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Porch column base rotted

24K views 17 replies 6 participants last post by  RickO 
#1 ·
Making needed repairs and window replacement before having house painted
..I have one of my porch column bases rotted and in need of replacement. It slightly loose and need to repair before any good size earthquake.. Its sitting on conrete with no protection except paint. House is from 1920's and my parents moved into it in 1948. I know that no repairs of any type have been made or needed to this porch up till today.
I have learned that I need to replace the base with an aluminum plinth. I found what I need from Lawler mfg. Its 12"X12"X1 3/4" has a 6" hole in center for venting. I wil need to add a 1 1/2" wood base above that for the cap to sit on for the correct height for column.
The columns are wood, 7 1/2 in diameter at bottom and sits on a 9" cap.
Do you see any problems with the aluminum plinth with a 6" hole?
Also saw a drawing of a simular set up with an added hole driledl on side of column at top for venting. Should I add that too?
The set up now is not vented which means I guess I would have to drill hole or holes in cap and added wood base. Present rotted second layer base was installed in 4 pieces pie shaped for some reason. And I saw a red wood replacement with cap and it was cut the same way, do you know the reason for the wood to be cut like that?
Since i have 2 columns close together I will be replacing both bases even tho second column shows no rot.
The columns are 7 1/2 in diameter at bottom and sits on a 9" cap.
Can you give any suggestions, cautions or needed info for this repair..
Not sure if I will do the work or have someone do it..




 
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#2 ·
check w/ manufacturer

Check w/ the manufacturer on the load capacity of the plinth, then you or somebody else needs to know what load is on the column (house and snow, if any, wind loads, etc.) A 7" column sitting on a 6" hole does not leave much for bearing area, so that is a concern, too. I have no idea what supports the edge of that 6" hole in the plinth, and something better be. I think you better show an engineer what you have and get a calculation or two done.
 
#3 · (Edited)
Check w/ the manufacturer on the load capacity of the plinth, then you or somebody else needs to know what load is on the column (house and snow, if any, wind loads, etc.) A 7" column sitting on a 6" hole does not leave much for bearing area, so that is a concern, too. I have no idea what supports the edge of that 6" hole in the plinth, and something better be. I think you better show an engineer what you have and get a calculation or two done.
The load capacity of the Aluminum plinth was of concern of mine with the 6" hole. I had called the manufacture and mentioned which plinth I was interested in and weight capacity of it. The answer for the 12X12X 1 3/4" mentioned is 2500 pounds per square inch. I figured 2500 pounds for one plinth was enough, but 2500 per square inch is over kill. If I can find a picture of it I will post it.
A 1 1/2" high by approx. 11"X11" square piece of wood has to sit on the plinth with cap sitting on top of it than column. That will make it the correct height matching the other posts.
No snow in this area, winds never excessive (City of Los Angeles)
I just spoke with the manufacture again and they claim to have had these plinths tested for strength in early stages of production..
www.lawlermfg.com in Alabama. Is sending me one for free to inspect..
 
#4 ·
no bearing area

A 7" post sitting on a 6" hole only has about 10 sqr inches for bearing area. I would wonder if that is enough for the wood you have. I have no idea what the load capacity psi of wood is, esp old, somewhat weakened wood. I'd sure ask an engineer about that; at least look it up online and get a feel. If your 2500 lb load is accurate, that leaves about 250 psi, which sounds like a lot to ask of a piece of wood. Sounds, but I don't know. If the plywood is in between the plinth (what a funny name!) and the column, then that should give more bearing area; maybe at a 45 degree angle? I believe gravel under footers does that. Food to ask a qualified individual about. Good luck, and let us know what you learn. Thanks. john
 
#5 ·
A 7" post sitting on a 6" hole only has about 10 sqr inches for bearing area. I would wonder if that is enough for the wood you have. I have no idea what the load capacity psi of wood is, esp old, somewhat weakened wood. I'd sure ask an engineer about that; at least look it up online and get a feel. If your 2500 lb load is accurate, that leaves about 250 psi, which sounds like a lot to ask of a piece of wood. Sounds, but I don't know. If the plywood is in between the plinth (what a funny name!) and the column, then that should give more bearing area; maybe at a 45 degree angle? I believe gravel under footers does that. Food to ask a qualified individual about. Good luck, and let us know what you learn. Thanks. john
Thanks John, I appreciate your info..
But did you understand what I meant that a one and one half inch thick square 11X11" block of wood will go on top of plinth (hell of a strange name) . Than the cap than the column. 7 1/2" column ( 6" at top 7-1/2" at bottom) will be sitting on the 11X11X1-1/2 square wood.. Just as you see the post in the picture except the aluminum plinth will be at bottom.. Would not use 1/2" plywood as I need the 1-1/2" height. But than can the 11X11X1-1/2" wood handle the 6" hole. Even thinking of a 1/4" aluminum plate on plinth with small hole in it covering the 6" hole..
 
