Where To Locate Control Joints in Concrete - Construction Math
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- Опубликовано: 15 сен 2024
- www.homebuildin... Click on this link for more information about patios, walkways and concrete building foundations. This video will provide you with a couple math formulas that will provide you with step-by-step instructions on how to figure out where to locate control joints in a concrete slab, patio, walkway, driveway or large building. It will also provide you with a simple formula for the depth of these cuts also. Don't forget to watch more of these helpful videos and increase your knowledge about construction.
There are two types of concrete. That which is cracked and that which is about to crack. As a concrete contractor, all we can do is control cracks.
Thanks for this simple explanation. I'm considering using saw cuts to add a decorative element to my concrete pool deck, which has not yet been poured. Is there a point at which there are too many cuts? I'm thinking of using cuts to make the slab appear more like pavers/tiles - maybe 2'-3' squares. Thanks for any insight.
I can't see why you couldn't do what you're suggesting on a pool deck or patio. Maybe not on a building foundation.
In your first example I thought you said don't go below 8 ft with a joint, then why is there a joint at 6 ft. Should not there of been only one joint , splitting the 20 ft into 2-two 10ft x 12ft sections?
There's not an exact science on concrete control joint locations, but most of the time 10 foot or less seems to work pretty good.
Very Very good follow up, on the concrete slaps, ? does this also apply to inside and
basement slaps too.
Yes it does, but it isn't always used in residential construction. I don't think I would cut any concrete that would be part of a structural building foundation, without the permission of an engineer. Thanks again for the great idea and I will be waiting for more in the future.
If you get a concrete "slap," it's going to hurt!
Someone mentioned installing bituminous foam between a slab and the abutting hard walls. Is that a good idea for interior slabs, such as garage floor and its three stem walls, or a basement concrete slab to the foundation walls? If so, is that a common practice to expect out of a new construction builder?
Thanks for the great video but I have a specific question. I just poured a 12m x 7m slab with mesh being SL92 [9mm bar with 200mm squares], has 11mm trench mesh all around the slab beam which is 550mm wide. The formwork was 235mm high all around. I did fill in the middle so the actual surface slab in 110mm thick [except of the edge beam which is 235mm of course. Almost 15 cubic meters of concrete in this girl! All of this was on a road base which was about 10mm to 40mm thick which was plate compacted many times. I am hoping I don't need to cut the poor girl, what are your thoughts please. Thanks.
Send me some pictures of your concrete. You can get our email address at the website.
Hello, I am wanting to remove an old driveway, and replace it with a new one. The dimensions are 24ft X 20ft. The contractor is recommending no expansion joints. My thought is at least one expansion joint in the middle of the slab. Will that suffice? Thanks
I agree with your contractor, but if you really want an expansion joint in the middle, then it might cost a few more dollars and simply tell them where to put it. Remember you're the boss.
my contractor only cut my control joints 1/2" deep at most on a 4" slab. i don't have any 90degree inside corners, but i do have a 45 and he did not cut any control joints to it. after just this winter i have some very tiny hairline cracks around this area (can't see standing up). i'm inclined to put filler in these cracks and cut all the joints deeper, as well as add additional joints. i have a 4.5" grinder w/ diamond blade. would that suffice?
I half-inch deep cut is usually perfect for 4 inch slab. I don't think I would use a grinder, but you could head down to your local rental yard for a dry cutting saw or purchase a diamond blade for a circular saw. There is a good chance you're not going to get rid of the hairline cracks, the control joints are meant to provide a little relief, not eliminate all cracking.
,Whats the purpose of that? Aesthetics? Just to prevent random looking cracks? Is it possible to just not do this?
,What if it's a poured concrete wall? Is this needed?
It serves two purposes one to control the cracks in the other two prevent them from being longer and the same thing would hold true on a concrete wall.
booger king
look at most basement floors that have no controlled cuts. they always crack.
@@JSmith-wy3yh yeah, I just pulled up all the old carpet in my single story home, underneath is all concrete, with cracks throughout.
question, I'm doing a concrete slab for my backyard but actually going to put individual pavers on the top of it for a better look, do you think it's even necessary to worry about cracks if I'm going to cover the slab anyway? Plus I don't really care if it lasts 20 years, five years would be good for my purposes 😁
I think I would worry about small cracks with pavers, but would if I was going to be installing tile.
so if i had a 10x20x6" slab can i get away with mesh and maybe a little added rebar down middle and ends so i wont have to do a control joint? thanks.
+Matthew Szczerba I'm assuming you're talking about the 6" x 6" mesh and your footing is going to be a rectangle measuring 10 x 20 and it's going to be 6 inches thick. I think you would be okay, but if it was me I would use the rebar and spend a few extra dollars, especially if you're going to use the 6 inch slab.
Thanks a lot . that answered my question😀
I recently got a quote on a driveway pad and the guy told me on 4” thick slabs they don’t use rebar they just use 4000 psi concrete . Does that sound right ? I’m thinking about doing it myself and saving a few thousand dollars. The pad will be 30’x30’ 4 “ thick
I've seen plenty of concrete driveways last a long time without any rebar and I've also seen them fall apart, so why not use the rebar and the stronger concrete.
