Dip in particle board sub floor

[tryandave]

I have removed the carpet in a spare bedroom and am going to install laminate flooring.
The sub floor is particle board and there's a 12" wide dip or valley that runs the length of the room.
At the center of the valley, the dip is approximately 1/4". You can feel it when you walk into the room.
My question is: What would be the best way to fill this dip? My concern with wet self leveling products is the possibility of causing the particle board to swell. I know particle board hates water. I believe Spackle would be fine, but can anyone recommend a leveling product safe to use on particle board? Thank You

Dave

 

[Silentrunning]

Do you have access underneath the floor such as a basement or crawl space?

You are correct- self leveling cement would be a bad idea on that board.

 

[tryandave]

Do you have access underneath the floor such as a basement or crawl space?

You are correct- self leveling cement would be a bad idea on that board.

Yes, I Do. I'm going to measure the location and check in the basement. Thank you for your reply.

 

[Silentrunning]

This could be a real easy fix. In some of the old houses I fixed up in Michigan I used what we called an FHA pole in the basement to support sagging floor joists. If you aren’t familiar with them I will elaborate.

 

[tryandave]

Hello Doug! I have determined the exact location of the Joist sag in question and would love to hear your Fix! I was thinking about jacking up the joist and inserting additional supports and then removing the jack. I'm not familiar with an FHA Pole. Please, share your fix! Can't Wait to Hear it!

 

[Silentrunning]

These are poles with a solid base on one end to set on the floor and a threaded flange on the top end. You could turn the top end by hand until it came tight on the saving joist. Then you could either use a separate pole and jack to lift the joist or beat on the crossbar on the FHA pole to unthread it farther. Jacking it was far easier. I was told that they were called FHA poles because the FHA wouldn’t finance homes with sagging floors. Not sure this is true.

 

[tryandave]

These are poles with a solid base on one end to set on the floor and a threaded flange on the top end. You could turn the top end by hand until it came tight on the saving joist. Then you could either use a separate pole and jack to lift the joist or beat on the crossbar on the FHA pole to unthread it farther. Jacking it was far easier. I was told that they were called FHA poles because the FHA wouldn’t finance homes with sagging floors. Not sure this is true.

I'll look into this. Thank you for your detailed and helpful response.

 

[Retired]

Hi,

Are these the kind of pole you mean Doug; we call them Acrows here?

https://www.heatonproducts.co.uk/products/acrow-props/

Kind regards, Colin.

 

[Silentrunning]

Yes with minor differences. The ones I used looked a little heavier duty. Those things were great. On my first house I sistered 2X12s on the bad floor joists and then supported them with the poles. The repair probably would have lasted for decades if the city hadn’t bought it and demolished it for a park.

 

[tryandave]

Hi,

Are these the kind of pole you mean Doug; we call them Acrows here?

https://www.heatonproducts.co.uk/products/acrow-props/

Kind regards, Colin.

Thank You for the Input!!

Dave

 

[Dirtmechanic]

You could pour a polymer on it, there are many and they are 2 parts like epoxy, no water. Better to fix the structure of course, but often even that does not work out perfectly.