Mid Span Blocking: Why Do It & How? || Dr Decks

[@1coolcontractor]

I’ve build about 40 decks over the last 20 years. I always let my joist run wild, start at the house and 2’ or so from the outside of the deck calculate my rim and facia with a 3/4” overhang and cut my joist accordingly. Thanks for all your great content!

[@BestSpatula]

Thanks for your content. I am almost complete with my first deck and your channel has been by far the most helpful.

[@fluxcapacitor1621]

Excellent presentation and explanation.

[@contractor556]

I’ve had an Irwin quick grip for about 3-4 years now, moderate to heavy use and man does that thing work amazing and grips as strong as it did brand new!

[@vl4n7684zt]

I re-decked mine with existing good joists and ledger connections, about 15 ft span. In addition to copper coat and joist tape on the top of the joists, I added blocking and it stiffened it up really good. made a world of difference. thanks for the tip!

[@douglasmichel6361]

Blocking is really for keeping joints plumb/vertical which is in their strongest state . Also for transferring loads from joist to joist as if they’re one. Each one assists the adjacent in carrying the live and dead loads.

[@cletusmax77]

Yea, it does all the other stuff the guy said in the video too.

[@TheChupacabra]

The failure mode of joists is twisting more so than snapping. The blocking fixes that

[@The_Red_Squirrel]

Good explanation of the purpose of strutting. Either solid or herringbone strutting are common forms of stiffening floor joists.

[@majermike]

@@TheChupacabra doesn't the decking prevent twisting?

[@FREEDOM_OR_DEATH_]

​@@majermikeThis takes the twist out before installing the deckboards.

[@alanmatthews9260]

I have 2 x 10 deck joists that go across Support beams. Should I put blocking at the support beam locations? And does the blocking have to be the same width as the joists that it’s blocking? By this video, I would say it’s not necessary, but I would worry about the irregularity in lumber widths when blocking at a beam location if I were to use 2 x 10 material to block my 2 x10 joists, thereby causing the tops of the joists not to be flush.

[@affordabledesertliving3487]

This so depends on having some nice quality straight lumber. Sometimes not so easy to obtain.

[@nagadsby9413]

Great idea on the clamp holding the blocks in place while you screw them in.

[@grumpytuber]

couldn’t you use framing nails here in stead of structural screws for the blocking?

[@miked5106]

tough to get hammer in the for top nail.

[@contractor556]

Even with a nail gun , nails always end up getting squeaky and sometimes loose. Idk how many nails I’ve had to pull out during floor installs and replace with screws.

[@TheRealStevenGoobers]

Love the vids, I'm not necessarily new to the building process, but I lack the knowledge of wood types used. What wood did you guys use for the fascia?

[@XYooper906]

I've never seen pressure treated lumber like this in the southeast US. What species wood is it, and why the patterned indentations on the lumber?

[@kylet3589]

I don't know what species he's using but the perforations are to allow the pressure treatment to soak in deeply

[@TheInsaneShecklador]

He's mentioned in a few videos that it's pressure treated Hemlock and isn't readily available outside of the West Coast. He also mentioned the indents help the chemicals soak into the wood during the manufacturing process.

[@majermike]

southern pine doesn't require incising for preservative uptake, douglass fir and hem fir require incising for preservative uptake

[@warrenlowe676]

What water resistant tools do you use? Cause doesn’t it rain everyday in Washington?

[@aclive2022]

can you just use 3-1/2" galv. framing nails?

[@dustinmarquand5301]

Good video. One note. I've been called out by my inspector here in WI/MN for not using full height blocking. I now usually just use joist material and rip 1/2" off for flushing up...

[@drdecks]

Understood. I explained that we’re running a waterproof bladder and needed to keep the blocks low.

[@dustinmarquand5301]

@@drdecks yep same here. I was using rain escapes. I think inspector just wanted to give me some grief.

[@majermike]

@@dustinmarquand5301 so how did you fit the rain escapes in?

[@dustinmarquand5301]

@@majermike we just recently did one again and cut a bare minimum "u" shape or dish out where rain escape passed over it. this inspector didn't look twice at it 🤷

[@Pro-ez9eb]

Code is 60% of joist depth, at least over a beam. I’m sure the inspector wouldn’t like to be schooled though…

[@theyard6958]

Holy shit! at least 30 flippin block, if they stopped at the corner. that 120 4' Timberloks. Thats a little less that 100$ just for screws, not including labor and blocking, DAAAANG! I love it. No expense spared! I would have likely not thought it necessary for those, over the 3.5 inch construction screw. Hey Dr., Do you think construction screws would be ok for this? They would be better than nails , right? Hey Doc. Thanks. Im new to the channel. I subscribed last week and already am about 10 videos in. Great helpful information from a master to a small-time contractor cutting his teeth! Again, Thank You!

[@MrDougfunny7]

he has that luxury due to customer base for the level of deck he is building. best practice isn't always affordable to everyone.

[@dilldowschwagginz2674]

I see you run Metabo tools too. I have just about every make/model of 1/4" impact you can think of but for most jobs I grab one of the triple hammers. They're just so damn good and compact to get in tight spots like between 12" centers joists

[@donpearsall7870]

Hello Doctor! Question: I will be installing decking boards with picture frame on the outside. I know I have to block the outside double rim joists to support the decking boards. Question is - will the 4" Fastenmaster screws be OK to fasten the blocking? Or does this require joist hangers? Thanks! I am learning a lot from your videos.

[@EtoTheKay]

Screws are fine

[@TimPine]

If I am working with a previouslyinstalled deck that has all the problems you mentioned, can I go back in and add in the blocking?

[@victorvek5227]

Glue & screw, or just screw, in a basement ceiling retro-fit situation?

[@tafisher4495]

I thought code requires mid-span blocking to be a minimum of 60% of the height of the joist....am I wrong?

[@bermudarailway]

In the UK its 75 %

[@majermike]

in the US there are various requirements for blocking, but since this blocking is not a structural requirement at all, no minimum exists

[@drumswest5035]

@@majermike in BC its a structural requirement and needs to be 100% depth, its stops the joist from twisting and spreads the load out.

[@majermike]

​@@drumswest5035 thanks drums, is it in the NBC? Im skimmed thru but didnt see anything that jumped out at me

[@ukiemanserg5163]

I believe it’s 60 % at least

[@SweeturKraut]

A good stiff deck is good to have.

[@Joe-jv5mm]

Tips and Hints 100% Thank You!

[@colinriley4348]

What are the dash marks in all your boards? I’ve seen that on a couple videos and I’ve never seen wood like that. Maybe I’m dumb for asking.

[@dharnish256]

That's pressure treated wood...The cuts are to allow for the chemicals to seep into the wood.

[@Gizmo82477]

It’s also called solid bridging. Makes the joists work together

[@tundrawhisperer4821]

They make a structural flat head screw, which would sit flush with your framing surfaces. 😁👍🏻

[@toterola451]

Thank you!

[@drdecks]

You're welcome!

[@mamounalmaslamani5319]

شكرا على هذا المجهود

[@jgeisler]

What drill/driver do you use? I like how compact it is.

[@drdecks]

Metabo HPT Triple hammer

[@Alaska-Bush-Mom]

What is the length of your clamp?

[@Palantir_Daily]

When would you do mid span blocking vs V bracing

[@MrDougfunny7]

mid span blocking is always needed. v bracing is used when needed to stop a deck from swaying.

[@majermike]

@@MrDougfunny7 why would mid span blocking always be needed? I'm a structural engineer and I don't see much purpose, "needed" is a strong word

[@EtoTheKay]

​@@MrDougfunny7 I thought midspan blocking was for swaying too?

[@gsxrsquid]

With those 4" screws, it spitting a problem on the blocks?

[@ahilbilyredneksopinion]

So my blocking does not need ta be flush on top?do I still tape them?

[@coreyk2998]

i think code says it needs to be at least 60% of the height of your joists. So if you are using a 2x8, you could use a 2x6, and you can keep them low so they are not flush with joists.

[@Historyprepares]

I think code says the block must be 60% or more of the joist height

[@tommywatterson5276]

Ties the joist together for additional strength and stops sagging.

[@ukiemanserg5163]

Your the best

[@edadan]

Can anyone tell me what type of lumber is being used here? I see some type of machining marks on the lumber but I don't recognize it. I live in the south and the only thing that I can get at Lowes/Home Depot is cedar of pressure treated pine.

[@drummerforpeace]

It's likely pressure treated douglas fir. Pressure treated southern yellow pine is a good bet too.

[@majermike]

@@drummerforpeace no, SYP would not have incising marks

[@tundrawhisperer4821]

@@majermikeWhat is SYP? Thx

[@majermike]

​@@tundrawhisperer4821southern yellow pine

[@malikto1]

How do you feel about self-supporting decks? Not needing a full ledger board attached to the house is something I like.

[@EtoTheKay]

If its not an elevated deck, then fine. But if its an elevated deck with a patio underneath, a free standing deck will force you to place posts by your walls, which is fugly.

[@egACRE]

What are the dimensions of this deck? Are far are the joists Spanning from the house ?

[@24June91]

Why do you ask that question? It is the first thing he said in the video. 16 Feet, 30 joist, 16inches on center.

[@MalleusDei275]

Did you crown the board you cut the blocking out of....then install each block crown up.

[@MalleusDei275]

Simple sense...😅

[@DailyBrusher]

So, on a 16-foot joist span, did you think about two rows of blocking? To make 3 sections of 5 ft 4 in each? I am working with 2x10 joists, a span of 12 feet, and I thought maybe I should have two rows of blocking, and that's 4 feet shorter than yours! But I don't know, that's why I'm asking!

[@drdecks]

I feel this method is sufficient

[@Joe-oi6eh]

@@drdecks the dr has prescribed 😎

[@adjusterneal1439]

Nails will loosen. Screws will hold tight.

[@FreshKicks4545]

I ran a similar method. Instead of a 12 foot span it’s about a 6 foot span. Would you recommend mid blocks in the center?

[@mikeyjohnson1696]

The log hog is the clamp Einstein

[@nestornarvaez8416]

Grasias

[@michaelshelnutt3534]

Is blocking required for 2x8 on an 8 foot span, 16" OC?

[@majermike]

no, why would you block it? what purpose would it serve? waste of money

[@tundrawhisperer4821]

Block mid span of anything 10’ or longer. 😁👍🏻

[@majermike]

​@@tundrawhisperer4821 why? just to keep joists straight during construction?

[@tundrawhisperer4821]

@@majermike Because it stiffens the floor system and prevents twisting over time. It’s a solid part of good framing. 👍🏻

[@majermike]

​@@tundrawhisperer4821 thanks tundra, doesnt the decking prevent twisting over time? wouldnt diagonal bracing along bottoms of joists be a cheaper and stiffer method of making the deck feel sturdy?

[@MrSubliminalStudios]

Anybody else see how they cut off one of the flanges on the joist hanger? Look at the joist by the corner of those. I hope Decks M.D. here makes a video about inverted flange joist hangers on the corners. Idk about simpson but mitek/usg says NEVER to modify their hangers.

[@dustinmarquand5301]

Looks like it's a corner joist/angle hanger. Different from an inverted...

[@drdecks]

It’s not modified. It’s a L90Z.

[@redmonkeymakers]

@@drdecks I didn't know you could use those at the start/ends of joist runs. I was planning on using concealed joist hangers, but would rather use L90Zs

[@nbco55]

​@@redmonkeymakersI still would use the inverted.

[@CybekCusal]

I prefer straight line blocking

[@Don-pq5gg]

How about using nails rather than screws? Especially since you are using the clamps.

[@vincentjackson3472]

Screws are always better, but nails do work ofc

[@drdecks]

Nails will work but may loosen up in the future.

[@leestebbins5051]

A 2x 12 is the same thickness as a 2 x 4. Twelve is the width of the board.

[@MarynJohnForever]

Why are you screwing blocks? S/b Galv 16d ringshanks Screw = way more time

[@raydavis168]

I’ve been building decks for 20+ years, I have never seen a 16’ deck without a center support, where are you building theses decks at. When you have a a deck 12’ in depth code requires a center support.

[@derekofbaltimore]

Why would a 16 foot deck require support in the middle but a 16 foot ceiling/2nd floor doesn't? Or maybe i misunderstood what you meant

[@raydavis168]

Because you don’t have a live load on your ceiling,where as your deck you have a number of people at certain times

[@derekofbaltimore]

@@raydavis168 i meant the floor joist of a second floor are the same joists for the first floor ceiling. There will be people and objects resting on those joists above... Right? I dont know. Ive never built a house or a deck so im probably missing something obvious

[@raydavis168]

@@derekofbaltimore my bad I misunderstood your question. I thought you were talking about just a ceiling.

[@MS-hd8yq]

On my joist span table a 2x12 can span 16'6" 16"OC and 18' 12"OC

[@westensanchez9483]

Just use nails for the blocks. Why would you waste all that extra money for structural screws?

[@majermike]

@h2s142 are you a bot?

[@robcollins3907]

Structural screws are stronger and hold together far better and longer than any nail. The technology with screws has come a long way. Screws always had the holding power and now with structural screws they have the shear strength as well.

[@BobHolster-om8rf]

HI. WHAT IS THE TYPE OF JOIST MATERIAL AND WHAT ARE THE MARKS? DOES IT HAVE SOME TYPE OF PRESSURE TREATMENT?

[@tomgray-kk7xf]

He said thick joists he meant tall

[@portagepete1]

Before long that will get all lose and wobble like It's not even there. You should use all thread with nuts and washers.

[@muntee33]

Your confusing people by forgetting to give simple direct instructions based on fundamental principles instead of unintentionally half winging it and thinking out loud. Ie; you take your blocking measurement off a consistent known, being the marking out along the end/s where they are to be fixed, in principle this is (should) the same measurements used for blocking. Perhaps your timber doesn't have perfectly parallel faces but these measurements should be safe to use or you need to pause and evaluate if not. So while your joists may be cupped twisted or simply leaning out of plumb the blocking is still the constant and once one joist has been verified / fixed in a plumb position then you have a known starting point and all that you need yo do is mark your vertical lines square from the top face down (you can use bottom if joists are perfect but its good practice to measure from the same edge /face and seeing the top face is the face that is the finished level its wise to consider that as your 'zero') Now its pretty simple, if your blocking fits snug at either the top or bottom face but not the other 99 out of 100 times I fix that end first and manipulate the other end/face of the joist to sit flush against the block face. Tacking initially to secure firmly enough to release pressure and the joist remains in place if the situation / work sequence calls for it. (hint a suitable set of stilsons work well for gaining leverage with the handle in the horizontal position and a decent clamp for gaining leverage with the handle in the vertical position. Some demo bars have a nub below the claw that can sometimes be spaced suitably for using in place of stilsons as the curved handle allows for better clearance. If using a common profile, a lever can be fashioned out of some hard timber or LVL and the joists width removed as a slot that is oriented as to give convenient positioning of the handle.

[@thomasschafer7268]

😅😅Hat man richtige Querschnitte braucht man das nicht. Keine Torsion. Nur bei euren STREICHHÖLZERN.

[@mikemarco76]

Why not just hire competent carpenters. Wouldn't that be easier and cheaper