How to sister floor joist

[@weremodel]

An engineering video I can relate to. The stuff that I have seen and still see and will continue to see means that you engineers will never be out of work. Thanks.

[@WillN2Go1]

Good video. Good tutorial on code allowances (plumbers on their first violation should have this tattooed on their arm). Brilliant strap. Do building departments accept it? (Or would you have to submit an engineer's sign-off?) When I was teaching 8th grade science the book section on Tension and Compression was so muddled and confusing it seemed to screw-up what I already knew. So to teach my students, I came up with a model of a beam. I'd ask "Which side is in compression and which in tension?" In about 8 years of asking students and teachers, two teachers immediately knew (one also an engineer) and one student - who was really sharp. No one else knew. I wanted a way that in a few moments everyone would always know. (Most people in your damaged joist examples would be trying to add as much material to the sides - when your strap solves the problem). I made a teaching model. About a 2' beam (just 1/2" ply) cut in half. ON the top were two blocks - that would squeeze a tennis ball (compression) over the split. On the bottom some dowels sticking out over which I'd put a rubber band (tension). Without one of these the beam would fall apart, on the side it would fall apart, upside down it would fall apart. (It's basically a physical proof of the concept).

[@ryanshannon6963]

You say they're on Amazon but I don't see them. The calculations at the end were an excellent touch. It's nice to know about how much stress is put on the joists and helps me know it's not insurmountable. Thank you!

[@nolanengineeringpllc2713]

Sorry you are having trouble viewing our products on amazon. We also have a shop on shopify: www.nolan-structural-products.myshopify.com - I hope this helps

[@TempoDrift1480]

Just make it. This isn't rocket surgery.

[@pauls3581]

You should do a video of you installing this system on actual floor joists under load.

[@firstmkb]

OMG, been putting off sistering a cracked joist for a few years because I know it will be a PITA, but this is so much better! Brilliant, and I'm glad I watched "just one more video" tonight.

[@nolanengineeringpllc2713]

Thank you!

[@donrondel8240]

Excellent video. TY very much. In our 50 yr old cape cod home we have three 1st floor 2x10x14 floor joists that have each developed a vertical crack from the bottom where knots are in the lumber. The cracks are 2 inches long 3 inches long and one 7 inches long. None of them penetrate the entire thickness of the joist...so they are only visible on one side. We were going to sister either 2x8's (for space reasons) or 2x10s, but this strap device appears to fill the bill. Our aim is to prevent the cracks from worsening, and to strengthen the joists. Will contact your firm to inquire about use in our situation and obviously cost. Cheers

[@Superman0820]

This is absolutely genius. Thank you guys for what you do! Any idea when this will be mentioned in the next code book?

[@jochimbenschneider1915]

True. We like web trusses. Can’t beat em. And how thick is this strap? That has to be pretty strong.

[@kenweis2291]

I built about 100 homes and most were junky commercial stick built....but i did 3 houses with 1 foot centers and 2 of those had 2x6 outer walls, the electricians were made to not drill the lumber as much as possible going up through the plates and over and down....let me just say it is extra wire and 1/3 more lumber but the strength of the houses was unbelievable....everything just came out better from the deck to the sheetrock Plus all the bridge blocks and half inch beads of glue....all sheet rock got 1/8 inch bead of glue...you can use less screws with glued rock

[@OpalKiss]

Would this work on a joist that is already cracked diagonally?

[@TheHeavyend81]

Well, saying you have come up with the idea is a bit of a stretch, straps such as this are widely available in the building industry (at least in the UK). My concern would be when the ceiling board goes up, this method means you would have to hack into the board to avoid the ridge of the securing bolts, also there is considerabled length where you would be unable to affix the board due to the strap. Really to make this fully work the stap (and bold heads) need to be recessed a little and a small sister baton fixed along the length of the strap, each side so a ceiling board could be affixed nice and flush. Idea is good but not fully thought through.

