Foundation support with a Tree????

Question

I just looked at a home built in 1900. The foundation is stone and actually looks pretty good (I have not had an inspection yet). The cross beams are being held up with about a 5' tall cut out of a tree. I am not too familiar with buildings that use actual trees to support the house from the basement floor. I thought it was odd and was curious to see if anyone has encountered this. Sorry I did not take a picture but I will probably visit again within the next week.

Also, could there be an issue refinancing this cash purchase since the foundation support is odd (at least it is to me)

Brian Rossiter · Answer

What we're talking about here is a log post in the basement supporting a beam in the first floor framing.  I, too, would like to see a picture.

Ryan is absolutely correct about the structural engineer.  The most likely conclusion will be that the post has a good performance history and would likely continue to perform adequately, but it would still be recommended to replace it with a new post.

There is difficulty in evaluating the load-bearing capacity of historical, non-milled framing members.  The majority of home construction in 1900 was performed experientially and was not engineered.  This wasn't such a big problem at the time, but nowadays there is a great deal of liability in construction.  There are many regulations and codes specifying minimum load requirements that were not seen back then.

Today milled lumber is graded so that the engineer can, with reasonable accuracy, calculate the maximum loads that it can handle and select the most economical member.  A log post could still be used today, but there would be a calculation or supporting documentation to verify it to be adequate.

Roy N. · Answer

I don't see the big deal.  We have lots of old houses here (back as far as the late 1700s) and using unmilled piers (literally tree trunks) in basements was very common in houses prior to the 1930s.

Remember, in these old houses, lumber was milled locally, in many cases on-site, and frequently by hand, so why would you invest effort to mill a support pier that will be unseen in the basement when it makes no difference to its function.

As Brian indicated, houses were built experientially back in {pre}Victorian era and lumber was not graded as it is today - mind you, much of the lumber was of a far higher quality than what we harvest these days.

The key thing to look at is whether these unmilled piers are set directly in the soil or if a footing (likely stone, but possibly concrete) was put underneath it.  Direct in soil, you will need to check for rotting, settlement and deflection in the beam being carried.  If the pier does require new support, it is quite easy to pour a new footing and place a (modern) steel jackpost in-place (and jack any deflection out of the beam if necessary).

Bill Gulley · Answer

Well, Brian nailed that! It's a log, not a tree. If it's tight and there is no regulatory issue and no evidence of failure, leave it alone. IMO

Kevin Martin · Answer

Eddie,

Do you have a picture of it? I'm interested to see what it looks like.

Ryan R. · Answer

Yes, I've seen support beams like that. I live in Texas, where basements are rare, so I've never seen one 5" tall. But yes, bark and all is still on the tree and it looks solid.

I've personally been under houses that were built with cedar tree post as piers. Failed foundations on a couple of these homes were not due to pier failure in and of itself, but rather due to insufficient pier depth and or insufficient crawlspace height and venting.

Here's the question: How long has this tree been acting as a support member? And what is the condition of the foundation associated with it?

You can have a structural engineer come in and take a look at it. He's gonna perform a load calculation, take a look at the support to see if it's exhibiting any stress and then tell you that it's been functioning for 113 years and will probably continue to function for years to come. Then, to cover his rear, he'll tell you that his professional recommendation is to replace it with a new steel beam.

Eddie Werner · Answer

If you looked at a tree that was 10 inches thick and cut out a 5' long portion, that is what is resting on the basement floor and supporting the cross beam in the ceiling of the basement.

I have only seen support beams like this made out of steel which is why I am questioning it.

Kevin Martin · Answer

Is it an actual tree supporting the beams, or is it a timber column/pile?

Ryan R. · Answer

Wood beams are made from trees. So while it may look ugly compared to a milled beam, it's not out of the ordinary for an older home.

I grew up in a house with wooden piers for the foundation. The house was built around the same period. That house still looks good to this day and is still sitting on those trees.

Foundation support with a Tree????

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