Installing Deck Joists

a conventional way of installing a joist to a ledger is to line them flush with the top and that way when the decking goes across is supported by the ledger and the joist as well but I like to do something a little bit different to help the drainage of the flashing in this area at the ledger by doing it the conventional way when the flashing comes down has a 90 degree Bend and then down the face of the ledger a little bit any water that gets trapped underneath that decking board because it's in direct contact with the flashing it's just going to remain there and it's also going to collect some debris so I like to set the ledger a little bit lower than the floor joist level so about about 5/8 of an inch so when I put a flashing in there I can give a slope to that flashing and it leaves a little air clearance between the bottom of the deck boards and the flashing so water can move right through now to get those joists positioned just right I use a joist hanger installation jig that I just make up out of some scrap lumber and that way I can get the height of the bottom of the joist hanger in cooperation with the height that I'm looking for and then I'll just put a couple of tack screws in and then you'll be able to see how this all planes out [Applause] now when the joist is seated into the hanger I've got that nice clear 5/8 of an inch space then when my cap flashing goes on with the slope on it decking board over water can flow through behind the deck board over and underneath the cap flashing clear out any debris so got a nice clean water-resistant joint so on some older decks you might see where the original installer took a conventionally flanged hanger like this and in order to support that end joist took and bent that flange that extends out past the ledger around to actually nail to the side--oh ledger something like this now that's not supported by the manufacturers or hardware and it's against code now we have what sealed flange hangers also called inverted flange hangers where instead of the flange going out away from the side of the joist hanger it's inverted to the inside so it's concealed and then we just install those and that handles the problem of the end joist on decks now the one thing you have to account for when you cut the end joist is that the fasteners you install to put this in place we're going to actually hold that joist off an extra you know 3/16 or a quarter of an inch so that means that joist is gonna have to be trimmed just a little bit and you're also going to have to make sure you install the hanger before you put the joist in place some people like to nail all the joists down with some tack nails and go back later and straddle the hanger around the joist but in this case with the concealed flange hangers you have to install it first so we'll just fill all these holes up and I'm using some structural connector screws we could use nails as well either of them you're gonna work to fasten this in place you don't have to use the screws so once we got the hanger in we can drop the joist in place drive nails or screws to the fastener holes on either side then we got a solid connection we're ready to move on with the rest of the deck there are pneumatic nailers and battery-operated nailers that drive the same nails that we can drive in by hand but do it with power assist so it's a lot quicker you'll notice I'm using a jig to set the height of my hangers this isn't the only way to set the hangers in place you can do it in number of other ways one way to do it is to take your joist put them in place tack nail them set all the joist up on your hole ledger board and then you can go back later slide the joist hangers up see them nice and level at the bottom and then pop them off you can also just by I set the bottom of the hanger to the ledger board and then adjust the width accordingly to match your lines and then pop it off whichever way you do it you have to count for the height of the Joyce Joyce vary in height particularly with pressure treated lumber somes at nine and eighth inches some nine and a quarter some nine and three eighths maybe we go up to nine and five eighths what I like to do is take my joists measure them all up and see what the range is and then I'll usually adjust those joists in an order in other words I'll start say with a nine and a quarter joist at the end build up into the middle of our nine and 5/8 joist and then taper that back down to my nine an eighth joist and that way I've got the bottoms all set the same this is just a slight crown that'll be in perceiving in the overall deck and that way I can set the hangers at all the same height location using my jig now alternative ways of thinking about that you may want them all flat the thing you got to take into consideration is that at some point all of those joists are going to end up shrinking down and then once it shrinks down it should be all flat so this jig that I'm using is just a scrap to buy block and this leg that comes down is just a whisker over an inch and a half which is usually the width of a pressure-treated joist because it usually still wet by the time we've got them you'll notice that this is set a little bit higher than the bottom of my ledger that's because I want all of those joists to be a little bit higher than the ledger boy to account for that flashing that I'll put on with the slope so all I do to use it is slight hanger around the bottom make sure it's seated a square at the bottom and then I can come in with my fastening tool and drive those nails in okay so we want to look at two things with regard to joist and joist