Frost Depth Contour Map For The USA

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Old 07-22-06, 09:52 PM
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Frost Depth Contour Map For The USA

Found a map for frost depth, of course this is from 1988, and is approximate. This is a PDF file. I thought this may help with frost depths. Check your local codes for actual depth of footings in your area.

Go here:

http://www.usace.army.mil/usace-docs/eng-manuals/em1110-1-1905/c-2.pdf#search='frost%20depth'

It's on page 2 of the PDF.

I live in the south east of of Indiana, right on the border of a 3' footing or a 4' footing.
 
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Old 07-23-06, 06:12 PM
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U.S frost lines

lightningwild posted

"Found a map for frost depth, of course this is from 1988, and is approximate. This is a PDF file. I thought this may help with frost depths. Check your local codes for actual depth of footings in your area.

Go here:

http://www.usace.army.mil/usace-docs/eng-manuals/em1110-1-1905/c-2.pdf#search='frost%20depth'

It's on page 2 of the PDF."
 
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Old 07-23-06, 06:15 PM
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lightningwild,

Welcome to DoItYourself.com and the deck forum.

That was great!! SO GREAT, in fact, that I made a sticky out of your post. It'll be at or near the top of this forum for a VERY long time.
 
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Old 08-24-06, 09:16 AM
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correction

Originally Posted by lightningwild
Found a map for frost depth, of course this is from 1988, and is approximate. This is a PDF file. I thought this may help with frost depths. Check your local codes for actual depth of footings in your area.

Go here:

http://www.usace.army.mil/usace-docs/eng-manuals/em1110-1-1905/c-2.pdf#search='frost%20depth'

It's on page 2 of the PDF.

I live in the south east of of Indiana, right on the border of a 3' footing or a 4' footing.
I just wanted to note that if you live in SE Indiana as you say and the contour map is correct, then you live along the border between the 2' and 3' footing and not the 3' - 4'. Just the same, thank you very much for your efforts.
 
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Old 09-16-09, 11:55 PM
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PDF appears dead. Here is a JPG

Re: deck addition - dslreports.com
 
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Old 09-17-09, 05:23 PM
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Here's one that doesn't go to your competitor's forum: http://www.soundfootings.com/pdf/US_...t_DepthAVG.pdf
Be safe, Gary
 
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Old 05-08-13, 04:37 PM
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Frost

Frost?

I’ve been a contractor most of my life. Back in the 80’s, I built a lot of decks, among other things. This was in the Ottawa and Gatineau Valley regions of Eastern Ontario and West Quebec. Most of the soil is a sandy Loam, with more loam than sand, or Leda (Blue) Clay. Blue Clay is the worst overburden for frost penetration.

At Edelweiss Valley, a ski resort, I had to put a waterline under the road and the digging was mostly clay so we went down 9’. I always put the good line inside of a slightly larger older line so that when it freezes and it did, you only have to dig down to the connection at the road. The intake water line enters the house just above the footing in the basement, so you can pull the whole thing into the basement and replace it, without digging it up. (It’s flexible plastic)

Two reasons why it froze;

Frost penetration is directly related to moisture content. No moisture, no frost. Clean, dry sand doesn't freeze. Blue Clay is mostly water, so it freezes like an ice cube.

The 2nd reason is that after the first few years at the ski chalet, someone built another further down the road, and they plowed the snow off the road for the first time. It goes to -30 C sometimes, during winter.

So initially, when building a deck, we played with different ways to establish a concrete footing below the ‘frost line’. In sandy loam, that would be about 3 ½ - 4 feet.

Then I found a different way. We insulated the structural posts from frost heave by placing a piece of high density Styrofoam underneath them.

In one smaller community of 250 or so new houses, I built a deck every Saturday all summer long. Myself and two carpenters had a routine that built a normal sized deck including steps, stairs, planters, benches, railings and oil stain/finish in about seven hours. BBQ ready they said. Beer ready, we said.

Starting with a ¾ ton pickup with a roof rack, we arrive with roughly 1000 B. F. of 2x6 Western Red Cedar. There would be enough 2x10 also, to skirt the platform and be the top rail of any railing, all on the rack. In the bed we had our tools, especially a Sears 10” Radial Arm saw, and other parts like 4” concrete blocks, Styrofoam, 6 mil black plastic roll, 12” galv. Spikes, joist hangers, lag bolts etc..

Because the insulated footing system is so simple and quick, we can afford to put in vertical support posts as required easily. That’s why we build everything from 2x6’s. If the main beam could have been a double 2x10 with no more than a 2’ cantilever on both ends, then two posts would have sufficed about 10’ apart for an overall maximum length of the main beam of 2’+2’+10’= 14’. Using 2x6’s, we would simply put an extra post mid span. Framing 16” O.C. was an option.