[@johnafagerquist8235]

I enjoyed the video. Well done. The cellar was dug out from under the house and, back then (1920's to 40's somewhere), they just mishmashed some beams, across the underside of the joists, supported by posts, wherever it seemed like it would help. The joists (if only by definition) are 2x4's (real ones) on their sides, so they're 2" deep. Who does that?! Even though they were originally on the ground, it's still weird... and wrong. If there were codes to meet, I'm certain they were not considered. I especially appreciate the general information with regard to joist depth, holes, notches, and cut-outs. I do not plan to go as far as having the local government inspect my work, but I now know I can bring the whole mess closer to compliance and, definitely, increase the structural integrity of my house.

[@nolanengineeringpllc2713]

I assume it is an older home, anything goes then, lol.

[@tomk6401]

Hello, one question if you could kindly reply, would such a metal strap work on joist's sideways in case bottom side is not available (due to drywall ceiling screwed to it)? I understand the calculation would be different but still it would improve the joist strength, right?

[@mattgardner1972]

maybe mortise the depth you need for the sheetrock to lay flush

[@ubacow7109]

Are the structural screws support to be installed slightly slanted?

[@nolanengineeringpllc2713]

They may point in towards the center of the joists slightly if you like or straight. Pre-drilling is a must.

[@jakerossgil3048]

What would be a true 2x8 max span on a second floor i had a Engineer say 12 ft was good

[@jam7453]

Great video! This is the 1st video I clicked on on this subject simply because of the fact that I knew an Engineer was actually going to do the video & not necessarily some DIYer who no offense to any of them but they might not have the right advice or the best advice necessarily. Now I may have been the only person that watched this video & actually wrote down your calculations & tried to figure out how you got some of them but I got a little confused with how you came up with the following: Tension force acting over 11.25’ & = 0.9375’ & T = 2,725lbs. So, if you’re talking about bending stress finding the max tensile force with the majority of the force being in the center 1/3 of the board (5.83333333’), force decreases & goes to zero as you get closer to the ends (correct?) How is the Tension Force acting over 11.25’? Is the that just knowledge that you already knew concerning 2 x 12 & you didn’t actually come up with the 11.25’ in the video? Have a few more questions regarding how you calculated this. If you’d like to explain that further that’d be great. You could be possibly helping a future engineer. Here’s how I understand: A typical floor system with a dead load of 10lbs/SqFt + first floor live load of 40lbs/SqFt = 50lbs/SqFt multiplied by accounting for 16” floor joist spacing (=1.33’) = 66.7lbs/ linear ft. Floor loading of 66.7 multiplied by 17.5’ board = 1,165.25 divided by 2 to come up with 583.625 which you rounded up to 584 Reaction Load at each end of board. THEN you split the board in half =8.75’ as to show the center of the board (left side) was where the board has been cut but also where the max tensile force is or most tension is, right? THEN you reiterated that the end reaction is 584lbs (bottom). THEN you stated the ‘moment caused by the loading of 1/2 of that’. Which is 584lbs (top) Which, how’d you come up with that? THEN you got 4.375 by dividing 8.75 in half & multiplied 584lbs & 4.375’ which you never really said anything about how that = 2,555 & what the calculations are to do with that number unless there’s more to it than that. Another way I took the last bit of calculations being done for this: =584(8.75)+584(4.375) is multiplying 584 by 8.75 = 5,110 & multiplying 584 by 4.375 = 2,555 & adding 5,110 to 2,555 = 7,665 If so, what to do with the 7,665? And again how’d you come up with 0.9375 & how’d you solve for T = 2,725? What about the positive side? What do you mean by that? Because the board is cut & the right side of the cut board wants move upward & to the left & the left side of the cut board wants to move upward & right because the center of the board has been weakened by the cut causing the board to bend?

[@nolanengineeringpllc2713]

Sorry about the late response, great questions. Probably easier if you just called me 518-376-0352

[@theimaginarygallery5935]

Who is going to check to make sure all of these codes are followed & if they are not, what are the consequences & who enforces them?

