2 layers of plywood subfloor. Use 1 1/4-inch screws for 1/4-inch backerboard.

2 layers of plywood subfloor Oct 15, 2018 · Replacing damaged parts of a plank floor that is 7/8" thick. So I'll have to work with smaller pieces near the edges. Paper prevents squeaks, nothing more: though in the old homes with plank subfloors tar paper also served as air barrier. – Jan 2, 2008 · Re: 1/2" plywood subfloor Nearly every house I framed in the 70s and early 80s was 1/2" subfloor with 5/8 particle board over in the carpet areas and 5/8" ULCX ply at the vinyl areas. Mar 8, 2021 · The first layer that is already installed is the subfloor. Two sheets of 1⁄2-in. These where done 10 years ago and still holding up fine, so yours should do well. In this configuration, two layers of plywood are installed, with the top layer offset from the seams of the bottom layer. I still prefer 2x centermatch to plywood for subfloor, running diagonally. I want to add an additional 3/8" layer of plywood, followed by floating 1/2" bamboo flooring. Mar 17, 2022 · Yes, you can add another 1/2" layer. I plan to put 1/4" cement board over the two layers of plywood. Do you need 2 layers of plywood for subfloor? Feb 1, 2024 · Double-Layer Subfloor. The number of layers of plywood required for a subfloor depends primarily on the joist spacing: three layers for joist spacing of 16 inches on center, and four to five layers for 24 inches on center. Aug 2, 2022 · Finished Floor Subfloor Materials Reasons; Laminate: You use plywood attached with a similar but thinner wood material as underlayment. The question is just how the underlayment should be attached to the subfloor, and whether it should be attached to the joists at all. This is new construction. I’m considering putting down a single layer of 1/2” plywood for underlayment, but I’m not certain I’ll be able to find sanded 1/2” plywood as easily as 1/4”. The underlayment should be placed in the room to acclimate for at least 48 hours before installing. Finishing touches. 1. The second layer is the underlayment for your finished floor. Place the staples. construction, IF its a higher quality material. Typically I'm replacing a previous "mud job" in a bathroom and sometimes in a kitchen, which means I'm making up for much more thickness. 5”. Sep 11, 2023 · It is strong, lightweight, and has no defects, such as voids within the layers that other types of plywood are prone to. Get it wet and you can sweep a hole in it. First is plywood, second is advantech Sent from my iPhone using Tapatalk Jan 5, 2021 · To level off I will be raising the den floor with 2 layers of 1/2" fir plywood. Since particle board is crap, two layers of OSB is much better. If you need to add some additional height you can use Ditra XL as well. Over 50 years it warped in some places and dips in other places. Aug 2, 2023 · I am currently replacing carpet with hardwood flooring. This thickness will suffice for most floors; however, codes will vary and a second layer is a good idea if your floor covering is going to be a heavy material like ceramic tiles or Mar 18, 2022 · When used as an underlayment, the plywood sheets are laid over the OSB (or plywood subfloor) for a two-layer base. exposure-1 plywood can be fastened without risk of penetrating the vapor retarder. In either case, you should add an excellent polymer to the grout and thin-set so it can bend without breaking. On top of that will be laying down 1/4" cement board and then tile. There is tar paper tacked in between the two layers of plywood, and there is tar paper glued to the top (linoleum-type tile was glued on top of that). However, if the joists are spaced further apart, it is advisable to use slightly thicker 3/4-inch plywood. Jul 29, 2023 · Generally speaking, it is best to use at least two layers of plywood when installing a subfloor over joists. Wd it be unusual to have our framer put down two layers of plywood over the joists (one ¾" and one ½"); that way, the ½" layer can be removed at exterior thresholds to get doors to fit with finished flooring a lot better? Also, it seems the joints between the two layers could be staggered to give more rigidity to the floor, too. Oct 9, 2023 · 1. Joists and Spacing Floor joists are made from 2x8 inch or 2x10 inch lumber, or