Thinking about a 12ft or 16ft x 20ft deck?

Reply

  #1  
Old 03-26-13, 04:10 PM
Member
Thread Starter
Join Date: Mar 2013
Location: United States
Posts: 81
Received 0 Votes on 0 Posts
Thinking about a 12ft or 16ft x 20ft deck?

Been kicking around building a wood deck for a few years now and looks like we might be moving forward. It has been many years since I have done one. Anyone have a decent amount of time on them? I'm not interested in composites, just good ol PT wood. I'm in central Fl, I have a decent slope going from the house so the side nearest to the house will be at ground level, but the other end will be 7-10" off the ground.

I'm sure I'll have a few more questions, but my first is what wood do you perfer? 5/4 deck boards? or 2x6's? I'm leaning more towards the 2x6's.

What spacing do you like? 16" on center?

Do you lay plastic on the ground under the deck? Never done this but someone suggested it.

What spacing do you like for your footings? Every 10ft?

How long do you wait until you seal/stain it? And what stain do you prefer?

Thanks
 
Sponsored Links
  #2  
Old 03-26-13, 04:27 PM
chandler's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2005
Location: USA
Posts: 39,967
Received 2 Votes on 2 Posts
Welcome to the forums! I prefer 5/4 #1 PT for decking. Along with that is the required 16" oc for the joists. I would use a product like Typar or another breathable ground cover to keep weeds out but let moisture fall through. Footings every 8'. I usually wait about 6 months prior to staining, but Marksr, our paint guru lived in Florida in another life, and can guide you better on that.
 
  #3  
Old 03-26-13, 06:57 PM
Temporarily Suspended
Join Date: Jul 2008
Location: NY
Posts: 10,986
Received 0 Votes on 0 Posts
You didn't mention anything about footings or if the deck will be free standing. I recommend free standing with 2' deep footings.
 
  #4  
Old 03-26-13, 07:05 PM
Member
Thread Starter
Join Date: Mar 2013
Location: United States
Posts: 81
Received 0 Votes on 0 Posts
The footings I figured would be the typical 12" diameter concrete, set 18" in the ground. I also thought the deck will be attached to my existing concrete patio slab by a ledger board.
 
  #5  
Old 03-26-13, 07:27 PM
Temporarily Suspended
Join Date: Jul 2008
Location: NY
Posts: 10,986
Received 0 Votes on 0 Posts
Ledger boards are outdated now. Free standing is the way to go. Posts should not rest on the patio. Footings should be under all posts.
 
  #6  
Old 03-26-13, 09:29 PM
Member
Thread Starter
Join Date: Mar 2013
Location: United States
Posts: 81
Received 0 Votes on 0 Posts
How do you ensure a smooth transition from a slab to a deck without a ledger to keep things lined up? It will be more or less free standing on 6 footings, plus the ledger.

I don't understand what you mean by post should not rest on the patio? If you mean the slab, that won't be under the deck, the deck will be extending the patio.
 
  #7  
Old 03-27-13, 02:44 AM
chandler's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2005
Location: USA
Posts: 39,967
Received 2 Votes on 2 Posts
How do you plan on attaching this deck to your slab? No more height than you have, making this free standing will ensure no pressure on the deck nor the slab should things shift. I think we have the idea you are attaching this to your house, which only allows for infiltration of water.

Decks we build here in the mountains almost always need to be attached to the dwelling as we can start at grade level, go out 8 or 10' and the edge of the deck can be 16' off the ground. Very difficult to build anything free standing. 10", I think you're good with free standing.
 
  #8  
Old 03-27-13, 03:30 AM
Forum Topic Moderator
Join Date: Mar 2005
Location: USA - N.E.Tn
Posts: 46,050
Received 118 Votes on 105 Posts
How high is your house slab off the ground?

How long do you wait until you seal/stain it? And what stain do you prefer?
6 months is a good rule of thumb. Depending on how wet the wood is when installed and the environment that the deck is in, it can be stained somewhere between 6 weeks and 6 months. It shouldn't hurt the PT wood any if you have to wait a whole year.

