Simpson AutoCAD plugin

Another note about doing your deck design, and Simpson hardware (which you will pretty much by default in most cases.)

If you do use AutoCAD for your design, don't forget to download the Simpson AutoCAD menu.  It's free, and is really useful for joist plans and footing plans.

Here is the footing detail from my own plans.  I think the detail from the post base and cap really show the strength of the design.

 

The menu is pretty straightforward.  After you download it, it will need to index overnight before you can use it.  Anyway, it makes your designs look pretty professional, and gives reviewers a good visual of what you are trying to accomplish.

San Diego Deck Permits

Well, I'm back from my first trip to the City of San Diego Development Office.  $505 dollars poorer, three hours more frustrated, and with no permit in hand.  A few quick notes on what I learned today:

1. The office keeps very short hours (10-2) on Friday
2. The actually workers are out for lunch from 12-1
3. Residences 50 years old or older require an additional historical review
4. The property line on some older houses may be out of compliance

Pretty tough day.  I've spent long hours focused on actually deck planning, slaving over AutoCAD, learning about deck building techniques... You know what?  After an entire day at the development office, no one has even looked at an actual deck plan. 

I know deck reviews will come (and probably be painful too), but the entire focus today is on our plot of land.  Our WWII box of a house has no historical significance, but they age triggers a review regardless.  It will only cost 1/2 -1 hour of their time ($75-150 of my money) but provided no value, and takes 10 days in the best case.  Painful.

In addition, our property is built up too close to the curb for modern standards.  That triggers a post review of the property.  I'll find out on Monday just how painful that will be, but I'm guessing the pain will equate back to more money.

Galvanic Corrosion... Say What Now?

If you've never heard of Galvanic Corrosion, you aren't alone.  But if you are picking out metal hardware for your deck, it's time to dip your toe into a little science.

I'd never heard of Galvanic Corrosion until I started asking why hardware manufactures always say not to mix different metals for fasteners and hardware.  After all, if you have zinc coated hangers (like I do) and want to use stainless nails (yup, me) that would be great right?  Maybe.  Or maybe not.  Depends on who you ask apparently.

The Escape Hatch

At a very high level, Galvanic Corrosion means different metals can exchange electrical currents, possibly causing one to degrade much faster than it would usually.  That may be enough info for some.  Got it, just use zinc nails with my zinc coated joist hangers... or stainless with stainless.  Good to go.  Jump off now before this gets complicated.

The whole story is way more complicated.

The Standard Line

Here is a quote I've seen repeated in various forms throughout the internet:

Can I combine stainless steel and hot-dip galvanized steel?
No. Stainless steel connectors or fasteners cannot be used in combination with galvanized connectors or fasteners. These two metals are sufficiently dissimilar that zinc will be protecting the entire stainless steel component and, therefore, will corrode at a more rapid rate.

this is from "Corrosion of Metal Connections in Preservative-Treated Wood Structures" on Toolbase.com, a research lab.

And another from DeckMagazine.com

For instance, because stainless steel will degrade galvanized steel, especially in a marine environment, don’t install galvanized joist hangers with stainless steel nails.

in a very good article "Fighting Fastener Corrosion".

So it sounds pretty cut and dry, even if they don't really site any scientific evidence.  Don't mix Zinc coated and Stainless hardware.  Except that isn't what everyone is saying.

The Heretics

So it gets a little more complicated from here.  Here is a quote that essentially contradicts (or at least qualifies) the opinions above.

When zinc-coated screws are used to fasten stainless steel plates, the screws will corrode rapidly. But when stainless screws are used to fasten zinc-coated steel plates, neither the screws nor the steel will corrode particularly fast.

this is from a Metallurgical Engineer in "Understanding Galvanic Corrosion" at Design News.  It's a very interesting article.  It isn't taking a position on whether you should use stainless hardware, just discusses the metallurgy behind Galvanic Corrosion.

Another, even more technical resource, gives a remarkably similar answer

Does galvanic corrosion occur when these metals are in contact?

