How To Seal A Gap Between Concrete Slabs

how's it going you guys it's scott with everyday home repairs and today i want to show you how to seal off and maintain an expansion joint between two pieces of a concrete specifically this is in my driveway now i've already done a video on the expansion joint or gap that's leading into my garage but that was a completely level surface in this case i have a little bit of a slope to my driveway so i can't use the same product that i did in that video which was the sitka self-leveling sealant great product works awesome and i'd recommend that video and that product if you have a horizontal expansion joint you're looking to seal you can look down in the description and you'll see the link to that video but this case because we have a little bit of a slope if i use that sikka it would just start to flow and pull up at the lower end of this expansion joint and it would kind of turn into a mess so instead i'm going to use a tremco product which is the volcan 45 ssl now the ssl stands for semi self leveling so it's not going to flow quite as much as that sitka product and you can use it on driveways that have a six percent slope now i'll show you how to quickly calculate that to see if you have a six percent or less which this product would be ideal for so your tools you're going to need are pretty minimal for this project first i'm going to start with the prep work and since it's fall in my area i got to get some leaves and some debris out to make sure everything is clean and ready to go i'm going to dig out the old expansion joint the twigs and the other debris in the expansion joint itself and vacuum that with a small handheld shop back might be a little bit more ideal for that now if i have any large holes where voids are starting to form underneath the concrete i do recommend some sand for that and filling those voids in before you seal off the top with the tremco product then you'll use backer rod because you actually only want to use about a quarter inch to a half inch of the sealant itself so it's key to get the right backer rod to tightly fit into the space and provide that surface for the sealant to sit on top of you do not want a loosely fitting back rod and in my other video i braided some smaller backer rod and actually i don't like that solution so we'll talk a little bit once you get past a three quarters of an inch gap that's what you'll find at like your home depot your lows so i'll let you know how to get that larger back rod just in case like me you have a little bit more than the three quarter inch gap so that's enough talking for the intro let's jump into the project starting with the prep work and i'll walk you through the full step by step on this project now just in case you don't know what the slope of your driveway is let me show you how to calculate that so what you'll do is you take two stakes one at each end of your driveway where you want to get the slope then you'll take a simple string and you'll position that lower on the stake for the high side so then you can pull it across to the other stake creating a level line by using a simple line bubble level here you get the bubble in the middle and then you'll secure that other side of the string to the stake and this is now your reference line why we want a level reference line is because this is going to allow us to measure both sides and get the difference in height which is called the rise which is half of the equation of calculating your slope so my rise ends up being six inches of height change or rise across the driveway so i take six and then i would divide it by the run which i'm measuring now and it equals 206. that will give me .029 but to get in percent you want to multiply by 100 and that gives me 2.9 percent which is well within the bounds of the six percent maximum slope of this product next step we'll just go ahead and clean up remember this is fall so i'm trying to prune back and get the leaves and twigs out of the way because when you apply the sealant it is very sticky so anything that falls on top of it will bind to that sealant so i just want to clean up everything as much as possible prior to cleaning out the expansion joint putting the back rod in and especially prior to putting the sealant down so just blow everything out of the way here and now that we have the surface clean i'll just take an old flathead screwdriver and you see that little kind of pieces of black material that is just the old expansion joy that's kind of dried up and broken down over probably about 20 years so i want to get all of that outside out of the expansion joint and then i'm just taking a little handheld if you have a shop back the more suction the better then i'll do the rest of the expansion joint again just getting everything out then once i go through there and vacuum it out i will also take a little wire brush now i want to just make sure all of the dirt or loose debris is off the concrete so the sealant can bond and there's all the expansion joint that's kind of broken down over time that we want removed prior to putting the backer rod in so now we're prepped and ready to start putting down the backer rod if you go to home depot or lowe's you're probably going to find this type of backer rod by md this is extra large so it's three quarters of an inch in diameter now again for my instance it's right at that three quarter of an inch mark so the back rods a little loose in certain areas and that's no good you do not want a loose back rod because that can again start turning into a mess once you put down the sealant the back rod might want to kind of float up to the surface and it just makes the project a lot longer messy and not the finished product you're looking for so there are larger back rods they're just not as common you can find md also makes an extra extra large back rod which is one inch diameter it's going to work perfect for my job this is easiest for me to get on amazon so i just prep for this project i'm going to do on the weekend order it on a wednesday and one thing to note the smaller background usually comes in 20 foot coils this is going to come into a 10 foot coil so you might need to get a couple more bags than you would with the smaller backer rod now i really didn't have any voids underneath the concrete that i needed to fill with sand but just know that is an extra step if you start seeing holes and you can't really see the bottom i would start to fill those with sand before you put down the back rod and then other than the back rod i'll show you what to do on the ends because you do not want to leave the ends open or obviously the sealant will just flow out and again start causing a mess all right so now let's put in some backer rod now i do read all you guys comments so i know in the past others have questioned why i'm not using knee pads so this job i'm using knee pads to kind of save my knees so i'll press the back rod into place this is pretty firm but that is how i like it it'll make for a really nice finished product where the sealant easily sits on top of the back rod i'm just using the handle of a putty knife to push it down about a quarter inch to one half of an inch below the concrete surface i just finished up that first roll of 10 foot of back rod and then i'm gonna push in the rest of this which is just about another six to seven foot giving a total length of right around 17 foot so here is the finished product and on this end i'm just using a shim so i just positioned the shim between the ground surface and the concrete to stop the sealant and then we have the back rod placed between a quarter inch and a half inch below the concrete surface stretching all the way across and then on the higher side i use just some gorilla tape and so i will have a little bit more sealant pooling up here but it shouldn't be too bad and then i'll stop the flow with the gorilla tape so now we'll put down the sealant and finish off the project so i have a 30 ounce tube i'm wearing gloves because this can get a little messy and also i have a cardboard box where i can set the tube in if i need to take a break so i just take my time and since this is semi self leveling it kind of does most the work for you just as long as you apply a relatively consistent amount of sealant as you go along now i am using one tube and i actually got across the entire stretch of 17 feet only using one 30 ounce tube which was great and that was a lot less than i thought and there's a leaf so you should be noted grass leaves anything will stick to this especially when it's fresh once you get finished here is what the final product looks like this is a limestone color there's different colors you can get overall it looks great now if you don't like that color you do have an option and we'll get that leaf out of there and that option is you could sprinkle some sand on top of the sealant and this should be pretty much right after you put it down so it's still sticky just sprinkling a light coating not too much and then after about 10 minutes i went along with my leaf blower and i just blew off all the extra so there was only a very thin coating of sand on top of the sealant to help it blend in with the concrete surface so that finishes up this project and overall the expansion joint is in much better shape it's going to help to keep that water out because in my area we go through many freeze thaw cycle so if i can keep the water out of the expansion joint that should help to extend out my driveway and the concrete life now when it comes to adding sand it does help to blend that in but do be careful on what type of sand you use and if there's a lot of moisture in your sand the sand i put down did have some moisture in it so within about 15 to 30 minutes i blew off most the sand so there's just that thin coat at the top and then the sealant itself could cure which does take several days depending on the temperature now if you're looking to do more maintenance around your house and you want to make sure your downspouts are in shape here is a video that'll show you the three different options you have to extend out your downspouts and make sure the water is getting away from your foundation so thanks for sticking around on this video and we'll catch you on that next one take care

Channel: Everyday Home Repairs

Views: 417,745

Keywords: sealant for concrete joints, sealing concrete sidewalk cracks

Id: ri2uhr3U9Wg

Length: 11min 16sec (676 seconds)

Published: Wed Nov 10 2021