[@nolanengineeringpllc2713]

We are an architecture and engineering firm that provides blueprints for both residential and commercial clients so we are well versed in building codes. Our products have been sold in all 50 states and Canada and have been accepted by code enforcement officials.

[@MyJeer]

Really well explained, but once all the numbers came out my brain froze! Lol. Thanks!

[@feralbigdog]

you didnt sister anything, i wanted to see the fastening schedual for a sistered board.

[@nolanengineeringpllc2713]

That is the point, no need to sister with these straps. Sisterring is a pain.

[@robertmeadows1657]

You must have been thrown off by the title: How to sister a joist.

[@martinw245]

So what if you can't access the underneath of the joist because there's a ceiling below?

[@nolanengineeringpllc2713]

Depending on the situation, the strap can also be applied to the side. We now have a few different options for joist repair if you visit our website - nolanstructuralproducts.com or you can use our contact form to send us a picture and we can provide recommendations.

[@irgtk]

Very informative, thank you.

[@MadRat70]

Why not just run 24-26 gauge galvanized straps across the bottom of all of your floor joists during construction? A slitter can cut a roll of metal so that your straps can be cheaply made for absolutely any length.

[@georgevalente4223]

This is valuable information!

[@nolanengineeringpllc2713]

Thank you!

[@martinjp1]

You have invented a product that already exists it's called an 18" piece steel.

[@nolanengineeringpllc2713]

Sure you can go out and make your own. Come up with the drawings, calculate number of screws, do full load testing, find a fabricator and have one made for $100 lol. But you, I didn't say it was rocket science.

[@chrisdonner2910]

True of many products. He's just making it convenient for those who don't wish to design, fabricate, verify, validate etc.

[@alexill]

Great knowledge. Thanks for this.

[@stevekirby5046]

If you do that to an upstairs joist, how do you put ceiling board back up with all those screw heads protruding?

[@nolanengineeringpllc2713]

The screwheads only stick out about a 1/4 of an inch. You can either add furring strips, or you can grind down the backside of the drywall.

[@jackhazen2900]

Best bet is to fur down. Espically if you have multiple joists to repair. Also celing drywall is usually 5/8 thick. If you try and grind out 1/4+ for those screws, it’ll be pretty “soft” there.

[@nolanengineeringpllc2713]

The strap and the screws will stick down about 0.25". You can carve out the back of the drywall in the strap area or fur down the entire ceiling.

[@MerchantNation]

ive got an off topic question... saw these anchor type sistering part for preventing slip between sistered joist. cant remember what they are called, but they look like little road tire spikes. if you know the name of the product and your take take on their usefulness in contrast to just glue and screw, that would be helpful.

[@nolanengineeringpllc2713]

Might be a truss plate?

[@MerchantNation]

@@nolanengineeringpllc2713 not those. this was to sandwich between boards and provide internal slip protection between boards when sistering. think of a cross between jacks (the kids games) and road spikes...small spiked anchor/tacks with opposing bite force

[@larinajohnson341]

I think it's called a cleat plate-both sides are covered in spikes so they bite into both joists, preventing them from moving up down or sideways apart from one another.

[@MerchantNation]

@@larinajohnson341 thx. That terminology makes sense. Still can't find and it drives me nuts. I affectionately refer to them as ninja floor spikes for sistering. It only makes sense in my head; it's a weird space in there.

[@dorhocyn3]

I have been working on a 4 foot load bearing cantilevered wall and you have to try and completely rethink the tension and compression sides of the joists. It’s getting metal

[@nolanengineeringpllc2713]

LOL, ok. For a cantilever, the top is in tension, bottom compression.

[@Allegedly2right]

Product name is?

[@nolanengineeringpllc2713]

Joist Repair Kit - available at nolanstructuralproducts.com/collections/joist-repair-kit

[@Allegedly2right]

@@nolanengineeringpllc2713 Proper proper stuff we don’t get it in the 🇬🇧definitely 10/10

[@totallygallactic3426]

what if you can not access the top of joist?