These houses all had large freshly sodded back yards, accessed from a patio door off the dining room. Poured concrete basements exposed above grade about 24” to 36”. Rough grade had been properly sloped away from the house. Perfect height for working.

Quick rough measurements would show us what sod to remove. We wanted to leave as much grass as possible because most of the area under the deck was 6” plastic covered with crushed stone, or bark chips or facsimile. After determining the height of the finished floor, we’d push a lawn mower under the imaginary lower edge of the deck to see how far in we could cut grass, without running the mower into the deck.

With sod gone and the proper slope double checked, we locate each post and using hand trowels and a 2’ level, carve out a perfectly flat, level place 2’x2’. You place a piece of 2’x2’x2” Styrofoam on the pad to check level. With Styrofoam pads in place, cover anything that’s not grass, with the 6 mil plastic. Don’t use clear plastic. Use the worst 2x6’s ripped in half lengthwise as a border between the grass and the material under the deck that covers the plastic. The 2x3 is placed on it’s edge over the plastic at the edges. Spike it into the earth. Cut off excess plastic on the grass side and spread crushed stone or what ever cover over the exposed plastic on the inside, under where the deck will be.

Next, place 4” concrete blocks, on their sides, on top of the 6 mil plastic and also on top of a piece of Styrofoam. You will have to push the bark chips out of the way and feel for the Styrofoam under the 6 mil plastic. The elevation of the posts is unimportant. I rip 2x3’s and gang them together in triplicate to make the posts. The center piece is cut 5 ½” longer than the two others creating a shelf on either side for the beam to sit on. Using a tripod level aka a builder’s dumpy level (from the beginning) we measure the height of each block and knowing the level of the finished floor, calculate the height of the post that will go on that block.

If the pads are level, and calculations are correct, you can place all the posts, and they’ll stand up plumb by themselves. Calculate and cut the main beam pieces and place them. All vertical end grain is smeared with silicon. Nothing like a radial arm saw for framing.

The area under the deck should now be uninviting to animals, it should be a zero maintenance place, and it should stop further penetration of water into the ground thus limiting frost heave and killing roots. The insulation allows the ground to retain enough heat that the frost doesn't form. I was thinking about the system when one day I drove along a section of highway being built and watched them place blue, Styrofoam SM under the entire road surface. They were going through a swampy area so the foam was about 4’ thick, as I recall. Great big blocks of it.

After years, I lost count at 70, of how many decks I built. Only about ten were in that subdivision, so I used variations of the insulated footing system a lot. I’ve never had a complaint. If any failed, no one told me. One deck was big and was close to the ground so that the framing pieces were 2x4’s. This necessitated putting posts every 4’. So we opted to just cover the ground in that area with Styrofoam. That cost a little more but was a fast solution. I was particularly worried about it. The owner is one of those good friends that you only talk to every few years. I asked him about it at 15 years and he laughed, saying it never moved. And that area of the city was problematic.

We only used Western Cedar for any part a person could touch. Never pressure treated except for the framing to save money and add strength and then only kicking and screaming. An acquaintance got a sliver from lumber treated with copper arsenate and they amped (surgical term) his thumb to stop a tumor a few months later.

Stop the water. Be sure the deck is high and dry or don’t build it. Check the roof, the irrigation system et. Al..

From the finished floor of the house, build the deck floor 6" or 7” lower. From the patio door, people will have to step down. Build another level lower than that if you can. In these backyard situations, privacy is big.

One man pulls the radial arm saw onto the tailgate. He then cuts the parts for all benches, railings, stairs etc.. He sorts through the lumber allowing us to hide the worst flaws. I would substitute a planter or a bench for a railing, when I could. This close to the ground, a railing is required 18” or higher but a cedar bench looks much nicer. If you always hide end grain in your designs, your deck will look more like furniture, than just a wooden platform.

After placing all the floor 2x6s I cut the excess off around the perimeter. Underneath is a 2x6 frame so I set the depth of the skill saw to 1 ½” and make the cut so the blade is flush with the outside of the 2x6 below. The edge of the decking is inset from the outside of the frame by the width of the blade. Then I attach a 2x8 or 2x10 piece around the perimeter that is flush with the deck floor and mitered at the corners. The inset saw cut was to imitate the line caused by the spaces between the deck boards. Use your zippy little router to re-establish round overs (easings) where required. Good framing skills make all this go very smoothly. If you’re learning, expect a little blood.

Those were some of the nicest contracts I encountered. Work was fun, everyone was happy, and we got to pay some income taxes.

Robert
 
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