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Replacing plywood subfloors, is it really bad for floor joist?(Poll)

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  • May 12th, 2015 9:32 pm

Poll: Replacing plywood subfloors, is it really bad for floor joist?

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Member
User avatar
Mar 23, 2015
207 posts
27 upvotes
Burlington, ON

Replacing plywood subfloors, is it really bad for floor joist?(Poll)

Hi Guys,

Do you think it’s bad for floor joist if I will need to replace some plywood subfloors? I need to get under the floors on my second floor in order to get access and install light in living room, fan in first floor bathroom, pass some internet wires. I also need to replace one bad plywood subfloor with a hump. I am currently about to start installing hardwood and have all my carpets removed. My Father says it’s a bad idea to open plywood subfloors because it will loosen and damage floor joist which will make them squeaky afterwards. What do you guys think?

Let me know what you think.

All the Best,

Dasm
27 replies
Penalty Box
Jul 14, 2014
1365 posts
349 upvotes
No idea but they have nail pullers for 11 bucks at hd.
Deal Fanatic
User avatar
Jul 2, 2001
5602 posts
3999 upvotes
GTA
Why another thread on the same topic? Your father has no idea what he's talking about.
Also that "bad plywood with a hump" is probably a joist that needs shaving down a bit.
Newbie
May 7, 2015
16 posts
7 upvotes
Ottawa, ON
I've done this many times and have never had a problem. Use a nail puller as suggested by the other posted. When installing your new subfloor, SCREW it down at every 4-6 inches directly into the joist. And use a min of 5/8 plywood (I would go 3/4). You can use OBS as well.. just as good (though I'm sure many will argue that plywood is better) but cheaper. I prefer plywood myself. Note, when installing your new hardwood, install the opposite to your joist and nail when possible into the joist.

BTW... the "squeaky" typically comes from the nails being loose and rubbing. I would also suggest screwing down your entire subfloor (the old one) before you lay any of that new hardwood.
Jr. Member
Dec 28, 2008
168 posts
87 upvotes
Etobicoke
Agreed on the OSB. It performs the same as plywood, especially since there is no concern of it getting wet.
Deal Fanatic
Mar 12, 2010
6112 posts
660 upvotes
SW Ontario
freehomeinspections wrote: I've done this many times and have never had a problem. Use a nail puller as suggested by the other posted. When installing your new subfloor, SCREW it down at every 4-6 inches directly into the joist. And use a min of 5/8 plywood (I would go 3/4). You can use OBS as well.. just as good (though I'm sure many will argue that plywood is better) but cheaper. I prefer plywood myself. Note, when installing your new hardwood, install the opposite to your joist and nail when possible into the joist.

BTW... the "squeaky" typically comes from the nails being loose and rubbing. I would also suggest screwing down your entire subfloor (the old one) before you lay any of that new hardwood.
I third the final comment there. Extra screws while you can for sure.. You want no movement between the subfloor and the joists.

Replacing some plywood (or OSB) should be no issue at all. If you house falls apart from doing that, then you have bigger issues.. lol

You could also just cut out along the joist, and replace the pieces of subfloor, but removing and replacing whole sheets is probably easier and better in the long run.
Deal Fanatic
Nov 17, 2012
5381 posts
5003 upvotes
Toronto
Glue 3/4 plywood down with PL and screw it.

Take the opportunity to add blocking between the floor joists if there isn't any. Will dramatically improve the solidity of the floor overall esp in older homes.

Get your father to explain what he means by harming the joists by removing the subfloor. Only way I could see that happening is if you used either explosives to blow the subfloor off or poured gasoline all over it and tried to burn it off.
Deal Addict
User avatar
Aug 12, 2007
4685 posts
830 upvotes
Waterloo
umm. isnt most of the framing for walls just done on top of the plywood on the floors?

If so how would you go about removing the plywood without taking down the entire house?
Sr. Member
Sep 12, 2008
580 posts
201 upvotes
Hamilton, on
Supahhh wrote: umm. isnt most of the framing for walls just done on top of the plywood on the floors?

If so how would you go about removing the plywood without taking down the entire house?
A Circular saw set to the depth of the subfloor so you dont disturb the joists. Where the joists are 90 degrees to the wall you can even use the wall as a fence
Deal Addict
User avatar
Aug 12, 2007
4685 posts
830 upvotes
Waterloo
GodSendHockey wrote: A Circular saw set to the depth of the subfloor so you dont disturb the joists. Where the joists are 90 degrees to the wall you can even use the wall as a fence
Which then begs the quesion why do all this in the first place. If the subfloor is not level ( with a hump ) you can either level it( plenty of you tube vidoes explain howto ) or install another sheet ontop of existing ( also taking into account leveling methods ).


