Insulated Slab Foundation

on the build show today we're talking about an insulated slab foundation this is the first time i've ever done this detail i got a lot of cool things to show you guys today's video is sponsored by halo insulation let's get going [Music] all right guys so a little context before we get into the details first off this is a texas house that my company's building and it's pretty common for us to do slab on grade foundations where you basically just have a huge concrete slab sitting right on the ground with some exterior grade beams that are dug into the rock now we do have a lot of rock in texas and we don't have much of a frost line to speak of so that's why it's pretty common to see slab on grade foundations but the same type of foundation can be used in a really cold climate you would just have deep exterior beams which would protrude below the frost line on the exterior now another big issue we have to deal with in the south is termites so before i get into the insulation details first let's talk about this slab and some of the termite details and then we'll get into the installation itself all right first y'all let me show you this non-toxic termite protection we did here that i really like this is an australian company called termini mesh and what you're seeing here is this is a pre-made collar that slips down over top of the pipe and then there's these stainless steel hose clamps this collar is made from a really fine stainless steel mesh that's so fine that a termite's body cannot actually physically squeeze through it so this is a physical barrier not chemical typically when termites enter the house they're going to enter through cracks in the slab through places that they can be unseen and then they're going to do that damage for months years maybe even a decade or two before you know about it what's happening here is when they try to tunnel up that crack between the pipe they're gonna hit this because this concrete is gonna come up a couple inches on top this will be embedded in the concrete and where that crack happens where the pipe basically separates from the concrete they can't get in that usual location now we've done that everywhere in the house we've done it on tubs we've done it on drains like you see here we've done it on water pipes and we've also done it on conduit all right now speaking of conduits these gray pipes that you see here is conduit which is going to get future wires or pipes or maybe even hvac lines at this particular location we use 2-inch conduit so we actually have electrical and low voltage going on here but the reason we need these is this very large slab like i said 600 yards actually has several different pods that land on top and we purposely made a very low basically no threshold between them so we have nowhere to run the wires to connect the building if we wouldn't have done these conduits now if you watch the videos at my house i also ran conduits all kinds of places on my two-story house this is basically a one-story house so we could go up and over but we can't go between pods and that's where these conduits come in handy you're also going to see that these exit sometimes with bigger pipes where we could actually run the freon lines on the outside of the house where the equipment's going to go all right next let's talk slab top insulation i got this detail from my buddy steve basic an architect out of boston and i really like it what's happening here is there's the curb around the whole outside of the house and that's ultimately where these benson wood panels that are being made in their factory will sit and then where my feet are you can see it's it's a pretty decent elevation drop what's happening is this slab that will get poured here is the structural slab meaning all the structure will sit on top of that but the actual slab that your feet will walk on comes later we've got kind of a modern look going on here with a concrete topping slab so this recess gives us the ability to run the panels and then later come back and actually pour a finished and pretty slab kind of like what happens all the time in the north with basements where they pour the basement walls and then later they come back and pour the slab we're basically doing doing that same exact detail here i've got my halo foam stocked in the uh the job shack for like a better term now one other thing i want to mention before we uh finish this part of the video see how the forms on the side of the house are basically two by sixes we've got an elevated slab here and then there's a few parts like on the other side here that are pretty far out of the ground effects we're like eight feet out of the ground over there and this little wing wall right here is probably four or five feet out of the ground that's going to form what we call board formed concrete when we pull the forms there's an impression on the concrete of the grain pattern of the wood and also you get this really pretty kind of horizontal line architects absolutely love it and clients die for it a couple things you need to know about that board form concrete though number one you need to educate your clients to say it'll never be perfect anytime you pull a cake out of the cake form if you're frosting it you don't need to worry about it but in this case there's no frosting there's no stucco we're going to leave that which means that it's very likely we're going to see some imperfections some minor honeycombing or places where there's an air bubble in there now the way to minimize that and also get really strong concrete is to make sure you vibrate that concrete really well or consolidate it now we're actually using a brand new product from milwaukee today a battery operated backpack vibrator the guys actually uh two or three vibrators going on this job because it's a pretty large job we have 22 concrete guys and we're pouring like 400 some yards today but what's going to happen is they're going to stick their vibrator down into the forms it's going to oscillate inside that concrete and it's going to force those air bubbles up and that will help get rid of honeycombing and again you need to really educate your clients that there could be some honeycombing there's going to be some bubbles we're just going to try and minimize that as much as possible and that cordless vibrator really is nice because now i don't have to worry about that cord from the vibrator damaging finished concrete and making an impression on the concrete as the guys are using that they're able to basically cordlessly vibrate all the way down that beam and it's really nice to have that mx fuel now we have several batteries too so we'll get full day performance out of that backpack let's come back when we're ready to start insulating [Music] all right guys so this is the first time i've done a concrete slab that's fully insulated i've done some perimeter insulation before but i could never get my mind around putting insulation on top of the dirt and then pouring concrete