How To Install Prefinished Moulding

Add a Finishing Touch!


Image removed.Adding moulding to your walls can dramatically enhance the overall ambiance of just about any room of your home. From crown moulding to base moulding, chair rails and more, moulding 'finishes' the look of your walls like nothing else can.

Installing moulding was once considered an overwhelming task. After all, moulding materials used to be bulky, hard to handle, heavy pieces of lumber that you had to prime, paint, cut and then maneuver into position.

The good news is that all of this can be a thing of the past! There is a relatively new category of moulding that comes prefinished upon purchase and is easier to install than traditional wood moulding. This means that you will save time and money on your moulding projects.

Working with prefinished moulding is easy. They apply easily, even to slightly imperfect walls. They're free of knots and resist the warping, splitting and splintering associated with traditional wood mouldings. And every piece is engineered to be consistent, making every piece one you can use. They cut, nail and repair like real wood, and they don't need to be sanded, painted or stained. Its low cost and easy installation makes prefinished moulding an economical alternative to wood moulding.

LP Moulding is the category leader for this product and offers prefinished moulding in five diverse collections, including today's most popular colors. From woodgrain finishes to traditional white, these mouldings can be used to add instant beauty and customize the look of any room in your home - traditional to modern.

You can install prefinished mouldings with just a few standard tools. So let's get started!

Project Steps

Step 1

In order to be able to buy enough moulding to redo your room, you'll first need to determine how much you'll need to purchase by drawing the floor plan of the room on a piece of paper. You'll be adding the measurements of each wall to that floor plan in just a moment. But from the very beginning of this project a second set of hands is a great idea. You don't necessarily need someone who's done this before, it just makes it easier to install by having someone help hold the long pieces of moulding.

Cool Tool: One great way to get that "helping hand" is to use the new Ryobi MultiTASKit. The MultiTASKit allows you to mount a "helper" arm to the base unit which will help you to balance your moulding in place. The MultiTASKit base unit also comes with a number of other great attachments like a laser level, light and tool tray. For more information, check it out in our Cool Tools Corner!.

Step 2

Now, using a tape measure, measure the length of each wall. Once you have a measurement for each wall, write it down on the paper floor plan you created in Step 1. Pay special attention to being very accurate as these will be the measurements you refer to when you go to cut and install your crown moulding pieces.

Cool Tool!: When measuring long distances such as a room's length, select a tape measure that is a minimum of 35 feet in length and that features a wider blade so that you can extend the tape measure out to more than 10 feet, without it losing rigidity. This enables the user to do more measuring work, on their own, without the assistance of a partner. It's also important to find a model that offers a blade with a protective coating on, at least, the first 12 inches so your marks won't wear away over time. We recommend the 35' Fat Max Blade Armor made by Stanley Tools.

Step 3

Now, add up all of the wall lengths to figure out how much moulding you will need. The easiest way to do this is to first add up all of the feet in each measurement; then add up all of the inches and divide it by 12; then add this second number to the number of feet to get your grand total.

JANE TIP: Expect to make a few mistakes when cutting your crown moulding. So, to prevent the need to go back to the store for more in the middle of your project, add an extra 10% to your total.

In order to know how much crown moulding you'll need to buy, first measure all of the walls in the room you'll be working in. Make sure you measure them accurately so that you can use these measurements when you start to cut. Add up all of the feet together and then all of the inches. If the inches are greater than twelve, then divide that number by twelve. Then add this number to the total number of feet you had previously. To be certain you have enough and don't have to go back to the home improvement store in case you cut something wrong, add another 10% on to your final number.

Step 4

mouldingUsing a pencil and a stud finder, mark off where the studs are in your walls. Just place the stud finder on the wall, activate it by slowly moving it across the wall. Once you've found a stud, the stud finder will light up or make a noise to let you know. Mark off these areas high on the wall near the ceiling but below where the moulding will sit because you'll need to see them later as these will be the points you'll nail the crown moulding onto the wall.

A great benefit in using LP® Prefinished Moulding is that because it is so lightweight you can water based adhesive to install it. It can't get much easier than this!

Use a stud finder to find the studs in the walls and mark with a pencil.

Step 5

Let's go shoppin'! Purchasing prefinished moulding products is easy. You can start the education process online at They offer a wide variety of styles and sizes, so you can see what's available and what works best for you. Once you've narrowed your choices, it's usually a great idea to purchase a few samples of different styles of moldings to bring home and see how they look.

When you do finally buy your moulding remember to get a few pieces that are as long as your longest walls if possible to avoid having to splice two smaller pieces together. Not that splicing them is all that difficult, but it is a timesaver when you don't have to.

JANE TIP: To span longer lengths, you may have to splice mouldings. The two pieces will overlap each other at 45 degree angles, to create a vertical seam. To splice your moulding, place the moulding with the flat side against the back of the miter box, cut using the appropriate angled slots for an inside or outside corner to guide the saw. It is advisable to join mouding pieces over a wall stud for additional strength and to prevent joint movement. Be sure to place your pieces of moulding in the room you plan to work in for at least 24 hours prior to installing it. This will help the moulding acclimate to the temperature of the room!