from engineered quiet beams, which are made from a thin layer of chipboard on edge between two lumber caps Apr 18, 2018 · First, I'd counter your plans to orient the second layer perpendicular to the subfloor. How should I best fasten these layers of plywood to the old plywood subfloor? My current plan is to apply lepage PL400 in lines 12" apart and on the edges, use 2 1/2" flooring screws and screw into the joists (12" apart), fill seams with floor patch on each layer The kitchen has multiple layers or wooden subfloor (at least 3, but it might be 4 or 5). If you’re using heavy material, such as stone or ceramic, you need at least two layers of plywood. Jul 29, 2023 · The existing sub floor is only 1/2 inch plywood. Some sources suggest using screws that are long enough to penetrate about an inch into the joist or underlying layer, such as 1 3/4" screws for a 3/4" subfloor. That way if there is movement of the subfloor, less of it is transferred to the tile. Adding this extra layer of plywood, would also allow you to run your new wood flooring in any direction desired. For added strength and stability, a double-layer subfloor is often recommended. On top of the OSB was a carbon-film heating mat, then a floating laminate floor. Cement Backer Board Underlay A cement backer board underlayment, also called a cementitious backer unit or CBU, is best for only mortar floorings such as stone, ceramic, and porcelain tiles. Jul 6, 2012 · I'm looking for some advice on adding a second layer of OSB to a 3/4" T&G subfloor. "All you need in this life is ignorance and confidence, and then success is sure". Then thinset and screw a cement backer on top with Redgard and megaflex thinset to lay the slate tiles. It is an easy process and you simply do it one sheet at a time. As you may recall from other threads, I'm going to be adding another layer on top of it, roughly 1/2", to bring it up to the same height as another part of the room that is on a different joist system. And while the latter two sources require joists spaced on 16-in. With any plywood assembly, proper spacing and orientation are crucial. Jun 12, 2019 · How Many Layers of Plywood for Subfloor? If you are using plywood for your subfloor, you should use a minimum of one layer that is between ¾” and ⅝” thick. How is the deflection of your Jan 30, 2005 · As to how many layers of subfloor, tile substrate should be a minimum of 1-1/8", best provided with two layers of 5/8" ACX plywood, never use osb or particle board under tile. The APA guide references both the TCNA handbook and A108. Mar 11, 2021 · Whenever you use two layers of material to build up to the required minimum thickness of subfloor they both need to be nailed to the joists. May 26, 2011 · Q: We have just added new felt over a 1/2 inch plywood subfloor and then put 5/8 inch plywood over that. Removing the old 3/4″ plank subfloor and going with two layers of 3/4″ T&G plywood and a 1/4″ cement board? Am I overkilling it? The first layer of 3/4″ will be glued and screwed to the joist. The hardwood manufacture has recommended that a layer of 1/2 plywood be added to the subfloor in order for the hardwood fasteners to properly hold. The results were very nice. The house has 24" OC Trusses with 3/8" plywood ( and H clips). I plan on using a 2mm underlayment between the second layer of plywood and the bamboo flooring. We have two different brands of plywood subfloor installed. His solution is to remove 1-2 layers of the subfloor before putting down the vinyl. So, plywood costs twice as much as OSB subfloor. I would then use smaller screws (1 1/2") through-out the "field" of plywood to make sure it's nice and tight. What length of screws should I use to secure the new 3/4” plywood to the old 3/4” plywood? 