Replies

1. 
   Guest_ | Jun 05, 2000 12:35pm | #1

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   Chris - One cautionary note is that when you move the ledger out and lose friction with the foundation wall, you put the bolts in shear. At that point, you need to use bolts (Hilti, etc.) that are designed for loading in shear.

   Plus I think you'll get some other ideas here on detailing.

   Jeff

1. 
   Guest_ | Jun 05, 2000 01:14pm | #2

   *I've said this before. I build my decks freestanding. No flashing/water penetration problems, don't care if the house falls down, don't have to work inside the basement or crawlspace drilling concrete and making a mess for the client.

1. 
   Guest_ | Jun 05, 2000 02:18pm | #3

   *Good point particularly in this case, Ryan. How do you deal with pier foundations close to the house, which would invariably end up in backfilled areas? Do you go down to undisturbed soil or do you move the closest pier footings away and cantilever to the house?Jeff

1. 
   Guest_ | Jun 05, 2000 06:40pm | #4

   *Excellent points J.C. and Ryan, I would not bother to lag in a ledger in this case. Make provisions to deal with the loose soils in the backfill area- ie. excavate to undisturbed soil, cantilever, or compact. Then place bearing beams and frame...

2. 
   Chris_Kovacs | Jun 05, 2000 09:14pm | #5

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   Thanks for the advise. I like the idea of building the deck free standing. It means digging a few more holes, but that could be better than dealing with stones being pulled from the foundation wall.

   Thanks,

   Chris Kovacs

3. 
   Guest_ | Jun 05, 2000 09:35pm | #6

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   Decks are light weight compared to houses. I typically cantilever the deck toward the house but only because it's easier to dig a hole and set a sonotube if you're not right up against the foundation.

   I've thought about the fact that sometimes I'm probably still in the backfill area but decided that unless I see that the ground has noticably settled and I use large enough footings, I'll take my chances. Frost here is 3' (of course you're in NJ too) and I'm not going to dig to 9' to make sure I'm below backfill.

1. 
   Guest_ | Jun 05, 2000 10:06pm | #7

   *i I'm not going to dig to 9' to make sureYou don't have to unless the excavation was really oversize. The normal relationship is a 45 deg. line from footing up, so if you're 5' away from the foundation wall you can be 5' higher, assuming the area was not totally excavated. I was interested because if you are 8'-10' away it's probably not an acceptable cantilever. I was going to suggest that he proceed as you suggested but, in addition, Hilti-bolt several angle brackets (with gusset) to the stone to pick up an end header at the end of your 'cantilever' in several locations (say 4' o.c.) to take any excess deflection. My reasoning is that it's too far for a true cantilever (probably greater than 1/3 the main span) but the loads would be light enough to be taken along several points of his own choosing (due to stone irregularity). Just thinking out loud ...i decks are lightweight compared to housesTrue enough, but requiring a 100 PSF code load in NJ (due primarily to collapses with injuries, notably along the shore).Jeff

4. 
   Mark_T. | Jun 06, 2000 12:04am | #8

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   Ryan:

   You say

   >"I've thought about the fact that sometimes I'm probably still in the backfill area but decided that unless I see that the ground has noticably settled and I use large enough footings, I'll take my chances. Frost here is 3' (of course you're in NJ too) and I'm not going to dig to 9' to make sure I'm below backfill."

   Sorry dude, I can't buy that. You gotta dig down to undisturbed soil unless you are planning on moving out of town within the next 5 years! Or, maybe get the footer hole signed off by a soils engineer. The suggestion about cantelevering was OK, but a 5' cantalever is too much, assuming you are building a wood deck. As far as compacting the fill dirt in the bottom of a footer - it ain't gonna do the job unless you compact the fill in 6" lifts which doesn't work in this instance.

   Sounds like you need to move down south where the footers are very shallow and "the siding is done once the rolled roofing is in place". That way you won't be too put out digging down to firm ground!

5. 
   Guest_ | Jun 06, 2000 02:47am | #9

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   I was waiting for someone to point to a previous discussion of freestanding decks. Might want to search the archives.

   In any other instance, I would attach a deck to the house but after some thought, I was going to suggest pulling the stones. Another thought comes to mind however, one that I have done before for a different situation but may work here. I needed to retrofit some 13 eighteen inch columns centered maybe 12 inches from the exitsting building and I didn't want to take a chance on any settling. I hired out an auger rig to dig a piling down to virgin soil and it was pretty cost effective because acces was good. Maybe 500 bucks for the lot. After all he was drilling through fill so it went quick. Might be an option for you.

   I have heard that on the west coast it is customary to compact backfill around foundations. That would be awesome but customers will not pay for it in my area.

   Did you mention where you are located Chris?

   Tom

1. 
   Guest_ | Jun 06, 2000 03:31am | #10

   *So, my choices are footings that may sink or flashing details that may leak or rot siding and sheathing. I still think I'll take the footings. I've only built a hand full of decks and if in 5 years, somebody calls me and says the deck's sinking, I'll be there, I'll fix it, I'll make it right. No risk on the home owner's part.A 5' cantilever's not gonna work on a deck, I'm picturing a diving board. And I can't compact fill in the bottom of a 3' hole. I like the footings alot more than I like the flashing.I hate to give the impression that I'm trying to get away with shoddy work, but we're talking about decks here. Even with the occasional 100psf load (like that's ever happened), they won't suddenly fall into the ground. I've been wrong before but I'd rather have the footings than the flashings on my own home.

6. 
   Chris_Kovacs | Jun 06, 2000 09:38pm | #11

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   Thanks for lots of good ideas. I am still not quite sure which way to go now that I have read more of your responses. The deck in question is going on the back of a hundred year old house in Massachusetts with a stone foundation. I imagine the back fill area is pretty much settled after that much time. In Massachusetts, we have to dig 4' for a footing. It sounds like my best option will be to dig my first set of footings 2 to 3' from the wall and cantilever into the wall. I like the suggestions of Hilt bolting a few angle brackets to the stone wall to support the rim. With the deck being 12' wide, this cantilever should be no problem. Thanks again for the suggestions.

   Chris Kovacs

7. 
   Chris_Kovacs | Jun 07, 2000 02:18am | #12

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   I would like a little help with the installation of a 19' ledger board for a deck. The ledger is going to be attached to a stone and mortar foundation. The wall is far from flat and I will have to shim (galvanized washers, I assume) quite a bit to get the face of the ledger plumb. Is this safe to do assuming the stone wall is in good shape? What is the best method for attaching the ledger? Any words of wisdom or cautionary notes are appreciated.

   Thanks,

   Chris Kovacs

8. 
   Guest_ | Jun 07, 2000 02:18am | #13

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   it's not that the footings may sink .. it's when they will sink.. and how much..

   decks can have extremely concentrated sf loading and it all goes to the posts..

   disturbed earth is still compacting after seven years ..the estimates i've seen are 9 years in areas witha good annual rainfall..more in dryer areas..

   if i'm doing the excavation we will dry lay block work to extend the undisturbed area to the frost minimums..

   also , if you get right next to the house you probably only have to dig 7 feet to get to the footing.. and you can stand a post on the footing..

   the post will be one piece and give a stronger rail system than one that is just bolted to the band joist.

   stair stoops.. posts for decks .. anything in the disturbed area is going to sink unless you design your way out of it....

   b but hey, whadda i no ?