... when stainless steel (300 series) are in contact with zinc, neither material will suffer additional corrosion, or at the most, only slight corrosion.  The slight corrosion is usually tolerable when in this bimetallic contact.

 This is from a PDF Q&A called Dr. Galv on the American Galvanizers Association.

I'm not even going to try to summarize the science.  I'll just say they make a pretty convincing case that as long as the stainless is smaller than the zinc, the corrosion effects will be minimal.

The Manufacturer

Since I've already selected my joint hangers - Simpson LUS210Z - what does Simpson have to say?  I emailed their customer service.  Here is their response:

Simpson Strong-Tie® recommends fasteners with a coating that meets the specifications of ASTM A153 be used when using ZMAX/HDG galvanized connectors.

We also recommend the use of stainless steel fasteners when using stainless steel connectors.  It is a known fact that the galvanic corrosion can occur when dissimilar metals are in contract in the presence of an electrolyte.  

Simpson Strong-Tie has not performed any research on galvanic corrosion or the extent of corrosion when stainless steel fasteners are in contact with a  ZMAX connector.
Attached is information on galvanic corrosion published by “The Specialty Steel Industry of North America (SSINA)”.

Thank you,

Customer Support Technician
Engineering Department
Simpson Strong-Tie Company Inc.

Here is the chart they referenced from “The Specialty Steel Industry of North America”.

 

The Verdict

Well, I'm going to email some of the sources above, see if I can get any comments.  Personally, if I could ask for one thing, it would be real field research on long-term effects of Galvanic Corrosion.  Particularly in the context of a marine environment.  I doubt I'll get it.   So unless my inspector enforces his opinion on this, I'll be left with conflicting information to make my choice.  

If I had to decide right now, I'd go with stainless nails on my zinc hardware.  I think the risks of corrosion of the zinc hardware don't overwhelm the known effects of ACQ pressure treated lumber and marine air on non-stainless nails.  Is it the right decision?  I guess I'll let you know in about 15 years.

Feel the tension in the... rail

Our house has a fence around the backyard.  It's about 60 years old, and is in rough shape.  It never fails though.  We have a party, and the minute any boy under eight arrives in our yard, he is trying to bounce off the fence.  Fortunately it has never failed us.  I'd like to say the same thing about my deck railing one day.

Poorly built railing injury more people than any other deck issue other than collapse.  So even if it's that last thing you plan on your deck, its worth spending some time focusing on.

Here are a few decisions you'll be facing:

Railing Posts

Post have to attach to your deck somehow.  Your options are:

1. Inside the joist, bolted to the joist 
2. Outside the joist, bolted to the rim

Personally, I am planning outside.  I like the way inside railings looks, but I think they have a couple issues.  They take away useable deck space, and they introduce a lot of cracks for water to get trapped in.  Good hardware can make outside connection plenty strong.

Lag Bolts and Carriage Bolts

I don't think there is any question here.  Carriage bolts, stainless in you can fit it in your budget, with a big fat washer.  Lag bolts can't be tightened over time without stripping out the wood eventually.

There are a lot of sources for carriage bolts, but your probably going to need to really long ones for this.  I'm looking at 1/2" x 7 or 8 inches long.  Take a look at Bolt Depot, and compare prices from there.  They have a good selection, including Stainless Carriage Bolts in 18-8 type stainless.

I've had some luck finding bigger groups (like 25) cheaper on eBay too.

Rail Tension Hardware

I'm adding some rail tension hardware as well as the Simpson DTT2Z-R2 Deck Tension,
over at Amazon, they have a 20 pack as well, which is a pretty good deal at $6 each.

These tie the railing into the joists on your deck.  That adds a couple thousand pounds of lateral resistance.  Not sure there are any major alternatives to this product.

Using the Bosch GLM 100C Laser Measurer

I've been playing with my new Bosch GLM 100C.  It's a really interesting evolution of the laser measuring device.  I thought I'd link together some videos of setting up and using this device with my Android OS Samsung Galaxy Nexus phone.