You'll want to use a water based or waterborne stain. Oil base stains don't hold up well in the florida sun. Solid stains [looks like paint] hold up the longest and clear sealers have the shortest life. I like to stain a new deck with either a semi-transparent stain or a toner/translucent stain. You'll find better quality stains at your local paint store as opposed to a big box paint dept. For the most part, the higher priced stains will last longer than the cheaper ones.
 
  #9  
Old 03-27-13, 04:50 AM
Temporarily Suspended
Join Date: Jul 2008
Location: NY
Posts: 10,986
Received 0 Votes on 0 Posts
It's not free standing w/ a ledger board & chandler is right about the water collecting there. The 6 posts should come up 3 feet above the decking & be used for the railing. The box gets hung between them. I built a second story deck like that, close to the water & it survived Hurricane Sandy.
 
  #10  
Old 03-27-13, 12:06 PM
Member
Thread Starter
Join Date: Mar 2013
Location: United States
Posts: 81
Received 0 Votes on 0 Posts
The deck will be an extension of the patio, not on top of it, so the top of the deck needs to be flush with the cement. I'm not attaching it directly to the house, the patio is a separate pour outside the block and is set 3 inches lower then the foundation. I don't mind doing it free standing, but what are the chances of it shifting? My foundation is one cord of block, so about 8", above grade.

There will be no posts used, and I'm not doing any railings, just a simple deck. I was going to set the beams right in top of the footers.
 
  #11  
Old 03-27-13, 04:09 PM
Member
Join Date: Mar 2013
Location: USA
Posts: 457
Received 0 Votes on 0 Posts
Read the label on the can of stain. They are all over the board; Olympic, ASAP; How to Stain Frequently Asked Questions from Olympic® Stains

Cabot- 5 days dry weather, Cabot Stain Problem Solver Wood Primer | Cabot

2 days; SW;Staining Tips & How To's - Sherwin-Williams
Pittsburgh; PPG Pittsburgh® Paints- Stain FAQs and Tips

2 weeks, max; How to Choose & Apply Exterior Wood Finishes, Paints, Stains

3 weeks; UMass Amherst: Building and Construction Technology » Wood Myths: Facts and Fictions About Wood

I would not wait a year, unless it has been "Wolmanized" because the fibers break down with extended UV exposure, greying the wood, so you have to sand it, "Sun damage"; Finishes for Wood Decks - Finishes And Surfaces, Decking, Lumber, Wood, Waterproofing - Professional Deck Builder Magazine
So, read the can or research it on-line from manufacturer.

Gary
 
  #12  
Old 03-27-13, 04:14 PM
Forum Topic Moderator
Join Date: Mar 2005
Location: USA - N.E.Tn
Posts: 46,050
Received 118 Votes on 105 Posts
If the wood turns grey before you have time to apply the stain all you have to do is wash the deck with a bleach/water solution, rinse and wait for it to dry. It doesn't take near as long for a deck to dry from washing as it does from the PT process. They also sell a deck brightner that can be used in place of the bleach/water solution.

Except for the handrails, the only times I've ever had to do any sanding on a deck is when some inexperienced person used a pressure washer on the deck and chewed up the wood from too much pressure.
 
  #13  
Old 03-27-13, 04:23 PM
chandler's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2005
Location: USA
Posts: 39,967
Received 2 Votes on 2 Posts
what are the chances of it shifting
Exactly my point. I'd rather it shift a little being free standing than to take a chunk of your patio with it. The patio won't stop shifting of the deck. Most likely your patio is only 4" deep, anyway, so very little space to attach anything of substance.
 
  #14  
Old 03-29-13, 05:36 AM
Temporarily Suspended
Join Date: Jul 2008
Location: NY
Posts: 10,986
Received 0 Votes on 0 Posts
You can set the beams, on top of the footings. That's not a problem.
 
  #15  
Old 04-01-13, 04:46 PM
Member
Thread Starter
Join Date: Mar 2013
Location: United States
Posts: 81
Received 0 Votes on 0 Posts
Ok thanks, I'm thinking about moving forward with a 12x20. I still need some assistance though. I think I have come up with a plan. I don't want to dig right next to my house cause the patio is only 4" thick or so. If I did once I get the 2x6 and 5/4 decking in there I'd have to dig down 3" below the slab, it would crumble soon after.

So now my plan is to cantilever the last 12" closest to the house. This will keep me from digging right next to the house.