4. Question I have is "If I add a second layer of OSB Two things in this video make me cringe. Drive screws every 8 inches around the perimeter of each board, 1/2-inch from the edges and 2 inches from the Nov 20, 2008 · If you are thinking of doing two layers of 1/2 inch plywood for the subfloor, think about doing soundproofing. It was common in the US during the 70s and 80s to use one layer of 1/2" plywood and a layer of 5/8" particle board. All layers of panels should be installed with strength axis perpendicular to supports. May 30, 2023 · To level it with the rest of the house, I need to install an additional layer of 3/4” plywood. I'm going to keep the existing 1/2 inch sub floor and lay new 1/2 inch plywood on top of it giving me 1 inch of sub floor. One technique of soundproofing is two layers of sheet goods (sheetrock on walls, too) with Green Glue in between them. Plywood? Plywood and OSB have varying factors that make them different from one another. If we now use hardwood flooring, rather than carpet, should we first place another layer of 15 pd felt on top of the 5/8 inch plywood, before laying the hardwood? Adding a layer of plywood would make for a stiffer floor, but 5/8 osb is ok for 16 o. centers, as well as subfloor and underlayment combinations that the other two don’t. Plywood and OSB have a strength axis that should run across the joists. Underlayment panel ends should be offset from subfloor panel ends by one or more joist spacings, plus 2 inches. Sep 29, 2024 · For a typical installation with two layers of 3/4" plywood, screws ranging from 1 1/4" to 1 3/4" in length are commonly used. Feb 4, 2023 · Most of the time, you’ll get the best results if you use two layers of plywood. Feb 19, 2023 · The plywood used in the subfloor is two different layers, where one is the subfloor, and one is the underlay. The crew stripped the roof and nailed a second layer of 1/2" plywood over top of the 3/8" existing layer. Contractor pulled the tile and carpet in three rooms and a hallway. Why add an extra layer of plywood over a subfloor? How does subfloor leveling work? 1. If you installed the second layer as you described in your answer you would not have a subfloor that passed code (at least in the US). I need to bring up one of our room's floor 1-1/8" so the flooring we will install will align with the neighboring kitchen tile. In fact, I've replaced the particle board in such floors with OSB. Yes, my understanding is this comes from the resins used in the manufacture. The minimum number of plywood layers for a subfloor is one, though you need to be sure you’re using a layer at least 3/4″ thick. I got an estimate from the local flooring company on Saturday and talked to him about how it could cause problems. Good base for vinyl sheet flooring. We ripped up 4-5 layers of flooring in our living room and dining room, including (1) laminate, (2) insulation layer, (3) parquet tiles, (4) plywood, and (5) some sort of cardboard base, along with two large jars worth of nails, all of which revealed The double layer of plywood is glued and screwed together, but not attached to the existing subfloor. There are several methods, including: • Floating subfloor: There are two common methods for this. You use plywood as a subfloor for laminate because it’s comparable to hardwood, albeit thinner. My subfloor is OSB. Jan 11, 2006 · In the course of a kitchen remodel in my 50's or 60's era home, I see that my subfloor in that room is a double layer of 5/8" plywood. Two questions: is the lesser plywood (Boise Cascade 22/32) acceptable despite it's reduced rigidity? And will 3/4" hardwood flooring ultimately remedy this? Jan 18, 2008 · From a basic sectional properties point of view, if adding the first layer of subfloor increases the strength of the joist (composite joist/subfloor section now) by 10%, then adding an additional layer of subfloor should increase the strength by an additional 10% if not more since the additional layer is further away (larger moment arm). The adjacent floor is over an inch higher with ceramic tile, so I’d like to build up the level of this floor a little bit. Dec 16, 2005 · My research is telling me to use two layers of plywood. Would it be OK to install a 2mm underlayment between the first (5/8") and second (3/8") layer of the subfloor? Dec 30, 2016 · Much to my surprise when I pulled up the 3/4" Oak hardwood floor; I realized that there is a 1/2" plywood subfloor which is then topped by a 2nd layer of 3/4" plywood. Plywood does not shrink and expand as much as lumber so no adhesive there will allow the joists to shrink and expand as necessary. I didn't follow all the other OP talk of adjacent rooms and such, but commenting to just say installing 1/2" like the original house might lead to lesser detailing problems everywhere. 