on top of that but this on the other hand makes a lot of sense to me so you saw already what we did in this foundation we poured basically a standard slab on grade foundation but you're going to notice on the perimeter that everything is lower so come on over here and you can see some of those details so for instance this slab here this is the original slab that we poured and you can see that there's a curb all the way around the building let's actually verify that curb height i don't remember what it is off top of my head okay so this curb right here from this ins or from this concrete to the top is just shy of 13 inches and then we're actually in a shower area and that's why this is recessed but you can see then we put insulation down everywhere else now this insulation is originally intended to be below grade foundation insulation this is two inches thick this is made by halo and this is their sub terra insulation so this is meant to be in an exterior location now we're actually using it interior here and you're going to notice that this building is fully finished around me not finished i should say fully weather tight around me we don't have any rain getting in so it's almost as if we're building or insulating a basement slab but in fact this is a single story slab on grade house now the panels that you're seeing here stay tuned for a future video these are all benson wood panels that were pre-fabricated in their factory so we built this house and we're weather tight in the matter of just two or three weeks it was very quick but then what we're setting up for now is all this halo subterra is down on top of the original foundation and what i like about this in comparison to other details is that all of my structure all of my you know all my panels all these columns that you're seeing over here all those are bearing on concrete and then i'm simply in filling everything else on top of the slab with this halo subterra now this product is around r5 per inch so with two inches thick i've got an r10 insulated slab here and then you're going to notice on the perimeters we're filling in the perimeters also with insulation now tomorrow the crew is coming to pour not this building but a second building on the site and we're going to be pouring a four inch slab the insulation is right now or pardon me the rebar is right on top of the insulation now but don't forget we're going to chair this up you always want your rebar to be in the center of the concrete that's how it's going to give that concrete its strength so we're going to chair this up right before we pour it but we didn't want to do that now just so it wouldn't puncture the foam now this foam does have a higher psi level and we verified all this with our engineer before we came to this stage but this is 25 psi foam that means that it's 25 pounds per square inch which means that we're like 3 000 3600 pounds per square foot before this foam will compress so we're going to have plenty of ability to pour concrete on top of this and then you're going to notice that there's no interior walls framed at this point when we designed this house with lake floyd or the architects and with bensonwood who was the panel manufacturer we designed it so there'd be really no load-bearing walls on the interior everything is bearing on the outside walls so that we could pour this complete slab on top here with a topping slab and then we'll frame our interior walls right now we're actually in the master bedroom area of this house and so when we pour that four inch concrete on top here that's going to be finished concrete for us that gave us a couple benefits it meant that my foundation didn't have to be absolutely perfect or precision it also allowed us to do the rough framing which typically can be hard on slabs you know you've got two by fours that are coming down to brace these walls as they're under construction how do you attach those without hurting a finished slab there's a lot of things that can go wrong so what we're doing here then with that topping slab is that can be our slab that gets perfectly flat and looks really nice because that's actually going to be the finished concrete for this house and as a matter of fact we're going to be coloring that concrete as well we've got a couple samples over there showing the owners what are some of the options for what that concrete's going to look like but this detail makes everything really easy for us as a builder and i think also gives the client the best chance of getting a house that's going to be really durable and long lasting for instance all these penetrations right here if you saw my foundation portion every one of these has termi mesh on those which is basically a stainless steel collar so the termites can't burrow up on all these penetrations and we've got a lot you know this is a a vent stack this is water we've got some electrical conduit over here we've got more water pipes all those have been termished which means that now this i didn't have to try and do something weird below this if i was doing this insulation right on the ground guys that's really it it's a pretty straightforward process the crew is coming tomorrow to pour that other slab we're going to pour that four inches like i said and share this rebar up and then when we come back later and frame this no one's going to know that insulation is buried in there that's what i really like about this process it's going to provide that thermal break and it's going to make a huge difference on this house now we're in texas which means that the big benefit of this insulation for us is going to be in the heating season massive heat loss through your slab in the winter time our slabs feel really cold and this house is not going to be that way this slab is going to be nice and warm and that concrete that's real thick on top here is going to take the temperature of the house and want to hold that temperature it's going to be a really nice thermal mass if you're in the north though the big reason to insulate your slab is for both heating and cooling reasons makes a huge difference now you're going to vary your insulation thickness depending on where you are but two inches for us that r10 is going to make a massive difference guys big thanks to our friends at halo insulation that's the maker of this subterra that we used here but they have several other options for their graphite polystyrene insulation that's going to be really perfect for multiple locations exterior interior below grade that sort of thing so check out their website for more information guys if you're not currently a subscriber hit that subscribe button below we've got new content here every tuesday and every friday follow me on twitter instagram otherwise we'll see you next time on the build show [Music] you

Channel: Matt Risinger

Views: 101,366

Rating: 4.937429 out of 5

Keywords: Matt Risinger, Build Show Network, The Build Show, Build

Id: MbyLy0---AU

Length: 13min 40sec (820 seconds)

Published: Tue Aug 24 2021