without all the work.

Lightweight and flexible, foam crown molding needs little more than adhesive to install and is easily cut by hand with a sharp carving knife. The “softness” of the foam means you can be generous with your cuts, as the foam will compress when it fits into a tight space, creating perfect joints and seams while hiding imperfections. Making a spongy material like foam look like a more solid product is what sometimes makes people question its ability to really replace wood as a molding material. In reality, the process of painting foam trim gives the installer the ability to make the foam look like any other medium. In this post, I’ll show you how easy it is to paint polyurethane foam trim and end up with a beautiful new space.

There are two methods of painting foam molding, and it’s up to you to decide which is best: spray painting or brush painting. Spray painting requires less work, fewer materials, and is quicker, but it doesn’t give you maximum detailing capabilities. Brush painting allows you to replicate the design or look of any other molding medium, but is slightly more labor intensive than spray painting.

Spray Paint Foam Crown Molding

After measuring and cutting the foam molding sections, prepare a work space in a well-ventilated area where accidental overspray is not a problem. Putting up a large tarp or tarp in the garage, basement, or even on the ground outside on a calm day works well.

When your area is ready and your trim is spaced out on the tarp, apply thin, even coats, being careful not to over-saturate the foam. Like an absorbent rubber sponge, the trim will take longer to dry if you do. After all parts are painted to your specifications and allowed to dry properly, your crown molding is ready to mount.

As stated above, spray painting has an advantage over brush painting in terms of speed and ease. Preparing the area, painting the foam and letting it dry are the only steps before assembly. The drawbacks of spray painting are little more than personal taste. There will be limitations to spray paint depending on the nature of your application; two-tone or intricate designs will not be practical. Also, the foam will retain its fluffy appearance with the spray method. The polyurethane foam used by most manufacturers has a small enough cellular structure that it is indistinguishable from a solid at viewing distance, but it is still a consideration.

Brush Painting Foam Crown Molding

For people who have an intricate or custom paint job in mind, or who prefer to have a solid, smooth surface on their trim, brush painting is the right choice.

Unlike spray painting, brush painting requires the foam to be covered with a diluted drywall joint compound as a sealer before painting to create a smooth surface. Also unlike spray painting, the trim will need to be assembled before sealing and painting. Mounting first gives you the benefit of the foam’s compressibility to create clean corners and seams before hardening the material with sealant and paint.

After the foam has been assembled, protect the room from the paint and joint compound with drop cloths and painter’s tape. When you’re done with the prep work, prepare your drywall compound mix. You will want to thin it down to the consistency of paint.

Once you have finished mixing, brush a thin layer over the entire surface of the trim. Joint compound should dry quickly, so in an average sized room, you’ll be able to start applying a second coat as soon as you finish the first round. Only two layers are needed, but if you prefer to add more, go for it. Once you have finished applying the drywall compound, give the trim a full 24 hours to dry completely.

The next day, the molding will be ready to paint. It should not be necessary to sand dry joint compound unless a defect is detected. If you need to sand the compound, use the finest grit sandpaper possible and wear a respirator or face mask. When you are satisfied with the surface of the siding, proceed to paint the trim as desired. Once the paint dries, remove the drop cloths and tape and you’ll have a newly transformed space that’s been upgraded with a fraction of the time, money and effort required for traditional crown molding.

final tips

Lastly, there are a couple of tips that apply to any painting method. First, avoid oil-based paints for foam. There’s little reason to use them anyway, as latex paints are more affordable and you won’t need indoor weathering. Second, the foam itself may be bright white when you first purchase it. If you plan on having white crown molding, you’ll still need to paint the foam, even if it matches your room. This is because the foam will naturally yellow as it ages. This is purely a cosmetic change and does not affect quality, but by painting it you will ensure that it always has the color you want.

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