 tahoejeffPremium
join:2001-07-01
Wisconsin Dells, WI
1 edit | deck addition I built this 12'x12' deck in 2003. At that time we had two chairs and a small grill so the deck size was fine.
Now with 4 chairs, a big grill, and pool access I'd like to widen the deck to the left.
I'd like to build a 12'x12' addition that will start where my tape measure sits in the pic (about 3' from the house), and extend 3' past the end of the current deck. The addition would extend 12' to the left, with mulch between the house and the addition. All lumber on the existing, and planned addition is green treated.
The questions:
I'd use carriage bolts to attach a new 12' 2x6 ledger board to the current 2x6 deck edge joist where the joist hanger sits in my pic.
This ledger board (correct terminology?) would not be supported by the beams under the current deck. Would the carriage bolts provide enough support for this new ledger board or should I place new footings/beams just off of the new ledger board (added work and expense, but I'm thinking maybe necessary)?
I'd dig 4' deep holes for the concrete footings 10' out from the new ledger board and place 2x6 beams on each side of 4x4 posts, just as I did on the original deck.
This will be the 5th deck I've built, with no failures. I do think I follow all codes, but the local inspector has never come out to have a look. I really enjoy planning and building a deck.
I welcome all constructive advice/criticism.
Don't ask about the "gallows" attached to the right side of the deck...It's a sunshade work in progress with an engineering roadblock.
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2 edits | hey jeff, so you want to add a boxsill to a boxsill (square frame to sqare frame). My thoughts are for one....don't use mulch next to your house, thats a breeding ground for termites and ants. Lava rock is cheap and so is river rock. Second; carriage bolts will be fine to sister the joists together. But I think 4' holes are excessive. Have you ever though about resting the posts on top of a column?
It works like this. A 2 or 3' hole down 8" in diameter. Once you've finished the hole, brush away all dirt around the hole so just the hole is exposed at ground level. Then you make a 1'square box with 2x4s. Cover the inside of the box with oil. Now center the box over the hole and fill with Concrete to the top of the box. Once dried. The 2x4s will just slide off( because of the oil) and you can rest your vertical post on the center of your column. The benefit of this is now your posts aren't stuck in the ground rotting over time. Column placement will be critical but the way I see it you really only need 7. From right to left. 3 @4 or 5 ' from the existing joist, and 3 @8 or 9' from the existing joist. These are incrementally being placed from the house too....
The seventh one may be optional...like 1 foot away from the joist and 2' from the end of the deck. This one will support the corner by the pool.
And I thought the gallows were in place in case Mr. Madoff came for a visit...I know I have a sentence I'd like to impose on him 
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1 edit | this is what I'm talking about in its most caveman format....MS paint. Get the steel cross bracing along with a steel Y brace to attach post to joist.
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 SparkChaserR.I.P. DocPremium
join:2000-06-06
Downingtown, PA
kudos:3
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| reply to S_engineer
said by S_engineer:It works like this. A 2 or 3' hole down 8" in diameter. Once you've finished the hole, brush away all dirt around the hole so just the hole is exposed at ground level. Then you make a 1'square box with 2x4s. Cover the inside of the box with oil. Now center the box over the hole and fill with Concrete to the top of the box. 2' or 3' doesn't sound deep enough for WI. 2' wouldn't pass inspection even around here.
Simpson makes several parts to connect the 4X4 to the footer »www.lowes.com/lowes/lkn?action=p···=simpson
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"Facts do not cease to exist because they are ignored." - Aldous Huxley
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 cdruGo ColtsPremium,MVM
join:2003-05-14
Fort Wayne, IN
kudos:5
·Frontier FiOS
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Frost line across the country |
said by SparkChaser:said by S_engineer:It works like this. A 2 or 3' hole down 8" in diameter. Once you've finished the hole, brush away all dirt around the hole so just the hole is exposed at ground level. Then you make a 1'square box with 2x4s. Cover the inside of the box with oil. Now center the box over the hole and fill with Concrete to the top of the box. 2' or 3' doesn't sound deep enough for WI. 2' wouldn't pass inspection even around here. You want to get below the frost line to prevent frost heave. The frost line is around 60" in the Dells area of WI according to the map, but check your local extension office if you want a specific number, or building department if you want what's required by code. |
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| reply to tahoejeff
My suggestion is to not insert post into the hole. You can either vertical set the post ther to be held by the weight of the deck, or tapcon into the new column with a steel post holder . You don't need to hit frostline when your resting the post on top of the column. However, frostline is 3' so if it made you feel better, then dig away.
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tahoejeffPremium
join:2001-07-01
Wisconsin Dells, WI | For the last two decks, I dug down 4' and dropped in one of those cardboard tubes, which I filled with concrete. Then the 4x4 posts sit on top of a galvanized bracket which is bolted to the concrete.
This image shows what I was expecting to do. The black 2x6 beams I had planned on, but didn't plan on an extra post in the center. The red beams I added after looking at your image, realizing they would probably be needed for support.
