Concrete Slab Foundation - Process & Best Practices
Вставка
- Опубліковано 21 лип 2024
- The most common foundation in the South is a Slab On Grade. In this video, Matt will give you an overview of the process as well as some Best Practice tips you can use on your #BUILD!
Best, Matt Risinger
Is there a pre-video to this? Ground preparation, insulating?
Thank you, it is so hard to find a well spoken and knowledgeable concrete guy! Lots of information that I can use on my fireplace pad that I am building myself. Thank again.
Man, I really have to tell you, I really like watching your videos. It's so refreshing to see people doing things right. I hate seeing shortcuts taken; they cause problems for everyone else later. Thank you for doing stuff right and showing us how its done.
His customers very obviously have more money than a lot of people, though. I mean this video is a perfect example. A ten car collector garage. You compare the cost of this foundation versus the average garage and I bet its about 5X the cost. Once you include the cost of the actual garage I bet its more like 10-20X the price of the average garage...Sure, it would be great if everyone could afford something like this but that isnt the reality. This quality of work is simply a luxury that most of us cannot afford.
Doing thing "right"? Shit, if this is doing things right, who the hell can afford it? Not even 1/4 of America.
That's what I'm talking about! I love it! I love to see you curing it--it's that 40% extra strength that no one seems to care about. I think I would have gone with macrofiber over the wire. I really like the 45 placed bar and the termite mesh around the penetrations. I think this convinced me that floor penetrations are to be prevented if at all practical.
I spent my summers, during my under graduate yrs, working for my dads general contractor firm - most years we had NYS DOT contracts to rehab elevated bridge decks on major interstate highways in the central NY region.... learned a lot about the science of reinforced concrete construction - expansion, damage caused by water seepage, rebar rust due to road salt, jackhammering out the existing concrete from around the existing rebar, sandblasting the rust off of the rebar forms so that they can be repaired/prepped for the new pour, setting up the pour machinery, curing the new pour and watering same.... every summer it was this or the equally difficult tasks of site prep for site clearing and foundation prep and then the post-construction site work of pouring asphalt parking lots, egress roads and framing/pouring concrete sidewalks
Do you get anxiety from the thought of job-searching? With credentials like that, I'd imagine you never had a problem getting hired.
@@Tubeytime hahahaha
Should have also included some thoughts on slab subgrade, arguably the most overlooked yet critical part of a good slab.
I'm planning a slab foundation for an addition to my house here in Pennsylvania, this is REALLY helpful. Thanks!
Great video, there were a few points in here I have not encountered in construction. The mixture of Steel mesh to prevent hairline cracks, 45-degree reo near penetrations and covering or flooding the slab. Maybe add a note about post-tension and its use in mutli-story buildings to save costs or increase spans between columns. But that's probably a video for another day.
Pretty good video. Looked this up to try and understand slab on grade casting for an exam. Helpful :)
Here in Japan it’s a rule to cover a foundation with vinyl or anti vapor film and finally I found this American YT video that is will explain in English the language that I 100% understand... thanks
Fun going back and watching some of these old videos. :)
I really appreciate your videos! They're very helpful!
Hi Matt, nice explanation, could you please advice when thermal insulation is required for concrete slab and how about waterproofing and thermal insulation of the underside of the pillars? Many thanks.
Outstanding video Matt! I've said it before but I'll say it again, your videos are short and to the point. Good audio and video quality as well. There's no waste of time. It's all pure information explained in simple words. Thank you :)
Question: is this considered "Monolithic slabs" ?
Very interesting. In Finland we stopped putting plastic vapor barriers under slabs in the 90s. For one because they could get damaged during construction, but mostly because it prevents the slab from drying downwards after pouring or a later water leak.
Instead with clay soil we use weeping tiles, washed gravel for capillary barrier and underside insulation. The climate is much colder here.
But in the south it might be different because the ground is so warm and high in moisture, a gravel vapor barrier might just not cut it?
Matt, as an alternative to Termimesh, I would suggest using a sealant that expands and adheres to concrete and wood, as the foundation contracts and a gap form between PVC pipe and concrete. I would suggest something like Contega HF. I actually hollowed around the sill plate at the PVC pipe stub-up and filled the hole around pipe with this stuff. Its pliable, and adheres to everything, and will never harden. Whereas, the Tertmimesh maybe a good product, but if the concrete cures and contracts, wouldn't the SS mesh pull away from the PVC pipe over time?
Could a project like this be done to an existing garage?
Love your videos man!!
