Best Proportions For Interior Trim – Why You’re Confused


Have I ever began a post with the word, “ugh?”

I don’t think so.


So, why ugh for the topic of best proportions for interior trim?


Can’t we just use the same proportions for the outside of the house as the inside?

Sometimes. Maybe. Maybe not.

Like I said: Ugh.

The prevailing idea is simply to follow the proportions of the classical orders. Usually, the Doric Order that we used in last week’s post about exterior architectural proportions is used.


After all; being the logical person, I claim to be, here’s my thinking. If we can use the golden ratio to come up with the perfect exterior proportions, can’t we also do that for the interior proportions?


Oh gosh. Maybe. I can really see why you guys are scratching your heads. The situations are endless and the choices are in the thousands.

However, we need to begin somewhere, and rather than the golden ratio, the prevailing reference is to the classical orders when trying to figure out the best proportions for interior trim. And, while I haven’t checked, I imagine that they are inherently related to the golden ratio.


As you may recall from last week, according to William R. Ware, the author of the American Vignola, the entablature is 1/4″ of the length of the column. If there’s a pedestal, the pedestal is 1/3″ the length of the column.


Golden Ratio Proportion - entablature -Vignola's doric order


If we go back and review the video explaining Ware’s proportions, we’ll see that we need to divide the entablature, column and pedestal into 19 equal parts.


via this is carpentry - doric order dimensions 10 foot ceiling - Best Proportions Interior Mouldings


The Doric Order via this is


But, but, but, but, but… this is for a ceiling height of 120″ or a ten-foot ceiling.

Thank you very much.

Yes, yes, yes, yes, yes! ALL ceilings should be at least ten feet high.

But… how many ceilings in residential buildings are at least that high?


And, there’s more concerning these rules of correct proportions for interior trim.


Laurel. Can we take a break for a minute. I have a splitting headache from all of these numbers.


Ya do, huh? Poor dears. Of course you do!!! My head just got up and walked out the other day it was so traumatized from trying to figure out all of this for a post. That is why we did the post about the charming renovation in Kentucky.


However, I hate to break it to you. We aren’t even close to being finished with the best proportions for interior trim.


So, take a break. Go clean out your fridge and come back. Or, better yet, head on over to Nordy’s before their anniversary sale ends! (I almost said annual anniversary sale. lol) It’s ending tonight, the 4th at 11:59PM.


I mean, the post isn’t going anywhere. Take a break and come back when you’re ready.


Okay, is everyone back? Well, never mind. Let’s keep going.

For argument’s sake, lets say that our ceiling height is 120.”

And, with a pedestal, our column diameter is 9.5.” (It’s all in the video from last week.)

You may recall, that in the entablature, the cornice and the frieze are each 3/4 of a diameter high. That would make each of those, 7.125.”

Please don’t stress yourselves out too much. Just go with it for now. This isn’t a matter of life and death. Usually.

Mulitply that by two and we get 14.250 inches. The archatrive is 1/2 a diameter which equals 4.75″ Okay, that gets us to our 19″ for the entire entablature.

The wall portion is 75.75″


And, the Dado or Wainscoting is only 24.25″ high. That means that the “chair rail” or dado or wainscot cap is at 24.25″ high. This also includes the baseboard moulding.


 Best Proportions Interior Mouldings - Metrie Mouldings



Yes, this is for a ceiling height of 10 feet. The wainscoting is only about 1/5th the total height.

I know. What about the chair rail that’s supposed to be at about 32″-36″ on an eight-foot ceiling? Or, one-third of the total height?

Does this mean that on an eight-foot ceiling, our chair rail should be 20% lower than the 10-foot ceiling?

That would make our chair/dado/wainscot rail/cap at only 19.4″ high.

Is that right?


No, I don’t think so. But, neither is an eight-foot ceiling height. And, I have also had to work with seven-foot ceiling heights! Then, what? Do we have a chair rail/wainscot that’s only 16″ high?


Of course, not.

However, yes. a 25.5″ dado height is classically correct for any height ceiling, up to ten feet. (and maybe higher too.) But, just hang on a sec; we’ll be tying up these loose ends, shortly.


french-apartment-moulding-and-parquet-floors - best proportions for Interior trim

One of my favorite images of applied wall mouldings from a French Apartment.


