Basement Support Post Cracks

[Deleted]

I had a feverish dream (nightmare) the other night about my house falling into the basement...

I've been wondering about something that must have spurred on the dream.

My house was built in 1930 and is all wood built over a cement block basement with a concrete floor. 

In 1968, a large wooden support post and what I believe they call a jack post were installed to shore up the main joist (?) that spans the center of the house. I know that's when they were installed because someone wrote the date on them.

The jack post is a wood post with a metal plate on top with what looks like a large car jack on the top. It's fine and shows no damage. It's in the center of the house and I assume takes most of the weight.

The other wooden post is cracked vertically from the top to about 1/2 way down. I assume it cracked from the weight of the house settling over time. 

Does the cracked post need to be replaced? 

I notice they make some all-metal jack posts. Could I put one of those next to it and just crank it into place to take the weight in case the post one day completely fails? 

I guess I don't know if I actually have a structural issue or not. I don't have sloping floors or any stability issues. Just that crack bugs me when I see it... ??

[bobosensei]

Did they say anything about it in the inspection?

[tskeeter]

A vertical crack in a post does not affect the load carrying ability of the post.  A demonstration of this is that multiple 2X4’s are nailed together to act as posts when walls are framed.  The result is a post with at least one crack that runs completely from the top of the post to the bottom.

If the crack makes you uncomfortable, the all metal jack posts aren’t very expensive.  According to the Home Depot site, they’re about $65.  You’re certainly handy enough that you and your DS can slip one in.  Then you have piece of mind that the house will stay up.

I suspect that the reason you have two unevenly spaced support columns in your basement is that the column in the center of your main floor joist reduces the span of the main joist.  Essentially making the floor joist stronger.  The second column probably pushes up a low spot in the floor above.

[Deleted]

Aug 11, 2020 19:49:54 GMT -5 tskeeter said:

A vertical crack in a post does not affect the load carrying ability of the post.  A demonstration of this is that multiple 2X4’s are nailed together to act as posts when walls are framed.  The result is a post with at least one crack that runs completely from the top of the post to the bottom.

If the crack makes you uncomfortable, the all metal jack posts aren’t very expensive.  According to the Home Depot site, they’re about $65.  You’re certainly handy enough that you and your DS can slip one in.  Then you have piece of mind that the house will stay up.

I suspect that the reason you have two unevenly spaced support columns in your basement is that the column in the center of your main floor joist reduces the span of the main joist.  Essentially making the floor joist stronger.  The second column probably pushes up a low spot in the floor above.

Thank you! That makes me feel a lot better.

I logically assumed that while the post may take some load now that things have settled over the years, it wasn't there when the house was built so it's got to be more for floor leveling versus actually holding up the house. But, the crack made me wonder if it's still effective. 

This house was made with wood milled locally and has the big wide hardwood floors laid at a diagonal with some big hunky joists milled back when there were older growth trees logged. 

The post is below my bedroom door and I can see where some big cracks were repaired in the past. I'd assume he got tired of fixing cracks and decided to shore up the floor. 

The one with the metal jack on top is interesting. In reading, it says you aren't supposed to use those jacks as a permanent support. Well, shit, it's been there since 1968 and appears to still be doing the job just fine! 

[tskeeter]

Aug 11, 2020 20:23:43 GMT -5 @shastasnewlife said:

Aug 11, 2020 19:49:54 GMT -5 tskeeter said:

A vertical crack in a post does not affect the load carrying ability of the post.  A demonstration of this is that multiple 2X4’s are nailed together to act as posts when walls are framed.  The result is a post with at least one crack that runs completely from the top of the post to the bottom.

If the crack makes you uncomfortable, the all metal jack posts aren’t very expensive.  According to the Home Depot site, they’re about $65.  You’re certainly handy enough that you and your DS can slip one in.  Then you have piece of mind that the house will stay up.

I suspect that the reason you have two unevenly spaced support columns in your basement is that the column in the center of your main floor joist reduces the span of the main joist.  Essentially making the floor joist stronger.  The second column probably pushes up a low spot in the floor above.

Thank you! That makes me feel a lot better.

I logically assumed that while the post may take some load now that things have settled over the years, it wasn't there when the house was built so it's got to be more for floor leveling versus actually holding up the house. But, the crack made me wonder if it's still effective. 

This house was made with wood milled locally and has the big wide hardwood floors laid at a diagonal with some big hunky joists milled back when there were older growth trees logged. 

The post is below my bedroom door and I can see where some big cracks were repaired in the past. I'd assume he got tired of fixing cracks and decided to shore up the floor. 

The one with the metal jack on top is interesting. In reading, it says you aren't supposed to use those jacks as a permanent support. Well, shit, it's been there since 1968 and appears to still be doing the job just fine! 

When your house was built, there really weren’t any building codes to speak of.  Things like how big a beam to use and what variety of tree the beam should be cut from were left up to the builder and local practice.  Some builder’s judgement was better than others and today’s access to a wider selection of lumber from all over the country has improved how many homes are constructed (any poorly built older homes fell down years ago).

Combine the absence of building codes with changes in our lifestyles and what was considered adequate doesn’t quite cut it any more.  In 1930, the residents of your house didn’t have a couple of hundred pounds of refrigerator and contents creating a spot load on the floor, or a bathtub that will hold 300 pounds of water.  These increased loads can crack old beams or cause beams and other structural elements of a house to sag, shift, or pull loose.  As with your house, structural modifications are often done to compensate for shortcomings that have become obvious since the original construction.

[Deleted]

Yes, when they added on the bathroom, I noticed they put the tub out where it's nearly ground level versus over the open basement space.

The jack post is under wall between the kitchen and the office. The kitchen floor is very, very solid. I think they put thick plywood over the hardwood floor under the "beautiful" linoleum. Perhaps the jack post is there to hold the extra weight of the additional wood.

Thankfully, the entire house was rewired in the late 1980s. There are inspection stickers in what looks like a newer power panel dated then and the entire house has Romex. I was glad, because that was something I assumed I might have to do. I can deal with lots of old house things, but ancient wiring isn't one of them.