Replies

1. 
   MikeSmith | Mar 05, 2006 01:49am | #1

   no matter how big the footing , you have to get it bearing on suitable material,

   if you have organic material under the footing , you can still get some subsidence

   other than winging it... you should dig out the unsuitable material  to undisturbed earth , then set your footing...

   if you get the  undisturbed earth  ( suitable material ), and you  have the bottom of the hole below the frost line, then the stone is unneccessary, just set the bigfoot and pour 

   if you want to leave the peat, then you should get a soils engineer to design the footing.. but i don't think  you really can..

    in deep peat areas they drive bearing piles thru the peat to refusal

   i know we're talking about a deck, but footings are footings

   Mike Smith Rhode Island : Design / Build / Repair / Restore
1. 
   Piffin | Mar 05, 2006 03:09am | #3

   digging down to bearing material goes without saying 

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

1. 
   MikeSmith | Mar 05, 2006 03:12am | #4

   i think he was hoping to leave the peaty material in place and compensate with a spread footing.. problem is we're all just guessing at the bearing capacity of "peaty material"Mike Smith Rhode Island : Design / Build / Repair / Restore

2. 
   Piffin | Mar 05, 2006 03:08am | #2

   I talked with a wood scientist once about comparing Merantii wioth Ipe1 He said that it has a much more open grain taht can wick in water, so it should only be used where it has plenty of drainage and airflow, no water sitting on it. So it is a good choice for outdoor furniture and railings, but should be carefully used on decks. some OK, some not.

   OK what was the question now?

   Oh yeah, bigfoot. We dig with equipment. No need for stone. That just creates a space for water to drain from the soil to in under the footer.

    

    

   Welcome to the
   Taunton University of Knowledge FHB Campus at Breaktime.
    where ...
   Excellence is its own reward!

3. 
   Toolpig | Mar 05, 2006 03:14am | #5

   Check out ASK This Old House on PBS.  They just did a story on installing a deck footing using the Bigfoot.  It already aired in Boston, but it'll air again soon.  Check your local listings.

   Here's a link to that episode...

   http://www.thisoldhouse.com/toh/tvprograms/asktoh/showresources/episode/0,16663,1110925-1150465,00.html

   TF

   Toolfanatic (a.k.a. The man formerly known as "Toolfreak")
1. 
   user-88093 | Mar 06, 2006 02:53pm | #8

   many thanks to the experts for your guidance.  I didn't mention that I had borings taken when we first moved here (house has settled,center dips by five inches) that revealed peaty soils down to 20 to 25 feet, which is why I am considering the Big Foots. ("Feet"?).  Anyway I may just dig to feet and put in stone for the first foot and an 8 inch sona tube to bring back to ground level.

   thanks for the TOH link

   Handy Dan

1. 
   davidmeiland | Mar 06, 2006 06:24pm | #11

   I think you're better off asking locally than here. Talk to a concrete contractor, a structural engineer, a deck builder... someone like that who deals with your conditions. Also talk to the building department.  Five inches of settling is a MAJOR amount, so you have some challenging soil issues.

1. 
   MikeSmith | Mar 06, 2006 07:26pm | #12

   dan.. 20' of peat would require a soils engineer to design your footings .. and recommend a fix for your foundation

   i did a slab on grade on top of a lot that had been filled over peat ( can you say swamp )

   we dug a trench  down thru the fill as deep as my excavator could dig

    say about 13' x 2-3' wide.. then we dumped 4"  crusher tailings  to bring the top up to the bottom of our proposed footings  ( say to a depth of 9'  or about 5' below  finished grade)

   worked great.. but that was when i was young & foolish.... tosay, i'd get a soils engineer to design the fixMike Smith Rhode Island : Design / Build / Repair / Restore

4. 
   Toolpig | Mar 05, 2006 03:16am | #6

   In the Boston area, you've gotta go down 4 feet (below the frost line).  I doubt you're gonna find peaty material down that far.

   TF

   Toolfanatic (a.k.a. The man formerly known as "Toolfreak")
1. 
   MikeSmith | Mar 05, 2006 03:45am | #7

   he said he wanted to put them on peaty material, which is why he was thinking that bigfoot with the spread base , would compensate for the peaty material..

   here's a bunch of BF-24's for the back deck

   View Image

   Mike Smith Rhode Island : Design / Build / Repair / Restore

   Edited 3/4/2006 7:46 pm ET by MikeSmith

1. 
   user-88093 | Mar 06, 2006 02:58pm | #9

   I meant to say dig to FIVE feet and use stone instead of Big Foot.

   HD

2. 
   user-88093 | Mar 06, 2006 03:00pm | #10

   Thanks Mike

   I see you used BF 24s for your footer.  May I ask how you dug the holes and determined the correct location before your pour.

   thanks

   Dan

3. 
   Toolpig | Mar 06, 2006 10:09pm | #13

   Yeah, but does it make sense to do that?TFToolfanatic (a.k.a. The man formerly known as "Toolfreak")