3/4" T&G was rained on several times. Use subfloor adhesive, and screw 8" at edges, 12" in field. Feb 18, 2024 · Adding an extra layer of plywood over the subfloor is the best way to create a secure foundation for your flooring. Is 1 1/8" plywood a good way to go, or will I gain by using 2 layers of 23/32" plywood? Apr 2, 2012 · Planks as the bottom layer in a subfloor are fine, but you will need to install 1/2" plywood over them if you want tile. He found two issues - 1) subfloor is not level and needs to be sanded down to make it level 2) subfloor is a bit spungy/bouncy in certain areas of the house. However my current plan is to glue and screw 1 1/8" sturdifloor plywood to the joists. It's slow on the install but sure is tough. 2. The sheets are typically 4 by 8 or 4 by 12 feet in size. Jun 18, 2016 · I first laid down 3" of 25 psi XPS in two staggered layers, then 3/4" T&G OSB sub-floor panels. For your install, plywood will work fine. What type of tile? If natural stone you may need to pull up the old 1/2, put 3/4 first then 1/2 (uncoupled) then ditra. Follow along as we explore how you can fortify your subfloor with an extra layer of plywood. Sep 4, 2014 · I tried to place the new plywood perpendicular to the old one, and the seams did not coincide. Use 1 5/8-inch screws for 1/2-inch backer board. Jul 6, 2017 · When screwing down a second layer of subfloor on top of the bottom layer, should I 1) use glue? 2) screw into the joists? These are two layers of 3/4". Then another 1/2" layer sandwiching the 1st layer to create a 1" thick subfloor. c. It is important for seams not to overlap between layers, and it's generally recommended that the screws attaching the top underlayment not go all the way down into the floor joists, since some degree of lateral movement needs to be How many layers of plywood for the subfloor? Only one layer of plywood is enough for the subfloor, but make sure the plywood is AC labeled and ¾ inch thick. First, using 1/2 inch plywood underlayment is inadequate by my standards. The best I can tell the two layers of plywood are 3/4” each. Nov 30, 2007 · 6) Additional subfloors: Depending on the product you're installing, you may need to install a wood subfloor over the slab. More critically, I want to add strength and stiffness to what is often an inadequate subfloor. Foolishly, the tile guys wanted to mud base over just the 1/2" so the tile wasn't so much higher tha the hallway and bedroom carpets. Most new panels intended for subfloor use are dense and water resistant enough to handle hardwood fastening just fine. Jul 9, 2005 · Framing, Flooring and Sub-Flooring - Adding second layer of plywood to existing subfloor - Project Homeowner (me) Putting down about 850 sq ft 5/8 bamboo flooring to replace carpet. As you indicated, stagger the joints. The cost of the Green Glue may surpass the savings over a single layer of 3/4 inch tongue and groove. 5" x 109. This means the 2nd layer is a structural subfloor attached through to the joists. The total height of the two layers is about 1. Also, if the new layer is 3/8” plywood, is it necessary to remove the toilet flange, or is an extender sufficient? Sep 17, 2009 · Build the subfloor with two layers of plywood. The first is to lay two layers of 3/8-inch plywood over the slab without fastening or gluing them to the slab. May 14, 2018 · On the 3/4" subfloor, you have the right idea. Two layers minimum Performance Category 19/32 APA Rated Sturd-I-Floor c Exposure 1 Two layers of minimum Performance Category 19/32 plywood APA Rated Sturd-I-Floorc 20 oc Exposure 1 (for joists spaced 16 inches o. Floor Span Rating must equal or exceed joist spacing. And, yes #2, this gets more complex in cooling cycles especially in humid hot climates. Oct 26, 2020 · When laying a second layer of plywood subfloor to support granite tiles, does the original plywood subfloor need to be leveled first or just level the floor after adding the second layer? I have about a 1/4” dip. The second layer will need to be glued to the first layer and screwed to the joist as well? Just wanted to update everybody on this thread we finally found the time to move forward on this project. Prepare the underlayment. A plywood subfloor uses 3/4 inch, 5/8 inch, and 1/2 inch thick sheets with one smooth side facing up and one rough side facing down. Instead of turning the top layer, simply stagger its joints with respect to those of the subfloor. Jun 22, 2024 · I spent the afternoon driving about 500 screws into my 1960s 5/8" subfloor (12" oc joists some places, 16" oc other places). John Feb 9, 2022 · The house is on a raised foundation and have 3/4 inch plywood subfloor from the 1980s. Particle board is a dense very hard slab of sawdust PARTICLES. 