This Is One of the Biggest Problems Keeping Floor Joists Straight

[@aaronroberts4722]

The way I've always done it is to lay a 2x4 over the top of the floor joists. Space the joists correctly and nail down the 2x4. Then cut half the blocks you need at exactly the correct width and install every other one. Finally you come back and measure and cut the missing ones individually and this takes care of any abnormalities in the wood. Saves a ton of remeasuring time and the plywood never misses the lips.

[@gethnoble4316]

Thats flippin smart! I will do it your way

[@brennenbartlettphotography1576]

Good tip, thank you.

[@cortezoid2072]

this is the way.

[@davidhouston2277]

Thanks

[@peterbarlow8912]

We just used 1 x 3 firring/strapping laid out along side top plates for rafters or band joists for floor joists. We nailed them on with duplex head nails before we had nail guns. Building a garage roof we had to plan out the sheathing stagger and make sure no rafters with a bark edged crowns fell on those 4 foot centers

[@huejanus5505]

I usually tack a 1x across the top of the joists to hold them at 16” oc and measure the spaces. The spacing usually runs from 14 1/2” to 14 3/8”, that 1/8” difference, if not taken care of, can add up to a lot of problems.

[@johnr.6029]

Excellent warning. I've built some sheds and outbuildings and wondered how things got "off". To correct the problem (drift) after the fact, I had to add 2 x 4 extensions to the floor joist for the neighboring plywood sheet to anchor into. More often I encounter this problem when fixing someone's old job like a deck with nails or screws that have popped out because the drift or spacing was not corrected when it was being built.

[@erinkennedy2417]

I cut my blocks a 16th short and have been living in my house for a year now. it's been interesting seeing the lumber shrink up. I ended up with the blocks causing squeaking in places but was lucky to have access to add some 5" screws to fix that problem.

[@SBNewMe]

Great video - easy to assume everything is square, or for whoever did the blocks to not really think it matters. How about laying the sheathing down at the outside edges first to see how the beams (rafters) line up - then do the mid-span blocks?

[@GGg-ug3jr]

I've experienced this in real life doing what I do. The cause of this I found to be joists that are cupped. If you're joist is cupped and your block is cut square on one side you'll have a gap in the middle of your block and the other side of that choice you would have a gap on the top and bottom. Good information here and good solution trim a little off when you need to.

[@gregvancom]

You've definitely had experience with that one before and your comment is sincerely appreciated.

[@rickbabcock6397]

I sheet floor first up to where blocks or bridging is located, then install blocks standing on subfloor. I'm old and lazy.

[@jonwikan3986]

When I work alone I hook a tape and stretch across the room. If something starts to drift I can adjust accordingly but I like the idea of having a jig prebuilt for every job. The other reality is not every joist is exactly 1 1/2"

[@gregvancom]

Excellent point.

[@superwiseman452]

I always put midspan blocks because it greatly strengthens the joist. Also, I used construction adhesive with the blocks- avoids and squeaks.

[@utubeaccess7]

His whole point is that the addition of error will lead to unsupported edges of floor sheathing.

[@superwiseman452]

@@utubeaccess7 ok i get it now...

[@Faruk651]

I removed middle blocking from a section that was 12' span 2x10 floor joists. 16'x12' area. Once the blocking was off, you could feel the vibration in the floor system when you walk or drop something. Makes a big difference.

[@bobblaszczak7972]

You also could lay the plywood down and make sure you’re hitting joists and put blocking in after either all of the sheathing is down (from below), or as you approach the point where blocking is needed. Glue the blocking. It helps with squeaking.

[@drew5334]

As a framer, I'll usually mark a board out at 14.5" increments (29", 33.5", etc) and then when cutting, take the saw down the middle of the line, so the 1/8" blade takes 1/16th off each side of the cut. Installed, these usually slide in with just a touch of tension, and work out to be within a 1/16" of layout even after 10 ft or so, and that's more than good enough for framing. In framing, you almost always find that stacking layers, you gain a little bit. hence taking a little off each block works out perfectly. I would double check layout every 8' or so, every other joist is excessive and wastes time. Even if you're a 1/4" off layout, that's acceptable, more than that is getting sloppy though and going to increase the likelihood of squeaks from shiners

[@9mmkahr]

You'd be hard pressed to find an 1/8" kerf framing blade.. most are 1/16 these days believe it or not.

[@adamnonnenmacher7774]

@@9mmkahrnot true at all. Almost every blade on the market is 1/8”. I am a framer and woodworker.

[@ericking4072]

Another thing rookies don't know is EVERY top nail IS a squeak as well.Pulled up to a completed underfloor the other day.EVERY block was top nailed.LOTS of subfloor glue is also a good stopgap measure.

[@gregvancom]

I like it, I never thought about that and I wonder if it would be better to install smaller blocks. If you were going to use 2 x 10 floor joists, maybe 2 x 6 blocks located near the bottom might eliminate squeaks.

