Porch columns and porch posts support a beam that supports the porch roof.
This may sound very simple but this is a crucial area that is frequently done wrong by carpenters today.
The design is actually very simple yet carpenters continue to mess up a good design.
Here we will discuss two basic types of porch supports: columns and posts. Entire books are written on this subject which is quite complicated but here I will show you the basics you need to know to avoid making common mistakes.
Columns are round and piers are square but we will use the term column interchangeably here. Porch posts however are narrower and the wood is usually turned – exclusive to Victorian homes.
Round columns are based on the Classical Orders of Design. There are features a column must have and strict rules for their exact location. There are formulas to determine the correct proportion based on the height of the column. There must not be any deviation from the rules of a properly designed column. Reputable manufacturers will state that their columns are “architecturally correct”.
Turned Victorian porch posts do NOT have strict rules although there are good and bad designs but that is not important for this article.
A porch column attached to a porch roof beam may seem simple but most carpenters do it wrong.
Starting from the bottom. The base of the column or post must be no wider than the porch pier supporting it.
The top of the column or post must support the base of the porch beam and the shaft of the column or post must be exactly the same diameter of the beam. No exceptions.
The shaft of the column is tapered and the top of the shaft (neck) must match the width of the beam it supports. The capital (top) extends outwards past the beam.
This is how a column must line up to the porch beam.
This is 100% WRONG. The contractor and architect both should end up in a medieval prison in a cold climate.
This is WRONG!! Never do this. This carpenter’s wife should be plagued with runners in her hose for life.
Turned porch posts line up the same way but the porch beam is not as wide. If your original porch posts are missing, you must have new posts milled with the top portion that is square – not turned be the same width of the porch beam. This is an easy way to determine the size of the original posts.
Turned porch posts are at least 4″ thick at the square (non turned ends). This matches the porch beam exactly.
Please ignore the vinyl bead board. I will find an example on a nicer house.
Here is a very good video by Brent Hull on Building Tapered Columns.
You can’t explain it better than this!
The following books are companion books and I recommend purchasing both of them. You will be very happy you did.
Both of these books are equally important and compliment each other – not duplicate.
Both of these books are equally important and compliment each other – not duplicate.
On the red column above, is it appropriate to paint an accent color on any of the details? If so, which ones? Thanks so much for all your information!
It depends on the house. If more of an Arts & Crafts then no. Otherwise on a pre 1920 house I would only accent the top and bottom band/ring and the small band several inches below the top band. Use either the body color or the sash color. I usually use the sash color for all accenting. I do this with a dark trim but if a white or cream I recommend not accenting for it will be too in-your-face looking.
“This is 100% WRONG. The contractor and architect both should end up in a medieval prison in a cold climate.”
I absolutely love your humor.
So happy I have discovered you website! We are redoing our porch (1906 World Fair brick house with Tudor gables) by replacing the actual horrifying rod iron vines (!!!!!!) and putting wood pillars. We might book a zoom consolation with you to make sure we will get things right.
Thank you for helping us be aware of how things used to be done and appreciate the true beauty of historic homes.
I am in the middle of a old house porch remodel and am worried.
I did the calculations for the right diameter columns in relation to the height of my porch. In my case a 12” (11 5/8) diameter gives me a 9.5 ratio of diameter to height, right in between Ionic and Corinthian. Good.
The next column size down was 10” (9) and would give a ratio of over 11 and beyond any of the orders. I feel these would be too skinny for my porch.
The problem however is that the bases supplied with 12” columns are quite large and now my measurements indicate there will be several inches of overhang over the porch on the corners. My contractor said we could simply cheat them in, but I fear this will result in your picture above where the capital is not correctly aligned.
Any suggestions? I fear having to rebuy all of my columns, and also fear the next size down may be too skinny. Thanks
I would always go larger instead of smaller but the bases should still have 1″ of porch floor showing at the edge. You may need to cheat a bit but I would contact the column manufacturer for correct sizing is complicated. Sorry for not being able to help. The experts on this are Gary Katz and Brent Hull. You may want to do a search on them.