Are trees 5 feet from property a serious threat to foundation?

Question

There is a tree within five feet of a property I have under contract. It's got a noticeable lean to it and the unanimous advice I've received is to remove it. However, what is more concerning to me is whether it is impacting the foundation. From what I've learned so far that won't be known for sure until the tree is removed. Does that sound right? The home inspector wrote in his report that it could be affecting the foundation given its proximity, but when I spoke with him he said that there were no visible signs of a problem and it was probably not much of a risk. He did suggest that I have an arborist take a look though. So I had a couple arborists take a look. One said there was a 50/50 chance it could be affecting the foundation. Needless to say, that was rather alarming. The second didn't give a percentage, but thought that it was not a problem. And for what it's worth the general contractor I'm working with said that the foundation seems fine to him. Is there anything else I can do to be more certain? Do any of you biggerpockets veterans have any experience with this sort of thing? I'm having a hard time judging the level of risk involved here

Thanks

Rob

Thanks

Rob

Account Closed · Answer

@Rob Condy, I presume that you are talking about a tree of some significance? If it's a tree that has been around for some time and there are no visible signs of it affecting the foundation, it seems unlikely that it will at this juncture (I'm presuming that the foundation is visible from within the crawlspace/basement).

John Teachout · Answer

I operate a tree service part time and have cut down numerous trees in proximity to structures. Any tree that diameter should not be that close to a structure. If the diameter is accurate, then I think the estimated age and height are not accurate. Oaks don't grow that fast and most of that diameter would be 7 to 9 stories high, not three. (unless it's been repeatedly topped)

As far as determining damage to the foundation after the tree is cut down, that makes no sense at all. If the foundation is damaged, it should be able to be determined whether the tree is there or not. But don't wait until there's damage to do something.

Rob C. · Answer

Thanks for the response Account Closed, and apologies for the delayed acknowledgement. Yes, it's an Oak probably about 30 inches diameter and maybe 3 stories high at the moment. Probably about 20-30 years old. I did quite a bit of research on the subject, and talked to a couple different arborists, and it sounds low risk. Yes, the foundation is visible from the crawlspace, and my home inspector didn't recognize any problem with the foundation. Neither did the other arborists. I'm planning to have it removed for about $2000.

For what it's worth, in my original post I had said I didn't think it would be possible to tell if there are any foundation problems until after the tree is removed; I've since learned that's not the case. Removing the tree won't reveal any more signs of foundation problem than is already visible. If any unforeseen complications arise, I'll follow up on this thread for the sake of others curious about the subject in the future.

thanks again, Rob

Ryland Taniguchi · Answer

check your zoning and set-back requirements as they usually have distance requirements from trees.

Rob C. · Answer

thanks for the feedback @John Teachout. I just realized I overlooked your response. I will doublecheck on the diameter now that you mention it. Strange... I honestly don't know personally what the age is but have been told 20-30 years from one arborist. Might be misinformation.

@Jd Martin, I'm planning to take it down, and agree with pretty much all you said

JD Martin · Answer

I would not leave a tree that big or of that species that close to a house that I owned. I have a lot of oaks on my personal property and they develop a fair amount of dead branches that like to come crashing down during storms; one of them, from a tree that was 20 feet from my house (and is now a whole bunch of logs) sent one down through my roof like a javelin. And these are healthy trees.

Roots close to a foundation can cause damage in lots of ways, including growing straight through the foundation if going around it is not easy. Roots can penetrate cast iron pipes, so they can go through cinder blocks or concrete piers like a knife through butter. I'm guessing the biggest thing you're looking for is a reason not to take it down because of cost, and removing a tree can be costly, but it might be less than the $1000 deductible you may end up with if it damages your roof, gutters, siding or windows (aside from the foundation) with wayward debris.

Rob C. · Answer

Thanks for the input @Fred Heller. Good advice about foundation companies offering to assess for free. Do you know if that is typically the case for properties under contract, or already owned? Those two ways you cited for damage are what I learned recently as well. However, I was also told that even if a tree's roots are growing under the foundation, they may be doing so in a way that does not necessarily cause damage. It is further possible if such a tree with harmless roots under the foundation is cut down then those roots could decay over time, which could possibly cause foundation damage (but that is a low percentage chance from what I gather). Like Fred, I don't claim to be in expert here, and am just relaying what I've heard from the guys who make a living with trees.

Fred Heller · Answer

If the tree has already compromised the foundation, there should be some evidence of that. Barring that, chances are the foundation is fine. The only way to know for sure is to have the foundation inspected. Most of the foundation companies around here will do that for free.

Regarding the original question, it is my understanding that trees can damage the foundation in one of two ways: 1) by sucking all the water out of the ground near it. The wet ground/dry ground balance is one way a foundation can be damaged, and/or 2) by growing roots directly under the foundation.

I'm not an expert, but that's what I've heard from the people who are supposed to be the experts.

Jeff B. · Answer

I have a LARGE tree on the property line and only three ft offset.  No signs whatsoever of structural damage.

Factors:

• age of property
• age of tree
• type of tree (a redwood has surface roots and spreads out massively, while others have a 'tap' root descending ~1/3 the height of the visible portion of the tree

Are trees 5 feet from property a serious threat to foundation?

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