Residential Footing vs. Tree Roots

[gdubb08]

Does anyone know of a good guide to residential foundation repair in regard to possible tree root damage. Photo attached.

Thx in advance,

G

 

[msquared48]

1. Chainsaw 101
2. How to use a Shovel
3. Concrete Crack Repair

Seriously though, have you noticed any damage and if so, what damage?

It looks like an old cedar and they love water and foundation/downspout drain lines. Probably have more compromised than just the foundation here.

Mike McCann
MMC Engineering

 

[gdubb08]

I don't know. I am going to go look at it tomorrow. The tree is planned to be cut down. No stump grinding, just cut.

 

[hokie66]

The photos do show cracking below the openings in the concrete wall, although not sure how they relate to the tree location. A tree that size should never be so close to a building. Good plan to remove it. The cracks may just need sealing.

 

[msquared48]

Yes, obviously - sorry but I didn't notice the other three pictures.

There also appears to be a block-out under the footing in that area for what appears to be cable passage in addition to the crawlspace vent that would weaken the wall section too.

I agree with Hokie here, just remove the tree and patch and sack the concrete wall.

Mike McCann
MMC Engineering

 

[gdubb08]

Looked at the footing today. A 6'-6" section directly in front of the tree was cracked on both sides of the tree. It appeared to be relatively unmoved, but rotated about 1/8" away from the house at the top which leads me to believe the foundation was being pushed at the base toward the house. We dug down inside the crawl and lots of roots. A floor beam was at the middle of the footing span and the beam and floor joists had been pushed up (a bit) as a result. I don't feel it is a deal breaker. My thoughts are to install a steel plate on each side of the section and install anchors to tie the short span to the rest of the footing so that once the tree is removed and the roots rot if there is any void below the footing will act as a beam. I want to install either a shim or grout under the plate prior to anchor torque. The floor does not bear on this wall, only the roof.

 

[eRok]

Also, keep in mind that that tree drinks a lot of water - if the house is in an area prone to expansive soils, you should expect to see some foundation movement in that area in the next year or so associated with the changing moisture content of the soil.

 

[gdubb08]

Not much clay in coastal PACNW..

 

[a2mfk]

In my experience, you are looking at a VERY long term maintenance issue if anything. Tree roots decompose VERY slowly when fully buried in the soil. Even as they decompose, you are talking about a very small volume change over a long period of time, and just about any decent footing will span over smaller roots. The worse tree root damage I have seen is when people try to remove them when they are already under a foundation, or the tree falls over and causes the roots to disturb the foundation.

Those cracks look pretty minor given how large that tree was.