Frostline / Foundation Depth

[knopfarrow]

I've looked through the referral links subforum and spent an hour on Google. Can't seem to find an online resource that tells me how deep I'll need to dig my foundation. Does such a thing exist, or is it only available with an in-person visit to the county building department?

[Don_P]

Theirs is the only opinion that matters, give them a call.

[rick91351]

I've looked through the referral links subforum and spent an hour on Google. Can't seem to find an online resource that tells me how deep I'll need to dig my foundation. Does such a thing exist, or is it only available with an in-person visit to the county building department?

I agree with Don_P.  Just give them a call.  If there is a close excavator he will know - it is sure not a secret.....  Then if your are going to have to have your plains stamps as I think last year you said because of the snows up there you felt it would need engineering.  Your engineer will have to spec it out to the local conditions..was it Snohomish County? If so try 425-388-3311

[rick91351]

BTW I would bet it would be the top of your footing would have to be 18" or 20" to top of grade. I would bet they will call for 8 inch footing with two runs of 1/2 inch or 5/8 rebar......

[Redoverfarm]

I've looked through the referral links subforum and spent an hour on Google. Can't seem to find an online resource that tells me how deep I'll need to dig my foundation. Does such a thing exist, or is it only available with an in-person visit to the county building department?

It varies from location to location depending on where you are.  Once that is determined you dig to where the bottom of the footer is below that distance.  If you want to play it a little safer you can set the top of the footer at that distance but the heave that occurs will only affect the foundation if it is able to push up on the bottom of the footer. 

Here is a map that estimates the frost line just to give you some idea. 

http://sqfoot.com/pdf/US_Map_Frost_DepthAVG.pdf

[rick91351]

Pretty much anywhere you go unless it is like 'Frost Bite Falls Minnesota'. You work off of 24 inch stem wall forms. Up here in our lots more stringent winter codes it is still same size footing and stem wall we would pour down in the valley.  Just up here was just bury them a little deeper - requirement top of footing up.  On our house we ended up with six inches showing when we back filled.  Which made us slope our yard away from the house pretty drastically but not anything too weird.