Hi! We are pouring concrete patio around existing deck posts. the posts are lower than the patio level and the contractor suggested we use expansion joint around the post to protect it from concrete for any rot. Is that a correct approach?
I don't think the expansion joint is necessary and you might check with other contractors in your area for more information.
@@gregvancom so are you saying I don't have to worry about concrete around the posts? Another contractor said the concrete won't do any damage and he will just pour around it.
Thank you!
Welcome!
At 6mins 15sec, why did you add control joints between the 4'? If it's 4 inch slab, then its well within the max 12ft
I don't know what you're referring to exactly, but most corners need a control joint coming off of them. Let me know if that makes sense.
At 6min 15 sec of the video, there's a horizontal control joint between the two 4' marks at the left side. If it's a 4inch slab, then I guess it's unecessary since the total length is within the 8-12 ft range. Right?
Even though the control joints are less than 4 foot, it's usually a good idea to have another control joint coming off of outside or inside corners as shown in the video. Let me know if this doesn't make sense.
Is it necessary to have control joints if the slab is about 2.5 or 3 inches?
A slab is supposed to be at least 4 anything less is not recommended
How about expansion joints? Is there a formula for those?
I don't have a specific formula and usually follow what I suggested in video.
my name's ramond so i need to know how should i cut the joins every 8' 6' .how many feet of distance
thanks a lot. but i need to know how many feets should be cut the control join . ( every 8 feet or 10 feet?
+Rosa Sursona It all depends upon the width of the concrete slab. For example if you have a 12' x 12' slab, then it would be a good idea to cut right down the middle, leaving you with four 6' x 6' sections. You wouldn't be a good idea to cut it into 8' x 4' sections. How big is the slab you're working with?
How many feet should be cut the control joint? I had 2292 Sqft and 4'' thk to make concrete floor for warehouse. My supervisor said me to cut 20'x20'. I am not sure it's can avoid to get cracks. Please answer me.
According to most of the information I gathered, they shouldn't be spaced more than 12 foot apart.
Most important thing about cutting control joints is just make sure you cut joints that’s it
good vid. thank you.
Glad you liked it!
Do you need control joints if it has rebar?
For a driveway, I would.
You talked about the depth of the cut... What should be the width of the cut be?
I've seen them as small as 1/8 of an inch but can be bigger.
Where do I need my control joints
My new floor will be 2metres wide and 6metres long and will be around 4 in deep it's only a patio floor
Many thanks
I think the information you're looking for is in the video, just convert the meters to feet.
What about formed grooves?
What type of formed grooves are you referring to?
What if there is a column in the slab, where should I place the control joints?
I will make a video soon and put a link here.
ruclips.net/video/xwYSUDasm5M/видео.html see if this helps.
can i get some advice from you about concrete slab?
Yes you can either e-mail me with your questions or leave them in the comment area.
Thanks but i already poured concrete slab. it was not as hard as i was expecting, it came out nice. thanks for your videos it helped me a lot!!!
You're Welcome
What about interior curb wall doorways?
You usually don't install control joints on interior slabs, but you can and they would need to come off of the corners of the footings on each side of the opening.
@@gregvancom even in a non heated enclosed barn?
Control joints are used to reduce the amount of cracks and you can install as many of them as you would like, but some people don't mind small cracks and would rather have a flat surface or floor.
@@gregvancom yep. I think I'll do flat.
Thank you for your time!
You're welcome and thanks for watching.
I think im gona end up with about 2.5 squares' of rebar so i may be ok. thanks!
+Matthew Szczerba Anything is going to be better than nothing and that sounds like it will be fine.
The beginning was a little hard to listen to. A little dull sounding. Great info though. You have helped my project immensely.
Sorry about the sound, but I had a few problems with a few videos and hopefully it doesn't happen again. Anyway, I'm glad the information helped.
"20 foot by 12 feet" That is interesting. Lol
Interesting indeed!!
you wouldnt divide .25 into 4 that would be 16. you would multiply .25 by 4... also your explanation for the ratio of thickness to control joins was super muttled. would be better next time if you just display the equation.
Thanks anyway!
Thanks for the corrections, I always appreciate it done in a kind way. Now I'm wondering out loud here, don't shoot the messenger, but it sounds like you have enough knowledge about math to understand everything in the video, so why did you end it your comment with thanks anyway. Did you find what you needed?
@@gregvancom my guess is that the OP understood from your video that 4" slab gets cut 1", and worked out the formula from that
my name's ramond so i need to know how should i cut the joins every 8' 6' .how many feet of distance
+Rosa Sursona If you're asking me how to cut a control joint, it can be done with a concrete wet saw and the joints can also be installed when pouring and finishing the concrete with grooving tools.
what about cold joints / day joints?
I haven't made any videos on them yet. I'm a little confused, are you asking for more information or making a comment about control joints.
gregvancom I think by 'cold' and 'day,' he is referring to construction joints specifically.
construction joints are both cold and otherwise. big issue for me (gym floors) is joints where we get people doing partial pours & then you have a cold joints between the pours. I'm always interested in cold joints prep etc...