Orac Decor - dado rail - best proportions for Interior trim

Via William Boyle in the UK. A very cool source to check out.


jessica Helgerson - instagram - beautiful mouldings - primed - Best Proportions for Interior Mouldings

I love this proportion in this room in progress by Jessica Helgerson. And, I love how the dado cap dies into the window sill. Brilliant designer by one of my favorite interior designers. And, then look at that crown and ceiling treatment. Yes, that’s right. We should all just give up and go home.

I don’t know if this is Jessica’s design. It could’ve also been an architect, the builder or it was copied from another building. But, the point is… I can give you some rules and guidelines, but when it comes down to it, it takes very careful planning to get this right.

And, there’s also an element of artistry as in all things design.

In addition, it does very much help to have a high ceiling. There’s just that much more to work with. And height in ceilings always lends itself to more drama. (the elegant kind!)


It’s when we have a lower ceiling, that we need to be exceedingly careful with proportion.


The point, of course, is that we have to develop a new set of rules.

And, that’s not just because of the best proportions for interior trim, but because of scale.

We have to scale down those measurements. But, not by a lot. It’s only when we start getting into the super high ceilings that we can afford to let loose with the fancy stuff.


robert-adam-country-houses Osterly Park - photo - Paul Barker - correct proportions for interior mouldingsOsterly Park – photo – Paul Barker via Architectural Digest


Amazing example of neo-classical architecture by Robert Adam. And there’s our Corinthian order.


This is the big difference between exterior dimensions and interior dimensions. Scale and proportion on an exterior are related to the building as a whole entity.


The interior scale and proportion is related to the human form which is also related to the size of the furnishings. Or, at least that’s how I see it.


So, Laurel, in your post that’s ALL about wainscoting, you state that the ideal height for a chair rail for an eight-foot ceiling is at about 35.” That’s what you had in your old home and you said that it was perfect.


So, even if you did the chair rail at 24″ like for the ten-foot ceiling, you are still 11″ off.


Which is it? They both can’t be right.


Well, actually, yes, they can.

The lower dado rail that’s akin to Vignola’s classical order is absolutely correct, as we saw in the three examples above.


best proportions for Interior trim

Gorgeous Parisian apartment. Original source unknown.


via the-houses-of-james-means - best proportions for interior mouldings

via Architectural Design blog – From The Houses of James Means

Oh, how I love architectural drawings. This was always my favorite thing to do when I was in design school. This elevation depicts a full paneled wall and a chair rail that’s at about 36″. I know that because I’m presuming that the window seat is at about 18″.

Therefore, the lower dado height of about 24″ is correct as is the taller chair rail that came into being most likely in the 18th century. It was built at that height to protect the walls from the furniture that often leaned up against it.


And, it was at about that height whether the ceiling was seven feet or 17 feet!


The only exception, I can think of, would be a double panel moulding or one meant to go up about three-quarters up the wall.


2 bedroom blues board and batten wainscoting - correct proportions for interior mouldings

Something like this.


Jessica Helgerson - instagram - Best Proportions for Interior Trim

Another beauty by Jessica Helgerson from her Insta showing a gorgeous tall wainscoting paneling.

This is what makes me a little bit nutso.


Well, one thing. haha.

Just because the room keeps getting taller doesn’t mean that the moulding keeps getting bigger and bigger. It doesn’t. There might be more layers and more of it, but the moulding itself isn’t generally that much larger.

There would be other things going on in the second story, like clerestory windows. And there might be two cornices. But, let’s not go there right now, because how many of us have a 20 foot ceiling?


Most of us have an eight – ten foot ceiling height. But, the majority of us have an eight foot ceiling.


So, for the sake of us not completely losing our minds, I’m going to focus on that number.

But, here’s another problem.

I read in several articles that to figure out the height of the baseboard, just make it 7% of the wall height.


The 7% solution. When sizing a baseboard in a traditional-style home, a good starting point is to use a ratio of 7%. So if your ceiling height is 8 feet high, try a baseboard that’s about 7 inches tall.


Therefore, if our wall is 96″ high, that means that our baseboard is 6.72″.  It’s a little tall. But, I would say 5.5″-6″ for an eight-foot ceiling. Therefore, closer to 6%.


But, what concerns me even more is that they say the same dimension is good for the crown moulding.


