Trim & Mouldings: A Quick Guide to the Finishing Details

Trim and moulding isn’t just the icing on the cake it’s an important architectural feature of your home and can serve to protect the walls from damage. Mouldings can bring an unfinished renovation to an almost complete space. They can also do an important job of covering the guts of doors and windows after they are installed. 

It can be a confusing puzzle to put together especially if you have original wood or plaster  mouldings. We thought we would share our tips and tricks to putting together a moulding plan that will bring your renovation from incomplete to polished. 

An example of a project where we matched original plaster mouldings with new crown mouldings

Moulding or Molding

First of all we need to discuss something that might be bothering you. Is it spelled moulding or molding? Unfortunately and confusingly the answer is…both! You may have guessed that the old word and original way to spell it is “moulding” but here in the US many words that had that pesky “U” have had it removed over the years. Both spellings are accepted, but some professionals and suppliers choose to go with the old world spelling rather than the modernized US version. Since we love old houses and most of what we write is related to them, we have chosen to stick with the old and more nostalgic spelling. Now, let’s talk a about mouldings! 


The original reason for most mouldings was to cover up gaps where building materials come together. Over time they became more ornate, but their original purpose still holds true. Crown mouldings can bring a feeling of elegance to a room. It can be a simple feature or an ornate focal point. There are many styles but we like to use a cove that can round out the transition where the wall meets the ceiling with additional features above and below it. Some crown mouldings consist of multiple pieces built up to achieve a larger and more ornate look. The height of the ceiling and proportions of the room usually determines how big to go. Many crown mouldings were traditionally made of plaster, and many still are, but it’s an expensive (but beautiful) option. A similar look can usually be accomplished with wood. More on that below. 


Baseboards are installed partly for aesthetic reasons, just as crown moulding hides the area where walls meet the ceiling, baseboards hide the joint where walls meet the floor, which might otherwise be unsightly. But baseboards also serve a very necessary function in protecting plaster walls from getting kicked or scuffed. They come in varying heights and details. Baseboard trim is usually much less ornate than crown molding, though in modern houses both can be starkly simple. Baseboard comes with a large variety of styles, such as smooth, beaded, ornate, and many more styles. Many traditional baseboards consist of multiple pieces. A flat board, sometimes with beading, and a base cap on top that is usually more ornate. Simple modern baseboards may even just stop at the flat board. The height usually depends on the height of the ceilings. We like to do baseboards in the 3”-5” range for low to medium height ceilings and 7-9” range for high ceilings (and more ornate details). 

Picture Frame & Rail

Picture frame moulding can instantly and inexpensively up the character factor in a room. It adds an touch of elegance to a space. The picture rail is a nod to tradition and history and was used to hang wall decor to avoid creating holes in plaster walls. This type of moulding will always curb a modern style to traditional. We like to use a low profile wall moulding to bring in some character but not make things too bulky. 

Door & Window Casing 

Like other types of moulding, casings were originally used to cover the gaps between the plaster wall and the door or window. It’s still used for that, but now to most people a home just wouldn’t be complete without them. Again, you need to consider the rooms proportions to chose the size abs style. You’ll also need to consider how much space there is around your doors and windows. In New York, space is tight and they may end up close to one another or a wall. You should consider the space required for the moulding to understand how big you can go. Usually the door trim will extend all the way around the door and to the floor. Sometimes a plinth is used as a base to the casing at the floor. The baseboard will then a terminate at the casings or plinth. At the top corners, and sometimes even on the sides, a decorative rosette can be used. 

Matching Original Moulding

One of the things that usually draws people to historic homes are their original mouldings. Rather than rip it all out and replace it, to keep its original charm you will want to restore it. But if some are damaged or if you move a wall or 2, you may need more.

Depending on which moulding you need to replicate with determine what to do. Your original baseboards and door & window casings are wood. It will likely be impossible for find your original moulding off the shelf. You can find a close approximation if it, or you can chose to have a millworker recreate the originals. This is not that much more expensive if you go to the right place. Many of the wood product shops in New York even have the knives (the tool used to give a piece of wood the exact feature of your moulding) on hand to match the more popular styles in local homes. If they don’t they can make it for a small fee. Then it’s just a matter of paying for the wood to be cut. 

Your original crown moulding is likely made of plaster. Fixing damaged sections or recreating it will require a skilled plaster craftsman to come into your home to spend many hours working to restore them. It can be expensive work, but the result will be beautiful. Once completed you will look at it everyday and will be glad you did it!

Finally, something to consider is that all the trim in a room should be part of the same family, with similar detail and proportions. If you have elaborate crown molding and very simple door casings, for example, it’s not going to feel right. All mouldings should be in proportion to the room size and each other.

Trim and mouldings serve an important purpose and are part of the architectural detail of your home. They hide the unsightly gaps between buildings materials and protect walls and plaster from damage, all while adding character and elegance to a room. Whether you are creating your moulding plan from scratch or restoring originals you’ll appreciate putting some thought into the plan! 

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