[@five-forty3431]

Excellent explanation of the issue!

[@gregvancom]

Thanks for the kind words and for watching.

[@creativesuit1930]

This is why we install the sheathing up to the line of blocking and then install the blocking slightly short or cross bringing that why the joist can be moved to exactly you want them when nailing down the leading edge of sheathing.

[@gregvancom]

Definitely another way to use and thanks for sharing.

[@JamesZaraza-wv3gt]

Snap your control line accounting for the tongue at the outside wall. Glue up your joists just shy of the 4’ mark.Drop your first sheet in a squared corner, ideally to break at 8’. Nail off your ends and tack each joist “perfectly” on layout with your tape measure hooked then nail off. Repeat as needed working toward your first set of blocks or crossties leaving enough room to maneuver your nail gun. Don’t forget you were doing blocking and run glue. If you have a few feet of space you can make adjustments with the sluggo you were using with your 4’ beater block (2x4 usually) and cut and install your blocks to fit, or precut the blocks “taking the line” when you cut. This plus a spot check every now and then ought to be sufficient.

[@disqusrubbish5467]

This.

[@turville1961]

Very timely . I’m building stud. Walls 3m tall by 10mx5m for my new gym in my barn. Im still trying to work out how to put a floor in about this structure. First time DIYer . Thank goodness for youtube

[@Duetmaster2]

A question I've always had is how subfloor sheets are laid over the center of the floor where the joist ends overlap over the center beam? For instance, as here, I have a 26.5' floor span so I'm using 14' 2x12 joists not cut to length - just leaving them overlap in the center. How do you handle laying subfloor sheets over that center portion?

[@johnf3326]

I measure spacing at each bearing end and take the average for a centre bracing. I also pva glue as well as screw. Bracing stops the joists from twisting and shares bending between adjacent joists to reduce movement (bounce)

[@gregvancom]

What is the glue used for, the screws?

[@mikeznel6048]

Tried to get my blocks dead nuts on. A 1/16th over 16 joists is one inch. I pull my tape on the joists to make sure they’re where they need to be. I mark 3/4” from one side and 3/4” from the other side in the middle on top of the joist I’m measuring so I get a center measurement. Then if my joists start wandering, I adjust the length of the blocking over a few blocks to buy out the of center. But like you said, constantly grab the tape and make sure they’re where they need to be. Any framing component really. You only screw yourself if you don’t when you go to sheath and you’re not hitting center with each panel.

[@bobbenoit8470]

This commentary is exactly right concerning mid span blocks but I will add that if installed correctly with an accurate and tight fit sqeaking can be a problem at first but eventually goes away after the first rain on the subfloor. The wood swells and the subfloor gets tighter. Also, if you glue your subfloor that creates a stronger floor with less bounce. It's a hassle but if you fasten your blocks using 3 inch decking screws, that will also reduce squeaking

[@nelus7276]

I work in Europe and we screw way more than USA framers. From watching videos I can tell they may be faster but I always wondered about squeaking and bouncing. Also floor joists here are mostly real beams, usually 3" wide.

[@bobbenoit8470]

@@nelus7276 you can't go wrong using screws. I'm a licensed builder here in the US and I have glued and screwed my subfloor down on a few houses. I always use subfloor glue regardless of whether I nail or screw. I read somewhere ( I don't know if it's true) that glue adds 30% more strength to the floor system. I don't know of any builders that use screws on the wall, ceiling, or roof framing. It's all done with nails. Now commercial builders tend to use more screws.

[@chvydrptop]

Greg is it a better idea to use cross bracing instead of mid span blocks?

[@gregvancom]

I've thought about this myself for decades and think that the solid blocking will be better. I'm going to go ahead and put this on my suggested list of videos to be made in the future, to provide more clarification.

[@Faruk651]

It is the cupped floor joist causing the problem. Even a slightly cupped 2x10 joist will cause 1/8 deflection when you add a 14 1/2" blocking in between. If you want solid floors, do the blocking. Screw the blocking to the floor joist with construction adhesive. Add couple nails after if you like. I removed middle blocking in a 12' span 2x10 floor joists in a section of the house. The difference was day and night. You could feel the vibration of the whole floor after the blocks were removed. DO BLOCKING if it is your house.

[@gregvancom]

You've got an excellent point, blocking sure seems like it makes the floor stiffer, but it's more noticeable on larger spans. Also great point about cupped joist.

[@j-moto1215]

Hey there - scenario for you… I’ve removed a 4x8 sheet of T&G subfloor in my house because I had awful squeaks. Determined if was the blocking so I removed it and the squeak is now gone. Want to replace it with good blocking but I’m noticing the joists are like you said cupped now which I think is what was causing the noises. What would you recommend doing in this case?

