How to Repair a Crack in a Concrete Foundation | This Old House

[Music] okay so we're gonna fix this with mortar but before we do that we want to fill the void inside the block with some triple expanding foam what I want you to do is take this can hold it upside down all right take the nozzle and stick it inside the void because we want to fill the center of the block so we don't want the foam to come out and fill the joint okay does we're gonna have to chisel it out to make room for the mortar all right it's been about five to ten minutes and you actually you can see the foam really expanding out so we put too much in there all right but that's all right we'll let it dry and it will chisel it out but in the meantime I want to open up this crack right here all the way down to the floor I want to make it bigger now you're gonna put foam in there no I'm not gonna put foam in there but I have to make the crack wider so the mortar won't fall out if I just put it in this crack probably fall out so I'm going to use my cold chisel use about 5/8 cold chisel and just knock out some of it making the gap wider now a cold chisel designed to break out in masonry so it works fine I don't have to go too deep that's probably deep enough you just want to make sure we clean it all out that foam is still expanding on us if it keeps coming in you're gonna have your old basement insulated all right now on the outside what I want to do John is we want to open up this crack to take the cold chisel and open it up all right that's pretty good John all right now you hold the drill and I'm gonna add the mortar mix to the water all right what I want to add now is some acrylic bonding agent to the mix so it will make them more to stick to the wall even better alright John let's take a look alright that looks pretty good we'll let that sit for a few minutes and then we'll start putting it on the wall all right all right this foam is really expanding out it's dry on the surface but it's soft inside so what I want to do is take my trowel and shave it off now the foam is still a little soft so I can push it back into the hole to make room for our mortar all right John it's always a good idea to wet the surface before you put the mortar on it because the wall is so dry it'll suck all the water out of the mortar causing the water to crack all right so now I'm going to just take the mortar out of the bucket and push it into the wall all right John let's see how we doing in here all right the foam is good and hard so we actually have a base now for a mortar to go against I'm just gonna scrape off the excess on the wall all right this is setup enough so I can now smooth it out using my small rectangular trowel just make it kind of flat so now what I want to do is I want to add some texture to it to match the wall so I'm going to take a sponge with some water I want to wring out my sponge pretty much I don't want it to be too wet and I'm simply gonna skim right over the wall really lightly and you can actually see the grit rising giving a little bit of texture to the wall now it matches the wall all around it alright that's it now we're ready to go back inside alright I had a little bit of extra mortar so i smooths out the sill right here and I'm gonna flatten our filled section and you can come in with a sponge yeah look at that perfect alright that's it so in a couple of weeks if you want you can paint it you

Channel: This Old House

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Keywords: This Old House, Ask This Old House, DIY, Home Improvement, DIY Ideas, Renovation, Renovation Ideas, How To Fix, How To Install, How To Build, Concrete, Foundation, Repair, cracked Home Repair, fracture, crack, Old, Tom Silva, kevin o'connor, Do It Yourself, tom silva this old house, tom silva house, tom silva construction, tom silva tools, tommy silva

Id: Wgq-DLrfKjU

Length: 4min 15sec (255 seconds)

Published: Mon Oct 27 2014