So I'm certainly no professional carpenter but im pretty versed in lots of things,..I'm getting started with the renovation if my recently purchased home. I got a couple questions with more to follow but here goes with what I'm doing now. 1. Is 1/2 plywood capped with 1/4in Hardie board acceptable subfloor for a 7w by 20l room with 2x6 floor joists 16on center with staggered braces, if it is to used for a low traffic tile laundry room? And yes I went back and supported the plywood joint with a 2x4 after I finished screwing it down. and yes the joints are staggered and the Hardie board will obviously run opposite of the plywood. 2. I'm taking a load bearing wall out in a 18w by 25l room the current ceiling joists are 20ft 2x6 16 on center, that the roof is braced off of , will sistering them with 2x8's carry the load or are 2x10's required? 3.the house has 7in wide 3/4 thick plank board subfloor that was capped with partical board, I've pulled that crap up, ideally I want to put 1/2 in sheeting down so it will match up to the bathroom floor , kitchen and living room, those rooms have 1/2 plywood already. Is the new Gen OSB better or just use plywood, I know the OSB will lay flatter which will help with the engineered flooring that will be going down, but OSB on a floor kinda scares me, but I hear it's much better than the original stuff idk?? Here's a pic of my mess ha, 4k sqft of heaven,.. This was an apartment with full bath, will be the family room 18x25 looks even worse now since I've pulled the ceiling down, been putting off pulling the 500lb cast iron tub out ha. And you KNOW I fell thru that hole where the toilet drain is last night, luckily my man parts stopped the rest of my body going through , my wife said it looked like my left leg was horizontal while my other never touched the ground ha
I've always been told to use 3/4" for subfloor and nothing thinner. The 1/2" is going to bounce and flex, which can cause tiles to pop loose, then your "redoing" your floor. If you remove a load bearing wall, it has to be replaced with a laminated beam placed where the wall was and supported on both ends or else it WILL dip and bow down eventually. Keith
The very best subfloor to use is advantec,it is 3/4.It is made to be A subfloor ,and take on water during new construction ,rain,snow.It is the very best subfloor out there .
I always prefer 3/4" sub floor. And also prefer 1/2" Hardie backer if there is 1/2" sub floor existing. When installing Hardie backer I install it with a bed of thinset mortar troweled on the sub floor with a 1/8" v-notched trowel and screws about 6" each direction. Also purchase the multi-flex type thinset. It is more expensive, but well worth it. You will want as solid a floor as you can get for tile or you could end up with tiles popping and/or cracking. If you are concerned about the floors matching the height in living room etc, you could go ahead and put the thicker sub floor in the part you are replacing and add 1/4" underlayment in the living room to match up. When removing cast iron tubs, I usually put on a pair of safety glasses and break it up with a sledge hammer. Then haul it out in smaller more manageable pieces. I have always heard that max span for 2x6 lumber for ceilings is 10 ft. Woody 1640 is correct, you will need to replace the load bearing wall with a beam. I have rebuilt a few openings and room expansions that didn't have a beam or large enough one that had started sagging. That is a lot of work that is preventable by building strong enough to begin with.
As mentioned a 3/4 Advantech subfloor is most always suitable. For the narrow space and type of finish floor you’ll probably be ok with the 1/2” plywood. Looks like it’s already down. Also very good that you supported the joints. I always glue and screw any subfloor. As far as removing the load bearing wall there are other factors that must be considered such as roof pitch and truss design. I forget what region your new place is in. If snow loading is a concern it must be considered. Roof truss design is important and dictates how small a joist can be used for the span. Be careful here as it may be difficult for accurate advice over the internet for this. It’s possible all you would need is additional bracing for the 2x6s or you may need a lam as stated. I’d have a professional access the requirement on this one. You could end up wasting money otherwise. I am not familiar enough with the new gen OSB. If it’s anything like Advantech it might be ok. Best to find someone who has been using the exact product for awhile. Just like decisions we make when we redo cars some of us tend to spend up to use best methods for longevity and construction is no different. Many corners can be cut and money saved if you aren’t very particular with outcome or longevity.