Here is a few pictures, The first is an over all plan, the green are the beams which are doubled 2x6's. The yellow joists are 2x6's also, except for the one closest to the house, it will be a 2x4. The red are the footers, which will be 8" or 12" diameter 2' deep. The second is how I will notch the beam for the cantilever. Let me know what you guys think.


 
  #16  
Old 04-01-13, 05:00 PM
Temporarily Suspended
Join Date: Jul 2008
Location: NY
Posts: 10,986
Received 0 Votes on 0 Posts
Why can't the footings closest to the patio support the patio & the deck? A 12'' diameter footing would be big enough.
 
  #17  
Old 04-01-13, 05:09 PM
Member
Thread Starter
Join Date: Mar 2013
Location: United States
Posts: 81
Received 0 Votes on 0 Posts
I suppose it could, but I'd still rather not chance digging right there, plus I'd have to move a sprinkler line and 2 cable lines right next to the slab.

If I did will the 6' span on the footers still be ok?
 
  #18  
Old 04-01-13, 06:36 PM
Temporarily Suspended
Join Date: Jul 2008
Location: NY
Posts: 10,986
Received 0 Votes on 0 Posts
A 6' span should be ok.
___________________
 
  #19  
Old 04-01-13, 07:06 PM
Member
Thread Starter
Join Date: Mar 2013
Location: United States
Posts: 81
Received 0 Votes on 0 Posts
Ok, if I do go with the cantilever, will my plan work? will the 12" be too much and make the deck spongy?
 
  #20  
Old 04-01-13, 07:45 PM
Temporarily Suspended
Join Date: Jul 2008
Location: NY
Posts: 10,986
Received 0 Votes on 0 Posts
I'll have to defer to someone else. I've never done one.
 
  #21  
Old 04-02-13, 03:54 AM
chandler's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2005
Location: USA
Posts: 39,967
Received 2 Votes on 2 Posts
The 12" cantilever won't cause any problems. In fact, I like the idea of not fastening it to the slab, and keeping it free standing. You have good support elsewhere, so the short cantilever is not an issue. It also keeps you away from the edge of the slab and the possibility of degrading it's support. If you were to get too close, you would have to undermine the slab and pour additional footings both under the slab and the deck. Good call.
 
  #22  
Old 04-02-13, 04:16 AM
Member
Thread Starter
Join Date: Mar 2013
Location: United States
Posts: 81
Received 0 Votes on 0 Posts
Thanks guys, that makes me feel better
 
  #23  
Old 04-04-13, 12:27 PM
Member
Join Date: Mar 2013
Location: USA
Posts: 4
Received 0 Votes on 0 Posts
Bigger joists/beams?

Around here anymore we use 2x10s for joist/beam and sometimes 2x12 for the beam. You are definitely within code there, but there is code then there is reality, and nobody likes a bouncy deck.

Make sure you run the design past your area inspector before you get going, or you could run into trouble later.
 
  #24  
Old 04-04-13, 12:49 PM
Member
Thread Starter
Join Date: Mar 2013
Location: United States
Posts: 81
Received 0 Votes on 0 Posts
No building inspector will be coming. I called and spoke to him about what I was doing, he thought it sounded just fine, but won't be coming to see it cause anything less than 12" off grade doesn't require a permit.
 
  #25  
Old 04-04-13, 01:27 PM
Member
Join Date: Mar 2013
Location: USA
Posts: 4
Received 0 Votes on 0 Posts
Ah, wow - you have a pretty lenient bunch there.
 
  #26  
Old 04-04-13, 01:55 PM
Member
Thread Starter
Join Date: Mar 2013
Location: United States
Posts: 81
Received 0 Votes on 0 Posts
Not at all actually, but remember I am in Florida, no frost lines and flat land. Not much can happen with an at grade deck, the most you can fall is 12". Now If I want to put an enclosure of some sort on it that changes the game.
 
  #27  
Old 04-04-13, 03:28 PM
Member
Join Date: May 2012
Posts: 1
Received 0 Votes on 0 Posts
deck stain choice

You should look into what stain to use very carefully. It could save you lots of frustration later. Check out "DeckStainHelp.com" for ratings of deck stain to use on PT and what works in FL. You might be surprised. They test various stains over a two year span in various parts of the country. They're very helpful and will respond quickly to any questions you may have. 5/4 PT will work as well but 2x6 will resist checking a little better. Secret to good looks and service over the years is to keep it stained with a good penetrating stain to keep it from drying out. I'm not crazy about water based as it tends to just sit on the surface. Good luck. There's a lot of good construction ideas in this thread.
 
