when it comes to installing a deck over concrete like i have here it's a pretty basic process just as long as the concrete is in a good sound condition the main thing is to keep those floor joists off the concrete and use construction grade timber that is rated for outdoor use and there is a plethora of options available in regard to how to attach those floor joists to the concrete either via metal brackets or plastic adjustable pedestals now that's all great but i have a bit of an issue and that is a load clearance issue from the top of the concrete to the top of the floor which is going to be the top of the deck is only 55 millimeters and by the time we run that out to the end of the deck it's 85 millimeters which means that there is not enough clearance to fit a plastic pedestal or a metal bracket and that means that i'm going to have to cut a taper on all of these joists fun times ahead just very quickly how's this about one hour after i shot that last piece of footage we had a massive hail storm like you've never seen before it's caused monumental damage to roofs cars and vegetation so i've spent the last couple of days repairing damage and cleaning up just a bit to go so stick with me and we'll get back to that deck the first thing we need to do is to start cutting those floor joists to size using my brand spanking new 12-inch dewalt miter saw seriously this thing is an absolute beast the next mission was to knock up a jig to make those taper cuts now using a couple of old fascia boards for the base i nailed down some blocks in two perfectly straight lines the width of the joist apart and next to them screwed a spare joist down to the fascia board to help support the saw base [Music] and all i can say is bring on summer as those legs could really do with a tan once you've worked out the height of the joist from one end to the other flick a straight line with your chalk line now just quietly this is one of the best little gadgets ever invented and i'll link to one down below if you're interested now the groove i made with the knife acts as a third hand and helps hold one end in the right spot as i make my way down to the other end of the joist [Music] time to cut the taper and with the joist squeezed in between the blocks on either side the cut will tend to close in on itself making it hard for the saw and potentially causing deadly kickback so to prevent that just place some small wedges in the gap behind the saw to keep the cut open and away you go [Music] on one of the offcuts i went ahead and made a whole template which indicates where i want the concrete anchors located so they won't interfere with any of the decking board fixtures and then just transferred those marks onto the actual floor joist using a spade bit i then countersunk the holes so that the heads of the concrete anchors are well and truly beneath the surface of the joist and then follow that up by pre-drilling the holes before we attach the joist to the concrete i'm just going to give the bottom and the ends a couple of coats of water-based bitumen paint to help protect against moisture and as per usual nibbles the apprentice is showing no interest whatsoever i'll tell you what it's hard to get good help these days [Music] now just before we commit to screw everything down do yourself a favor and give it one last check just to make sure that everything is nice and level beautiful and don't forget to nail the appropriate size packers to the underside of the joist these will keep the joist off the concrete and i'm placing mine at 380 millimeter centres which is directly beneath the concrete anchor hole [Music] with the joist positions marked out on the slab lay out the joist and start drilling the holes this first step is just basically to get a mark on the concrete now find yourself some tape and set the drilling depth on the masonry drill bit just remember that most slabs are only about 100 millimeters thick so make sure you don't drill all the way through or you may have moisture coming up through the hole now i set mine to a depth of 75 millimeters now go back and drill those holes to the set depth and then blow the dust out of the hole with something like a bike pump or an air compressor we can now attach the joist to the concrete with one of these masonry anchors now this one's called an anchor screw but i've also seen them called screw bolts and just be warned you will need a good quality impact driver to drive these things in now just in regard to those fixings we do have a few options like i said before i'm using these concrete screw bolts but you can also use dyna bolts or even these plastic plugs with a bugle screw now these are a great option if you don't happen to have yourself an impact driver and remember because we're working outside these fixings will need to be galvanized [Music] now a very important thing to remember when working with the subframe and that is where possible avoid timber touching timber as that only encourages water to seep into those joints which speeds up the rotting process can you hear those baby birds must be feeding time they are going nuts now a good example is around your posts try and leave a gap so that any water can get away since we're constructing things did you hear the one about the construction worker who walked into a bar with a slab of asphalt under his arm the barman asks what can i get you mate and the construction worker says one beer for me and one for the road classic asphalt road [Music] now with the last joist i'm attaching it with the plastic anchors and bugle screws as i don't want to risk blowing at the edge of the concrete which is a possibility if i use the impact driver and the screw bolts and then just give the joist a bit of a love tap with your foot just to make sure everything's screwed down nice and secure [Music] do [Music] and this is how you want your joists to finish up flat level and ready for the decking boards beautiful great tip knackers [Music] now here's a really cool trick for getting really tight butt joins and that is place a thin strip of wood about i don't know four inches or a hundred millimeters away from where the blade comes down and then when you place your board on top of that that's going to cause the blade to come down and give us a bit of an undercut and that means that when the two boards meet you'll finish up with an ultra tight joint [Music] apply a coat of oil to the ends of each board before screwing down for added protection to get perfectly straight boards i like to use a string line for every run a little time consuming but well worth it if you'd like to know how to tie a tight string line which is very important make sure you click on the card that should be popping up now on the top right of your screen [Music] a couple of gentle taps with your hammer should have that string line sitting just right [Music] line the string line up with the outside of the board and away you go to achieve consist