Yea I know and agree 100% 3/4 TG is the standard and if it were a larger room I would have went with it for sure. But I just kept thinking it's only 7ft and the joists are are overbuilt. Along with the Hardie board going down and the fact my wife is 115lbs and she will be the only one in there 90% of the time. I got alot of sqft to cover and at $32 a sheet for the 3/4 TG it would take forever. On the ceiling joists, there is no real concern for snow load, I'm in SC most I've ever witnessed here was 6in and it's gone in 3days. It's a stick built rafter and 8ft of the 25ft span was unsupported as it was because of the opening for the kitchenette. Granted it was on one end if the room and not in the middle.
Looks like all the bases have been hit . Three-quarter inch advantech. Put a beam under that span and smash that tub with a sledgehammer. I'll stay tuned but it appears you are in good hands. Jim
You will have some flex with the 2x6 joist no matter what the thickess of sub floor. With 1/2 inch you will get flex in between the joists. Not up to code here but, if that's what your using than at least add a couple more supports in the middle of floor and that will help a lot with the bounce. With the hardy board that will help but go 3/4 if you can
I just went thru a subfloor replacement because our house had 1/2” ply with 3/4” mdf on top under the carpet. I spent 3 entire days ripping it up and replacing with OSB tongue and groove subfloor. I think it was listed at 23/32”. Ended up shimming a little bit to get things perfectly level and the engineered hardwood layed down nice and flat. No more squeaks. I also used a lot of subfloor adhesive because I don’t plan on ever doing that again.
No need for a laminated beam if you have enough room to install the proper sized lumber for the span you're trying to support. This may help; https://www.mycarpentry.com/joist-span-table.html A laminated beam is more so to be able to bury it in the ceiling so its hidden. If you have enough ceiling height or don't care if the beam hangs lower than the rest of the ceiling, then standard building span load can be used. Just remember that if there is an upstairs then you would use floor joist span loads, not the ceiling joist span loads. Here's the home page of the above link for the other span tables; https://www.mycarpentry.com/span-tables.html So exactly how far do you have to span the ceiling joist for the wall that was removed?(hard to tell what's going on from the picture) I have been in carpentry jail for a while now and have been doing my homework for many years on this crap.(would rather be engine building) Sounds like a cool project that you will enjoy for many years after completion. P.S. You can't go by what your wife weighs now, you have to guess what she will weigh when she is older if you plan to stay there for many years. A good reference is what her mother looks like now is what your wife could look like when she gets older?
So a 16 on center 2x6 spanning 76in isn't sufficient?? Just curious I was originally going to do 2x8's but couple of local fellas said that was overkill. It's done now but for future reference,..
IMO, that should be plenty according to the span chart from the link I posted. Says you can do 24" on center and the 2x6 will span 9' 11" with #1 grade(kiln dried) or 8' 8" with #2 grade on 24" centers.
As mentioned above, it's hard to properly advise on your situation without physically seeing it. If you remove load bearing walls, it would be good to have someone actually look it over. Even if you don't have much of a snow load, just the weight of the structure has significant weight that can sag over time if not built strong enough. Laminated beams are great, but not always necessary. A lot of times they are used when they will be exposed. As somebody already mentioned, you can do headers with dimensional lumber. If you don't want them exposed and have the room in your attic space, you can tuck them in flush with the bottom of the existing ceiling joists and use joist hangers to support the joists on the side of the new header. Remember, you have more than your wife's weight on that floor. Laundry appliances, cabinets, whatever you end up storing in there etc. Plus the normal expansion and contraction that every home gets. Don't scrimp on the subfloor. Might be saving now, but a lot more expensive to rebuild later on. I'm not claiming to have all the answers, but in 42 years of working construction and remodeling, I have had to rebuild several things that were scrimped on when done the first time. Interesting project you got there, hope it all goes together great for you!
