Sherriff Posted October 30, 2007 Report Share Posted October 30, 2007 I currently have some ceramic tile that is a mess, cracked and the grout is coming up in little chunks. I am planning on tearing it all up and have so far torn up about a 4x8 area. What a job that was... The sub floor under is OSB particle board. My question is, should I put down 3/8 inch plywood over the old sub floor, (adhesive and screws) so that I have a nice new surface to lay the hardwood over? I want to avoid tearing up the old sub floor as well. After the tile and mesh come up the OSB is a little hacked up so I am not sure if I can simply lay the new 3/4 inch hardwood over top. Also this hardwood will be covering the entire main floor so I do not have to match the new height of the floor to anything else (other rooms flooring) which helps... Any help would be great... Thanks Sherriff Link to comment Share on other sites More sharing options...
Gerritt Posted October 30, 2007 Report Share Posted October 30, 2007 (edited) Your tiles were cracking and the grout was coming out because the floor was flexing.. if you lay your hardwood over it as is, your going to have squeaking.. your best bet is to cut out the floor and put in 3/4" T&G plywood, glued and screwed to the floor joists... I would also add some 2x8 bridging as well... or you can run 3/4" Ply along the sides of each joist... You need to remove the movement in the floor. or you just asking for problems... Gerritt. Edited October 30, 2007 by Gerritt Link to comment Share on other sites More sharing options...
Fishingfever Posted October 30, 2007 Report Share Posted October 30, 2007 definitely, add the 3/4 inch over top first and screw it down you will have a seemless squeakless floor. You will not regret the extra work! John Link to comment Share on other sites More sharing options...
KyleM Posted October 30, 2007 Report Share Posted October 30, 2007 Hope it aint glued down like particle board subfloor usually is or your in for a real treat. Also, do you have a drywalled basement ceiling? If you find any squeaky flooring you can always sink the PROPER sized screw into the bottom of the board. Always do it right the first time, dont cover up mistakes or your askin for trouble. Link to comment Share on other sites More sharing options...
charlied Posted October 31, 2007 Report Share Posted October 31, 2007 Like the guys said you can just put it over top...never be afraid to stick alot of screws in it either...the more srews the tighter it will be. I hope your house isn't a really old one like mine...I did hardwood all summer long as a job so i tackled my house this summer also as soon as I bought it...put down a subfloor and screwed it down really good. Then found out after that they use to use 2x6's as joists back like 50-60 years ago....well this causes alot of movement over a large area when there is high traffic and stuff as I found out cause I have a ton of hardwood boards splitting now and I figure within a year I will more than likely have to replace it...there is $1000 down the tubes....oh well live and learn I guess. I would also recommend putting screws down on the original particle board to tighten it up first, before putting the plywood on top. Link to comment Share on other sites More sharing options...
stuntman Posted October 31, 2007 Report Share Posted October 31, 2007 Check out the Holmes on Homes fan forum....they have beaten subfloor to death: http://www.mikeholmesfanforum.com/ Link to comment Share on other sites More sharing options...
Gerritt Posted October 31, 2007 Report Share Posted October 31, 2007 He is using OSB... on no doubt 16" centres... it WILL flex... as it is doing now... adding more screws is not the answer here... he needs to beef up the framing underneath and I would replace the subfloor with 3/4" T&G ply. adding 3/8's is also not the answer as the sub-structure will still flex.. besides he does not want to do the whole house to bring things to the same grade... If you have any intention on staying in this house for sometime to come.. do it right. Add support to the 2x8s... with 3/4" ply running along the joists and add bridging. cut out the floor and lay new 3/4" T&G...Glued with PL and Screwed very 8-10". as for removing the OSB if it is glued and you have bit n pieces still attached? a "stand up" floor scraper and a heat gun will do the trick. But what do I know... Gerritt. Link to comment Share on other sites More sharing options...