  #28  
Old 04-04-13, 06:04 PM
Member
Join Date: Feb 2011
Location: USA
Posts: 8
Received 0 Votes on 0 Posts
That's a lot of overkill on the posts so you can frame in with 2x6s. A deck is more aesthetically pleasing with wider framing. I would be using double 2x12s for the outer box and inside with 2x10s sitting on a ledger on 16"oc. I take it you want the decking running perpendicular to the house. That way you can eliminate many of them posts which what you have is overkill.

The footings instead of going with a round form I usually just free dig the hole and make a 16" ID box out of 2x4s or 2x6s. Below ground doesn't have to be pretty.
With a square design you can round over the edges and again it looks better and is stronger if you bump it with a mower.

I like using 6x6s for the post continuing up for your rail design.

Definitely screw your decking because the hot Florida sun will draw the nails back out. That's the purpose of the raised footings is all the rain you have down there. Setting the posts in the ground just invites rot.

Cantilever is okay if you chose. You can cantilever 1/2 of what's behind it. So if you have 65" behind it you can cantilever 32 1/2" if you chose.

You can dog ear the four corners to eliminate any shifting.

I really need a picture of the house and what siding you have. Stucco? Is any part of the porch at ground level?

I'm not sure of your diagram but framing resting on framing looks cheesy to me.

Give me about a couple hours and I'll draw you some plans of how I would do it.
 
  #29  
Old 04-04-13, 08:24 PM
Member
Join Date: Feb 2011
Location: USA
Posts: 8
Received 0 Votes on 0 Posts
After rereading your post again which I read wrong, lol...

I thought you said 7-10 feet off the ground instead of 7-10 inches. I even drew up a nice plan.

Your only logical solution is to extend with a concrete pad or you could go with patio stone/pavers, stamped concrete, concrete/tile. It would cheaper and you could trim the outside with raised plant beds/retaining wall.

A 20' x 12' x 4" pad is 3 yards of concrete or about $240.
 
  #30  
Old 04-05-13, 10:49 AM
Member
Thread Starter
Join Date: Mar 2013
Location: United States
Posts: 81
Received 0 Votes on 0 Posts
Lol, thanks, I was wondering where you were going with all that.

We've been getting quotes for a Concrete pad. Around here it's quite pricey. For a 12'x18'x4" it will be $1300-$1800 because it does have to be permitted and will require footers bordering it for a future enclosure. We've gotten I think 5 different quotes, and the $1300 was with a discount. Problem is I would need a pump truck to get back to where I want it because I have a fence and no side access. Pavers are about the same or slightly more.

I can do this deck, with the premium decking, for under $800, at Home Depot prices. Honestly I love wood too, I would much rather have a deck then a patio.
 
  #31  
Old 04-05-13, 01:37 PM
Forum Topic Moderator
Join Date: Mar 2005
Location: USA - N.E.Tn
Posts: 46,050
Received 118 Votes on 105 Posts
Just remember that the wood will have a lot more maintenance than concrete. There is a good chance you'll have to clean the mildew off every year and if it gets a lot of sun, restain every 2 yrs. Make sure you use either a waterborne or latex stain. Oil base stains don't fare well in the fla sun.
 
  #32  
Old 04-05-13, 03:14 PM
Member
Thread Starter
Join Date: Mar 2013
Location: United States
Posts: 81
Received 0 Votes on 0 Posts
That doesn't seem like much maintenance to me. If I did the pavers I'd have to pressure clean and seal them every year anyway. The concrete would need to be cleaned as well and restained every few years too.
 
  #33  
Old 04-05-13, 06:23 PM
Member
Thread Starter
Join Date: Mar 2013
Location: United States
Posts: 81
Received 0 Votes on 0 Posts
So knowing that It is only a few inches off the ground, is what I'm doing still over kill? I don't want a bouncy deck, but wouldn't mind saving some money either. Could I get away with 3 beams instead of 4? What if I did 3 beams, but went to 12 or 14" OC instead of 16" for the joists?
 
