# Diagonal boards over joists - rip up?



## Bob Mariani (Dec 1, 2008)

That would be a good plan. And check the joists for blocking and that they are level and flat. This will allow you to shim or sister any wandering joists. A flat floor will help in preventing squeaks.


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## Just Bill (Dec 21, 2008)

differing viewpoint: this is obviously an older house and that is 3/4T&G subflooring. It runs under the wall, so to proper replace it, matching levels exactly, you must cut it at the wall. A better solution, IMHO, it to go over it with 1/2" or thicker multiply plywood. Thicker will make a stiffer floor, but may create too much of a step to other rooms. C/D plywood is ok if doing anything but vinyl. Ceramic tile needs a min of 1 1/4" of SOLID floor. Apply new rosin paper between the floor layers, to reduce squeaking.


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## Maintenance 6 (Feb 26, 2008)

Like Bill said, the diagonal sub floor likely runs out to the ring joists. All of the sole plates for the exterior and interior walls are nailed through that sheathing. Removing it will be almost impossible and cause some serious problems where walls are setting on it. Screw it down to eliminate squeaks and go over it with heavier plywood. Use construction adhesive between the new ply and the subfloor.


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## vetting (Jan 6, 2009)

I would just put plywood over it, but I dont think I'll be able to get it level enough and I dont want a 1" transition between floors that are going to eventually match. I spent about 2 hours reading online yesterday about removing the old planks when they run under the wall/ontop of the sill plate. Of course half of the posts say dont do it and the other half say its fine. I was thinking on just cutting it off flush with the wall, adding a new nailing board around the entire edge and just laying down 3/4" squared off plywood down. Is there anything wrong with that approach?


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## Bob Mariani (Dec 1, 2008)

Sounds like what I said to start with. But I would only use T & G plywood. Can you use something more then the 3/4" This by itself will not suffice for a tile job. 1/2" CBU offers no additional structural strength


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## vetting (Jan 6, 2009)

http://www.lowes.com/lowes/lkn?action=productDetail&productId=51596-353-1640VS

I bought this saw in order to flush cut against the wall. Going to go with 3/4" T&G plywood. Are there any special kind of screws I should use? Should I just use 2" deck or drywall screws to screw it down to the joists? Also, I'll be putting solid 3/4" red oak floors over the top.


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## buletbob (May 9, 2008)

vetting said:


> I would just put plywood over it, but I dont think I'll be able to get it level enough and I dont want a 1" transition between floors that are going to eventually match. I spent about 2 hours reading online yesterday about removing the old planks when they run under the wall/ontop of the sill plate. Of course half of the posts say dont do it and the other half say its fine. I was thinking on just cutting it off flush with the wall, adding a new nailing board around the entire edge and just laying down 3/4" squared off plywood down. Is there anything wrong with that approach?










DON'T DO IT!!! you will weaken the integrity of the floor. even by putting nailers under the wall sections this will not do anything. as stated above you are dealing with an older home. more then likely there is no floor beams under the partitions. buy cutting the diagonal subfloor out around the walls and installing the nailers and new subfloor what is going to hold these walls up??? they will sag down into the floor cavity. BOB


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## JazMan (Feb 17, 2007)

Some people care too much about transition heights than doing a good proper installation. I see and hear it everyday when people are asking how to prepare floors for ceramic tiles especially. 

As far as transition levels go, I always say, "You want the same level, then install the same flooring in all the rooms". The first concern should be doing the work right.:thumbsup:

Jaz


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## vetting (Jan 6, 2009)

buletbob said:


> DON'T DO IT!!! you will weaken the integrity of the floor. even by putting nailers under the wall sections this will not do anything. as stated above you are dealing with an older home. more then likely there is no floor beams under the partitions. buy cutting the diagonal subfloor out around the walls and installing the nailers and new subfloor what is going to hold these walls up??? they will sag down into the floor cavity. BOB


2 of the walls are on ouside walls direclty on the foundation - one is a non load bearing wall that runs perpendicular to the joists and the last wall is sitting right over a steel beam. Its not like those planks are actually doing anything...they sag in most places when you walk on them. Is there really even difference since the new plywood will be only 1/4 inch away from the old cutout flooring.


