How to Remove and Replace a Rotten Subfloor

[Music] i'm b cody and i'm ashley whether you're remodeling your entire home or just sprucing up a room with a fresh coat of paint we're going to show you how to do it right [Music] this house is in pretty good shape but there's one project that we have to tackle before we get to anything else look at this floor it's terrible and we need to replace it but it's not as scary as it looks i promise there are two common ways to build a house the first is called slab on grade a mold is built out of wood all of the sewer and water lines are laid out within the mold reinforcement wire is added and then the mold is filled with concrete the second method is to build a house with a crawl space or basement this house has a crawl space and sits about two feet off the ground on concrete blocks the floor joists rest on top of the blocks plywood is then added to the top of the joist to create the subfloor some flooring can come in several materials you have particle board osb board untreated plywood or untreated tongue and groove plywood before we repair anything we need to figure out why this floor rotted in the first place subflooring rots due to moisture but where did the moisture come from maybe there's a leak or something that was fixed in the past that we don't know about if this damage was caused by a leaky water line we'd probably find more rot near the kitchen sink or dishwasher the floor isn't rotten under the window so we can rule out a leaky window and the attic spaces look dry there aren't any signs of rotten wood up there i'm pretty sure the moisture is coming from the ground the lot that this house is on is a little low so i'm thinking that underneath the house it holds a little moisture all the time yeah the summers here in florida get really hot so i bet that moisture is evaporating up into the subfloor i totally agree but some good news is the 2x8 floor joists are in great shape i didn't see any signs of wood rot when i was crawling around down there that's great but how are we going to minimize the amount of moisture in the crawl space well for starters we can install a crawl space fan to increase airflow and reduce the moisture down there right now the water runs off of the roof to the ground directly next to the foundation by adding gutters and downspouts we'll be able to direct the water away from the house we can also install a vapor barrier underneath the house it's a plastic sheet which blocks moisture from collecting under the subflooring and the floor joists all of these little fixes are really going to help us with our moisture problem but now it's time to get to work on the actual rotten floor there's two ways that we can repair this floor we could patch the existing hole with plywood but getting the new subfloor to match up perfectly with the old subfloor is not something we want to tackle so what we're going to do is take out these cabinets and completely demo these kitchen floors which means we're going to be starting from scratch but that's a great thing it will ensure that our floors are completely level there's a lot of tools we could use to cut out this subfloor in this case we're going to be using a circular saw before you start any demo be sure you're wearing your safety gear we've identified where the plumbing and electrical lines will be but to be on the safe side we're going to take it slow we're going to cut back the sub flooring a section at a time use the pry bar to remove the subfloor and pull out any nails we find and inspect the next section for plumbing and electrical i started the demo by removing the rotten plywood this stuff was so brittle all i had to do was let the weight of my sledgehammer do the work this part of the demo didn't even feel like work it was actually a lot of fun the tedious part was removing all of the nails from the floor joists i don't know of a quick way to do this you just have to rip the nails out one by one the last thing we want to do is cut into the floor joists so what we're going to do is measure the thickness of the sub flooring and adjust our blade depth to match be sure to keep your hands out of the way of the blade while you're adjusting the depth cutting up the floor into small squares makes ripping them up and carrying them to the trash a lot easier but this process still took a long time some parts of the floor actually had two layers of plywood to cut through and pry up and i took it slow because cutting my leg on a rusty nail or having an accident with the circular saw wouldn't make ashley very happy after i cut out all of the subfloor i used a reciprocating saw to clean up the edges of the flooring near the walls and to get rid of the rotten subfloor beneath the hardwood i removed several pieces of it to expose the rotten wood then i set the blade depth of the circular saw to match the depth of the hardwoods and subfloor so i wouldn't cut into the floor joist then i used the existing edge of the hardwood as a guide to clean up the edge after a little bit more demo of the rotten wood we are ready for the next step now we have a huge hole in the floor we need to cover we'll start by measuring the area to figure out how much plywood we're going to need you can measure with a standard tape measure or use a laser tool like this looks like we have approximately 250 square feet to cover plywood comes in four foot by eight foot sheets so i'm thinking eight pieces should work but we can't just lay down plywood we want to attach each side of the plywood to the substructure of the house we need to add boards in between the floor joists to screw the new subflooring into we're going to use two by six pressure treated lumber like this we also want to make sure all the flooring joists are level if they're not level we'll either shim in pieces of lumber or add boards to level the floor joists looks like the floors are level so it's finally time to lay down the sub flooring to prevent the floor from squeaking when you walk on it we're going to add a bead of glue to each joist so the plywood subfloor doesn't separate later i like to use two inch exterior deck screws on projects like this with a cordless impact driver it's important to leave a 1 8 inch gap between each sheet to allow the wood to naturally expand during the seasons we started out by laying down as many full-size sheets of plywood as we could it felt really good to cover up almost half of the floor without cutting a single piece of plywood well we can't fit any more full sheets of plywood into this space so we're gonna have to start cutting pieces to fit into the spaces it's kind of like one giant puzzle piece by piece we applied the measurements from the floor to the uncut plywood struck lines with a chalk box and used a circular saw to make the cuts after adding more glue to the floor joists we dropped in the plywood and screwed it all down see that wasn't so scary but it was a huge project it was and that's something to consider when doing home renovations like this and there's no shame in hiring a professional to do the work but if diy is how you roll now you know how to do it right hey guys thanks so much for watching this video be sure to hit the like button and let us know in the comments any questions that you have if you want to try out any of the tools we used in this video we left links in the description below as well as some links to additional articles to help you out with other flooring projects and if you want to see more of our how-to videos hit that subscribe button and stay tuned to the lowe's youtube channel

Channel: Lowe's Home Improvement

Views: 1,620,751

Keywords: how, to, diy, lowe's, lowes, how-to, repair a subfloor, subfloor repair, rotten subfloor, fixing subfloor water damage, replace subfloor, replace subfloor in kitchen, repair subfloor, how to replace a subfloor, how to repair a subfloor, moisture issues in crawl space, repair joists beams, add floor joists, how to fix a rotten floor

Id: Tzi7rftE7Pw

Length: 7min 27sec (447 seconds)

Published: Thu Jan 24 2019