[@Faruk651]

@@j-moto1215 Are they all cupped? It is labor intensive but i would fit the blocking snug between the joists and use PL construction adhesive and screw them with construction screws. The cupping will create gaps depending on which side of the cupping your blocking is. Apply some glue in those gaps and drive wood shims from both sides. Gluing and screwing is a must for joist blocking.

[@Chad_Martinson]

We used to lay the subfloor up to the point of where the mid span blocks would go before installing them. That way we could keep the joists running straight.

[@gregvancom]

That's an excellent idea and it also provide you with a nice flat surface to stand on while installing the blocks.

[@Novasawildone]

We're about to raise our sunken living room so thank you for this. I actually love checking to see what videos you have when trying to think through a project.

[@jonwikan3986]

Greg, great video! I also see people laying out block on a long 2x10 etc using a speed square, so would this framer be essentially losing 3/32-1/8 from the blade kerf after cutting each piece? I guess it would create a bow in the opposite direction. After 8-10 blocks you are an inch short. I noticed my brother does this type of work with a partner so he can call out the measurement in real time after he nails the block in. That way he can keep checking as you go.

[@gregvancom]

Glad you like video and cutting the blocks out of square or different sizes or even the inability to nail the joist tight enough to the blocks, seems to be the biggest problem with this process.

[@chaconjohnson]

I'm glad I watched this. I always gain from your videos. I'm doing a foundation with three beans 20' long and 5' apart. I was considering adding blocking at 2.5' across but after watching your video, now it seems like a waste of time and unnecessary. Would you agree?

[@francoisbouvier7861]

Another idea is to install the first row of decking. It seems to give a little stability and acts as a staging area.

[@pcatful]

blocking requirement also depends on joist depth. How did you get your model to bow the jsts.?

[@devthecanadian775]

I have a problem in a new to me 30yr old house where all the joists are bowed across the whole span. by over 1/2inch in some spots. I jammed some in there not on every joists just to hope it helps, as I am installing a full tile floor up top, and Built structural supporting walls underneath for certain areas.

[@gregvancom]

I don't understand your question.

[@russriley3005]

15 and three eights...if you got it square then pull 15 and three eights and set your joist and first stud at that point, all your plywood at that point will land on layout as long as you make sure your reveal is right and nail the front of the ply on layout. codes require blocks sometimes but for the spans shown, I wouldn't add them just because of the problems this guy just stated. if they are required, I put them up later to avoid foresaid reasons

[@chrisyaritz2180]

Great tip...thanks for posting. just curious...what if you block, after the floor sheathing (providing you have access from the bottom) just thinking then you would have no problem lining up the sheathing in the middle of the rafters.

[@gregvancom]

Yes, that would work.

[@marksokolski5125]

Was about to start blocking my floor and saw this, SUPER HELPFUL thanks 😊

[@gregvancom]

Fantastic!

[@SIE44TAR]

I use blocking all the time, even on short 6 or 8 foot spans, because it makes a really solid floor. Using 3 or 4 3" ring shank nails end nailed on each end of staggered blocking, engineered 23/32 tongue and groove sheathing like Advantech or LP 350 with subfloor adhesive and 2-3/8 ring shank nails. And glue and nail the sheathing to the blocking, and glue the tongue to the groove. Solid floor, no squeak.

[@gregvancom]

Thanks for sharing and some more things for us to consider.

[@Faruk651]

I laugh when a contractors say blocking doesn't do anything. They don't want to do it because it is a lot of work to do it properly. You can't just cut it 1/4 short and throw some nails. Anyways from my personal experience. The difference is night and day with blocking and not blocking.

[@bman6502]

@@Faruk651 agree, I’m addition to keep the joists upright, blocking also distributes the load across multiple joists…

[@grizzlygrizzle]

@@bman6502 -- That was a glaring omission in the video.

[@richvail7551]

Very thankful for the heads up. Starting in the spring to build my camp. Saving this video for a better build.

[@gregvancom]

Glad it helped and thanks for watching.

[@utubeaccess7]

If you have access to the underside after subflooring, how about adding the blocking after the sheathing? Then you can space all the overlaps perfectly and cut the blocks to fit... Just an idea.

[@gregvancom]

It might be a little more time consuming to do it that way, but it could provide you with a method to eliminate any blocks that would've been installed in the wrong location.

[@jimmydyurko]

I've done it that way. Long ago when I was a laborer for my uncle. I was a young kid, and not too skilled yet, so it was a job that kept me busy, built skills and got things done right. Good solution for a DIY project, or a crew with a new guy who needs practice. Not sure if that's how I would do it now.

[@JoshStaley]

i am a first time home builder, i mean builder not G.C. im doing it all including engineering and design. im a union pipe-fitter by trade so there has been a lot a research on my part. i am building a 40’x52’ home on a crawl space. i want to know if i can put in a lvl style beam at 13’3 and 13’3 and span the 40’ floor using three 16’ 2x12

[@boedillard8807]

Nice video! Is there anything similar for trusses or IJoists?

