Repairing rotten OSB subfloor

[LD1]

Long story...

I have a 3-unit rental over top of a concrete crawl space.

The hot water heaters all have the T&P valve piped down to a PVC floor drain that goes into the crawl space, makes a 90, goes over 4', then 90's down to a floor drain.

One unit had the T&P valve fail. And they didnt catch it. Best guess is it was leaking for 4-6weeks. Well at some point, the steam/water softened the subfloor that the drain pipe was screwed to and it broke loose out of the floor, resulting in hot steamy water must dumping into the open crawl space. When I got their to replace the T&P, it was flowing at probably 50%-kitchen sink rate. Which is alot.

Nothing flooded in the crawl space, due to floor drains, but that hot steamy water had everything at 100% moisture. It was literally RAINING from the subfloor and joists.

No moisture percolated to the above flooring, because its all laminate or tile and grout. And the laminate has the vapor barrier under it.

Confirmed this when the company the insurance had out there to dry everything took readings of subfloor below, and above. Laminate flooring was under 10%, but all subfloor was 99-100%

Well, that was last month. Everything is dry, and adjuster was out last week to assess the damage. Decided to have an engineer come out to determine exactly what subfloor needs replaced, and what is still good.

Now my question......is there any way to make a satisfactory repair from below? Given that everything is either tile and grout or laminate, repairing from topside is already gonna be a big project. Then factor in that its a 3-unit rental, displacing 3 tenants, etc.

So a couple of ideas that I have kicked around....given that the OSB is now DRY and we wouldnt be trapping any moisture....what about what about cutting strips of subfloor to fit BETWEEN the floor joists, pressing up tight to the "rotten" subfloor, and sistering the existing joists with some 2x4's See pic: Black is existing joists and subfloor, red would be added.

OR another idea....what about a structural closed cell foam sprayed underneath in the effected areas?

Im torn on this. I want to be as minimally invasive as possible, and not have to displace tennants, and make the most cost effective repair. But also want this done right since this is an insurance job.

Obviously I am gonna have to go with whatever the insurance company and engineer decide to do, but just thinking outside the box....wondering if there is an "approved" way of fixing rotten subfloor from beneath.

 

[CH4Ohio]

Isn't the OSB delaminated, falling apart, cupped, crumbling, etc.???

The laminate floor might be strong enough to span the gaps and still leave a fairly level surface, but over time I think that old flooring will just continue to disintegrate and work its way out of every crack.

Need to pull the flooring up and replace the subfloor. Since you already have your insurance involved, your cost probably doesn't change beyond the basic deductible.

 

[Rockbadchild]

is it really rotten or simply bulge ? if it's moldy or rotten Id say no they will want to remove but if not option A should definitely work but usually the owner dosent have much word to say because the insurance take the word of the contractor but you can go though him, they will recommend or demanded that you paint all the affected wood with the anti mildew paint but that not a big deal.

tiles need a very sturdy surface to avoid movement so it all depends on the level of deterioration.

 

[CH4Ohio]

Also, just thinking about the day when you have to fill out an information sheet about the property for potential buyers -- listing any concerns or condition issues. This would be a red flag.

Even more concerning would be questions from people looking at all that additional patching, framing, and scabbing from below. I think the sight of that would reasonably concern potential buyers and inspectors.

Also, "STRIPS" of flooring between the joists would sag over time. This would not result in a good long-term solution. Need to just pull it up and fix it.

 

[2manyrocks]

Is there any insurance coverage for temporary housing for the renters or loss of rental income while this is being repaired for certain? Once the insurance company pays whatever, it seems like all the future risk and potentially greater costs of repairs are on you if this isn't totally fixed today whatever that may entail.

 

[ultrarunner]

Renters insurance covers temporary accommodation should unit become inhabitable.

Lost rent should be part of your owners policy.

Code here requires PTR valves to be piped to daylight and the piping heat rated so almost exclusively metal but there are composites approved to withstand heat.

At this point sounds like you are all in for new floors.

 

[Egon]

It should be fixed to The standards of the local building code. Insurance will probably demand this for repair payment and ongoing insurance.

with renters you have no option other than an approved fix.

 

[LD1]

Also, just thinking about the day when you have to fill out an information sheet about the property for potential buyers -- listing any concerns or condition issues. This would be a red flag.

Even more concerning would be questions from people looking at all that additional patching, framing, and scabbing from below. I think the sight of that would reasonably concern potential buyers and inspectors.

Also, "STRIPS" of flooring between the joists would sag over time. This would not result in a good long-term solution. Need to just pull it up and fix it.

I would be able to fill out a form for no concerns or issues with a clear conscience if its an insurance approved repair.

As to "strips".....how would they sag any more than the existing subfloor. If anything, with the sistering of joists it lessens the span.

 

[LD1]

Just to be clear, I am not trying to dodge an "approved" fix. And I am not advocating any of these repairs.

Yes my insurance covers loss of rent. But I still hate the idea of displacing the tennants.

No matter how the repair is made.....nothing is gonna come back on me. Because I am not repairing it, nor paying for it. I am leaving it to the insurance company.

This thread was to mainly inquire as to if there were any "other" approved methods that others have seen or heard of. And I gave a couple of examples in which I though would possibly work.

 

[LD1]

Is there any insurance coverage for temporary housing for the renters or loss of rental income while this is being repaired for certain? Once the insurance company pays whatever, it seems like all the future risk and potentially greater costs of repairs are on you if this isn't totally fixed today whatever that may entail.

I dont understand this logic. How would future repairs, risk, etc be my burden....if the insurance company chooses an approved repair other than total replacement?

If THEY choose a more cost effective method, and it fails in the future.....the structure is still insured by them.....its STILL their problem