Protection of softwood timber below ground level 2

[raligt]

We are working with an architect who wants to use timber posts to support an entrance canopy. The architect does not want to see the bottom of the post. We have proposed the attached detail, where the ground level finish is gravel. i am concerned about the softwood timber potentially degrading below ground. Is there a better detail which would work? or is the note regarding timber treatment enough to prevent degradation?

Thoughts appreciated.

 

[XR250]

Many Arch's in my area specify these. You could just back fill to the top of the plastic. Is the lumber treated?

https://www.strongtie.com/retrofitpostbases_postbases/cptz_base/p/cptz

 

[jerseyshore]

Count me in as one of those people who always specify that a timber post is not to be in contact with the ground. I count gravel in there as well, although I am interested if people have buried a post like this in gravel and had no issues long term.

XR250 posted a common Simpson connector that I see used for the hidden look. I've also done some similar hidden knife-plate details like that before. Still don't want that wood near the ground.

 

[GeorgeTheCivilEngineer]

Tell the architect to get back in the real world. Even medieval timber frame buildings were built off a cill beam on a raised stone/masonry plinth. Timber in contact in the ground is ok for fence posts, car ports and short lived structures. If this is a house or other permanent structure then it's a no.

150mm above ground level and clad the bottom 150mm in treated timber:

 

[BAretired]

I agree with George. The timber must not be in contact with ground.

 

[phamENG]

Permanent wood foundations do exist, but they're a regional thing. Wet/ high water table and/or lots of termites I'd say no. Lots of engineers don't like them, and for good reason, but they can be done. Here in the US there is a special lumber treatment and marking scheme for the lumber used below grade as well as lots of water proofing and water control details.

With all that said, I'd follow George's advice. He's the closest to you geographically, and is the most likely to give you his advice based on "local" conditions.