Matt can you cover how to remove load bearing walls on a slab? Would I have to dig out forms for the jack studs or just put the jack studs directly on the slab? The spans are about 15-20' with a steel beam... wondering if it'd be worth it to redo some of the slab with rebar as I can tell there are some hollow spots under the hardwood floors which is driving me nuts! Any ideas?
Have you ever used pre-pruf by WR Grace, we used it a lot for positive side concrete waterproofing
is concrete cure & seal inferior to water spraying? Or simply not used so as not to interfere with some other sort of covering to be applied later?
Where did you learn your Moving Hands Technique (MHT)? The visual emphasis really amps up your delivery. Thanks.
Quick question just got my engineered drawings back and I too live in Texas and clay soil is beneath. However the soil guy recommended bell bottom piers and slab on grade. So I have 30 or so piers that are going to add a considerable amount to my house budget. My question is do I really need them?
Have you ever considered replacement of steel rebars with fiberglass ones?
I live in the Central Texas Area and have a plot with solid limestone starting at varying depths from 4-10" down. How would you go about pouring a slab for that? The back left corner drops off a bit and will need to be back filled to bring it to height. Could/would you use a grade beam in that area and spread footings for the rest?
Is this your standard build (concrete slab) for homes without a basement or crawl space? Thanks!
Is there a way to pour a post tension slab with a grid-like pattern well, or no?
Are J-bolts only used in the rebar method (or also on a post tension slab)?
Your vapor barrier is right on, I just read some comments on another presentation and most were saying the use of the plastic was to keep the moister from being sucked out of the concrete by the ground and/or the concrete needed to stay moist or it would be brittle. One guy said the more layers of plastic the more concrete it would support???? I have no idea what that one was about. I guess it takes all kinds....over heard a roofer telling a trainee that the purpose of the felt paper on a roof was to keep the sheeting dry until they can put shingles down. I guess the felt paper has no bearing on the integrity of the water proofing of the roof. I guess if you can put sheeting and then just shingles before it rains your good to Go. OMG
You never know what people think the reasons are for doing something, but, I guess as long as it is getting done right, it shouldn't matter.
I'm a Geotechnical Engineer-In-Training, and I was always under the impression that the Stego barrier was meant to help keep the moisture content in the soil maintained.
For the suspended slab, re-bars are placed 20 mm (clear distance) above the the bottom of the slab. What about for the slab on the ground, where do we position the re-bars? Please give your explanation for the answer.
hi there, how to cut those channels for the strength of the grid? sorry for the basic question.
I have watch a couple of your slab on grade videos. I seen one that was being fixed or re leveled. In the pacific north west we have TerraFirma foundation systems. That jacks the slab or footing back to level using foam. Can you do a show on this repair?
Informative! Also, Matt looks like he could be Mike Judges brother. LOL
So far everything except what I asked for. How to prepare the base when you are on clay ground.
I wanna pour a 14m2 workshop floor of about 10 cm high however, there's a 5cm slab (about 75%). Do you think it is alright to pour on it or should be removed, or at least break it up and stump it prior to pouring? It appears to vibrate in some parts, especially near the edge, when I stump on it, but not in the middle, yet. It used to be a pigsty floor, what do you suggest?
Have you worked on tilt up panel Jobs? If so, then do you have a video on that?
Hey Matt, just wondering would it be a benefit to wrap that vapor arrier for the slap under the exterior wall and may wrapping around or extending outward?
Great video!!
That's winter? I need to move. What's your frost footing depth there? We are 42" but in the last 10 years we've been over 48" deep which causes havoc on some bldngs. I go 48" minimum on all frost footings and it's been worth the extra money even when I have to eat the extra, just for a better product. I like your atitude on doing things better than recommended minimums that most people get
Excellent work
Much appreciated!
Expert craftsmen like you Matt are far and few in between. Another excellent video.
What do you do with the vapor barrier by the edge? Do you wrap it up the form or something?
Great video, Matt! How do you protect a slab on grade during the construction process that uses the concrete as a finished floor? We're building a SIP house in NY and want to protect the floor from the elements (rain), glues, and bangs and chips during the weathered in time frame of the build. And then protect the floors (ram board?) during the interior finish. I didn't know if there was one product we could roll out and leave for the entire process. Thanks!
I would like to know this as well.
What’s the curing time for home slabs?
I have a small, wooded, level lot in very sandy central Florida. If you dig it's endless sand. I'd like to partially clear it, compact it and drop in a bunch of #57 in the form of a driveway to a clearing patch in the middle. But not just compact enough to drive over, but also a base for an eventual foundation for small/lightweight metal frame single story offgrid house. Is this possible and are their specific requirements I need to meet in Florida?
