Subfloor repair

My subfloor needs repair. The sheets are bowing up against each other and creating ridges in the carpet you can both see and feel. I can actually see an 8x4 perimeter ridge in one area.

I have contacted a few flooring sales/repair places. They either haven't returned my email/call or won't take on the task unless I'm buying new flooring and installation. Carpet re-stretchers only do the carpet. 

Does anyone know a company/contractor who can fix my subfloor and re-stretch the carpet? Alternatively I've considered fixing the subfloor myself but I'm not sure of the best way to go about it, sand and level or replace the plywood. One day I will be putting laminate down, so the floor will need to be smooth and level so I might as well fix it right this time.

Is this a newer home or an older home? The first thing you need to do is figure out why the plywood is bowing and unfortunately the most likely guess is water. Wood  shrinks when it dries out and swells when it gets wet, so the fact that it's bowing seems to indicate it's swelled and that's why it's bowing up. Is the carpet damp where the worst bowing is? If your issue is water/dampness you'll need to sort that out first.

Thanks,I will have a look once I pull up the carpet. 

The house is 29 years old, old I've lived in it for 11 years and we replaced the carpet 10 years ago. I never inspected the subfloor when the carpet was installed . The floor has never been wet since I've lived there, and there are no water marks or leaks on the ceiling below the room (bare drywall). My thought is that it's from age and heat, as the room faces west and is the floor directly above the garage, both are hot in the summer.

Try a moisture analyzer to see if the moisture content is high.

Also check dimensions and levels as a shift could also cause the buckling.

Read this as surf board repair. 

Carry on

<div>I just did a few flooring projects in my place. Has this problem been a seasonal problem? I've overheard a conversation at home depot where someone had a similar issue with what you described, except it was his laminate floors buckling in warmer weather rather than your subfloor. The Home Depot guy said it was due to the lack of clearance that allows room for expansion between the laminate floors and the wall. In this case, it could be your subfloor expanding against your walls which is what causes it to buckle. He also said a dehumidifier \(or something similar, can't remember what exactly he said\) would fix the problem.</div>

<div>But if your plywood got wet, it would likely rot and you would probably be able to smell, or even crumble it with your hands.
</div>

<div>Also, removing subfloor (atleast in my experience) was a fuck'n major bitch when I did it for my bathroom. Or maybe I was just doing it all wrong. 
</div>