First step is pairing the GLM 100C with your phone:

Unfortunately, the directions are pretty sparse on the pairing.   Here are the steps I used to get it up and running:

On the Bosch GLM 100C

1. Turn it on
2. Press the Bluetooth button
3. The Bluetooth icon appears on the screen

On the Phone

Get the Bosch GLM Measuring software

1. Download a "QR Code Reader"
2. Scan the QA barcode 
3. Follow the link and download the application 

Pair the Bosch with your Phone

1. Go to your settings
2. Open the Bluetooth settings
3. You should see the Bosch under "unpaired devices"
4. Select the Bosch GLM100C, and it will automatically pair

Using the GLM Application

1. Open the app
2. Select "Remote" from the bottom menu
3. Open the menu in the top right
4. Select "Bluetooth Connection"
5. Select your Bosch GLM100C from the options

Take some Measurements!

1. Black bar above will say "Connecting to Bosch GLM100C"
2. Go back to the "Remote" screen, the remote button should now be red

The applications for deck building are pretty obvious in general.  Another feature I'm pretty excited about is the ability to calculate a triangle.  I'm not sure I'll need it for this deck, but if the deck had any elevation at all, it would make a lot of sense.  Did a quick instruction video on that as well.  Pretty simple, but cool.

Joist Hangin Around

Regardless of how your deck is designed, you'll be hanging some joists before you are done. With stacked joists, you just need a few for your ledger and header. For my free-standing deck, with flush joists I'll need a lot more. My current plan calls for 16" OC (on center) gaps between joists on a 12' wide deck. That comes out to 9 joists. With 4 beams to hang joists between, that comes out to 27 joists, and 54 hangers. That's a lot of hangers, and a lot of nails (or screws.)

So how to figure out what joist hanger is right for the job? Let's simplify the choices a little first.  What are we looking for for deck construction?

Face Mount 

There are top mount hangers, but we can mostly ignore those.  Face mounts are attached right into your beams or ledger.  Perfect for the exposed wood of a deck.

Z/HDG/SS

That stands for Zinc, Hot Dipped Galvanized, or Stainless Steel.  Only hangers somehow protected from the elements should be used.  If they are touching any pressure treated lumber, they will corrode even faster.  Zinc is the most affordable option.  Stainless is the best, but will cost you at least 4 times as much.

External or Concealed

External flanges are cheaper, and work for most applications.  If your hangers will be visible from outside the deck, consider concealed.  Also, if you have end hangers that can't be attached on both sides (like the end joists on a flush mounted deck) they can work.

Size it Up

Since your joists are probably 2x lumber, you just have to worry about length.  You can go to the Simpson site, they will tell you which sizes will work with your lumber.  There is usually a range, a 2x8 hanger can work with a 2x10 joist is it's rated for it.

Check Your Loads

This is a little more complicated.  This is a chart from Simpson that shows loads for some hangers.  It's great to know the loads, but you will need some engineering to understand what you need.


Here is another chart that shows loads with nails rather than screws.



I'll leave the nails and screws for another time.

Alternatives to Pressure Treated

By way of a spoiler, I've done my research in this area, and still plan to use PT lumber for framing.  That said, I think it's worth mentioning some of the other options.  Maybe they are what you are looking for, especially if cost isn't an issue...

Redwood

This is a pretty obvious one.  Naturally resistant to rot and termite damage, pretty long lasting.  It is more expensive that PT, but it also looks better if you have exposed framing.  The stuff for framing is called Construction Common, or con-common.  It should be heart wood, not sap wood.  A 4x4x8' board should run you about 50% more than you average PT board.  Most of what I've read leads me to believe redwood won't last quiet as long as PT.  Especially the young growth they sell now.  This article from UC Davis Selecting Lumber and Lumber Substitutes for Outdoor Exposures says young growth is only moderately resistant to decay.  This chart from the article says a lot about the expected life of young redwood:

Acetylated Wood

Of the alternatives, this seems the most interesting going forward.  The largest manufacturers seems to be Accoya and Eastman.  Like a lot of manufacturers, you can't buy direct, you have to try one of the distributors on their website.  Not that many listed right now, so you need to see if there is one near you.  The big disadvantage is cost.  When I heard 3-4 time the cost of PT, I can to kick this option to the curb.