[@jamesoncross7494]

You can also lay out a story pole marked out and tack it in place to put them 16" on center to start. Then just measure as you go. ;)

[@gregvancom]

Yes, I've seen that done with long spans of trust joist without blocking, but if some type of blocking is required, then it might not be necessary. It is a good idea and I've used it myself before.

[@jamesoncross7494]

@@gregvancom taking steps like that speeds up things. By making a simple story pole ND tacking it down, it makes cutting the blocks easier, and laying out the plywood perfect with no stopping and having to adjust. Learning to spend your time wisely makes the best craftsmanship and speed things along. Guys try to cut corners and ends up shooting them selves in the foot and wasting lots of time. It actually takes much longer if you don't set things right in the 1st places. A lot of guys just don't get that.

[@gregvancom]

You bring up a good point about some of the problems that can be created by doing things incorrectly and even though I'm not totally sold on your idea, understand that it works and would imagine that it creates a nice floor layout and thanks for sharing.

[@ScottieBMan]

Mine is 20 years old and they did not block, they are bowed pretty good, should I just use X bracing?

[@gregvancom]

Yes, anything to stabilize it.

[@9mmkahr]

Well that's why we use Bridging and not Blocking. I had a nice lengthy back and forth with a structural engineer about deflection of solid sawn lumber floor systems, assuming blocking was stronger. Basically he said NO and why bridging was better, structurally, than blocks.

[@grizzlygrizzle]

Agreed. And if you nail off the tops first, and nail off the bottoms off after the sheathing is done, you end up with bridging tightens itself up to precisely the right length for the cavity, after the joists are straightened out by reference to the sheathing.

[@9mmkahr]

@@grizzlygrizzle exactly! Cheers

[@victoryfirst2878]

Most of the time squeaking happens because of using nails sloppy stick construction by contactors that are just plain either drunkereds or dopers. When wood deck screws are used properly you will have a solid floor without any noise. It is also a barrier to slow down air flow. The rest of what you are saying is right on. What question I have for you is what would you prefer for stud header ends insulation fiberglass or rockwool ???? Thanks

[@lotus_8773]

Victory First yup and a small line of floor sealant on the joist if you have it, will make floor literally never squeek

[@smartbuildengineering]

Noggins (aka blocking) are the number 1 reason for floor squeaks - the joists will shrink over time (yes, even kiln dried) and the resulting gap between joist an noggin allows just enough movement on the nail for creaks to occur. The best solution is to use herringbone struts (modern metal versions are quick to install) as they actually tighten as the joists shrink. Solid blocking is fast, but no way would I ever use them in my own house.

[@grizzlygrizzle]

The strapping/furring bridging is fast enough, if you cut them all just a bit short and nail the tops as you go. You can straighten the joists with the sheathing, and then nail off the bottoms later. This way, when you push the bottoms up and nail them, you're tightening up any slack in the joist cavities in a way that achieves maximally tight fit with no adjustments. Besides, the metal ones can "ring" when there's a sudden impact on the floor. If it were my house, I'd do it with strapping/furring. -- As for solid blocking, we used to sheathe the floor out to just short of the midpoint, straightening the joists with the sheating, and then take out an armful of 14-1/2s with a bunch of scraps, use the pre-cut ones where they fit, and cut the scraps to fit otherwise. Trying to cut the blocks all the same length and expecting no tolerance build-up seems idiotic to me.

[@jameslambert4487]

I'm building a 10' x 12' building. I have 2" x 6" floor joist on 16" centers. I will need to cut a 4' x 8' sheet of 3/4" plywood in half to make the 12' run. My question is, do I need to double the 2" x 6" joist at the seam or could I just split the difference and just screw down 3/4" of each sheet to one single joist ?

[@gregvancom]

They can butt together on a single joist and usually require an eight inch gap between plywood sheathing.

[@elchoppo9248]

If i was to jack up a sagging joist till it gets level and add blocking will blocking keep it level?

[@PepperLion]

I wish I knew this BEFORE I made my shed floor. I had a big bow and had to work around it for the rest of my project.

[@EmileJrManigat]

Thank you for this video. I am glad I have found it before starting framing my floor.

[@gregvancom]

You're welcome and I'm glad it helped.

[@deanwild4971]

Would some kind of tounge and groove flooring help to mitigate this?

[@victorvek5227]

Is there any advantage to putting PL premium on 3 sides of the solid blocking to “fill” any small voids that happen over time… or does the construction adhesive create more problems down the road? Retro-fitting mid-span blocking in a 30 year old house right now and the variances are unreal. I know if I squeeze the large cavities too much, I’m surely going to create squeaking. Help!

