Home Repair forum - Re: Frost line depth map?

Author

Re: Frost line depth map?

slatts

2006-05-27, 2:21 am

Tim and Steph Wrote:
> I live in Fairfax, VT, zip is 05454. I'm building a deck, and I'm going
> to
> be pouring concrete into sonotubes. Everything I've read states that
> the
> bottom of the sonotube must be below the frost line. Nowhere does it
> state
> how deep that might be. I assume that the USDA or the department of
> the
> Interior must have a map on this kinda thing, but for the life of me,
> I
> can't find it. Any ideas?

I live in Toronto. We're around the same latitude, and 42" is the
standard here. Building codes must err well on the safe side, so 42"
is probably more than safe. Unless you plan to have your local
government issue a building permit, then I can assure you that 42" is
perfectly safe.

--
slatts

Tony Hwang

2006-05-27, 3:21 am

slatts wrote:

> Tim and Steph Wrote:
>
>
>
> I live in Toronto. We're around the same latitude, and 42" is the
> standard here. Building codes must err well on the safe side, so 42"
> is probably more than safe. Unless you plan to have your local
> government issue a building permit, then I can assure you that 42" is
> perfectly safe.
>
>
Hi,
I am in Calgary. We go down 4 to 5 feet.
Local building inspector ought to know.

Bill Kitterman

2006-05-27, 8:21 am

"slatts" <slatts.28gjk5@diybanter.com> wrote in message
news:slatts.28gjk5@diybanter.com...
>
> Tim and Steph Wrote:
>
> I live in Toronto. We're around the same latitude, and 42" is the
> standard here. Building codes must err well on the safe side, so 42"
> is probably more than safe. Unless you plan to have your local
> government issue a building permit, then I can assure you that 42" is
> perfectly safe.
>
>
> --
> slatts

Five feet would definately do you, but call 802 849-6111 and talk to the
building inspector first.

Bill

John McGaw

2006-05-27, 11:21 am

Tony Hwang wrote:
> slatts wrote:
>
snip...[color=darkred]
> Hi,
> I am in Calgary. We go down 4 to 5 feet.
> Local building inspector ought to know.

You got that exactly right. The magic number is whatever the local code
says it is and they aren't going to let facts about actual frost depth
into their considerations. In questions like this, it is always
mandatory to know what the local code says and then to stick to that or
go a little further. In the more restrictive codes they will also
require that the soil at the bottom of the hole is undisturbed
(generally worded something like "undisturbed mineral soil") and that
the area of the pour is sufficient to support the structure above.

--
John McGaw
[Knoxville, TN, USA]
http://johnmcgaw.com

krw

2006-05-28, 1:21 pm

In article <slatts.28gjk5@diybanter.com>, slatts.28gjk5
@diybanter.com says...
>
> Tim and Steph Wrote:

My server doesn't have the original post...

I live right down the street from you (Essex Junction). Depending
on your soil type frost can go down a *lot* further than common
knowledge. Several years ago, during a particularly cold stretch,
water mains all around Chittenden County froze and broke 7-8' under
roads.

I put my sonotubes down 48". Over the past ten or so years, they've
pushed out at least 2' (one completely). Every year I have to
relevel the deck, often requiring a concrete saw to cut the pillar.
I was told 48" but it clearly wasn't enough for my soil (clay on
ledge). With all the rain, it'll likely be mid July before I can
do it this year. :-(
[color=darkred]
> I live in Toronto. We're around the same latitude, and 42" is the
> standard here. Building codes must err well on the safe side, so 42"
> is probably more than safe. Unless you plan to have your local
> government issue a building permit, then I can assure you that 42" is
> perfectly safe.

42" isn't even close. Also, backfill the sonotubes with gravel,
*NOT* dirt.

--
Keith

Goedjn

2006-05-30, 2:21 pm

On Sat, 27 May 2006 09:21:47 +0100, slatts
<slatts.28gjk5@diybanter.com> wrote:

>
>Tim and Steph Wrote:
>

If you've got solid rock anywhere within 8', ignore the code
limits and go right to the bottom.

Robert Gammon

2006-05-30, 2:21 pm

Goedjn wrote:
> On Sat, 27 May 2006 09:21:47 +0100, slatts
> <slatts.28gjk5@diybanter.com> wrote:
>
>
>
> If you've got solid rock anywhere within 8', ignore the code
> limits and go right to the bottom.
>
>
8 inches SHOULD be enough.

Wikipedia states that the length of time that the air temp is below
freezing and the time that the air temp remains below freezing are both
important factors.

According to weather.com

Fairfax has about 90 days where the average high temp does not get above
freezing but record lows put below freezing temps for all months except 3.

I suggest that you consult with

A. Local building permit authorities
B. Local Agricultural Dept officials (state or Federal)

To get more information on local conditions.

If you have STONE several inches below the soil, then if you reach
stone, you have a stable foundation regardless of frost Line conditions.

LinkBot