Silica-Infused Wood

It seems like this is a one company product right now, with TimberSil.  I've read a lot of strange reviews about this product.  Basically the Silica glass is baked into the lumber, creating a barrier.  Some reviews have brought up strange mold and "fur" issues.  Also seems to have some issues with distribution on the west coast at least.  Worth a look though.

Treating Your Cuts

One thing that you really need to do: coat all your cuts with some form of Wood Preservative. They one I used on my fence, and plan to use on the deck is Copper Green, which contains Copper Naphthenate.

Here is one link over at our Amazon affiliate so you know what you are looking for:



Green Products 210-294 Wood Preservative, Copper/Brown

Although they make a brown product which I used, the color fades anyway, so I wouldn't worry about the color. But it treats the cuts to prevent rot. The middle of most PT wood is not treated, so when you cut, you are exposing the wood to the elements.

There are other wood preservatives.  I'm not aware of any definitive comparison of these products, so all I can say is I have had good experiences with this one.

More Deck Protection

Let me throw another tidbit out. Put some felt asphalt along the top edge of all you beams and joists. Just like tar paper for a roof. Also, you can put this between your pressure treated wood, and your hardware. PT lumber is corrosive to galvanized steel, even hardware with lots of zinc is not immune.

It's a cheap and easy way to keep moisture off of your framing.  Here is a link to the option I'm planning to use over at our Amazon affiliate Vycor Deck Protector 4" x 75' 

Check out this PDF over at the Grace Vycor site if you want to read up some more.

Another alternative on Amazon is Cofair DFB375 Self Adhesive Deck Flashing 3" X 75' Roll/75'

What Happens to a Deck of Cards in the Rain?

They get wet. So will your deck... unless you are planning to cover it completely. I have no plans of permanently covering my deck. As the song says "they say it never rains in southern California, but man it pours." Well, it does. At least for a couple months anyway!

A couple points I'd like to hit here. Pressure treated lumber - I am going to use it for all my framing.  I think you REALLY should too, even if your code says you don't have to. The lumber is the strength and support of a free-standing deck. If it fails, all this is for nothing.

There are different levels of "PT" lumber:

1. Ground Contact
2. Above Ground

All Lumber will be clearly marked with tags stapled on the end indicating which of these they are.  This image is a label from an article at familyhandyman.com called "Identifying Treated Lumber", which described the subject in great detail.

It's important that at least your post be Ground Contact.  If your beams are within 18" of the ground you should probably make those ground contact too.

Deck building resources

Inspecting a Deck, 

by the International Association of Certified Home Inspectors (InterNACHI)

This is an excellent resource.  It isn't really about HOW to build a deck, although it has plenty of information on building.  It's about what inspectors should look for in a deck... or put another way, how NOT to build a deck!  They also have some good free-standing deck advice.

PrescriptiveResidential WoodDeck Construction Guide 

Based on the 2009 International Residential Code by the American Wood Council.

Excellent reference.  Especially if your locality doesn't publish their desired dimensions.  Joist span tables, footer size, Beam sizes.  Even a nice illustration of a free-standing deck, and excellent descriptions of bracing for free-standing decks.

Recommendations for the Construction of Code-Compliant Decks

by Simpson Strong Tie.

Yes, all their recommendations are bound to be Simpson products, but the language is clear, and their examples are good.  Frankly, most of us will end out using at least some Strong Tie products since that is really all Home Depot seems to carry these days.

Don’t Build Decks That Rot  

by Professional Deck Builder March/April 2007

An interesting article on the North American Deck and Railing Association site. Strong opinions against some deck building practices like notched posts and built up beams.  Some interesting techniques as well, such as wider deck board gaps borate treatment on the frame.