[@gregvancom]

I've never used it, so won't be able to provide assistance.

[@crouchingspinach]

Question sir. I have several joists that are bowed laterally like this. Not because of blocking because there never was any blocking. I have sistered some of these joists and the sister is bowed with its mate. Beside the big problem with the sheathing not lining up on the joist, what load bearing issues are there with laterally bowed joists and would adding blocking help with load bearing ? Thanks

[@gregvancom]

You can add blocking and try to fix it, but most of the time this problem will require removing and replacing damaged joist.

[@chocol8milkman750]

@awesomeframers had a good video in this the other week. Think he said that his theory is that the nail heads stick out a bit, which adds a bit to width so you need to cut those mid span blocks to compensate.

[@gregvancom]

That shouldn't be a problem if the mid span blocks are staggered, but could be if they were installed in a straight line.

[@jaybaker8027]

Not sure if you are still responding to comments. Found your video while trying to figure out why our subfloor choice are off in the center. We're pretty sure we're going to have to remove some blocking. Do you think we should start with every other one? Is there a good method? We have 14' 4" long joists and started with two rows of blocking up middle, then added a row down each end of joists. We have this X two. I'm tempted to just have 3 rows of blocking per joist length when we go to redo

[@durangodave]

thanks great video. This time im not doing floor but a ceiling of carport and your tips are great. Im using 2x6x12 for joists n carport is 12f wide. I want to do blocking to help keep joists from bowing as they dry out. Does blocking always have to be center patern or can i space them out a bit more from one joist to the next joist?

[@gregvancom]

Usually they're centered and staggered like in the video, but in some cases you might be allowed to off center them. For example if the span is 14 foot and the blocks need to be installed at a maximum of every 10 foot then you could place them at 4 or 5 or even 7 feet from the side. Let me know if that doesn't make sense.

[@thudang3039]

Thanks for the reminder, and the content! As someone who doesn't do a bunch of DIY projects like this, it helps to be aware in advance. =)

[@gregvancom]

You're welcome and thanks for watching.

[@michaelmanara58]

I had a new kitchen floor put in 5 years ago. The grout kept on breaking up and coming off. The contractor kept on coming back and redoing the grout. I went into the basement and noticed that the floor joists in the ceiling that holds up the kitchen floor are all un-level vertically thus making the foor move. I was wondering if I put blocks in between to level the joists and ensure they are level vertically,, will this then secure the floor itself and stop having the grout loosen up because the joists are level? the floor itself is level from the plywood they put down. Thank you for your help.

[@gregvancom]

The grout can break and crack when there is any movement in the floor and if you think that you can reduce the amount of movement in any way by shoring it up, then go for it. Feel free to email me some pictures and I'll take a look at your project if you're looking for more ideas. Keep in mind that I cannot provide the structural engineering vice.

[@thomastucker5686]

This is quite old, however, can I just install the blocking after the sheathing is installed? I'm anal about layout in the first place and would notice something bowing at an eighth on 12'.

[@JLyons314]

Diagonal 1x3 bridging screwed between joists. Rock solid and cheap. Blocks wind up squeaking. Metal bridging squeaks. I've never had problems with diagonal 1x3 as the framing package shrinks down and settles.

[@robertearlburke]

I am remodeling my basement, and moving a duct into the space between 2 joists, and need to remove the mid-joist block. Is there a thin metal bracket I can use that can go under the duct to maintain the distance between the joists? Or, is this unnecessary since there is already a plywood subfloor attached to the top of the joists?

[@gregvancom]

You can move the block a few inches or feet sometimes and I don't see why a brace at the bottom won't work. The floor sheathing is preventing the upper section of the joist from moving and a brace could do the same for the bottom.

[@byronmilla9865]

This is great !!! For teaching with out wasting lumber!!! 👍👍👍

[@gregvancom]

Glad you think so!

[@11219tt]

I need to replace some floor joists, they have center blocking with 2x4 cross pieces. making an X shape. Do I need to do any bracing of other joists to remove one? i don't want the floor to collapse.

[@gregvancom]

Most of the time these braces aren't going to be a problem to remove. Maybe remove a few as needed and replace as soon as you can.

[@scorpio6587]

Idea: First install the blocks in every other bay, then every other remaining bay (every fourth bay), and so on. Starting in round two, if a block feels tight going in, shave off a sixteenth. I think this should result in a good straight floor. Another possible solution would be to install first the rows of sheathing that do not cover the blocking location, then do the blocking, then the final row of sheathing.

[@zenyfilmsrambo]

brother do i need blocking for a rom of 6x6 meters

[@gethnoble4316]

Thats smart, sheet a bit before blocks😃

[@commoncents6889]

We normally use cross blocking and Nail the tops then put your plywood on and then go back and nail the bottoms. Makes for a lot better floor the standard blocks.