01, but not the APA’s guide. Plywood installation. I understand the installation method, but I can't figure out what I am doing would be considered underlayment or second layer of subfloor? Oct 31, 2014 · By not gluing or screwing into the joists for the second sheet, you allow for uncoupling of the two layers. Use 2 layers news paper will work just fine. Plywood subfloors generally consist of three to five layers, with three being the minimum and five being the maximum. BOTH layers of plywood are nailed into the joists. When I was cutting it out, I found that there were two layers of plywood, the subfloor attached to the floor joists and then another layer over top of the subfloor. Prepare the subfloor. If you use adhesive for the underlayment, you can get away with fasteners every 8" using ring shanked nails. This will ensure that the subfloor is strong and secure. 3/4" T&G is glued and nailed. Then, screw the backer board into the subfloor using special backer board screws. Can I 'glue and screw' a two thinner pieces of plywood (1/2" and 3/8"), or do I need to source 7/8" plywood? I would use pl premium and screws for compression between the layers. Is 1 1/8" plywood a good way to go, or will I gain by using 2 layers of 23/32" plywood? I've been thinking to use flooring adhesive (called something like PL400 found at HD in a caulking type tube) to glue the two layers of plywood, and then use 2 1/2" or 3" deck screws to attach both layers of plywood to the joists. Need a level surface to lay another 1/2" plywood subfloor layer. centers, the APA has details for joists on 24-in. Dec 4, 2015 · Without a backerboard or membrane, the minimum recommendation for residential applications (F150) is nominal 5/8-inch plywood subfloor plus 1/2-inch plywood underlayment – for a total thickness of 1-1/8 inch for joists 16 in. or less) a. Apr 6, 2021 · You should aim for two layers of continuous below the ditra, 3/4+1/2" for the best chance at controlling movement, the top 1/2" should only be screwed into the layer below without penetrating the joist. In many projects, the walls are framed on top of the floated subfloor. 5. Dec 2, 2021 · Adding an extra layer of plywood over the subfloor is simply a good idea. Nail schedule 6"OC 12 in grid 4"OC edges. Other notes in case important: exisitng 1/2 inch plywood is nailed down but I will be screwing it to the joists, second layer will only be screwed to the first layer and not to the joists (found info. My question: Mar 17, 2022 · But yes, I am using "subfloor" to refer to the existing 1/2" plywood that is already nailed to the joists, and "underlayment" to refer to the new layer of 3/4" plywood I need to install. Marine plywood is pressure-treated, and layers are affixed together with waterproof glue, so it holds its strength and shape even when exposed to moisture and heat. Use 1 1/4-inch screws for 1/4-inch backerboard. 01. Oct 11, 2015 · The other was 2" of blue foam over a concrete slab, with a layer of 2'X2' squares of OSB with plastic dimple board as a floating floor over the foam. For the 1/2" underlayment, ideally, you want to screw every 6" all across the panel. I'm thinking of adding a layer of 1/2' or 5/8" OSB on top of the 3/4" T&G after the roof is on, which should be mid-next week. May 7, 2017 · I'm laying down two layers of 3/4" subfloors for my bathroom remodel. You can use a particle board for a completely flat surface for best results. But to summarize, the worse performing plywood is Boise Cascade 22/32 and is described as being for wall and roof sheathing but also flooring. First plywood, then advantech (moisture resistant). One has more flex than the other (the knotty one). Not sure how standard or acceptable this is for subfloors. 