Smart Deck-Framing Strategies

by Mike GUERTIN originally published in Fine Homebuilding 2008, on Bostich.com

Another article with a few tidbits.  The deck they are building is elevated, so it has some information about temporary supports and working at heights I won't cover here.  Another advocate of using flashing around deck hardware to keep the PT lumber from corroding the hardware.  Also uses brackets to attach the ledger to the house, which is a nice concept if you can't do free-standing.

Porches, Decks, and Outbuildings

by Fine Homebuilding, 1997

A bit dated.  Google has posted parts of the book online.  The link should open to page 63.  The picture of the effects of 14 years of exposure stainless and galvanized nails.  Pretty telling.

Two 6 beats a pair of 4?

Just a short post on posts...  See what I did there?

For most decks, you really get to choose between 4x4 and 6x6 posts.  Some really big decks can go big on posts, not us.  In my area, they define any deck over 8' as requiring 6x6.  

I think from a looks perspective, as well as strength, most decks should go 6x6 over 4x4.  From a lumber cost perspective, the impact isn't massive. Online HomeDepot.com has 8' 6x6 for about $21, and 4x4 for $8.  There are downstream costs though.

For my 12 post deck, I only need 6 of those, maybe a couple more for angle bracing. Lets say 8 boards.

Here is my cost impact that I see:

1. lumber (21-8) * 8 = $104
2. post bases (35-27) * 12 = $96

One possible advantage in 6x6 I see though, is the ability to notch the posts.  Obviously you need a little more post in terms of length, but only 1' per post max.  Then the trade off is post cap vs. bolt prices, which should come solidly on the side of notched posts.  If you have to use post caps though, it adds even more cost!

Cap it off?

As I write this, I don't know the answer to this one.  How to cap off the post?  Almost all deck designs have the beam resting on top of the post.  The question is, how do you connect them?  What is strongest?  What's the best value?

• Notch the post

• Use a hardware cap 

I've got to get on the horn with my local development office.  I've read that notching is not up to code in California due to earthquake concerns.  It's also a concern as a water collection point, which could lead to rot an instability.

The CCQ caps above are crazy expensive though.  The CC66HDG is $83 at homedepot.com, which would be about a thousand dollars for a 12 post deck.  Ouch.

UPDATE: In the end, I settled on using the BC series.

Mine are the BC46Z here at Amazon, which they also have in 10 packs over at Amazon.  That is in the Z-Max series, and works with 6" posts and 4" beams, which is what I am planning to use.  They average about $8/ea with shipping for me, and provide about 1000lbs of lateral load support. Should be an excellent addition.

Base Camp

A friend asked me today "how do you start a deck?"  My answer was to make some drawings... but what he meant was, what do you physically do first.

Column bases are something I've already been thinking about a lot.  Free standing decks need as much bracing as you can give them.  There are a variety of Post/Column bases over at Simpson Strongtie.  I've already selected mine.



The CBSQ66-SDS2HDG. The bottom half is embedded in the concrete, and the top straps go around the 6x6 posts I will be using.  Lot's of strength there.  Simpson does make a point of stating on all their bases that they are not designed for decks without top support.  So these are no substitute for bracing, but they should provide excellent strength.

Notice the HDG in the name.  Mine are HDG - or Hot Dipped Galvanized. We live within 3 miles of the ocean. That means metal will corrode VERY quickly. Even "Stainless" outdoor things rust here. HDG are coated in Zinc, which should hold off the rust a lot longer. Ideally everything would be 316 marine stainless, but that's not practical for heavy pieces of metal like this.

AutoCad... yet another skill you don't have

Not everyone needs to get their deck permitted.  If you don't know, check with your local development board.  If you do, or maybe even if you don't, you should learn how to make drawings of your deck.

I downloaded the free trial of Autocad and did a plot plan for our property.  That's just the mile high view of the property.  You just need to measure your property (ideally with a laser- this is my review of my Bosch GLM40) and make pretty one dimensional pictures.