If the subfloor is squeaky , I would add another sheet on top 1/2 in or 5/8 in.
Deal Fanatic
Mar 12, 2010
6112 posts
660 upvotes
SW Ontario
Supahhh wrote: Which then begs the quesion why do all this in the first place. If the subfloor is not level ( with a hump ) you can either level it( plenty of you tube vidoes explain howto ) or install another sheet ontop of existing ( also taking into account leveling methods ).


If the subfloor is squeaky , I would add another sheet on top 1/2 in or 5/8 in.
Umm. Because OP needs access to below the floor as per the post.

I said it could be cut out. But patching it up might be more work than just replacing a few sheets. But depends.
Sr. Member
Sep 12, 2008
580 posts
201 upvotes
Hamilton, on
Supahhh wrote: Which then begs the quesion why do all this in the first place. If the subfloor is not level ( with a hump ) you can either level it( plenty of you tube vidoes explain howto ) or install another sheet ontop of existing ( also taking into account leveling methods ).


If the subfloor is squeaky , I would add another sheet on top 1/2 in or 5/8 in.
What are you talking about? Your question was about how to remove the flooring when the wall is overtop. That is the answer. The REASON to remove the floor could be anything under the sun.

Why bother asking the question in the first place.
Deal Addict
Mar 29, 2015
1999 posts
158 upvotes
Wood Bridge
kalani13291 wrote: No idea but they have nail pullers for 11 bucks at hd.
Your kidding? The Home Depo sells them for $10.99 as well.
Deal Addict
Mar 29, 2015
1999 posts
158 upvotes
Wood Bridge
You can easily remove a piece of plywood but make sure you cut it at the joysts so it can be supported when u put it back. if thats not possible put some two buy for braces to give u something to nail it too
Deal Fanatic
User avatar
Jul 2, 2001
5602 posts
3999 upvotes
GTA
Supahhh wrote: If the subfloor is squeaky , I would add another sheet on top 1/2 in or 5/8 in.
You're funny.
Deal Addict
Oct 17, 2010
2059 posts
359 upvotes
freehomeinspections wrote: I've done this many times and have never had a problem. Use a nail puller as suggested by the other posted. When installing your new subfloor, SCREW it down at every 4-6 inches directly into the joist. And use a min of 5/8 plywood (I would go 3/4). You can use OBS as well.. just as good (though I'm sure many will argue that plywood is better) but cheaper. I prefer plywood myself. Note, when installing your new hardwood, install the opposite to your joist and nail when possible into the joist.

BTW... the "squeaky" typically comes from the nails being loose and rubbing. I would also suggest screwing down your entire subfloor (the old one) before you lay any of that new hardwood.
ring nails sufficient?
Deal Guru
User avatar
Jan 11, 2004
10408 posts
1123 upvotes
Toronto
torontotim wrote: Glue 3/4 plywood down with PL and screw it.

Take the opportunity to add blocking between the floor joists if there isn't any. Will dramatically improve the solidity of the floor overall esp in older homes.

Get your father to explain what he means by harming the joists by removing the subfloor. Only way I could see that happening is if you used either explosives to blow the subfloor off or poured gasoline all over it and tried to burn it off.
I second to that! glue it and Screw as Mike Holmes says! go watch a few of their episodes! if you want a stronger floor double up the floor joices with ripped play wood, glue and then add blocking to increase floor strength.
"When operating the viewfinder diopter control with your eye to the viewfinder, care should be taken not to put your finger in your eye accidentally."
Deal Guru
User avatar
Mar 8, 2002
13462 posts
4622 upvotes
GTA
akito925 wrote: I second to that! glue it and Screw
Me too. When putting in hw floors in my daughter's bedroom, my carpenter cousin suggested this and the floor is extremely solid.
Deal Expert
User avatar
Dec 26, 2005
17068 posts
1830 upvotes
Thornhill
akito925 wrote: I second to that! glue it and Screw as Mike Holmes says! go watch a few of their episodes! if you want a stronger floor double up the floor joices with ripped play wood, glue and then add blocking to increase floor strength.
I'm under the impression that blocking doesn't help transfer significant amounts of load between joists - it just helps to prevent twisting of the joists.

bjl
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