Make sure you purchase moulding that suits the size of your room. If moulding is too big (thick), it can appear to "shrink" the size of a room, whereas if it's too small, it will get lost. A key to remember, however is that you will always be seeing moulding from a distance and for that reason it will appear smaller. So what might seem big in your hand, may seem perfect once up on the wall. Be aware that if you choose a moulding larger than 4 ¾;" you will need to install a "backer" nailing blocks which are triangular pieces of wood that run the length of the wall that will give you something to nail the molding into.

Step 6

When using prefinished moulding, you get to skip the priming, sanding, staining and painting. Remember, because prefinished moulding comes ready to install upon purchase, you are ready to begin your projects. And with none of the traditional prep needed for this type of moulding, you'll save a lot of time and money.

If you do need to paint, we find it helpful to paint the moulding before you begin cutting. You can certainly paint the pieces after cutting but even the slightest amount of paint on the edges can sometimes throw off your cuts.

Apply your paint with a beveled paint brush with strokes going from side to side and not up and down. This will minimize your brush strokes.

Jane Tool Tip: Purdy Professional Paint Tools offers a great set of paint brushes for true quality work. One of the things we love about the Purdy brushes is that we have little if any problems with "shedding," and the bristles are so well cut that we can paint in an almost perfect straight line which limits the need to mask!

Let it dry and then apply a second coat if necessary. When choosing your paint type, remember that your walls have a flat sheen to them, so giving your moulding a semi-gloss finish will show them off just enough to help catch the eye.

Step 7

Once your pieces are completely dry it is time to cut. You can either use a miter box and back saw combo, or for more efficiency (and fun) you can use a compound miter saw to make your cuts. If you use the compound miter saw and find that the edges of your moulding pieces are a bit rough, be sure to use the rasp to file down any excess material. This will help to make your pieces fit together more smoothly.

Step 8

This is one of the reasons we absolutely love using the prefinished moulding product. Normally at this point, you would need to make your 'corner' or mitered cuts. These cuts are the most difficult because of the imperfection of the angles between your walls and ceilings. Usually, you're stuck with getting as close to a 45 degree angle as you can and then patching the gaps with spackle.

With prefinished moulding hanging any moulding is simple, just begin from any corner in the room and nail the corner piece in place.

If you have one available, a power nail gun, set at 95 PSI or less (too much power can damage the moulding), can speed up your installation. Place nails everywhere you marked there is a stud on both the top and bottom of the moulding. Be sure to drive your nails to within 1/4" of the surface of the moulding to prevent scarring the moulding face. Make sure you are wearing your protective eyewear and also hearing protection as nailing guns can be extremely loud.

Any nails that remain above the surface will need to be hammered below the surface with a counter setter to drive all nails below the surface of the moulding.

Step 9

At this point you'll need to use spackle to fill in any gaps or holes. Let dry and lightly sand if necessary. Touch up these spots with paint and any areas that were scuffed during installation.

Step 10

If you're installing crown moulding and you look up and see gaps between the walls, ceiling and moulding, don't panic we expected this to happen. Remember when we said your walls aren't flat and your corners aren't square? Well, here's proof in living color. You didn't do anything wrong. This is where our motto of "caulk and paint'll make it what it ain't" comes in.

All you need to do is to caulk the edges of the crown moulding to fill in any gaps. Apply a bead of water-based painter's caulk with a caulking gun and then go over it with your finger and a damp disposable shop towel (extra strong paper towels). This will help to push the caulk into the open spaces left behind as well as to make it look finished. You'll want to wear gloves while you're doing this as it can get quite messy. This should eliminate any spaces between the walls, ceiling and crown moulding. Remember if you painted it any other color than white, caulk will be very obvious. But once it dries, you can simply cover it with paint as need be.

Jane Tool Tip: Caulking isn't exactly the hardest task, but one way to make sure you get a professional looking line is by using a power caulking gun. Ryobi makes a great unit that comes with a variable speed lever to adjust the discharge rate to control the bead of caulk. With over 500 lbs of push force, the Ryobi power caulking gun can handle most higher viscosity materials, too!

A Few Special Notes When Working With Prefinished Mouldings

Since prefinished mouldings are, well, prefinished, simply touch-up nail holes and joints with a color coordinated putty, caulk or spackling. Shoe polish, latex stain, a felt marker or crayons can also be used. Avoid wood fillers that contain solvents harmful to the moulding's finish.

You may need to coordinate your moulding to existing trim. Fortunately, prefinished mouldings will accept other coatings, so you can simply use your favorite high quality interior latex paint.

See? That's all there is to it! These are the basics for just about any moulding project. So don't hold back! If you have another room you'd like to enhance, get creative. Add a chair rail, frame your ceiling, add baseboard moulding - we promise, you'll love the results. Have fun!