Aug/090
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′ 2×10. The edges of the trusses are simple 2×4 material, so that means that my lags would need to be about 4″ in length (1 1/2″ 2×4, 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.
Aug/090
Building a Deck, Day 5 – Cutting Posts
Concrete may not cure instantly, but it does cure quickly. The Quikrete I used (Quikrete 5000) stated that it could support a 1500PSI load after 1 days of curing. That’ll be strong enough for me to setup and mount posts, and by the time I get around to add the deck boards, it will most likely be past the strength that I need it to be at.
DAY 5 – Cutting Posts
I didn’t have a water level or any fancy site levels, so I instead came up with the idea to use a standard laser level on a tripod at dusk. I setup the tripod a few feet further away from the house than my cement piers, leveled the laser (with the built-in level) and shot it at the ledger. I adjusted the height of my tripod until the laser was level with the bottom of my ledger, effectively marking where the top of my beam would rest. Mark that location, subtract 9 ¼” for the height of my beam (2×10’s) and mark a line to make the cuts for my beam. I did this for all 4 post locations and called it a night.
After sleeping on it, I realized that by just being off level a little could have thrown my measurements way off base. I was shooting from about 12 ft from the house. If my level was off by a mere 1 degree, my post could be cut ¼” too long or too short. Not the worst possible issue, but what if it was off by 3 of 4 degrees? Now we’re talking about the post being cut too long or too short by nearly an inch. Being cut too short would be a huge issue as it would require yet another trip to the lumberyard (they know me by name at this point). So, to verify my measurements, I used a 2×4x10’ on edge nailed to my ledger (eyeballing it to make sure it didn’t have a sag or a crown). Turns out my measurements were short by about ¼”. Looks like the level on my laser level doesn’t quite live up to its name – I’m sure there’s an error percentage built in somewhere in the manual, but at this point I wasn’t interested – I had what I needed. Since the posts are PTP, I need to cut them so that my deck will sit level. As the posts age and dry, they’ll shrink slightly, creating a minute pitch away from the house that will aide in shedding water. If I build this pitch into the design, it would only worsen over time.
Four cuts later, my four posts are ready. To keep them close to level after setting them up, I need a few scrap pieces of 2×4 that I can screw into stakes I’ve pounded into the ground and into the posts. Using a post-level in this instance makes this step go much faster than a conventional level:
The tricky part is even after you have screwed your posts to the scrap braced you created with stakes and 2×4, you still have to keep them relatively straight while you nail them to the post mounts in your cement. A few good smacks with the hammer on a 16d nail and the post may shift a little. Probably nothing to worry about, we’re only talking about a couple of degrees off level, but if you’re anal…..
Aug/091
Building a Deck, Day 4 – Pouring Concrete
DAY 4 – Pouring Concrete
Not nearly as fun as you would think – even if you think it might be the slightest bit fun. Bags of pre-mixed concrete are extremely dusty, so a mask is a must, unless you would prefer to have a mustache made of cement.
SO, how much cement will you need? The formula is rather simple. Take the radius of the tube in inches (which is ½ the diameter), multiply it by itself, then multiply it by Pi (3.14), then multiply it by the height in inches. So, an 8” tube that is 4 ft in length would be 2411.52 (4*4*3.14*48). Divide this number by 1728 – the amount of cubic inches in a cubic foot – to find out how many cubic feet of cement you will need per tube. That means for an 8” tube that is 48” in length, you would need 1.40 cubic feet of cement (figure on 1.5 cubic feet to be safe). In my case, I was planning on cutting the tubes to 40” and leave the last 8” as a wider earth-formed footer to my pier. The holes I dug were about 12” wide, so I instead would need a total of 1.68 cubic feet per hole – 4*4*3.14*40 = 2009.6 / 1728 = 1.16 cubic feet for each tube plus 6*6*3.14*8 = 904.32 / 1728 = .52 cubic feet for each footer. I rounded that up to 1.75 cubic feet when buying my cement, which is how I came up with 12 bags (Quikrete says their 80lb bags will produce approximately 0.6 cubic feet of cement).
<RANT>
So, Home Depot, I’m calling you out. When you see a guy grabbing one of those platform carts, strolling over to the bagged concrete section, don’t just stand there and watch. Better yet, when you ask him, “How’s it going?”, and he replies “Good, but these bags are heavy,” don’t just pass him buy on your way to the break room. I know, foolish me, I forgot to say the magic words, “I could use a little help here,” but for f*** sake, it is implied. I wasn’t dressed like a construction worker, I didn’t have 4 buddies helping me out, it was me by my lonesome on a Monday morning, loading 12 bags of concrete onto one of those flat pull carts, then huffing them out to the parking lot where I again had to load them onto my trailer. No help what-so-ever. Shame on me for not asking for help? Shame on you for not offering.
</RANT>
During my trip to Home Depot, I decided to further punish myself by renting a cement mixer from their rental department. My previous rant is almost negated as the guys behind the rental counter were awesome. They fully explained the ins and outs of the new-style mixer (plastic barrel, very lightweight) and that you had to hose the entire thing out before using to minimize the amount of release-agent they spray in the tumbler. I’ve only mixed cement one other time in my life, and it more like helping mix cement, as I was probably only 10.
Once I got everything home, I made sure to wrap the cement tubes in plastic before putting them in their holes. This theoretically will help prevent water from seeping into the cardboard tubes from the outside and then freezing in winter, causing a mini-frost-jacking effect. I suppose if you are required to use rebar in your piers, you probably have less to worry about. We have a relatively high water table with clay soil in our area with that holds water like a high-school grudge, so I want to do everything possible to keep water away from these piers. After wrapping the tubes, I set them in their holes (8” tubes made my Quikrete – seem as good as the Sonotube brand) and leveled them off, making sure to tack them to some scrap lumber I had to prevent them from shifting, fired up the mixer, and started mixing some cement!
Mixing and pouring cement is not an easy task. It seems easy enough…just add water. But getting the right consistency so that you can pour/slide it out of the mixer while not having it turn out runny is delicate balancing act. I followed the recommended water amount that Quikrete provides on their bags, but found the cement not nearly wet enough to work with (it was almost clay-like). After tampering with the amounts, I found the best method was to just add water with a garden hose, 1 second of flow at a time, until the cement was about the consistency of oatmeal. This would allow me to tip the mixer over the hole and run about ¾ of the cement out of the barrel, leaving me with only ¼ of the original mix that I would have to slide out with a shovel. I had to mix 11 ½ bags to fill my four 8” tubes (~40” in length with an 8” earth-formed footer that was ~12” in diameter). Oddly enough, completing the pours by myself took just over 2 hours, much faster than I originally thought. I happily returned the cement mixer to HD to take advantage of their 4 hour rental window, rather than being charged for the full 8 hours.
Before my concrete cures too much, I needed to insert a single J-bolt into the each form. This will allow me to later add a post mount to the peir, and allow for a little bit of play. I decided against the wet-cast post mounts for this specific reason – once you set them in place, they’re in and they don’t move. If you realize after the concrete cures that you’re alignment was off by 1/2″ or so, or that you’re mount is slightly twisted, you’re screwed. You have to work with what you’ve got at that point. With a J-bolt, I can align the bolt with my strings (which when put back in place should show the center line of my posts) and if it happens to be off by a little, no big deal! The post mount that accompanies the J-bolt allows you to slide it up to 1″ in either direction from center, not to mention that it simply slips over the bolt, so you can rotate it 360 degrees, ensuring that you’re posts are not skewed in relationship to each other (extremely important when trying to mount the beam on top).