  #34  
Old 04-06-13, 08:54 AM
Member
Thread Starter
Join Date: Mar 2013
Location: United States
Posts: 81
Received 0 Votes on 0 Posts
Ok I laid out and remeasured. at the house I have 3.5" to the grass, and 12' out I have about 6" to the grass. So assuming I dig down another 1.5" I'll have 5" at the house and 7.5" at the end. I'll be digging everything 2 feet wider and putting mulch down around the deck instead of letting the grass grow up to it. So here it is, will it work? I dug a small hole to check the patio slab, it's 4.5" thick.

Think I will have any water issues? I was thinking of doing a french drain under it just for added insurance? Thoughts? Here's what the back yard looks like.
 
  #35  
Old 04-06-13, 10:02 AM
Forum Topic Moderator
Join Date: Mar 2005
Location: USA - N.E.Tn
Posts: 46,050
Received 118 Votes on 105 Posts
I can't imagine a ground level deck not being a nightmare, you'd be better off with concrete!
 
  #36  
Old 04-06-13, 03:22 PM
BridgeMan45's Avatar
Member
Join Date: Oct 2011
Location: USA
Posts: 3,196
Received 0 Votes on 0 Posts
Based on the recent photo, it appears close to the bottom half of all beams and joists will be below top-of-ground elevation. To avoid that, you'll either have to raise the deck (and step up onto it coming out the door), or excavate a very huge hole in an effort to keep the wood from being buried. Wood floats, so there's a chance parts of the deck will be subject to uplift forces when the hole fills with water.

Believe it or not, but we're trying to keep you from making a big mistake. For your situation, a concrete patio is the practical way to go. Do it yourself for less than $500 in material costs (concrete, mesh and curing compound).
 
  #37  
Old 04-07-13, 03:53 AM
Member
Thread Starter
Join Date: Mar 2013
Location: United States
Posts: 81
Received 0 Votes on 0 Posts
I know you guys are, and I appreciate it. I'm just really dead set on not having another chunk of concrete around the house. After talking with my wife again, if we don't go with a deck, then we won't go with anything and forget about using the backyard. We've been in the house for 5 years now and we haven't really used it due to the ants. Before anyone offers suggestions for the ants, we've already been through them all, including multiple professional services that had to refund our money when they couldn't get the job done. The ants won't come up on a structure though, they just stay in the ground.

I've got one more idea someone suggested to me. This is my back up and punt last ditch effort before I just give up. A guy I know who has built many decks up north asked me why I just don't use 2x4's closer to the house, and make sure they are well supported? He said a 2x4 can span a 5' space and still be solid. This would give me the 2 inches I need, but I'd need to add another row of footers.
 
  #38  
Old 04-07-13, 05:06 AM
Forum Topic Moderator
Join Date: Mar 2005
Location: USA - N.E.Tn
Posts: 46,050
Received 118 Votes on 105 Posts
Unless you make underneath the deck lower than the yard which is a water related disaster waiting to happen, you still won't have enough air circulation under the deck to dry it out when it gets wet. That will shorten the life of the wood even though you'd being using PT wood.
 
  #39  
Old 04-07-13, 06:52 AM
BridgeMan45's Avatar
Member
Join Date: Oct 2011
Location: USA
Posts: 3,196
Received 0 Votes on 0 Posts
Concrete doesn't have to be boring. You can apply an exposed aggregate surface, possibly made even more unique by broadcasting/floating in colored aggregate. Done properly, it will enhance your house and yard, and literally make you want to spend more time out there.

Don't know what to tell you about the ant problem.
 
  #40  
Old 04-07-13, 11:03 AM
Member
Thread Starter
Join Date: Mar 2013
Location: United States
Posts: 81
Received 0 Votes on 0 Posts
I've already got a concrete patio and we don't use it. Concrete is cold and hard, decks are warm and inviting. I've got friends who do decorative concrete coatings for a living, we just don't have any real interest in spending that much money on something we have very mixed feelings about.

I thank you guys, but it seems this is a pipe dream so I'm gonna shelve the idea. Maybe revisit it in a few years.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
 
Ask a Question
Question Title:
Description: