Concrete Joints

This video shows you how concrete can be joined and the different joints that can be used and why you would use them. Joints are used to control cracking, allow for expansion and to join two slabs together so they act as one.
If you like this video please subscribe to my channel / buildsum
For similar videos check out
• Why use reinforcement ...

[@masonorantes276]

this is the greatest video i've ever seen in my life. zero fluff.

[@Buildsum]

Thanks Mate, I'm glad you like it.

[@edwardarakelian8315]

This explanation left nothing untold.
Perfect video.
Subscribed.

[@Buildsum]

Hi Edward, thanks Mate, glad you like it, thanks for subscribing.

[@BobfromSydney]

This video explains every concept clearly and also summarises information at the end of each 'segment'. Really great. 10/10

[@Buildsum]

+BobfromSydney thanks bob glad you like it

[@bbbbbback]

Informative and down to earth, with this video in perspective view we can easily understand the concept behind, rather than looking at the section solely. I am a Melbourne Uni student studying Architecture and find this 100 times better than our construction lecture.... good work mate and keep it up. :)

[@Buildsum]

+bbbbbback Thanks Mate glad you like it

[@yeongtan4356]

Clearly,clearly explained to accountant trying to understand concrete slab work!

[@Buildsum]

Thanks Mate, I'm glad you like it.

[@geromepacete905]

Before, I had a hard time distinguishing these joints from one another. But you explained it clearly. Thank you so much!

[@Buildsum]

Thanks, Gerome, I'm Glad it helped

[@Ricktherealtorsc]

i wish this video was out years ago. it would have saved me a lot of time

[@michaelblake9110]

Very informative and easy to understand. Thank you!

[@randyjohnson3412]

Consider yourself SUBSCRIBED! What a fantastic video. You have a real knack for explaining things and simply illustrating it.

[@Buildsum]

Thanks Randy, I'm glad that you like it. Hope you find some of the other useful as well.

[@edwardarakelyan9807]

Thank you so much for your video. I have joined construction recently and there is so much to learn. this video perfectly explained 3 things which I had to familiarise with at one 6 minutes long video. Saved me so much time.

[@Buildsum]

Thanks, Edward glad you like it.

[@brocklesnar7599]

your amazing sir thanks million of times. that was exactly the thing i searched about it in many websites but finally, i found it in your video. that was so clear and fantastic explanation i have ever seen it.

[@Buildsum]

Thanks Brock Glad you like it, hope you find it useful.

[@sarahhovsepian]

I read and watched so many videos and I didn't understand it until I watched your video. AWESOME, thank you so much for explaining it clearly.

[@Buildsum]

Thanks Mate, I'm glad it helped!

[@delaramsanei4854]

Thanks for your thorough and simple but detailed explanation.

[@Buildsum]

Hi Delaram, thanks for your comment.

[@antonyharris6904]

Thank you “Buildsum” Really appreciate how you explain this so clearly with excellent clear graphics. Much appreciate the knowledge share for us budding builders! 👍🏻

[@Buildsum]

Thanks Mate, Glad it was helpful!

[@fayeh4412]

Your video is absolutely brilliant! I really appreciate the effort and time you took to model and set up the views in sketchup to support your explanation, just great mate!

[@Buildsum]

Thanks Faye, I'm glad you like it.

[@PhiNguyen-oj6ms]

This video is amazing. Thank you so much for your information. It helps me a lot.

[@Buildsum]

Thanks Phi
Glad you like it

[@lukepercy8525]

thanks for the vids really helping my construction management studies !

[@Buildsum]

Thanks, Luke, I'm glad you find them helpful

[@886014]

Such awesome videos. I never knew to grease the dowels on the drilled side, but it makes good sense. Thanks so much

[@Buildsum]

Thanks Mate, I'm Glad it helped

[@saurabhkulkarni2142]

very detailed n quality video. Thnx!

[@raykarena4595]

Cheers thanks for that, I asked this question at work and got different answers, now I know ...

[@Buildsum]

Thanks Mate, glad it helped.

[@RAF0769]

Thank you, exactly what I was looing for.

[@Buildsum]

Great to hear!

[@navids5275]

Really nice job. Left you an applaud!

[@Buildsum]

Thanks Mate, I'm glad you like it.

[@thedumbapple2339]

This video is great and very helpful. Thanks!

[@Buildsum]

Thanks Mate.

[@Timothyhyderabad]

love guys for giving a wonder full clarity about joints
make some more videos that like us engineering students can learn well
thank you

[@user-up6yi6hq2u]

Very interesting, and well explained, with diagram. Thank you!😊

[@Buildsum]

Thanks Mate,Glad it was helpful!

[@TheSideshowFirefly]

Great video, thanks!

[@hungle4092]

nice video. Explained them very well.

[@rickhorridge7355]

Exactly what I was looking for. Spot on, thank you.

[@Buildsum]

Thanks Mate, Glad to help

[@MohammedMohammed-jt6cq]

thanks dude you are really a life saver

[@Buildsum]

Thanks Mohammed Im glad you like it

[@larrylawson6408]

cheers mate , i knew the expansion joint but not the other two , thank you

[@Buildsum]

Thanks, Mate, Glad I could help.

[@Alrukitaf]

Great work. Nicely explained

[@Buildsum]

Thanks, Mate, Glad you like it

[@Jamil1989]

Thank you very much Sir. Very simple and clean expalnation of a subject I am having trouble with. God bless.

[@Buildsum]

Thanks, Jamil, Glad you like it.

[@Krizbonz]

I've read several construction books on this, and they've all failed to explain the purpose behind the Key and Dowel Joint. Thank you!

[@Buildsum]

Thanks Mate, I'm glad it helped.

[@jonoozzo737]

so good. I read all the time but to be visual is amazingly simple and clear to learn or refresh

[@Buildsum]

Thanks Mate, I'm glad you like it.

[@MrChongbangshereng]

best illustrative and laminated video in you tube. keep it up

[@Buildsum]

Thanks Mate, glad you like it.

[@ApprenticeGM]

This is the best explanation of concrete joints on the web - well done and thanks so much. Your imaging tool makes it very clear and easy to understand - great job. Your audio on this one was very "hot" or overloaded leading to distortion - recommend a good quality mic and check your audio levels before recording.

[@Buildsum]

Hi Mate, thanks for your comment, Yeah i had a few issues with the audio in the start. I have upgraded my software and mic and seem to have had better results in the more resent videos.

[@TramTran-tx7fx]

Very clear and informative video!!!

[@Buildsum]

Thanks Mate, Glad you liked it

[@fatu5410]

Put simply & perfectly explained thank you for this video. Even more wholesome is seeing everyone's replies from years before! Legend

[@Buildsum]

TThanks Mate, Glad it was helpful!

[@fogbreath6548]

Thank you, sir! This video is amazing!

[@Buildsum]

Thanks Mate,Glad you liked it!

[@yutianjiang4490]

Thank you so much!

[@ultraali453]

Thank you for the video

[@civilographybsbd1817]

Thankyou .this was really useful . I watched it day before exam, n i was able to write about it

[@Buildsum]

Thanks, Mate, hope you get a good score then.

[@sinarongbou556]

Very detailed and informative.

[@Buildsum]

Thanks Mate, Glad you liked it

[@itsGuevara]

Great explanation man.

[@Buildsum]

Thanks Mate, Glad it was helpful!

[@bodyandsoul24]

Thanks very informative

[@faizalk4463]

Thanks for this...very useful

[@Buildsum]

Thanks Mate,Glad it was helpful!

[@united3689]

Your videos are great mate, keep it up.

[@Buildsum]

Thanks, Mate, I'm glad you like them.

[@terryjones6219]

Killer video, excellent

[@Buildsum]

Thanks Terry, I'm glad you like it.

[@waynethorpe9384]

excellent vid. well done.

[@Buildsum]

Thanks Wayne, I'm glad to hear that you like it.

[@ahmedelsaman7986]

Thank you so much for your awesome video

[@Buildsum]

Thanks, Ahmed, I'm glad that you like them.

[@glen0626]

fantastic explanation !

[@Buildsum]

Thanks Mate, I'm glad you like it.

[@Evan_Adams]

a lot of cracking is due to curling and differential drying of a slab . would love a video on that. will check out your channel.

[@sinakhokonkesithole601]

This video is helpful and informative.... Thank you so much

[@Buildsum]

Glad it was helpful!

[@stardust1342]

Best video on joints ...
Respect😇

[@Buildsum]

Thanks, Mate, Glad you like it.

[@jctotsways1345]

Sir thank you! Been finding for days a video that explains about these concrete joints completely and easy to understand. I already subscribed and liked your video. Keep educating us😊

[@Buildsum]

Thanks Mate, I'm glad it was helpful!

[@jctotsways1345]

@@Buildsum definitely, keep uploading useful stuffs sir :)

[@sinaNlini]

thank you.. love the video

[@firstgabion7741]

great video, thanks a lot !

[@Buildsum]

Thanks, Mate.

[@matthewl.5085]

BEST VIDEO EVER!!!

[@Buildsum]

Thanks, Matthew, Glad you like it.

[@andyrock1207]

Thanks, very informative

[@Buildsum]

Thanks, Mate, Glad you like it.

[@2k_]

Thank you very much.

[@Buildsum]

Thanks Mate

[@truthcantbehide]

thank you Sir

[@jackkallemdjian3945]

very informative thanks

[@Buildsum]

+Jack Kallemdjian Thanks Jack

[@mazenmuradagha222]

thank you so much, very usuful!

[@Buildsum]

Thanks mate, glad you like it.

[@SalmanKhan-fk6fc]

great video

[@Buildsum]

Glad you enjoyed it

[@christinageorge9718]

Thank you. you are amazing

[@Buildsum]

Thanks, Chistina, I'm glad you like the video, hope it helps.

[@Anthony-xo3rv]

Thank you

[@sheratongallacher5318]

you are a legend

[@Buildsum]

Thanks mate, glad you like it.

[@maanasmathengeorge627]

thank you

[@MrBmxbrawler]

i really love your videos. I dont know what program your using but it is very detailed. and even though i know these things its great to see a different perspective. thanks

[@Buildsum]

Hi Mr Bmxbrawler, I use Google Sketchup for all of my drawings

[@MrBmxbrawler]

Buildsum Great work man. very informative

[@tapiwatsopotsa712]

Nice presentation

[@Buildsum]

Thanks Mate.

[@piaulin2078]

Thank you so much

[@Buildsum]

Thanks Gwan, Glad you like it.

[@S-Saha.19]

Amazing Sir
cleared my concept

[@Buildsum]

Thanks, Mate, glad you found it useful.

[@S-Saha.19]

Can you provide one on warping stresses in cc pavements?

[@Buildsum]

Hi Mate, sorry this would be the closest that i would have to that
ua-cam.com/video/vuZcPTp51Zk/v-deo.html

[@S-Saha.19]

Watched the video...my concepts are getting clearer day by day... subscribing.

[@mohanarakeri007]

Simply amazing.. full pavement class i was sitting without knowing wt am i learning? 😵😵😵

[@Buildsum]

Thanks for your comment i hope the videos help

[@petercrane8216]

Thank you for your videos, I now understand so much more and have learnt lots. A question if I may, in an area where I can not get a cement truck and can only mix by cement mixer, a slab on ground with side footings that go into ground, as in your slab on ground video, it will be impossible to pour the full slab in one day. I wish to use the key joint method , my question is do I do each section with edge footing, or do I do the whole edge/footing first then the slab on top, also not so sure how i will do the key joint with the mesh layed out. Any advice would be great and thanks again.

[@Buildsum]

Hi Peter, it is possible to pour the footing and the slab separately. Once the footing is poured to slab could even be done in small sections as required. As for the Key Joint, it is easier to set up the formwork and key joints first and then cut in the reinforcement however you can layout the reinforcement and then cut a slot for the key joint to go into. Remember the reinforcement does not cross the key joint.
Hope this helps

[@petercrane8216]

@@Buildsum, thank you very much for your help..

[@PaztelLofi]

Awesome video, much appreciated. Obviously you cant stop the concrete from cracking, but does moisture eventually pass up the crack and rust the rio?

[@Buildsum]

Hi Mate, thanks for you comment, Yes it will eventually and in some cases this causes the concrete to break off, called "spalling", which then lets more water in. Also called 'Concrete Cancer".

[@Alex-iq5tt]

Hi Buildsum,
Thankyou for that very informative video. The only issue I have understanding the joints used in construciton is now is that surrounding the 'Isolation joint' what is the difference between these joints you have explained and the isolation joint?
Thanks.

[@Buildsum]

Hi Alex
An Isolation joint would be similar to the expansion joint shown in this video. The Isolation joint basically separates the concrete from other materials that may move at a different rate.
Hope this helps

[@Alex-iq5tt]

Thank you very much.
Regards,

[@MrChagomota]

Awesome Well done! Very well explained, Really, really helped. Thanks. Saludos!

[@Buildsum]

Thanks Mate glad you like them

[@dozdeshabb]

And its amazing how many professionals ignore the proper spacing and expansion joints. . Thats why you see so many sidewalks are popping and have to be shaved.

[@Buildsum]

Hi Mate
I agree, you see it so often, I don't know what they are thinking. Thanks for your comment

[@lanesmaster]

Slab gasket

[@sravan086]

Its really nice video out of all. Thank you for the video. but there are a couple of questions need to be clarified 1) Is expansion joint only be at the edges? If the foam board is kept at the middle of the panel then is it called an expansion joint
2) Is it Reinforced concrete slab or concrete slab, if reinforced concrete slab then how the steel bars will be placed ?
Please explain this questions. Thank you

[@Buildsum]

Hi Raghu, Thanks for your comment. In reply to your questions 1) Expansion Joints could be incorporated into all of these joints. If you had a lot of construction joints it would be worth making them a combination construction/expansion joint to stop them wanting to lift up. 2) It is very rare to have a concrete slab without reinforcement in it. Here are a couple of videos that may help with the placement of the steel.
ua-cam.com/users/edit?o=U&video_id=vuZcPTp51Zk
ua-cam.com/users/edit?o=U&video_id=0Um_Ttv95Ko

[@sravan086]

Thank you for the reply, But both the videos are not working. can you send it again, please?

[@Buildsum]

Ok sorry try these
ua-cam.com/video/vuZcPTp51Zk/v-deo.html
ua-cam.com/video/0Um_Ttv95Ko/v-deo.html

[@mahmoudhozayen6543]

you're crafty (Y)

[@sypher0101]

Q: What's better, Key joint or dowel joint ? Great video btw :)
Q: Does concrete expand, & shrink, even after it's set? or only during the time it's setting ?

[@Buildsum]

Hi Mate
Both do a similar job, however, it would depend on what you need to do. If you were joining on to or extending an existing slab that has been poured for a while you would have to dowel it to connect to it. If you were just stopping the pour and continuing the pour the next day I would use the Key joint as there is less work involved to form the connection.
Concrete will shrink as it sets, as the water evaporates however it will also expand and contract with changes in temperature for the rest of its life.
Hope this helps

[@josephalsamour6808]

So part of my assignment suggest that after the first slab pour we discover that the diamond dowel system was done incorrectly and asks us to propose three solutions to ensure once the second slab is poured we have no issues. I am proposing drilling new holes and adding dowel bars as one solution. I wanted to recommend a key joint but the question is : CAN YOU ADD A KEY JOINT AFTER SLAB IS POURED?? please help also can you suggest any other solutions considering first slab has been poured…

[@Buildsum]

Hi Joeseph, no you cant add a key joint after the slab has been poured, doweling is definately the best option. Im not aware of any other soloutions however there may be some patented systems on the market that you could use.

[@skutsenkow]

This is a great video! If you are using dowels, does the concrete need to be able to expand and contract with the dowels or can it just shift with the pad it's doweled into? Meaning both pads move together. Also, if you are going to plan on using dowels, do you just run your joiner tool on the one first pad while it's wet? Essentially your tool is only running along half a pad.

[@Buildsum]

Hi Steven, Thanks for your comment, the dowel has to let the slabs expand and contract independently, this is why the dowel that goes into one of the slabs are lubricated and protected so they don’t grip the concrete. This will allow independent side to side movement but not up and down movement. As for the edging or finishing generally, the slabs would not be poured at the same time so they are finished independently.

[@skutsenkow]

@@Buildsum excellent. Thank you. What I was meaning with using the groover tool was how do you get it to appear like it was poured at the same time. Can you bevel the one edge and then pour the second pad the next day and then bevel that edge?

[@Buildsum]

Hi Steven, it takes a degree of skill but yes you can.

[@ejshelby5460]

Can I still ask questions? My 15’ by 15’ garage just got new concrete laid down. 4 inches and more. This large shed has wood around the base perimeters. Some were rot so we replaced those too. The builder laid down metal mesh, and poured one piece in one day. Lots of work but they emphasized the importance of one piece. Because the previous concrete was done in four slabs and the panels shifted up and down. But, he didn’t do co trip joints and not sure about expansion joints around the edges. Would it be a big deal? Maybe the wood sill/frame allows the expansion and shrinkage?

[@Buildsum]

Hi Mate, the timber would allow for some expansion however i would still have control joints in the slab.

[@ejshelby5460]

@@Buildsum would it be possibly to carve it after it’s cured

[@Buildsum]

Hi Mate, yes you can cut them in after as long as you dont go to deep and comprimise the reinforcement.

[@SethWP1984]

Just had a 1200 sq ft patio poured. Simple rectangle shape, 3 sides are open to the yard with nothing against it. One side its full length is against a poured concrete basement wall. Contractor claims that there is an expansion joint between those pours but I can't see it. There are saw cuts about every 7 foot by 7 foot square over the whole 20 by 60 patio. Patio has rebar. Is that enough for expansion since 3 sides are not against anything?

[@Buildsum]

Hi William, It is possilbe that there could be an expansion joint betweeen the slabs with a small layer of concrete over it so you cant see it so it could be there. Given that it is open on the other 3 other sides it is not going to be as important as if it was enclosed. As for the control joints that sounds like there is easily enough. Hope this helps

[@SethWP1984]

@@Buildsum Thank you for the reply. The outside 3 edges of the patio is also rather elevated from the surrounding landscape and really has nothing impeding its expansion on 3 sides, justvdont want a crack in my basement wall in the future.

[@Buildsum]

Hi William, i dont think you are going to have any issues in this situation.

[@thomasturner2890]

Hi Buildsum, how can you tell visually if something is a control joint or a construction joint if you're inspecting a finished concrete floor say in a warehouse?

[@Buildsum]

Hi Thomas, not really as they can look exactally the same however the Contol joint wont have any expansion joint in it so is generally thinner where as the construction joint could ( but doesn't have to) an expansion joint so it would be approx 10mm wide. Now days most Control joints are cut into the slab a day or so after it is poured so if it just looks like a cut that is 3mm wide it would be a Control Joint. Hope that helps.

[@damodaraomalley3974]

How many metres or feet between control joints. Also placement specific. I.e. corner of a building? Also deping on thikness. Is there a set formula for this. Thank you, Damo

[@Buildsum]

Hi Damo, there are alot of factors, like the ones you have mentioned, that would go into the placement of the control joints. There is no formula that i am aware of. Thinner slabs would need more, internal corners as well.

[@MrRdt1970]

How do damp roof adjoing slab

[@Buildsum]

Sorry Mate, I dont understand what you are asking.

[@antonios4926]

Thanks for the video. Would a concrete window sill 2.25m X 0.40m need an expansion joint in the middle?

[@Buildsum]

Hi Mate, no not in the middle however i would make some allowance to movement at the ends especially if it is supported on a different material like brickwork. Hope this helps.

[@antonios4926]

@@Buildsum Thanks for the advice. Not many You tubers bother to reply. Be safe be well

[@beingateenmommy]

Curious what concrete design app is that it looks very useful.

[@Buildsum]

Hi Brittaney, this is not an app, it just a drawing done in SketchUp

[@beingateenmommy]

O ok thank you

[@akaceejay3915]

Does a concrete basketball court need joints

[@Buildsum]

Hi, for something of that size and if it was just the court without any additional sections or attached to a building or another slab, i would say the they would be optional however if it was my job i would at least put in a control joint in the middle of the slab in both directions.

[@Ilovecash10]

Hi please answer.so lets say i poured already my floor concrete and then want to pour a wall.i put construction joint or expansion between wall and floor???because i pour concrete on concrete so it’s construction joint but at the same time its two element wall and floor so its expansion joint

[@Buildsum]

Hi Mate, it would depend on how the wall would be fixed at the top. If the wall was going to be freestanding like a brick wall then you wouldn't need anything however if it was going to be connected to a concrete ceiling for example you would have to allow for expansion and movement (slip Joint)

[@Ilovecash10]

But the bottom of the wall that is connected to the concrete floor will have expansion joint right? Not construction joint

[@Buildsum]

Hi Mate, Not necessarily as the wall could move up and down without causing damage if it is not fixed at the top.

[@marccalderon3701]

wow great video.. but just 1 question regarding construction joint, how is the main steel rebars will do at the end of the C.J. Are they will be terminated or hook or its just fine to continuously extend the main bars for the next day concrete pouring, instead of using dowels?

[@Buildsum]

Hi Marc
Thanks for your comments
If you extend the main bars there will be no allowance for the differential movement between the two slabs which will subject the slab to tension and possible cracking. The bars should be terminated and the slabs joined with dowels or a key joint.
Hope this helps

[@marccalderon3701]

Thank you sir for your response.. sorry i need to ask and seek your professional advice because at the moment I am doing structural details (slabs-on-grade). The scenario is this, I want to have a Construction Joint inside the residential project due to some construction material storage issue. Anyway going back, if I make/create this C.J. and after I will laid out my floor tiles covering the joint. Is this ok? Or should I terminate my floor tiles at the line of the joint?

[@Buildsum]

Hi Marc I would not run the tile across the CJ unless you put in an expansion joint in the tiles themselves (something like this tilingtoolsdelivered.com.au/expansion-joints/expansion-joint-aluminium.html) If you do they will almost certainly crack along the joint.

[@marccalderon3701]

Thank you sir! really thank you very much.. I learn so much with you.. God bless!

[@marccalderon3701]

for the last sir.. can you give me a full detail about Construction Joint that I can use as a reference like a shop drawing. Hope you can give me! Thank you again..

[@durothean]

great video! i keep hearing cold seam be tossed around with concrete...what is that?

[@Buildsum]

Thanks, Matthew, I haven't heard of a cold seam but have heard of a cold joint. This is where you are extending onto a section of concrete that has been poured previously. You would have to use the Dowel Method to join the sections and prevent the differential movement.
Hope this helps

[@durothean]

Thanks!

[@durothean]

how do you control/account for differential movement/settlement on say concrete pours like a walk-way or patio where the concrete is thinner?

[@Buildsum]

You can still use the same methods, the Keyjoint is good for thinner slabs.

[@naveedladha2204]

All three joints should be used once??

[@Buildsum]

Hi Naveed, while it is possible to have all three joints in the one slab it is not necessary. In some cases, you may use the same joint multiple times.

[@wheres_bears1378]

do you have online courses anywhere for sale ?

[@Buildsum]

Hi Sam, no sorry just the videos on my channel.

[@ataulshaikh2886]

Is it a construction joint or contraction joint?

[@Buildsum]

Hi Mate, it is a construction joint.

[@hatemwaheed1126]

what about cold joint

[@Buildsum]

Hi Hatem
I believe that a cold joint would be the same as the Construction Joint as it is joining to a Cold or Set surface.

[@natebrady6039]

Do you happen to know what a "Day joint" is? Also is a crack - inducing joint the same as a control joint?
Can you help me by anychance? Do you happen to know what a 'Day Joint' is?... also is a crack-inducing joint the same as a control joint?

[@Buildsum]

+Nate Brady HI Nate Personally i have never heard of a Day Joint or a Crack inducing joint however i would imagine that the Day Joint would be the same as the Construction Joint and the Crack inducing joint would be the Control joint.
Hope this helps.

[@Pfsif]

A "Day Joint" is where a person lives during the day, opposite a night joint.

[@domingosalandanan4139]

we kindly remove the sroove asphalt surface coverings ..it' is concrete and stabilized roadbed compaction problem ..gday po.

[@Buildsum]

Hi Domingo, I'm not really sure what you are trying to say.