After that, it gets a little harder.  My area requires a whole host of plans.  They want a

framing plan
foundation plan
elevations
cross-sections
connection framing
connection details

I really bogged down trying to do an elevation plan.  Then my 30-day trial ran out.

For doing my little doodles on this blog, I did find the AutoCAD 360 Web is free (at least it is now.)  Nice little tool that is not as complex as the full version.  Not sure if it's good enough to do a full design document, but maybe the connection details, or top down framing plan?

Anyway, one more thing to know if you want to pull this off by yourself.

A Stacked Deck... or Straight Flush

My deck is exactly the wrong height. Too high, and too low at the same time.

Here's the issue. In my area, if a deck is under 30" high, no permit is required. My deck will be 41" at the highest point. That's an expensive eleven inches I'm afraid. I also have a crawlspace access door that is 3 feet from the ground to it's top. To top it all off, the lower end of the deck is only 24". We also are required to have 18" clearance under the deck, so that will be tricky.

It didn't really occur to me that I wouldn't be stacking my joists across my beams when I started this project. It seemed like that's how everyone does it, unless they were building a deck right on the ground. However, it does increase clearance in any deck. In my case, I have 11" between the top of the crawlspace access door and the deck surface.

Here is a simple visual of the problem:

After decking, we're already 15". That's with a modest 8" beam, and 6" joist. I'd like bigger support members to allow wider post spacing, so I'm looking at 10" beams and 8" joists right now.

I also think that flush design could add significant strength to a free-standing deck.  Simply put, a beam that wants to twist, has to force all the joists to twist with it, and force them out of their joist hangers.  Now, obviously bracing provides most of the stability, but I like redundancy, and I think flush joists will provide some.

So, for me, it looks like I'll be going for the straight flush. Too many deck of card references. Ok, got it.

free-standing ain't free

I'm sure there are other decisions you should make first. Location. Cost... Whether you want to just hire a contractor and stop reading blogs...

For me, it was ledger-boards. Never liked them. From the moment I started my backyard deck project, I'd always envisioned it as a free-standing deck, even though it will be next to my house.

Here's the pros and cons of a ledger-board as I see them:
Cons

1. Caused almost every deck failure I've seen
2. Could add lateral force to your house in an earthquake
3. Could compromise the water seal of your house

Pros:

1. Provides stability to your deck
2. Saves money on posts
3. Makes it easy to level your deck

For me, I could have stopped the list at the first bullet point. Over 90% of deck failures can be directly attributed to the ledger board. That's reason enough to consider free-standing. Yes, the problem can be mitigated by hardware. However, if you have a problem, how would you know?

Image an story from MyFoxAtlanta.  Just search deck collapse on google.  You won't find many that don't look at lot like this.

Our house contributes to the second con as well. It's a post and beam box from 1948. It hasn't has a seismic retrofit (yet) so it needs all the work Simpson describes here Seismic Retrofit Guide. That will happen eventually, and add a lot of strength to the house. Even then, I'm not sure I want to find out what a few thousand pounds of deck feels like adding lateral force to my house in an Earthquake.

So, that means I lose all the pros. More diagonal reinforcement will be required. Another row of post, costing hundreds more. And I need to level the deck without a nice straight ledger to guide me. So be it, I'm going free-standing.

About our backyard deck...

Well, it doesn't exist yet. I'm writing this late in the planning stage. I've been thinking about this deck since we bought our house a couple years ago. Probably planning off an on for 6 months... not steadily mind you, just a little at a time.
Who am I? Nobody really. Just a homeowner in California. I'm not a contractor, or carpenter, or anything special. Just a guy in his early 40's who thinks he can build a deck.
Why this blog?
Well, in part it's for me. I want to capture my thoughts on different design points... free-standing or attached? flush or stacked joists? post cap or notched posts?
The other part, it to share. I already posted reviews on youtube, and think I could capture some of my experiences there. But that lacks continuity. I'd like others who are thinking they could build a deck to share in my thought process. Maybe it will help someone?