hangers where they connect up to the ledger the first thing is the allowable gap if any that we have between the ledger and the end of the joist and the other is the fasteners that go in diagonally through the hanger into the joist and then into the ledger board so first off when you put a joist in it's critical that you be tight up against the ledger board but no more than an eighth of an inch gap in other words you could have up to an eighth of an inch gap any more than an eighth of an inch gap and you're not going to get the same capacity out of the hanger primarily because those diagonal nails that go in these two nail holes here and the same on the other side aren't going to trap enough of the wood of the joist to be able to fold that down into the seat of the hanger if you have a cantilever on the other end of the deck now the length of the nails is important too you can see here how if we use regular short nails or short screws and we put them at an angle they only get about a quarter of an inch penetration into the ledger board so what we really need to use and what the manufacturer calls for is using a two and a half to a three inch screw and nail and that way when it diagonally goes in and penetrates almost all the way through the ledger board or all the way through so we're getting uplift capacity resistance as well as with rural resistance so the rim joist is a real structural part of the deck you can't overlook the importance of it it's going to resist the tendency of the joist to roll or twist when we load the top of the deck especially on a cantilever like this so what we're going to do is instead of nailing the end of the rim joist into the end of the joists we're gonna put structural screws in these are going to go through the rim joist and embed into the joist themselves by anywhere from three to eight inches now that's going to be dependent on the posts to frame connections that we'll do later on but for this case we're just gonna put in these five inch screws let's drop this down and we'll screw that top screw in and we can work our way along [Applause] we're framing a deck one important connection we can't forget is the joist to beam connection there's a bunch of different ways of doing that depending on where you are in the country you might use hardware you might just use toe nails an area is not subject to high wind uplift loads or seismic loads you can get away with just putting in some diagonal toe nails going through the joist and into the beam check with your local code on what the requirements are there usually it's like two 16 penny nails or two ten penny a hot dip galvanized nails in the hardware realm we got a couple of choices starting with structural screws these can be driven diagonally up through the beam and into the joist there's lots of different sizes available just make sure they're compatible with pressure-treated lumber for exterior use in the hardware group there's a bunch of different choices and we're just going to look at three this one would just nail in to the beam and then nails in the side of the joist here another piece of hardware is a strap style and this will orient to the beam catching a few nails there and then the side of the joist here and another one similar but just a slightly smaller size will orient to the side of the beam and then up onto the side of the joist now these don't necessarily have to be installed to the outside facing part of the beam these could be installed to the inside facing part of the beam so you don't really see them that way if you've got an open above grade deck it's not going to obstruct your view or the appearance of the deck in general so I'm installing a row of blocking directly over the top of the beam between each of the joists and that's going to help resist the tendency of the joists to twist or roll when the deck is loaded with the you know people and their friends and family it's also a requirement of the code so it's not something we want to forget now that blocks have to be centered over the beam and they have to be nailed into the joist on either side as far as the height of the blocks we don't actually have to make those blocks to full height of the joist themselves they only have to be according to code 60% of the height that's just a little over halfway so in the case of these 2 by 10 I could actually get away with say a five or a six inch block but well I'm installing some two by eights just because they're readily available the advantage there is when I set in the shorter block if I'm doing an under direct drainage system where I've got some material that drapes down between the joists sort of like under deck gutters that's going to channel the water away from the area under the deck I can clear the top of that membrane over the top of the block so that they've got some continuity for the drainage so now I'm going to set the block in place now this can be in direct line with all the other blocks or you can offset them it depends on how you like to nail them I like to keep them all in line if I do that I can but nail through this joist into this block but then when I come back here I got a nail at a slight angle but I'll still pick up the nail right into that block now I'm just going to finish up and roll through the rest of these blocks and then we'll be able to move on with the rest of the deck [Music]

Channel: finehomebuilding

Views: 678,557

Rating: 4.865777 out of 5

Keywords: Shop Class, Critical Deck Connections, FineHomebuilding.com, joists, framing, joist hanger, blocking, remodeling

Id: uAaD_0WnOYk

Length: 11min 29sec (689 seconds)

Published: Thu May 30 2019