[@gregvancom]

Great info.

[@darkflux]

the squeaking floor from blocking doesn't happen as often if you use screws in your blocking.

[@NoName-gv6nm]

What causes joists to start tilting? My 60 year old house has some tilted joists.

[@gregvancom]

It's usually going to have something to do with movement of the foundation or framing over time.

[@NoName-gv6nm]

@gregvancom Thanks. It's a pretty solid house overall. I figured it just had to do with the typical aging of a house.

[@hankespinosa9474]

Can I use Simpson strong tie hangers with 2x8 for mid span blocks on 2x10 floor joist that extend 14’? Just trying to sure up the beams before we finish basement. Thanks in advance.

[@gregvancom]

It's probably something rarely done, but I don't see why you couldn't do it. Now for the big question, what is your reason for doing it?

[@hankespinosa9474]

@@gregvancom Mainly OCD, finishing basement and I thought it would be a good idea to replace split blocking with midspan blocking, but I can't nail in the mid-span blocks on both sides near the walls. Also, I sister joisted 5 runs under my kitchen island so didn't see how I can nail through double planks. Thanks for the reply.

[@athhud]

Glue for the squeaks and install blocks after sheathing if possible.

[@gregvancom]

What would be the reason for installing the blocks after floor sheathing installation?

[@Iahusha777Iahuah]

Ya that's what my old company did . Well if its sheathed isn't it common that the juice are lined up and square like a box because the sheathing.

[@gregvancom]

The joist might be lined up and positioned perfectly, but they can still twist and deform, without some type of blocking. If it deforms too much, then it could lose structural strength.

[@athhud]

The blocking prevents joist deflection and increases the load capacity of the sheathing and makes for a more rigid structure that won’t have as much “bounce”. Especially important if you are installing a tile floor over it.

[@olvisacevedo4539]

If you lay a long 2x4 across the joists, marked with joist lay out, temporarily nail and then attach blocking. Remove 2x4 after blocking is complete

[@MustPassTruck]

can you add blocking under the edge if they don't line up right? attach a 2x4 to the joist, then screw plywood to the 2x4?

[@gregvancom]

Yes, that sounds like it would work.

[@Raymond-mk8cb]

IF you insulated between the joists and then nailed plywood on the bottom of the joists.....like you might do in a basement to create a ceiling......would you still need to do the blocking ?

[@gregvancom]

That's a good point in my opinion I don't think you would.

[@lynnwhite3220]

Everything I read says that solid blocking in floor joists does not cause squeaking, that it actually prevents squeaking when done properly. What is the reality?

[@gregvancom]

I thinks it's this simple. If the joist on one side sags or moves then you could have a squeak and if it doesn't then you might not. My dad was a firm believer in leaving them out if he could, but other than that I don't have much else.

[@robbyvenetian]

Thank you for another great video! As always, I have a question. Would you add midspan blocking on a 12 feet larger floor? Thank you.

[@gregvancom]

Usually you put mid span blocks in joist with 10 foot or larger spans, but we didn't do it all the time, to prevent floor squeaks. My opinion, might suggest leaving them out, unless there is a structural issue.

[@robbyvenetian]

@@gregvancom, thank you very much!!!

[@disqusrubbish5467]

Throwing my two cents in - yes, use the blocking. Less "bounce", distributes weight better, and not mentioned here, helps prevent joists from twisting. When you put down the sheathing, use adhesive on the joists, then screws for the sheathing.

[@kmilton1593]

First time seeing any of your vlogs, and you did an excellent job. I am about to try and "level" my rough-cut full-dimension 2 x 8 rafters which have dried and bowed some up and some down while putting in blocking at the same time! Hope to use a hydraulic jack with three foot rafter-spanning boards and a small chain on each end. (will be very time-consuming!).

[@gregvancom]

Good luck!

[@Devoneakapimp]

Question please. I'm building a tiny house on a trailer frame. The floor is 9 feet wide by 29 feet long. What spacing do you recommend and should I use blocks?

[@gregvancom]

I cannot provide you with structural engineering advice, but 16 inches on center usually seems to work pretty good and if it's only going to be 9 foot wide, I wouldn't install any mid-span blocks.

[@Devoneakapimp]

@@gregvancom Undersood

[@ferretsandbirdsandwhatnot]

My house (with flat roof) has mid-span blocks inbetween the roof joists, and the blocks were all cut too short. Over time, the roof joists became cupped, causing the roof to have low spots that pond water when it rains. I believe if the mid-span blocks were cut and checked correctly, it would have prevented the joists from being able to cup, thus keeping the flat roof flat - and we wouldn't have ponding water roof problems. But then again, it's a flat roof, so you're pretty much guaranteed to have roof problems in the future.

[@gregvancom]

It could be, but more than likely the rafters aren't strong enough and are sagging.

