What Constitutes A "Free Standing" Deck?
Front view of deck
I paid to have a "free standing" deck with a rear support beam and rear support poles. What we got is a fully attached deck with a beam and support posts installed at the end of the deck build.
My question is, what classifies, or makes a deck to be considered in the industry as "free standing?"
Over 60% of the joists have an air gap between the underside of the joist and the beam closest to the home. The joists are in no way anchored to the rear beam. They are all anchored by joist hangers attached to a ledger board that is fully attached with lag bolts to the house.
Our Virginia county inspector agrees that we did not get what we paid for and the rear beam now only serves as a show piece with no purpose. We are not even sure anything can be done at this point. Thoughts? Suggestions? Insights?
This story you have shared has really surprised me as I have never seen anything quite like this before. Your deck is definitely not a "free standing deck". I would call this a "faux standing deck" to be honest. Same initials - FSD
- but totally different.
Let's break this free standing deck concept down into bite size pieces for everyone to understand. I would hate to see other people find themselves in this predicament.
What Is A Free Standing Deck?
For a deck to be free standing it really must be unattached to any other structure like a house. It can be within 3/4" to 1" from the siding or exterior of the house and appear like it is connected to an untrained eye but it is truly freely standing from the house.
There are plenty of very good reasons that a homeowner would like to have a free standing deck. These kinds of decks are often built in a renovation project after the house has already been constructed.
Avoid Connecting To Ledgers If Possible
When you build a deck that is not connected to the ledger you obviously avoid all the complicated carpentry and building techniques that are required and often mandated in order to do it properly.
Things To Understand About Ledger Connected Decks
Here are a few of the challenges you will experience if you decide to ledger connect your deck. You will have to carefully remove whatever kind of exterior siding, cladding, masonry, stucco material your house uses. You will have to remove it high enough up that two layers of mechancical flashing can be installed properly to make the connection water tight.
There are now some good alternatives to mechanical flashing such as many of the adhesive membrane materials. But again, this is critically important work.
You will also have to gain access to your floor joists from your basement to determine which way the joists run. You will also have to note whether the joists and rim joist are dimensional lumber or engineered joists. You may have to install dimensional lumber blocking depending on what your investigation reveals.
You will then have to attach the ledger to the rim joist and carefully follow one of several accepted building techniques. Just so you know this very issue is one that is constantly talked about in builder circles as to what is required, what is overkill, what is necessary and on and on it goes.
Trust me, there are only a few situations where you definitely should and indeed must build a ledger connected deck, second storey walk out decks are one very good example. But a free standing deck is by far the first concept you should be considering.
Well Then What Is A Floating Deck?
You will often hear the term "floating deck" interchanged with "free standing deck"and you along with many other people may wonder what the difference really is. Think of this...All floating decks are free standing decks. But not all free standing decks are floating.
I just mentioned that one of the benefits of building a deck that is not connected to your ledger allows you to avoid all the labor, skill and cost involved to properly open up a building's envelope and surgically connect, waterproof and install a ledger board and re-install the siding to make it look like new.
What I did not mention is that the deck itself can now be set on footings which are poured cement and buried deep into the ground with the underside below the know frost line depth - ergo a "frost footing". Or the deck can be supported on "non frost footings" making it a free standing and floating deck.
When the deck is supported by non-frost footings it becomes a "floating deck".
What Is Unique About A Floating Deck?
A floating deck will move very slightly over the course of seasons but always within a predictable range. So if you live in a northern area where a good winter freezes clay (water laden) soil to a depth of 36" or more you will - if you are willing to measure before and after - be able to observe an upward movement of your entire deck proabably about 1/2".
This movement is imperceptible to the eye. You will have to make a mark against a non moving structure - like your house - in the summer and then measure or observe it in the middle of winter and you will see your deck has risen a tiny bit. Then in the spring when the soil thaws your deck gently and imperceptibly descends once again to its natural and happy resting place. It will do this annually if you have cold enough winters and soil with a lot of moisture. If you have sandly soil where water drains quickly you may not see any movement.
That's all for now on floating and free standing decks. Let's take a deeper look at Craig's faux standing deck.
An Inspection Of Your Faux Standing Deck
Taking a look a the first photo it appears like one of the support posts for the outer carrier beam is missing and the posts are asymetrically located. Or was a fourth post later installed? Can't really tell from this photo.
Lots Of Bracing Is Required
One thing you must do is build in lots of bracing from posts to beams and joists as well as cross brace the joists underneath in order to make the structure as stable as it can be. It is supposed to be standing firmly all by itself if it is a free standing deck.
What Is The Height Restriction For A Free Standing Deck?
There is no stated height restriction that I have been able to find in the IRC. What there is however are limits to the square foot area of a structure like free standing decks (See Section R403.1.3.1, Exceptions 1 to 4). There may be local ordinances that differ so be sure to check.
For those visitors from Canada, I have also read the CBC and it has a section that permits decks to be built on non-frost footings so long as the deck is not attached to the house. But it applies an arbitrary height restriction of 24". This presumably is intended to address the use of concrete blocks but does not recognize that above ground pools decks as just one example can be fortified like a brick house and built on non-frost footings.
So that is just a quick summary of the height restrition issue regarding free standing decks in North America. Things may be different in the UK or elsewhere.
But just as a general rule it is not wise to build a walk out deck as a free standing deck. It's one of those situations where almost always and for good reasons, a ledger connected deck is built and supported on deep set concrete footings that will never move regardless of the climatic conditions.
So here you were trying to build a free standing deck and it appears to be a ledger connected deck which is in retrospect a very good thing - provided that your ledger connection was done properly.
A Good Rule Of Thumb For Height Restrictions
I can speak from years of experience that free standing decks can be built extremely strong easily up to six or seven feet high. This requires 2x6 diagonal bracing from post to beam and cross bracing underneath the deck framing. But the end result is a geometrically indestructible - and hopefully beautiful - free standing deck.
Going higher than that is possible I suppose but you start to get into a second floor walkout deck which really takes you into the territory where you should be building a full on ledger connected deck.
What Use Is The Beam Near The House?
This is a head scratcher. Your deck is connected to the ledger. I can only assume it was done properly with all the waterproofing measures that are needed. And if that is the case, then this beam which does not even make full contact with the underside of the joists is for aesthetic value only. Its only possible purpose is to serve as a fail stop should your ledger connection magically fail one day. Your deck would then drop down onto the beam and not fall to the ground.
In Virginia you probably do not have much to worry about in terms of deep frost in the average winter. But for our other visitors, consider the risk that this type of construction creates if you are in northern climate...
The Inside Beam Must Never Rise Up
Since your deck is connected to the ledger it is very important that the beam near the house never be subject to any uplift for any reason. Otherwise it will cause stress against the ledger connection. On the other hand if the soil near you house is disturbed from recent construction and not settled you can expect some subsidence to occur over the next two years or so. If that is the case the beam will drop further below the joist framing. Keep an eye open for this.
Your situation has raised a number of discussion points and hopefully most of them have been well covered. The bottom line is your deck is not a free standing deck but rather what I would affectionately refer to as a Faux Standing Deck