[@Free-g8r]

I have a joist that's starting to crack. Can this be used to reinforce it? Should I jack up the joist and remove tension before installing the strap?

[@mariopanteli7924]

Great vid 👍👍

[@lou704]

Outstanding.

[@digitaltransplant403]

It looks like there are quite a few fasteners with this solution. Does this have any impact? Should these be pre drilled to avoid splitting? Thanks

[@noconsentgiven]

Yes, thats what he says in the video.

[@digitaltransplant403]

@@noconsentgiven Thanks, I must have missed it the first time around. Thanks

[@noconsentgiven]

@@digitaltransplant403 Np😋

[@nolanengineeringpllc2713]

Yes, and we provide a drill bit in the kit for the pilot holes.

[@Chris-jd9wg]

So you notch a joist to fit around any plumbing, electrical, etc. How in the bloody hell do you install it now with a strap covering the notch? Plus, even if you install the joist, what if it's a second floor? How do you attach drywall now? This seems like an incredibly haphazard way of "repairing" a joist.

[@nolanengineeringpllc2713]

No you don't purposely notch a joist. It is to repair one that someone else notched. If you have drywall then you have to take it down install the strap and put the drywall back up. Whether you use this strap or not, the fix could very well entail removing the drywall.

[@bloodeaglehohos7099]

great info thx

[@Aneedness]

Thank you.

[@nolanengineeringpllc2713]

Thank you!

[@victorvek5227]

Impossible to evenly attach ceiling drywall to that floor joist now though.

[@nolanengineeringpllc2713]

Yes, you have to either carve out the backside of the drywall or shim everything down. These are used a lot in the basement where there is no drywall.

[@eltonnoway7864]

@@nolanengineeringpllc2713 Hmmm... to a DIY'er I assumed that was a common sense solution. I already had my drywall up before I saw your response and never saw it as a problem. When I was installing the brace I knew it was going to be an obstruction to the drywall. Instinctively after putting the brace up I simply gouged out a small section on the back of the drywall so it would lay flat.

[@bxblack]

Thank you

[@nolanengineeringpllc2713]

Thank you!

[@JB-Brack99]

One of the problems is that you're using spruce instead of good ole yellow pine which is 5X stronger than spruce. You need to spend more time in the field.

[@MyUnquenchableThirst]

Great video but the scratchy mic is very distracting.

[@firstmkb]

The worn out blue marker on the white board got me, but the product sounds like a winner!

[@nolanengineeringpllc2713]

Yes, sorry, I am not audio/video expert.

[@nolanengineeringpllc2713]

Ha, thanks.

[@devthecanadian775]

People drilling massive holes etc in joists must be brain dead, I don't understand what they are thinking..... Ohh what this is holding the floor/house? lets drill a bunch of 4-5 inch holes everywhere. I have the same problem in my new house on a few.

[@nolanengineeringpllc2713]

Yes, have to wonder what they are thinking.

[@Pocketfarmer1]

There is no such thing as “pre-drilling” . It is just drilling, which always happens before something else anyway.

[@jimnasium452]

Pre-drilling rather than drilling with the fastener.

[@Pocketfarmer1]

@@jimnasium452 sorry to disagree. Drilling is making a hole. Your with fasteners would be screwing . How do you make a hole (drill) before making that hole(predrill). Predrilling is a term that is meaningless which has crept into the language i think to make the speaker sound more professional. All drilling happens before some other action , therefore all drilling is “pre” and the “pre” is redundant.

[@jimnasium452]

@@Pocketfarmer1 Well, every self help video (including those from those "radicals at This Old House) refer to it as "pre-drilling," so good luck with your semantic crusade.

[@Pocketfarmer1]

@@jimnasium452 Well thank you. It is just that, a semantic crusade and nothing more .