Gerritt Posted October 31, 2007 Report Share Posted October 31, 2007 Check out the Holmes on Homes fan forum....they have beaten subfloor to death: http://www.mikeholmesfanforum.com/ LOL... I love the "Privately Owned site devoted to Mike Holmes" I have worked for Mike Holmes and Jim as well as the director for both shows, Micheal Quaid... while they are good guys they are just the "faces" for the actual shows. Infact if you ever down by Bronte you can see my work.. Look for the yellow house built out of straw... it has my blood sweat and tears in it. Gerritt. Link to comment Share on other sites More sharing options...
danc Posted October 31, 2007 Report Share Posted October 31, 2007 If I had any home improvement questions, I'd take Gerritt's word as the gospel. If he isn't 100% sure sure, he lets you know it. He sounds pretty sure about this one. Link to comment Share on other sites More sharing options...
irishfield Posted October 31, 2007 Report Share Posted October 31, 2007 (edited) In addition to what Gerritt said...if you have "silent beams" you'll never get rid of the flex/bounce in the floor (that caused your tiles to crack). I have a 16' span..with 2 x 10 SB's on 16" centers and 3/4" T&G plywood glued and screwed to them... and the floor was good for almost a 1/4" give as you step on each joist. Part of this is the SB companies don't want any x-bridging...as that would make them squeak possibly. I ended up having to X - brace on 2 spots on span and diagonally brace the underside with 1 x 3 straping to get my projection TV to quit going out of alignment. Floor still sags as you walk across it..but at least the bounce is gone. All our upstairs halls and our dining room are 3/4" hardwood. They are nailed directly to said Silent Beams and 3/4 " T&G and no issues in 10 years. They still look like new. Our only marble area in our foyer was put down after another layer of 1/2" plywood was glued/screwed every 6" square on top of the 3/4 T & G. Luckily this area also has a main fiberstrand (forget the real name) beam under it...or I think it would probably have cracked by now. Wish I'd never used these things..but couldn't go 16' with conventional 2 x 10 joists. Edited October 31, 2007 by irishfield Link to comment Share on other sites More sharing options...
Gerritt Posted October 31, 2007 Report Share Posted October 31, 2007 In addition to what Gerritt said...if you have "silent beams" you'll never get rid of the flex/bounce in the floor (that caused your tiles to crack). I have a 16' span..with 2 x 10 SB's on 16" centers and 3/4" T&G plywood glued and screwed to them... and the floor was good for almost a 1/4" give as you step on each joist. Part of this is the SB companies don't want any x-bridging...as that would make them squeak possibly. I ended up having to X - brace on 2 spots on span and diagonally brace the underside with 1 x 3 straping to get my projection TV to quit going out of alignment. Floor still sags as you walk across it..but at least the bounce is gone. All our upstairs halls and our dining room are 3/4" hardwood. They are nailed directly to said Silent Beams and 3/4 " T&G and no issues in 10 years. They still look like new. Our only marble area in our foyer was put down after another layer of 1/2" plywood was glued/screwed every 6" square on top of the 3/4 T & G. Luckily this area also has a main fiberstrand (forget the real name) beam under it...or I think it would probably have cracked by now. Wish I'd never used these things..but couldn't go 16' with conventional 2 x 10 joists. TJI's do afford some deflection Wayne.. and the 16' span is compounding the problem they are designed to flex though unfortunately.. if they did not they would snap... we also bridge TJI's on occasion if it is required to help eliminate deflection.. in your basement are they on hangers connected to LVL's or paralams? or are they running the entire span connected to Rim-Joists?? Here is a real simple mathematical equation to determine deflection... PS. I googled the explaination I know the equation but this was just easier then typing it out L/360 = unsupported span of joists in inches/360 For example: a floor joist which spans 10 feet with an L/360 limit is designed to deflect no more than 120"/360 = 1/3 inches under live loads. If you have a floor with joists over an unsupported span of 12' ... the floor should not deflect (bend downward) more than 5/16" A quick test is to put a glass of water in the centre of your room and bounce on your floor a couple times. If the water ripples there's movement which exceeds L/360. This isn't an accurate test ... it's simply a visual way to determine movement, and any movement should be considered a sign to investigate. Hope this helps anyone that is interested. G. Link to comment Share on other sites More sharing options...