No. The crown for an eight-foot ceiling would be about half of that!

And to be clear, this is how one measures a crown moulding.

via easy crown moulding - crown moulding dimensions.Easy Crown Moulding


crown mouldings dykes lumber


Above are three beautiful crown moulding profiles from Dykes Lumber. The one in the middle is the one I used in my townhouse. It was perfect for our eight-foot ceiling.

One important thing to remember amongst many. There’s a lot of discussion about a cornice and then a crown moulding. While there are some petite cornices, usually, those are reserved for rooms with at least a nine-foot ceiling.

However, below is a gorgeous example of a 10-foot ceiling with a classic cornice and crown moulding combination.

via Remodelista - cornice and crown moulding - 10-foot-ceiling-height-ShadowArch-Riverside-Drive-Living - best proportions for interior trim

via Remodelista


Incidentally, the wall color is Benjamin Moore Marilyn’s Dress, one of the 144 beautiful paint colors in the Laurel Home Paint, Palette and Home Furnishings Collection. 


correct proportions for interior mouldings - wainscoting from Dykes Lumber


These are the mouldings we used for our wainscoting applied wall trim. I loved those too!

The questions is… How can we figure out the proportions? Well, in this case, I’ve done so many eight-foot ceilings, I pretty much know. But, I’m going to attempt to make it more scientific.

Here’s what I’ve done to find the correct proportions for interior trim for an eight-foot ceiling.


This is from the video we saw on last Sunday’s post. You can go back to review it by clicking here.


via this is carpentry - doric order dimensions 10 foot ceiling

Above is the Doric Order for a ten-foot ceiling via This is Carpentry.


If we chop off the pedestal, we’re very close to the eight-foot ceiling height.

So, that’s what I did by submerging it under the floor.


best proportions for Interior mouldings 8-ft Ceiling Based on Doric Order


You can see it faintly below the floor line. By submerging the pedestal, we are left with 15 = parts measuring approximately 6 5/16″ of an inch or roughly 6.33″.

By the way, please be feel confident that the scale here is eight feet; because when I made my graphic, I slid a layer of virtual graph paper behind everything on picmonkey. Two squares equaled one foot. When I was finished, I just deleted that layer. That way we aren’t looking at a grid.

It works out very nicely.  You can see on the right side of the graphic the corresponding placement and sizes for the applied wall mouldings.

You probably won’t have a picture rail for an eight-foot ceiling, but I think if you do a smallish crown, no larger than 3″ and a low chair rail, no higher than 32″, you could have one. But, it’s not necessary.


The truth of the matter is that there is no exact measurement for any of your mouldings. There are only guidelines for the best proportions for interior trim


Once, we have the eight-foot dimensions set, all we need to do is increase them by about 10% for each additional foot.

But, here’s the thing.

I belong to the school, if there is such a thing that when it comes to mouldings, a little too small is much better than a little too big. And, when I thought about it some more, some of the dimensions don’t really change much if at all even though the wall is taller.

Below, I made a cheat-sheet graphic to show approximate sizes and heights for the chair and picture rails for eight, nine and ten foot ceilings.


cheat sheet for best proportions for Interior trim, mouldings and dimensions

Of course, there’s still so much more to cover. But, for more about mouldings, please check out these posts.

All about Wainscoting

Can a modern style home mix with traditiional mouldings?

Boxy, Boring Room is there any Hope?

How To Make Small Rooms Look Bigger

Rooms with Great Bones Architectural Mouldings

Architectural Plaster Ceiling Designs


I just came across this beautiful English Country Home. A lot of these guidelines have been put into play, but you can see beautiful proportions for all of the architectural elements, plus the interior wall mouldings. Gorgeous property too!


Well, I think that’s it for now. I hope that some of this info about the best proportions for interior mouldings has been helpful. I know that it’s a lot to take in, but my best closing bit of advice is to make a mock up of what you’re planning to do.  Some contractors I’ve worked with have done this and it’s very helpful to see it in real scale first before committing to an entire room.



PS: Please check out the great hot sales this weekend and also only hours left until the Nordy’s Anniversary sale is over until next summer.


Welcome To Laurel Home!


Hi, I’m Laurel, and Laurel Home is the website and blog for Laurel Bern Interiors.
I’ve been creating new-traditional interiors since 1988. The blog is where I share all.

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