Foundation Site Preparation - Roots
Foundation Site Preparation - Roots
(OP)
We are constructing a timber structure building. The foundation soil is sandy gravel with some silts and clay containing very irregular boulders 0.5 m diameter occasionally to 1 m. We have removed the top soil and see some roots (some decayed but most are fresh roots).
The question is what size of root can be tolerated under the foundation. If we want to get rid of all roots we may need to excavate 1.2 m down, which is very costly for the private owner.
I would appreciate a feedback, if possible.
The question is what size of root can be tolerated under the foundation. If we want to get rid of all roots we may need to excavate 1.2 m down, which is very costly for the private owner.
I would appreciate a feedback, if possible.





RE: Foundation Site Preparation - Roots
If I had to set a root size to remove from under a house foundation site, maybe a diameter of 5 cm and larger might be cause for removal, but not for under a floor slab. Even that is quite fussy, especially if scattered. Earth has a way of arching over weak places, like animal burrows.
However, boulders are another thing, especially if their former location was not well compacted. Under a building corner that condition can present itself later with cracks.
RE: Foundation Site Preparation - Roots
WI east side store was being built in early 60's, they called and wanted a sample of soil that the floor slabs would sit on. We sent it. That contained some plant roots about 1 mm diameter, as well as a few worm holes. That office bound "engineer" complained that the presence of roots would not be tolerated. Somehow we managed to convince that person all would be OK, and of course it was. It goes to show how non-field guys can cause unnecessary delays on jobs.
RE: Foundation Site Preparation - Roots
Agree also that the boulders are an issue. Several issues exist with boulders....load distribution, unknown voids, etc.
RE: Foundation Site Preparation - Roots
RE: Foundation Site Preparation - Roots