How to Paint Foam Crown Molding: DIY Techniques, Tips, and Tricks!

One of the smartest ways to add tasteful decor and depth to a room, crown molding is a subtle alternative to many of the over-the-top adornments some people fill their homes with. For years, molding has been almost exclusively made from wood, which results in a process that requires hyper-detailed calculations, expensive tools, and woodworking skill. Foam on the other hand, represents a newer, simpler, and more cost-effective alternative that can give you the same appearance 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. Foam’s “squishiness” means you can be generous with your cuts, as the foam will compress when fit into a tight space, creating perfect joints and seams while hiding imperfections. Getting a spongy material like foam to look like a more solid product is what makes people occasionally question its ability to genuinely replace wood as a molding material. In reality, the process of painting foam molding gives an installer the ability to make the foam look like any other medium. In this post, I’ll give you a run-through on how easy it is to paint polyurethane foam molding and wind up with a beautiful new space.

There are two methods for 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 faster, but doesn’t give you maximum detailing capability. 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 Painting Foam Crown Molding

After measuring and cutting your foam molding sections, prepare a workspace in a well-ventilated area where accidental overspray won’t be an issue. Putting down a large drop cloth 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 molding is spaced out on the tarp, apply thin, even coats, taking care not to oversaturate the foam. As an absorbent sponge rubber, the molding will take longer to dry if you do. After painting all the pieces to your specifications and allowing adequate time to dry, your crown molding will be ready to mount.

As previously stated, spray painting has an advantage over brush painting in terms of speed and ease. Prepping the area, painting the foam, and allowing it to dry are the only steps before mounting. The drawbacks to spray painting amount to little more than personal taste. There will be limitations to spray painting based on the nature of its application; two-toned or intricate designs won’t be practical. Also, foam will retain its spongy appearance with the spray method. The polyurethane foam most manufacturers use has a cellular structure small enough that it will be indistinguishable from a solid at the distance from which it will be seen, but it is still a consideration to take into account.

Brush Painting Foam Crown Molding

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

Unlike spray painting, brush painting requires the foam to be coated with thinned drywall joint compound as sealant before painting to create a smooth surface. Also different from spray painting, the molding will need to be mounted before sealing and painting. Mounting first gives you the benefit of foam’s compressibility to create clean corners and seams before you harden the material with sealant and paint.

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

Once you’re finished mixing, brush a thin coat onto the entire surface of the molding. The 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 go-around. Only two coats are necessary, but if you prefer to add more, do so. Once you’ve completed applying the drywall compound, give the molding a full 24 hours to completely dry all the way through.

The following day, the molding will be ready for paint. Sanding the dried joint compound should not be necessary unless you spot a flaw. If you need to sand the compound down, use the finest grit sandpaper possible, and utilize a respirator or face mask. When you’re satisfied with the coating surface, proceed to paint the molding however you desire. Once the paint dries, remove the drop cloths and tape and you’ll have a newly-transformed space that you upgraded with a fraction of the time, money, and effort needed for traditional crown molding.

Final Tips

Lastly, there are a couple tips that apply to either painting method. First, avoid oil-based paints for the foam. There is little reason to use them anyway, since latex paints are more affordable and you won’t need weather resistance inside. Second, the foam itself may be bright white when you first purchase it. If you plan to have white crown molding, you will still need to paint the foam, even if it matches your room. This is because foam will naturally yellow as it ages. This is purely an aesthetic change and doesn’t impact quality, but by painting it, you will ensure it will always be the color you want.