Sherriff Posted October 31, 2007 Author Report Share Posted October 31, 2007 Thanks for all the info folks. Looks like doing it right is the way to go. First job it to get the ceramic out this weekend.... Sherriff Link to comment Share on other sites More sharing options...
irishfield Posted October 31, 2007 Report Share Posted October 31, 2007 Mine are full length Gerrit...sill to sill @ 30 feet long with the center (well 16/14) sitting on a supported 12 inch steel beam. Wish I hadn't done that either...as they act like guitar strings..noises go room to room and you can bounce in one and the other room feels it. Only did it as the building inspector wanted 2 x 12's on 12" centers for our family room with the 16' span I drew into our house design..and to keep the floors all one level I went 2 x 10 TJI's. If I did it all over again...I would have done the whole place in 2 x 12's...but that doesn't help Jeff. I just offered up the TJI issue as the possible cause of his tile letting go in the first place...and the fact that our hardwood floors have stood the test of time (10 years) even with the deflection of TJI's Link to comment Share on other sites More sharing options...
tinbanger Posted October 31, 2007 Report Share Posted October 31, 2007 We installed 18" sg ceramic in our front hall and kitchen area 8 years ago . 5/8 ply over existing OSB . apx 2500 screws ( one every 4-6") and a high quality mortar ( no mesh) .No loose or cracked tile . Span was only 10' . Not hardwood I know but I was pleased with the results . One other thing was we placed sound insulation bewteen the joists prior to finsihing the basement , nice and quiet. TB Link to comment Share on other sites More sharing options...
Gerritt Posted October 31, 2007 Report Share Posted October 31, 2007 We installed 18" sg ceramic in our front hall and kitchen area 8 years ago .5/8 ply over existing OSB . apx 2500 screws ( one every 4-6") and a high quality mortar ( no mesh) .No loose or cracked tile . Span was only 10' . Not hardwood I know but I was pleased with the results . One other thing was we placed sound insulation bewteen the joists prior to finsihing the basement , nice and quiet. TB 5/8" Ply is a whole new ballgame compared to 3/8" underlayment Something he is not wanting to do... as he would either have transitions throughout the house or he will have to bring all the floors to the same grade. Also judging by what he mentioned in PM the joists probably switch directions. I am unsure as to their spans. But you did the right thing tinbanger and added some soundness to your floor. Did you have to lift all your cabinets in the kitchen and rework the plumbing due to the added height? G. Link to comment Share on other sites More sharing options...
Sherriff Posted October 31, 2007 Author Report Share Posted October 31, 2007 5/8" Ply is a whole new ballgame compared to 3/8" underlayment Something he is not wanting to do... as he would either have transitions throughout the house or he will have to bring all the floors to the same grade. Also judging by what he mentioned in PM the joists probably switch directions. I am unsure as to their spans. But you did the right thing tinbanger and added some soundness to your floor. Did you have to lift all your cabinets in the kitchen and rework the plumbing due to the added height? G. No transitions at all Gerritt. I am doing the hall, living room, kitchen and dining room. It is a 4 level backsplit so the entire main floor will be one level.... Sherriff Link to comment Share on other sites More sharing options...
tinbanger Posted October 31, 2007 Report Share Posted October 31, 2007 Didn't touch the cabinets however the cabinets being an inch lower ( floor up 1") was only noticble for a short time . Have since sold the house and already thinking of what we will do in the new ( to us) house. Most likely lift cabinets / add island. Also will try and do all flooring on main floor in one shot ( tile , hardwood) not in stages over 5 years ! TB Link to comment Share on other sites More sharing options...
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