3. (I have questions in the flooring board on that subject) House Specs Built in 1979 In Maryland, USA, in a humid (June-September) area If the underlying floor joists are spaced 16 inches apart or less, it is suggested to use standard 15/32-inch plywood. Sep 18, 2007 · I've done three layers of half inch separated by felt, and each layer perpendicular to the previous. I rarely see plywood with so many knots on BOTH sides used for much. Jul 14, 2022 · A plywood subfloor generally uses 1/2-inch to 3/4-inch-thick sheets of plywood with one rough side (which faces down) and one smooth side, which faces up. Subfloor is 1/2" plywood, not tongue and groove. I would not glue the bottom layer of plywood to the floor joists. 5". 4. C. A floating subfloor is the best way to install a wood floor over concrete. My research is telling me to use two layers of plywood. It is so much much better especially when joists change direction. Apr 24, 2015 · If you space your 2x6 floor joists 16" apart, two layers of 1/2" plywood should be fine. on this already), and the finished flooring will 3/4 inch by 3 inch hardwood. Nov 5, 2024 · Should I install a layer of felt paper between my structural board subfloor (1*6 planks) and the 1/2" plywood underlayment that I'm going to install? Thanks! Plywood Quality for Subfloors. My stud to stud measurements are 99. The subfloor is OSB laid on-top of joists. I-joists are 16" oc. A comparably sized sheet of plywood subfloor panel costs $40. 6 days ago · The subfloor (plywood or OSB) does just fine by itself. Floor joists are 2"x10", 16" O. . If there is any deflection in the subfloor when walked on it would be advisable to add an additional layer of 3/8" or 1/2" thick plywood underlayment glued and screwed down over the wood plank subfloor to add stability to weak subfloors. No fasteners in the OSB. b. or 5⁄8-in. May 14, 2018 · On the 3/4" subfloor, you have the right idea. By floating the plywood layers, there is no vibration path to the structure caused by mechanical connections. I don't know how they handled the H clips, but we never went over the original sheathing, we stripped it and started with new plywood. Oct 30, 2024 · OSB subfloor is the most budget-friendly subfloor material. Some flaking. Start with a ripped half sheet and stagger the butt joint by two joists. on-center. Jan 4, 2024 · Method 2: if it's the second layer of the subfloor, then you glue in between the boards, and use longer screws so the second layer, 3/4" ply, can also be fastened to the joists. Ed Mar 28, 2013 · I have almost a similar setup as Tom. Sep 7, 2023 · Walk gently on the panels to set them into the thin-set. By staggering the seams, the subfloor's overall strength is enhanced, reducing the risk of deflection or squeaks. Jan 15, 2024 · What Is Better: OSB vs. One sheet of 23/32-inch OSB subfloor costs about $20 per 4-foot by 8-foot panel. I am using 1/2” exterior grade plywood for the second layer of subflooring. I used to believe that the underlayment would be situated between the subfloor and final floor. Cost: $2 to $4 per square foot Feb 10, 2006 · can i have ONE monolithic layer of 1 & 1/8" plywood down for the subfloor, OR would it be better (cost-wise, structurally, or whatever) to have TWO layers (laid @ 90 deg to each other) as long as they add up to the requisite 1 & 1/8 inches? IF the two layer approach is ok, should they be the same thickness? one thicker than the other? Jul 26, 2023 · Let’s dive into more details about determining the size of your plywood subfloor, as well as the correct size of a few other common subfloor materials. The planks expand and contract too much with seasonal temperature and humidity changes, and the plywood will isolate that. Professional floor builders will add particle boards most of the time. I used OSB sub-floor panels instead of plywood to reduce the chance of the panels curling. The first layer should be at least 5/8″ thick, and the second layer should be at least 1/2″ thick. I have a few questions about the proper way to do this (assuming my strategy is valid): The TCNA handbook references A108. Panel underlayment edges should be offset by at least two inches from subfloor edges (many tile installers prefer an offset of at least 6 inches). ocesk mkzprpl yylorxd bpcnhah prqxbnha ines yfc tljrdi sgnv ncgbsc