Minimum distance, grade to beam

[MountainDon]

I know this answer, or at least did once. My brain's playing tricks. (forgetting stuff). I have a number in mind, but require confirmation.

What's the minimum distance from finished grade to the lowest non-treated wood (as in beam or built-up beam in a post/pier foundation)?

John has posted this in response to at least one other inquiry.    Can't search it up.  

[MountainDon]

I found the answer, though it's not what I thought it was.   Section R319 of the IRC 2003 states, "wood girders when closer than 12 inches to the exposed ground in crawl spaces or unexcavated area located within the periphery of the building foundation." ...require use of an approved species of wood pressure treated...

I thought it was less; 6 inches.    

[Amanda_931]

18" is what's in my mind.

In ground termite country.

Not sure if that's true nationwide or even still true here.

[MountainDon]

Hi Amanda.

I believe 18" is listed as the min distance, grade to floor joist bottom edge.

Good to see you. How's things?

[Amanda_931]

Kind of a mess.

I have been doing some quilting.

And Egoscue exercises for my knee.

[MountainDon]

Look after the knees; hard to get around without them.    
Best wishes.

[glenn kangiser]

Hi Amanda.  Nice to see you here.  Hope your knee gets better.

[desdawg]

Amanda I had been wondering where you went since I bopped back in here myself. Good to see you posting. I know people get busy and come and go. I do that myself.

[glenn kangiser]

crawl spaces or [highlight]unexcavated[/highlight] area

What if it's excavated?

[ScottA]

I'm getting ready to buy the lumber for my beams so I have a similar question. My block piers are about 16" above grade which exceeds the 12" requirment but I've always heard that wood that contacts concrete should be treated. Do I need to use treated wood or no?

Scott

[MikeT]

Scott, that is my understanding and that is what I am doing.  Depending on the situation, I have also heard of separating the wood from the concrete with tar paper.  I would think that would be better vertically than if it were vertical contact.

mt

[MountainDon]

If you use some type of steel (Simpson) bracket/mount that breaks the concrete to wood contact. Ditto for an asphalt shingle or similar.

Mu solution is having the concrete block piers end no more than one block above ground and using PT posts up from there, with post bases on the block supporting the built up beam.


Glenn, I wondered about that [highlight]un[/highlight]excavated word too. It seems to me to make no difference how the clearance is achieved.  :-/  

One of my ways around the sloping ground where we have decided to build, finally  , would be to excavate the high ground a little. That'll happen some when we push over the trees and remove the root stem.  It's only a matter of maybe 12 inches; that;ll put the cabin end at low ground about 3 feet above grade.

I'm going to run level lines this weekend and will know more after that.

[glenn kangiser]

Don, my point is -- say if the whole house is excavated foundation and crawlspace what is to prevent one from having 2 inches clearance to the excavated crawlspace area soil -- seems the code would not prevent this if you get technical on them -- I haven't read it all and am going from the quote above.

I'm not saying it's practical.  I just like to argue incomplete issues I find in the code.  I have won on major plumbing issues.  Inspector was pi$$ed but I won.  His bosses sided with me after a building department meeting.

[ScottA]

The way some inspectors interpret code is almost comical. I've had new inspectors tell me stuff I've been doing for 20 years doesn't meet code. I'd tell them- "So what your saying is that all the houses in this subdivision need to be torn down and rebuilt?" That will usually shut them up.

Scott

[glenn kangiser]

I used schedule 40 abs about 12 inches underground outside the foundation.  Practice in Fresno county for 20 years previous was to make you use cast iron if 12 inches or less from the surface even on a residence.  I told them code said if it was approved for use in the walls it could be used 12 inches or less and even above the surface.  I prevailed.  I don't think it has changed since.  Fresno changed their policy.

I just didn't want to buy 12 inches of cast iron pipe to please the inspector.

[ScottA]

Glen you where correct. We had the same issue for years. Seems the cast iron makers lobbied pretty hard to keep their products in use when plastic pipe came out. Took several years before we could use PVC or ABS underground at all. Now that's all anyone uses except on heavy commercial work.
Scott