Post and Beam Foundation Question?

[oakey]

I got my site prepped and fixing to start digging some holes for my foundation. I am using the mild climate footing meathod from the post and beam foundation page. As far as the crushed stome underlayment goes, the only material I can find in my area is some stone that is sold at a garden center near me. They called it all purpose stone "natural crushed stone". I can buy it by the truck load. It is gravel like with various sized peaces, not big or very small, maybe 1/2" to 3/4" size. Would this suffice as "crushed rock" for the underlayment?

[rocking23nf]

I would use something like a gravel/sand mix myself. You can tamp it down nice and flat.

I would like to see what some other members think though.

[oakey]

I had thought about that, doing a sand mix with it. Thats the bad part about being waaay out. No road dept or concrete centers around to supply what I need.

[MountainDon]

The sand and gravel mix at my local rock yard would be totally unsuitable; can't say what others may have.  The reason their mix would be unsuitable is the gravel part of that is not crushed stone, it is river gravel. ncient rivers mind you but river rock all the same. You need crushed rock with all the angular edges for this type of foundation. When tamped they will lock together, sort of. River rock never will and that is suitable for some things, like mixing concrete.

[John Raabe]

What you want is something that is solid and once settled will stay and carry the forces down and out into the underlying soil. Angular machine crushed sharp rock is almost as solid as concrete when placed in a confined space such as a footing hole. You do not want something round like river rock. Sharp clean sand might be alright if you can compact it. Still, I would vote for crushed rock or concrete.

[cmsilvay]

I would look in the phone books for someone who does driveways or parking lots and ask them for the materail. Sometimes its called diffeernt names in certain areas. I know in my area the term for base is SB and then followed by a number for size. When I lived up north we just called it blend if it had dust in it and clean if it had no fines in it.

[Texas Tornado]

Down here it is called "road base".

[MountainDon]

, not big or very small, maybe 1/2" to 3/4" size. Would this suffice as "crushed rock" for the underlayment?

As long as it is crushed, edges and corners nor smooth, use it. Doesn't matter what it is called. You want crushed.

[Okie_Bob]

Oakey, can I ask where you are building? Down here we don't usually consider 'frost' lines when designing foundations. When it does freeze, it only stays below freezing a few hours max so most people don't worry about it. I've actually run water lines (pvc) on top of the ground and never had them freeze in some or our worst winters.
When I built my house I used pier and beam and the footings were only about 18" deep and only because of some very sorry soil. Foundation has been in for about 5 years and it still looks great.
Okie Bob