#6 ·
guess

Yes; got it on the plywood "load spreader". Sounds like it will work, but I really don't know at what angle the load will spread into the plywood and then the plinth, so I don't know how much more bearing you will have. My guess is you'd be fine w/ 1 1/2" of plywood, as you'd then have (if 45 degree angle) a 10 1/2" wide post, effectively. That is a lot more area than a 7 1/2" post. Run the area numbers and see what your psi reduces to; I'd still run it by an engineer, as I am making assumptions here about angle and psi that would will take in compression, etc. Have a good one. john
 
#7 ·
Yes; got it on the plywood "load spreader". Sounds like it will work, but I really don't know at what angle the load will spread into the plywood and then the plinth, so I don't know how much more bearing you will have. My guess is you'd be fine w/ 1 1/2" of plywood, as you'd then have (if 45 degree angle) a 10 1/2" wide post, effectively. That is a lot more area than a 7 1/2" post. Run the area numbers and see what your psi reduces to; I'd still run it by an engineer, as I am making assumptions here about angle and psi that would will take in compression, etc. Have a good one. john
Thanks John, will consider checking with an engineer..
 
#9 · (Edited)
Update: I move slow as you can tell by the dates. And I can not believe it was back in May.. WOW !!! time flys...
Have all the parts needed for my repair and replacement of column bases. I will be using a 1/8' aluminum plate not mentioned before. It will sit on top of the aluminum base as shown in picture. I had 4 round caps made and 4 blocks of wood cut to go onto base. All vented from bottom and will be vent at top area as needed. Also have stainless steel screening to keep bugs out of column. All pieces will be screwed together with stainless screws. The round caps cost $15 each to make using my wood, thought that was a super deal. All Wood is the premium douglas fir, not cheap.
Will also be drilling 2 holes in concrete for metal studs that aluminum base will sit over. They will be under 2 corners of base caddy corner from each other to stop any movement from an earthquake. Present column set up never was secured to ground or at top and has gone thru the worst So. Cal. earth quakes without movement since 1948 when my parents moved in. Wood railing is what was holding poles in place, were not secured to ground in any way. Right column was not sucured to top either.
Will be installing these new parts this week in preparation for house painting. Last picture is just loose fit, not installed, as I have other primed pieces ready.

First picture right Column now in place and secured. 2 metal studs in cement under aluminum base at 2 corners caddy corner from each other to keep from sliding .
Porch was extremely easy to lift, cannot be very heavy.
Comments welcomed.






 
#10 · (Edited)
The columns have been done for months now but the painting of the house that followed was completed in Dec. Thought I would show results. I mentioned the front windows would be replaced but decided to keep originals. I added a few strips of wood to top part of windows for added looks. Added red wood to front door area and porch ceiling. The porch surface was ground down and sealed.
1920's Craftman Bungalow






 
#14 ·
Hi Rick. I have a 1925 Victorian home I am getting ready to paint and I live the colors you've chosen for our house. If you could shar the paint code or the name of the paint and brand I would appreciate it.

Thank you,

Jonie
Looks to be light green, dark green and white.
 
#16 ·
Thank you Rick. If you could get the white color that would be fantastic. I don't want to stark of a contrast and with so many variations of white and I like how yours blends with the lighter green.

My husband is getting ready to replace the plinths on our columns. Ours our rotted and sit at the edge of the porch where they get hit with water whenever it rains. I showed him your post and he may have a question or two.
 
#17 ·
Thank you Rick. If you could get the white color that would be fantastic. I don't want to stark of a contrast and with so many variations of white and I like how yours blends with the lighter green.

My husband is getting ready to replace the plinths on our columns. Ours our rotted and sit at the edge of the porch where they get hit with water whenever it rains. I showed him your post and he may have a question or two.
No problem asking questions, I'll do what I can do answer them.
Will have to wait to ask my Wife about the color codes.
 
#18 ·
Jonie, got the info you want.

Benjamin Moore
Moorgard low lustre
Main house color- Code HC98 providence olive
Off White trim-Code 915 cameo white
Dark green- Code HC-135 Lafayette green

You can check these colors out on line, just type in code and color name only. For me, I had to see these colors test painted on the walls, even than I was not sure till the whole wall was painted, than WOW !!!
Good luck,
Rick
 
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