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## vetting (Jan 6, 2009)

JazMan said:


> Some people care too much about transition heights than doing a good proper installation. I see and hear it everyday when people are asking how to prepare floors for ceramic tiles especially.
> 
> As far as transition levels go, I always say, "You want the same level, then install the same flooring in all the rooms". The first concern should be doing the work right.:thumbsup:
> 
> Jaz


The rest of the house has 3/4 red oak directly on top of the 3/4 planks. Replacing the subfloor with T&G plywood should strenthen and tie everything together.


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## JazMan (Feb 17, 2007)

If the old planks are exactly the same thickness as new 3/4" plywood, I would cut the old planks short of the wall. I would then install blocking under them and fasten both the old and the new subfloor to the blocking. 

However, it's my experience that the new plywood will be a little thinner. So a few layers of tarpaper should do the trick.

Jaz


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## buletbob (May 9, 2008)

vetting said:


> 2 of the walls are on ouside walls direclty on the foundation - one is a non load bearing wall that runs perpendicular to the joists and the last wall is sitting right over a steel beam. Its not like those planks are actually doing anything...they sag in most places when you walk on them. Is there really even difference since the new plywood will be only 1/4 inch away from the old cutout flooring.


 Its the one wall that is perpendicular to the floor joist I would be worried about. It does not have to be a bearing wall in order for it to sag , it will over time start to sink down if there is no support under it. like I mentioned before with most older homes the decking was laid and walls where installed anywhere. Depending on the quality of the house. with the out side wall on the foundation you will have to install blocking between the floor joists to support the cuts.and seam of the new subfloor. And I guess the other wall that sits on the foundation that wall is perpendicular also correct! on that one I would come in one floor beam double that one up and cut the planking on one and use the new joist for a nailer for the new subfloor. where the floor beams that rest on the foundation i would do this, I would not go 1/4" away maybe 12" in case you have to get into those bay areas at a later date. and you say the other wall rests on the steel beam. I cant invision this could you post some pictures of the floor from underneath. BOB


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## vetting (Jan 6, 2009)

I was mistaken about one of the walls.

Here are the walls

Wall 1 (Outside wall) - Sits directly on the foundation








Wall 2 (Outside wall) - Sits directly on the foundation








Wall 3 (Inside wall) - Lays directly on a joist
















Wall 4 (Inside wall) - Lays perpendicular to the joists and is directly above the steel beam.


















Here is an example of damage to the plank floor.

These cracks are all over the place and a lot of the boards are warped/crowned. The one with the black marks on it is crowned over an 1/4 inch in the middle.


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## buletbob (May 9, 2008)

OK you have two exterior walls, one wall runs with the floor joist and is unsupported. ( no beams under it ) and the other wall is supported by the girder. lets start with the order In which i ask above 
1) the exterior wall by the sink. This subfloor I would cut 12" away from the wall.install blocking between the floor joists to support the old subfloor and to grab the new subfloor. The 12" will give you room in the basement for future access.
2) the other exterior wall I would cut the old subfloor along the inside edge of the first floor joist. then add an additional joist along side that one and spike them together. this will give the new subfloor a nailing surface. 
3) now for the unsupported wall do the same as what you have done to the opposite side but install some blocking under that wall to help prevent bellying later on down the road. try to keep it as close as possible to that wall, even if you had to install two new beams in that location.
4) as for the wall over the girder same thing as the sing wall, but with this one you can block right up to the wall staying away about 1-1/2" the width of the saw table. plus leaving some nailing surface of the old subfloor.. try to predrill all nail holes in the old subfloor to keep them from cracking, Construction adhesive would be a good idea also. doing it this way would be your best bet I believe. if you want to go one step further what I do is use LVL's to keep everything the same width so there would be no shrinkage of the regular lumber. it all depends on your budget.


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## SNC (Dec 5, 2008)

vetting said:


> 2 of the walls are on ouside walls direclty on the foundation -


sounds like you have a baloon fraame, yes i would tear out the old garbage (that is all it is) make sure to block all unsupported edges of ply wood, you can get plywood greater than 3/4, use glue like pl400
i am also a big fan of LVL aka micro lams


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## vetting (Jan 6, 2009)

Thank you for all of the advise. I followed everyones recommendations and blocked around the entire room and tied the old planks into the new subfloor. The floor is level from side to side within 1/16th of an inch and is rock solid. Here are some photos
http://remodel.myauctionlinks.com/kitchen2.php


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## SNC (Dec 5, 2008)

:thumbsup: Thats a nice looking floor
that old counter and sink gave me a flash of some place a long time ago.


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