Building a Deck, Day 6 – The Ledger
DAY 6 - The Ledger
Fun fun fun... I discovered a little secret today while working on the dual ledger for my deck. If you have floor trusses in your home - maybe this is true for I-joists as well - you most likely do not have any type of ledger skirting between the trusses and the outer sheeting for your home... meaning, you cannot simply just punch holes every 24" for the ledger lag bolts. If you do, you'll only be sinking the lags into the sheeting fiberboard on the outside of your home, which is not nearly strong enough to hold a deck. Good thing I decided to check by drilling a few pilot holes first before drilling all of the holes in my ledger. Oddly enough, our home has floor trusses spaced 20" oc (on center). That's a strange amount. Not 16", not 24", not even 18", but 20". Odd... Regardless, being empowered with this will save me from a future trip to the lumberyard for a single 14' 2x10. The edges of the trusses are simple 2x4 material, so that means that my lags would need to be about 4" in length (1 1/2" 2x4, 1 1/2" ledger, 3/4" sheeting? - who know how thick the outside fiberboard is on the house). I stuck with 1/2" diameter lags, even though now looking at it, those might have been overkill. The lags will be spaced about 1 1/2 - 2" from the outside edges of the ledger (too close to the edge and they may cause cracking, too close together and they won't provide the utmost stability). The downside to large diameter lags is that you not only need to drill out a hole through your ledger the same size as the shank (1/2" in my case) but you also need to then drill out a pilot hole into your house to make it easy to install the lags without cracks or splintering of the wood beneath. I found the website Portland Bolt to be very helpful in determining the size of pilot hole I would need.
Once I had the holes drilled out on my ledger for where my lag bolts would need to go, it was time to start drawing out where the joists were going to fall on the ledger. This is where I ran into an issue. My whole plan was to surface mount the lag bolts on the ledger, rather than countersinking them. Well, if a joist falls on or near where a pair of lag bolts sit, you have no other options other than to countersink. Trip number who-knows-how-many to the hardware store to buy a 1 1/2" spade bit that I'll most likely never use again. Chalk it up as a deck expense.
Notice the surface mount and countersunk lag bolts. Countersinking was only necessary if a joist was falling near on the ledger.
Don't forget to caulk your holes after you mount the ledger! This can be a easy target for water infiltration into your home. It may only be a small amount, but it only takes a small amount of water for mildew and mold to grow.