God help anyone who has to cut into that slab, on some distantly-future date, to make plumbing repairs. Thank goodness a video exists, for benefit of owner.
In 1976, I had a garage fire in my parents' southern California garage, caused by an accident when working on a car. I was unhurt, but the whole-tank-of-gasoline-fueled fire ruined the finely-finished slab-on-grade garage floor. The highly-cracked floor was a mess. The whole slab had to be jackhammered, down to the dirt below, all the way to the peripheral foundation, and re-poured with new concrete. I suppose this replacement would have been vastly more expensive, had the floor been as heavily reinforced with re-bar as is the floor demonstrated in Matt's video.
Do you have videos have to make the plumbing, before the foundation?
Anybody know why irrigation systems are designed to water slabs on grade in Dallas TX? I am in Kentucky. We try to drain water away from the foundation.
Did that plastic mess up the finish on that slab? Ive used 1/2 drywall or sandbags to create a pool, but never plastic.
Yet another great informative building video
Does anyone ever use non-galvanized a36 holddowns / anchor bolts for the sill plates in south Texas (or otherwise)?
Nice one! You've shown pier and beam and slab on grade both going over clay soils. I wonder where the line is that requires the use of one or the other. Is it entirely based on soil composition, or are there other factors?
What is the final finish for the concrete?
... And can I see the car collection when this is done?!
Great video.
Nelson Rockwood there are other factors. Foundation type controls the amount your slab and the rest of your structure moves. It's mostly due to moisture. Clayey soils will expand when wet and contract when dry (you can actually see the cracks in the surface during dry conditions). This changing in volume is what causes the foundations to move which will lead to cracks in the slab and walls etc. a stiffer footing system generally means less movement. Good drainage will also control footing movement. As will the presence of large trees and plants. (Avoid trees near the structure as they suck water out of the ground). Sands are not as reactive as clays and so do not often require such a stiff footing system.
It also depends on what the structure above is going to be. Is it built from steel? Timber? Brick? Brick veneer? Articulated masonry? They move differently and some require stiffer footings. Also the bearing capacity of the soil will need to be taken into account.
These are all reasons for why you should get an engineer involved from the start.
How do you ensure proper preparation for underreams “beams” before pouring the concrete
finally Matt wearing manly men jeans Bravo
How thick is the slab or how far down is the plumbing?
Verry good job for your slab on grade project. Georges Paquet P. Eng.
Very informative.
What was the plasticity index of the soil?
Matt , when you are going to do a TV show, like a This Old house.
I think that you are at that level already.
Matt talk about "Helix Steel" micro rebar, why don't you use it instead of rebar??
There’s a better twisting tool for rebar tying instead of a plier. Also, no mention of expansion joints at all?
Rookie here: Isn't that a raft style foundation? If not, what are the blocks under the Stego? Thanks for anyone's help!
its a commercial style slab thats all
the way thing are to be build
housing built home is minimum requirements
My slab on grade house was built in 1939. It's cracked; I doubt it has as extensive support ribs as yours. It sure would be nice if I had a good solid slab with radiant heat in the floor.
Could you tell me what the best method is to cure foundation walls?
I’m curious to know your take on insulated slabs
Can you do this in sections using a mixer and wheelbarrow. This is great and all but someone I know just spent 30 grand on a slab
Types of foundations:
1. Crawl Space Foundation
2. Steel Reinforced Rebar Slab-On-Grade Concrete Foundation
3. Post Tension Slab-On-Grade Concrete Foundation
3. Basement Foundation
Basement forms and concrete or basement with CMU block? Also what about ICF foundations? Couple different kinds of crawl space foundations as well....
What goes first plumbing or making all those groves ?
My new house just started being built and has majors cracks.... needless to say the process didnt look as nice and handeled with care of this video. :( wish they were working on my house.
great video
Are slabs for new homes poured over a gravel base?
How about foundation house in marshes land?
Hey Matt, what ever happened to the videos for the rest of this build. I have looked all over for AUTO HOUSE.... Being a car guy, this one has grabbed me...
How much concrete should I order for my slab Matt? I want it thick and hard and personally delivered by you.
Thank you
Ive seen masons use their trowels to cut the vapor barrier so the could get the concrete to dry out enough to finish.
Hey everyone!
Merry Christmas to all!
How much cost to do a foundation like this one ?
Very informative video. Question: during the curing, is the process to leave the black plastic on for four or five days then to sprinkle it for another 4 or 5 days after removing the black plastic? Or is it to begin the sprinkling while the black plastic is covering it? We will be pouring in the middle of this upcoming HOTTT Texas summer it appears. We have a contractor hired but I will be hovering during the process!
