Building Code

[dpg]

Can anyone attach the link to any applicable building code(s) for decks? Tried to goggle it and I can't seem to find anything specific for NH. Moultonborough if that matters.

[Descant]

NH Building Codes
These can be more complex than simple project like a deck.
https://www.nh.gov/safety/boardsandcommissions/bldgcode/nhstatebldgcode.html ( I Googled NH Building codes) (I take that back. I Googled building codes" and got nothing, but Chrome/Google suggested "Building Codes NH", "Building codes MA", etc.)

Most lumber yards have plans for a variety of projects, and the good deal is, not only does it meet code, you get a materials list. I bought a set of plans many years ago (pre-internet) and modified to fit my space. Way overbuilt, I'm sure, but the vendor probably wanted to be sure that if an amateur messed up, it would still be sturdy and defensible.

I Googled "deck construction plans" and got several sites with design tools, instructions, materials lists, etc.

[depasseg]

You could ask the Moultonborough CEO (Code Enforcement Officer):
http://www.moultonboroughnh.gov/code-enforcement-officer

Here's a document from Londonderry, but Moultonborough might have their own tweaks:
http://www.londonderrynh.org/Pages/LondonderryNH_PlanEcoDev/bldgdocs/Residential/7

[DesertDweller]

Here is the International Residential Code (IRC).

http://www.awc.org/codes-standards/code-adoption-map

Here are the links to deck building for both the 2009 and 2012 versions of the IRC.

http://www.awc.org/codes-standards/publications/dca6

These are wood decks only (not composite) as far as I can tell.

[DickR]

In recent years, the IRC has been updated to incorporate design features that address the many horrific deck failures reported over the years. Of critical importance are the method of attachment of the ledger board to the house and its flashing against moisture intrusion, plus provision for lateral force protection, which ties the deck framing securely to the house floor framing. Even if the state/town's adopted version of the IRC isn't up to date with current version of the IRC, you ought to follow the more stringent version that addresses safety concerns.

[RUGMAN]

there is also a height maximum after which you will need a rail. think it is 30 inches from grade.. I know this first hand because we keep are height under the max so we would not be required to have a rail system

[DesertDweller]

In recent years, the IRC has been updated to incorporate design features that address the many horrific deck failures reported over the years. Of critical importance are the method of attachment of the ledger board to the house and its flashing against moisture intrusion, plus provision for lateral force protection, which ties the deck framing securely to the house floor framing. Even if the state/town's adopted version of the IRC isn't up to date with current version of the IRC, you ought to follow the more stringent version that addresses safety concerns.

Very good points. I had issues with both the ledger board attachment and flashing in addition to the stairs when we bought our home in NH. Cost me a small fortune to fix my deck but at least now I don't worry about it. There are a lot of really poorly constructed decks out there.

[dpg]

Wow thank you all I'll need to look through all this.

[CaptT820]

I built a 1400 sq. ft complete wrap around deck with farmers roof on my last house, so if you have any questions regarding code, I could probably answer them as I have run into nearly every possible issue during construction. I even had to work around the existing electrical meter, as it was at the exact height of the proposed ledger board. As others have said, the ledger board is by far the most important item on a deck as far as strength of connection to the house and flashing to prevent rot. The best thing to do to make sure of a secure ledger board is to use Fastenmaster LedgerLok screws. The screws are much faster to install than traditional nut and bolt systems, and actually have more strength as well.

[DickR]

... As others have said, the ledger board is by far the most important item on a deck as far as strength of connection to the house and flashing to prevent rot.

A good alternative way to attach a ledger, if you have access to the rim board inside the house, as would be the case with new construction, is with Maine Deck Brackets (http://www.deckbracket.com/). They through-bolt to the rim board. I used them for our deck for two reasons. First, the base plates are very easy to flash dependably against leakage after being bolted through to the rim. Also, if at some point down the road you have to rebuild the deck, including the ledger, you simply unbolt the ledger from the outer flange of the bracket. With a ledger bolted/screwed to the rim and with flashing out over the ledger itself, you have to do major surgery on the house structure. Another advantage to using the deck brackets might be if you have vinyl siding. Having a ledger bolted directly to the rim at an inconvenient height with respect to where the siding laps go might be a problem, because you can't fasten the ledger to the rim with any siding sandwiched in between.

Depending on the height of the deck relative to the top of a concrete foundation, another way to build the deck might be to avoid a ledger completely. I did this on another house, which did have vinyl siding. I had several beam pocket brackets welded up for me, and which I bolted to the foundation below the bottom of the siding. Those supported beams coming out perpendicular to the wall. The beams in turn supported the joists for the deck, which ran parallel to the wall. There was no interruption of the siding at all, and thus no flashing issues.

[CaptT820]

As DickR mentioned and I'll elaborate on, you could just eliminate the ledger board altogether by not attaching the deck to the house. The advantage to attaching the deck to the house is obvious, as you can eliminate 2 piers or more by attaching it. The advantages of building a free standing deck are that you can remove easily if need be in the future, there is no chance of the ledger board failing, and there is no flashing required. You can place your piers near the house at a distance of 2-feet off the existing foundation and cantilever the boards towards the house and still meet code. Just food for thought. You have a lot of options here.