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wthPremium
join:2002-02-20
Iowa City,IA Reviews:
·Mediacom
| reply to S_engineer
said by S_engineer:It works like this. A 2 or 3' hole down 8" in diameter. Once you've finished the hole, brush away all dirt around the hole so just the hole is exposed at ground level. Then you make a 1'square box with 2x4s. That could/probably be a disaster, as the frost WILL push up on that one square foot "box" of concrete sitting over that 10" dia hole and break the concrete down about 15" - 18" deep. I know because 3 of us just demoed an old 33 year old 2 level deck of about 300 sq ft last Thur & Friday. 2 of the concrete frost footings poured just like you described were cracked/broken off as described. My uncle who has been building decks for 30 years pours all of his 42" deep with no sq form at the top. Just set a ground contact rated 4x4 in the hole and fill with cement. Pour the cement so it's about 1" above the ground. If you don't want to set your post in the concrete, then stick a half inch or 5/8's rerod all the way down and leave about 3" sticking up to set the post on after you drill a hole in the post. Code in our part of the country would require 10" dia hole, 42" deep. The pic shows 2x6's 12" on ctr up by the door, as this project will be topped off with composite decking & rail. I'll be back out ther Wed or Thur and will take a pic of those 2 broken concrete footings. |
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SparkChaserR.I.P. DocPremium
join:2000-06-06
Downingtown, PA
kudos:3 Reviews:
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| reply to tahoejeff
said by tahoejeff:For the last two decks, I dug down 4' and dropped in one of those cardboard tubes, which I filled with concrete. Then the 4x4 posts sit on top of a galvanized bracket which is bolted to the concrete. This image shows what I was expecting to do. The black 2x6 beams I had planned on, but didn't plan on an extra post in the center. The red beams I added after looking at your image, realizing they would probably be needed for support. I did the same for the posts. I used 2X8 for beams but I think I have a bit more room. I thought I was close to the ground How high is your deck from the ground?
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"Facts do not cease to exist because they are ignored." - Aldous Huxley
"The only time I feel alright is when I'm into drinking
It can sort of ease the pain of it and it levels out my thinking" - Ralph McTell |
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 mityfowlPremium
join:2000-11-06
Dallas, TX | reply to tahoejeff
1st of all there is no thing as too much deck.
I put in a big pool and a bunch of deck then and guess what? I didn't put enough deck in for the table and chairs. So the next year I put in a a lot more decking.
You really might want to consider stamped or textured concrete. |
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tahoejeffPremium
join:2001-07-01
Wisconsin Dells, WI | reply to SparkChaser
sparkchaser, the top of the decking is around 13" above the ground. You can see in my original pic there is barely room to squeeze in the 2x6 beams.
wth, I used to drop the 4x4 posts down into the hole and then fill it with concrete, but read somewhere that just setting the posts on top of the concrete with a galv bracket was sufficient (and easier).
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1 edit | said by tahoejeff: but read somewhere that just setting the posts on top of the concrete with a galv bracket was sufficient (and easier). thats exactly what I'm talking about. I live in Chi-town (where it gets a tad bit frosty), and have never had any problems by pouring close to frostline. If you put the posts inside the hole, you may have problems with twisting posts. Eliminate that problem by using a shorter post that sits on the top of the column. With a 2x4 box over the hole, you now have concrete 3.5" above grade.
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cwm1276
join:2004-01-16
Stillman Valley, IL Reviews:
·Comcast
1 edit | reply to tahoejeff
I would just turn it so the new deck joist run parallel to the old ones run your new beams in the same direction as the old ones. I would say 8 ft apart with 2 ft hanging past on the house side and the yard side. Think of it as freestanding deck. Then just fasten as needed to the existing deck. Each deck is only supporting itself so your fasteners between the 2 should not need to be too substantial.
This way all your decking is running in the same direction, on both decks. |
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tahoejeffPremium
join:2001-07-01
Wisconsin Dells, WI | cwm, my wife likes the idea of the decking on the addition running perpendicular to the old decking. Would there be a structural advantage to your suggestion?
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SparkChaserR.I.P. DocPremium
join:2000-06-06
Downingtown, PA
kudos:3 | reply to tahoejeff
I don't see any structural advantage to either direction. Either way it is free standing. |
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tahoejeffPremium
join:2001-07-01
Wisconsin Dells, WI | reply to S_engineer
s_engineer, you suggested 7 posts. I'd like to stick to 5 posts as shown in my edit of your drawing. Do you think this would be enough?
If each post is set in 2' from the deck edge, they would only be 8' apart.
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cwm1276
join:2004-01-16
Stillman Valley, IL | reply to tahoejeff
I would just do 4 posts, 2 on each beam. Direction really does not matter. Just think of this a freestanding deck.
Then you can just connect them together with some fasteners. |
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| reply to tahoejeff
4 would be a minimum, but the reason I suggested the oddball number is because of the pool. The 2 in the middle were for extra support. Those would be optional. That free standing corner would be where everybody would be stepping on to access the pool. Thats where My concern would be.
Heres an idea. Move the column over (the fifth or seventh, whichever you choose) so theres a single post on the inside of the corner. This way you can run carriage bolts through your boxsill or ledger through the post, or even countersinking lag screws would work.Give me a min...I'll show ya/....
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| reply to tahoejeff
another rudimentary type drawing. This is with the assumption you'll have a pool in that area for some time. If you decide to go with 4 columns for the middle, then you'll have to bring the distance between the columns closer together to avoid any sagging in the middle. If you use the "optional" posts in the middle, that would allow you to bring the columns closer to the ends. The corner post is for could be moved to the next bay or left where its at. But this would support the added traffic to the pool.
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1 edit | reply to tahoejeff
I've been planning a 12' X 14' treated lumber deck. Instead of using 2X8s for the beams and joists, I priced it out using 2X10s for the joists and 2X12s for the beams. It added less than $50 to the deck cost. The live load went from 40 lbs/sqft to 116 lbs/sqft. It's a little overkill, but if I ever decide to put a hot tub on the deck, I won't have sleepless nights. Mine is 3' off of the ground so height isn't a problem. |
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