How to Rebuild a Concrete Block Retaining Wall | Ask This Old House

[Music] we moved in about a year ago uh and one of the things the inspector pointed out was that he thought the retaining wall was built with the wrong type of bricks at the time it was leaning a little bit but not too big a deal flash forward a year from now through the winter now the sides are falling apart uh we've tried to patch it where we can but we're really not sure what we're gonna do about it we're worried the whole thing's about to collapse right so eventually it will go so glad you emailed but uh a few obvious things that i see right off the bat is the paver stone although it's good quality and built pretty well these pavers are they're really designed for something else uh maybe rim a tree maybe border your driveway you see that lip right there not really not really enough to bear not really good for this application as you guys can see we're retaining a lot of land we're retaining you know it captures water even if you guys look up to your neighbor's house you can see that you know he's 30 35 feet in the air above you guys so as you know everything runs downhill that whole hill all that pressure is bearing down on this wall and that's why we see the bulging and all the inconsistencies in the wall and that's what we're here to do is alleviate that pressure give you a new wall and go from there that's great okay so what i want to do is rebuild the wall with the right material while i go get that why don't you guys pull the hostas so we have some room to work [Music] once the old pavers are out we need to dig back a few inches and give ourselves more room to work we just want to make a nice clean path yeah does this all need to be cutting uh i don't know yeah all that all that should come out in that pile okay okay guys so now we've dug down we've got rid of the wall we've dug back to give ourselves plenty of room to work and as i've been digging i did discover that the first person who built this wall did use gravel uh they didn't use nearly enough so we're going to continue to dig down we're going to add more gravel we're going to take that first course of block in we're going to bury that in the driveway for more stability and then we're going to add gravel to the back of the wall as well why is having more gravel better more gravel is better because it helps with the drainage again the big problem with this wall is that it had no drainage so anytime the water would come down the hill it would build up behind the wall create ice and push that wall all over the place as we saw it the more gravel the better the water comes through the gravel dissipates through the block and into the driveway and we don't have any buildup [Music] okay guys so this is the new material it's a nice concrete block it's good as you can see much bigger much stronger than what we had originally yeah a lot bigger okay another difference is you can see these two channels we're just going to pop this little horizontal connector into that channel i think you can see one on the other side right there yep that makes the wall a lot stronger look at how that doesn't move yeah so also guys notice the color okay and we found this color in the original so we kind of mixed that in with the gray and came up with this yeah it'll look nice with our house too yeah good okay okay we're gonna bury the first course about halfway to keep it level i will set a block every six feet or so and level those to each other get it out of the groove onto the block [Music] this fabric liner will keep dirt and contaminants away from the gravel i can set a string line to guide the level and the face of the rest of the course then we can backfill with more gravel [Music] to lay the second course we need to line up the channels but we want to make sure the joints on the face of the wall don't line up all right guys so now that we have the second course up what we want to do is we want to install this perforated pipe in the back behind the wall as you can see this pipe has preparations all the way around it to catch and disperse water it will act as a second line of defense just in case the gravel gets clogged with dirt or other contaminants once the pipe is in and we've backfilled with more gravel we can start the third course [Music] the final course is going to be this cap which will secure with construction adhesive it'll hide the grooves and give the wall a nice finished look all right guys while we finally get the wall up you guys put your plants back in they look great thank you look this looks really really good it's a huge improvement over what we have all right great scott not only does it look good but what we did behind the wall with the drainage the gravel the pipe all that that's going to make this wall stand up for a long long time so hope you enjoy it thank you so much

Channel: This Old House

Views: 733,340

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, Episode, TV Show, DIY rebuild, concrete block retaining wall, wall, Mark McCullough, TOH, how to build concrete block retaining wall, concrete block retaining wall construction, concrete block retaining wall design, mark mccullough this old house

Id: 57HG5r5bqWs

Length: 5min 58sec (358 seconds)

Published: Mon Jan 22 2018