Installing and Blocking Deep Joists


In this video what I want to show you is the Installation of the Deep joists to? the floor for the second storey of this house I’m going to show you two different methods or two different materials that you can use and how you go about blocking them so they, don’t want to fall either so the first material is your standard natural for some timber and of course you’re going to purchase the lengths that are required and make sure that they are deep enough to span the distance that you require and the biggest problem with natural timber is that it tends to twist and bow so what we have to do is we have to stop it and the way, we do that Is that the Code in Australia says that every 1.8, or 1800 Millimetres what you have to do Is put a row of blocking or strutting in to stop it from bowing so what I’ve got here Is what We call Solid Blocking so that’s just blocks of a similar material to the actual joist a little bit narrower in between the other option is to use what, we call Herringbone strutting so 30 x 38 Or 50 x 50 Timber Just nailed Into the angle both the blocks and the Herringbone Strutting are usually a little bit less a little bit narrower than the actual Joists just so we don’t get any chance of them sticking up and disturbing the floor and especially With the solid blocks leaving them a little bit short just allows for some airflow to move around the joists so that’s our natural timber blocked and Herringbone strutting every 1.8m to stop it from twisting and bowing the other option we can Use and the most popular option nowadays is LVL and I-Beams in this case we have a fairly long span through here so I’ve Installed a steel beam that transfers all the way through to the floor both sides and throw in our I beams and our LVL’s The LVL’s are the more structural members they’re there to carry the weight and because we’ve got an opening here for a stairwell I’ve done LVL on both sides to pick up the extra weight that this saddle trimmer would replace because it’s carrying the load of those two joists there the rest of the floors are I-beams or I-joists or whatever the particular manufacturer wants to call them very lightweight and a lot longer span you can actually buy them in pretty much any means that you want so there’s no need to join them over a wall They still only have a certain span but you can just put continuous links all the way through, no need to join them In this case we’ve had to join them on the steel beam so what we do again to manufacturer’s Instructions you can cut into the top and bottom flange of the beam I think, off the top of my head it’s about 12mm maximum so you need to fit it around the beam as tightly as you can and then of course we need to block these to stop them from falling over but, we only have to block the ends so we just use the same material, just the offcuts, so they just get cut between and the gap here allows for the airflow and the other end the other option is to use what they call a Rim board which is just basically a piece of 20mm Ply which has been cut, to the same height as joist and it gets nailed onto the end and that stops the joist from falling, over we also need to make sure that we block them at the steel to stop these sliding along the steel that locks all the joists in the big advantage of the ideas that don’t need to be blocked in the middle only thing you have to do in the centre of the spans is just tack them in place with a bit of a batten while you’re laying the floor and then as you lay the floor that can come out and that will hold the joist straight while you laying the floor Other thing you need to do before you finish your floor is you, need to make sure that you’ve got trimmers above all your Internal Walls that are running in the same direction as the wall so the line of trimmers through there That’ll pick up this ceiling later on So there you go there’s our Deep Joists installed Into this job using either a natural timber or a man-made timber product to create our floor for our second story

13 thoughts on “Installing and Blocking Deep Joists

  1. @Buildsum Hi Buidsum, thank you for the info. I downloaded SketchUp before, but I never realised that you could use it for timber framing. Did you design the I joists yourself, or were they downloaded? Thank you, Jake. 

  2. Your videos are fantastic and so insightful. Really appreciate you doing these videos! Im a engineering student from Melbourne. 

  3. I'm going out on a limb here, but I believe cross bridging with lumber is not really used anymore., although some form of bridging is used.

  4. Hi Buildsum,
    First of all thank you so much for uploading these fantastic videos on you tube website.
    I have got a question.
    As you have showed , you have considered I- beam for portion of that building, can I use LVL joists for that portion as well?

    Thanks a lot
    Babak,

  5. I thought you do not need to use the whole row of blockings unless
    1.you are using unseasoned timber and
    2.span>3m and
    3.no ceiling installed underneath the joists

  6. Hi Buildsum,

    I am placing some treated pine joists (240mmx 45mm MGP10) for an external decked walkway on a 2 storey house and had to resubmit a plan to the building inspector, as the draftsman designed it incorrectly, based on the way we wanted the decking to run. The building inspector just approved my solution and proposal, and said, "The deck joist proposal looks fine. I can check over at the Final Inspection to ensure joists are booted etc."

    What do you think she means by 'Joists booted'?

    The joists sit on steel beams, so they will not be hung, as I thought she may have meant joist hangers?

    Thanks again for all your help and videos.

  7. you need 2 2×4 on top your wall, on your 3d design you only put 1 , check the code and other framing video to learn why, otherwise nice work

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