My guess is he would water down slab each day and replace plastic. I had same question.
Best practice is to use purpose-made concrete curing blankets that have a felt liner that holds moisture. Then you can add water as needed to keep the felt damp. You should try to keep the slab continuously moist - black plastic sheeting doesn't do that (although better than nothing - but not much - unless you are constantly checking to see if there is sufficient moisture - the problem is that the sheeting doesn't retain moisture and if there is any slope involved, the water runs off or ponds). Some put sprinklers on slabs but the amount of water required can be significant.
why is vibration not done to the concrete ?
my only real question is, how are you able to find clients that appreciate paying to have a job done right? I wouldn't mind seeing a video on that process, as much as I learnt from this video, I could do with some advice on customer communication and convincing that long term a job well done is cheaper then short term monetary savings. Great video and channel btw. I hope you keep it up. And I look forward to the Wranglerstar collaboration, that is who introduced me to your channel.
Over engineered doesn't mean done right.
Nathan McIntosh Matt does high end work for customers who are more concerned about building it right than building it cheap. I know nothing about construction but I imagine a lot of it is referrals and such.
The act of building a 10 car garage for an assumed collector of assumed high-value automobiles, one that has a cantilever construction with ancillary living accommodations on its 2nd story, implies that the client is wealthy and that the home to which the addition is being added, is most likely valued in many multiples of the addition’s cost
MrEndzo it means its done better.
Who defines better? The builder or the client?
id assume that this is overkill for redoing a garage floor and driveway but great work.
I've noticed more of this kind of foundation construction being utilized. What I have noticed though, is that most contractors do not use a vapor barrier. I'm from the old school and believe in keeping water away from under the slab; however, here in Texas most people water their foundations during dry weather to prevent shifting and cracking of the foundation. This occurs in/on soil, heavy in clay.
ACI 302 has more or less made it so a vapor barrier is now always required.
it keeps the humidity/water out of the concrete as to prevent it from hydro cycling which can cause cracking, especially in colder climates
I've never heard that phrase before "hydro cycling". It is just perfect. I am going to use that!
Are those footings cured before you spread the concrete foundation on or fill in the footing then add the rest at.
looks like it was a continuous pour
Rebar reinforced concrete is fine strength wise but it's always going to crack more than pre-stressed concrete.
Would piles be overkill on the corners of slab and grade?
If the foundation is designed and constructed properly, then piles are not needed.
No relief cuts required with this type of beam slab?
I'm fairly certain to don't want to penetrate that slab as its a monolithic design to move as a unit
How long will stego last?
Is this ok in Canada?
How thick is the slab
I have heard of the importance of adding crushed stone under the slab (before putting the moisture barrier) Now this is not mentioned in this type of foundation. My question is: if you are channeling the footings like you show in the video, is crushed stone/gravel not needed under the vapor barrier for drainage?
I am a homebuilder here in North Texas. This type of foundation is engineered in a way that the gravel is not necessary. These types of slabs are very strong, but could always benefit from installing extra rebar.
Please tell me, do this pro tip you gave apply to Board Formed Concrete ?
If its winter time … Cover Concrete with Black Plastic for 5-6 Days … to prevent water in concrete from evaporating too fast
If it’s summer time … continuously flood concrete with a sprinkle for 4-5 Days … so concrete can get all the water it needs
Does anyone have a study on how long a foundation built this way will last?
That vapor barrier that keeps the ground moisture off could also keep the foundation and house moisture in no?
Ground moisture and radon gas are what you need to keep at bay. Moisture from the house should be taken care of by air exchange and hvac.
No insulation??
Amazing what you do
Question: Have you considered using basalt reinforcing rods in your concrete? Their coefficient of expansion is the same as the concrete (unlike steel), they do not react to moisture (all concrete absorbs moisture which rusts steel and spalls concrete) and their strength is better than the steel. "Concrete best practices" in your videos is excellent, but this would raise it to a higher level.
You need more subs
Is there gravel underneath the vapor barrier or is there any at all.
gravel is only required per design, for this application the vapor barrier he shows does the job.
Depending on AHJ (Authority having jurisdiction), gravel is required to prevent water retention under slab.
Best to remove organic topsoil down to native solid bearing soils.
I wish I had invested in a better vapor barrier, taped the seams, especially around any protrusions, and then got better cement. I have bad lime efflorescence that is now costing big bucks to cover up.
Efflorescence coming up through the floor?? yikes..