[@phil-spinelli]

why use blocking overbridging? I'd use 2 x 3 bridging. that will tighten that floor right up, just like a truss right across the joist. And nail them up correctly so the don't touch each other so they don't squeak. And if you know how to install them correctly, you nail the tops before laying the plywood, then after you install the flooring, you'll go and nail the bottom. And even if you use blocking and allow for "growth" by cutting them smaller then 14 1/2, the joist will still shrink over time and now you have another problem. Use a good solid cross bridging, I think it's the best way.

[@gregvancom]

Great ideas.

[@claymulvaney3643]

I'm building a 16x20 cabin im using 2x12x16' floor joists I don't want to put in blocking i really don't want my floor to squeak do you think I need them or can I get away without?

[@gregvancom]

I cannot provide you with engineering advice, but can tell you that if you don't use them, it wouldn't be a bad idea to nail a 1 x 4 on the bottom and run it across the center of the 20 foot span to prevent the joist from moving.

[@scotttprosser4719]

Solid blocking is not that common in our area. We use cross bridging in floors, 16' span gets 2 rows. We just chalk a line and install pieces alternating on either side of the line nailed at the top only, install the plywood, joists will still move at this point. Then nail the bottom of the bridging from the basement after the plywood is all down.

[@gregvancom]

Great tip!

[@CHLEOMENTETV]

What is the distance between joist sir?

[@gregvancom]

Usually 16 inches from center to center joist or with 1.5 inch thick lumber like a 2x10 there would be a 14 and one half inch space between joist.

[@CHLEOMENTETV]

@@gregvancom if i have a 2”x3” joist and i will use a 3/4 inch plywood for floors, what will be the best distance between joist?..Iam planning to construct a subfloor.. thank you sir..

[@mikevincent2811]

I used to skip every fourth block then back fill ensuring they were on layout

[@Z-Ack]

16oc.. lol. I wish i had two matching joist distancing. Mine are everywhere from 14" to 21"oc.. house is built just like the one in the rendering.. except the builders used or tried to use wood x braces that every one has pushed out or fell out.. and by pushed out i mean nails stil attached and boards pushed down past the bottom of the joists...

[@gregvancom]

What a bummer and it would have been nice to know why they did it that way.

[@tillmansr2002]

Greg, if you have a room of 8 x16 with joists 16, is it necessary to stagger the sheathing? Four pieces of 4x8 would work perfect, but I've heard to stagger the plywood

[@gregvancom]

It's always better to stagger the sheeting from an engineering point of view. However, I couldn't tell you whether or not the building was going to fall down, if you didn't do it.

[@adammacer]

4 pieces of 4x8 will still work perfect if you stagger joints - you just lay two end to end, then cut one of them in half (or to whatever dimension your joists dictate) and put the two halves on either end of the 3rd whole whole sheet.

[@jp89702123]

Thank you for the informative videos .. at approx 48.5 sec into the video i think i heard you say gleek or gleak didn't find it Merriam-Webster dictionary. Did i hear incorrectly ??

[@gregvancom]

"Squeak" is the word I was trying to use. Maybe I shouldn't have added the dramatic flair to the word. Sorry about the confusion and thanks for watching our videos.

[@gordondawson8576]

Greetings from Manchester Great Britain...I heard squeak....but I suppose I would having squeaky wooden floor boards... Greg, for what it is worth, kudos to you in passing on your knowledge and insights

[@gethnoble4316]

Wise words! Grazie mille!

[@Mike-su8si]

The worst you explain looks like our old 4x4 joists under the front room I'm wanting to redo it all because I know most are bad joist I've redone 4 with new pine wood What's under ours is 50 year old hornbeam 4x4 joists or is red oak. What type of support is under your joints cause they can sag down to

[@gregvancom]

The video wasn't meant to provide the details you're requesting. I would go to our website and check out some of our videos on home building and crawlspace framing or repairs.

[@debnelson8127]

Is there anything different that you do when blocking ijoists?

[@gregvancom]

I would follow the product manufacturers installation instructions.

[@theropesofrenovation]

I agree that was a PITA continually measuring back. A zillion cuts. Absolutely exhausting!!

[@muttBunch]

My house was built in 87 and they used metal bridging. Omg you can hear them when you walk on the floor. It’s so annoying. Was going to do 2x10 wood bridging but now, not sure what to do

[@gregvancom]

Yes that is disappointing. The only thing I could suggest would be to try secure the bridging to where it isn't moving or squeaking. Not much help, but I can't tell you to remove them or replace them, because I can't provide structural engineering information to my viewers.

[@Jay-tk7ib]

Metal bridging. You could also measure and mark your sheathing on layout, and then adjust each joist to center the sheathing before nailing through it. Personally, I've never seen a problem with cutting 14 1/2 inch blocks, but I know it could be a problem if your joists are warped, or if you accidentally cut a block a little long or short. Like you said, measure and make sure you stay on layout.

[@gregvancom]

I'm not about to suggest that you can't cut blocks the exact size needed, but I can tell you that it's never worked for me.

[@stevenlake5278]

Is making a Is template not helpful for the blocking , and always checking 16 on center good idea ?

[@ryanyerkess]

Maybe I'm wrong but I thought all the noggins as we call them I can't remember what you call then should be all at the same length and then everything's square and all the ply or any other material you go to lay down should fit from centre to centre

[@gregvancom]

If layout and blocking is perfect then then you should be okay.

[@tilingmyway]

Great video and explanation! So needed.

[@gregvancom]

Glad it was helpful!

[@GregoryKane11]

What a great headzup ... thank you so much.

[@gregvancom]

Our pleasure!

[@angelachouinard4581]

I am not a pro but I have seen all these issues. Great video and also very useful comments, as always

[@gregvancom]

You're welcome and I usually go through the comments to get rid of those that might waste someone's time, but of course I keep all of the ones that have the words thank you, awesome and these are the best videos ever :)

[@ThaylorHarmor]

What if the blocks were cut at an angle so you could pull-in/out each board to be 16” on center? Would that defeat the purpose of the block?

[@gregvancom]

It sounds like a time-consuming process, but as long as the top and bottom of the joist are stabilized in a way that will prevent them from twisting or deforming in a way that would weaken the structural strength of the floor then it should work.

[@fsoileau]

I like your channel and you bring very good content to the people. but alot of older framers including my self get this wrong. mid span blocking or "Bridging R502.7.1" is not required if your joists are nominally 2x12 or less throughout the span table. The old rule of thumb under the UBC was mid-span @ 8'-0" max is no longer valid.

[@gregvancom]

Thanks for providing me with the building code number and I looked it up. You are correct, but your local engineers and building department officials will have the final say in this matter. Again, thanks for sharing in comments like yours are always appreciated.

[@grizzlygrizzle]

Not "no longer valid," but "no longer judged suitable by bureaucrats."

[@mikewhitaker2880]

your assuming the boards are not naturally bowed and that all the cuts are 100% square... this also includes the factory edges on the sub-floor sheets.. assuming they are 100% square on all 4 corners can easily make your boards off... for that matter, maybe the sheet is an 1/8 inch off either longer or shorter, from the factory even.. at some point it will cause a deviation that won't match those 16 in OC joists.. with or without blocks... i mean, you make good points, but those points assume everything is/was done perfect.. and we are talking about rough framing, not cabinetry... a saw can get off square very easily, getting off line is very easy, even with the best of the best doing the cuts... and rough framing usually worries more about speed than accuracy, specially since getting the job done quick lets the crew move on to the next job.. and since the pay is by the job, it makes sense to do it as quick as one can... also, if blocks ARE needed, they can be placed AFTER the sub floor is installed in some cases.. there are other tricks that work too, like temp bracing to keep spacing correct until you can block.. even then, if the sheets of sub-floor are off from the factory, you will still wind up off center with a joint or 2...

[@gregvancom]

I wasn't assuming most of what you suggested, but defective lumber can create problems for joist layout.

[@mpybals8002]

Another wizard here to tell you what to do. Snap your line for blocking but don’t install blocking until you sheet out to it. I always mark my sheets 16 inch on center or whatever your spacing is so when you finally get to the blocking you can just mark the blocks 14 1/2 cut down the middle of the line and install. Not to mention the plywood makes an easier platform to stand on.

[@gregvancom]

We thank you wizard and this works great.

[@mpybals8002]

@@gregvancom back when I was younger every once in a while I’d be building something and the old guys would show up and critique everything I was doing. One job the homeowner told me the wizards are coming over to watch you guys work and to this day that’s how I label the know it alls. Now I’m the wizard know it all funny how things change.

[@cb4920]

Cut and use bridging but only nail tops. Center your sub- floor as you lay it then nail off the bottoms of the bridging. Stronger than blocks/ cats and a hell of a lot less squeaking. The straightest of joist. Old school.

[@francoisbouvier7861]

It seems to me the Canadian code used to be anything over 7'4". Hence your 14 foot remark.

[@darkflux]

i think it is better to have too large a blocking than too little. then just measure as you go, and if you are off by a fraction, you can just sand down the end of your blocking. you can't STRETCH a block, but you can trim it!

[@aaronfredrick7705]

I have just found your channel and am really enjoying your videos. Regarding mid span blocks, what would you do for a floor with 12’ lengths of 2x10 that have no blocking but show leaning, top of boards 1/3” toward exterior foundation wall?

[@gregvancom]

If you can, send me some pictures. You can get our email address at the website.

[@loramcclamrock5549]

​@@gregvancom

[@dwightdancy5163]

We block AFTER sheeting...