Your nightmare project - my piece of cake

[ChpBstrd]

Spent 2 years trying to figure out why my house had high humidity and occasional mold outbreaks on furniture and leather shoes. Bought a dehumidifier and it helped, but couldn't keep up. Finally bought a $6 hygrometer from Lowes and started placing it around the house. This revealed the humidity was highest in my bedroom, also the area with the most mold issues. By placing the hygrometer in different areas of the room, I found the humidity was highest - over 80% - at floor level right next to one wall on the North side of the house.

I knew from previous experience crawling under the house that this particular wall had been worked on. I could see some minor subfloor rot and the previous owner had shoved a couple of 2x10s on top of the sill plate for extra support of the subfloor. I figured the rotted subfloor was porous enough that a narrow stream of crawl space air was getting through under the baseboard and quarter round. When we ran the bathroom fan and put the house in a vacuum state, cool, humid air would suck in through these small gaps and that was enough to humidify the whole room near the floor.

So I crawled under the house and poked around behind the extra 2x10's. It was mush. Fock... The extra 2x10s weren't just propping up rotten subfloor planks, they were hiding a bigger mess!

I pulled out the newer boards and realized everything behind and below them was rotten. The sill plate. The band joist, and about a half-foot of the subfloor was all stuff I could pull apart by hand, and so I did. The wall's sole plate looked OK, but I could see the bottom side of my hardwood floors from under the house, meaning they were only supported by their own tongue and grooves. There was no joist - only spongy crumbles of what was once wood, and a few sections I had to remove with a reciprocating saw. Soon I was looking at my brick facade from the crawl space, which is not supposed to happen, but at least the demolition was easy.

The wall was completely unsupported, and had been unsupported for an unknown number of years. Apparently, the diagonal bracing in the walls was so strong that the room did not collapse because the rigid walls were suspending everything like a cantilever, even the floor. There were not even any wall cracks and no signs of sagging underneath either! This situation extends for 4' on one wall of the room, and at least 8' on another. I say at least because there is another set of extra 2x10s that I dare not remove until the section with the most issues gets some support. It could be fine, but I doubt it. So probably 20' of wall unsupported. :)

Here is a diagram of the damage (gray spray paint denotes absolutely rotten wood) and some of my first couple of pics from under the house.

I'm going to DIY this thing. I have a plan to repair it from underneath without removing the hardwoods. The plan involves replacing all rotten wood back to something like the original design. I will use a skill saw upside down to cut a straight line in the subfloor and remove all rotten parts. Then I'll attach a 1x12 from underneath. The new subfloor board will be held in place by the new band joist and brackets that will go between the new band joist and the adjacent original joist. I'll also be using lots of screws and liquid nails. I think the hard part will be getting the new band joist and sill plate wedged in place. Because I can't nail from the outside, I'll use metal brackets and screws to tie everything together nice and tight from the crawl space.

Will post updates as I get the chance. Should take me another week (INFAMOUS LAST WORDS, LOL).

Time invested: ~6h so far

[bacchi]

Be careful. Working in a crawl space is hard enough without a power tool near your face.

[SndcxxJ]

It sounds like you have a plan to repair the damage, but why is this damage occuring?  Is there a faulty grade?  Leaking plumbing line?  Downspout pouring water right outside this area?  If it is coming in from outside you may consider removing the bricks and redoing the water proofing and grade differently.

[sonofsven]

Yeah, I'd pull that brick facade off, sounds like it's leaking.
I dislike brick and stone (fake or real) for this reason.
The wall you're talking about, is it a gable wall or an eave wall?
A gable wall isn't holding anything up but the wall itself. The eave walls do the heavy lifting of supporting the roof.
Also, don't go crazy with metal brackets and tons of fasteners, it's usually overkill. I use 3" or 3.5" construction screws in lieu of framing nails in these situations. Just toe screw the rim into place then a longer section of 2x10 inside the rim joist as a patch.
You might also need to box a section of the joists with blocking so you can add joist support under the subfloor where it's been cut
Also when doing these types of repairs it's often difficult to remove old nails that snag on the new boards . I don't try to pull them, instead I use an angle grinder (new cordless is my fave) with a thin cutting wheel to clean everything up.
Sawsall, oscillating saw, angle grinder, impact driver, good headlamp.

[ChpBstrd]

Thanks for the advice @sonofsven . It’s both a gable and an eave - goes around a corner. I’ve had good luck with a door undercutting tool in the past and will try that this time. It does not spew sparks and debris.

It sounds like you have a plan to repair the damage, but why is this damage occuring?  Is there a faulty grade?  Leaking plumbing line?  Downspout pouring water right outside this area?  If it is coming in from outside you may consider removing the bricks and redoing the water proofing and grade differently.

There’s no plumbing here, so I think the issue is either

1) condensation forming on the back sides of the brick on this North side of the house and running down the wall, where the old tar paper vapor barrier has crumbled,
or
2) water intrusion through the mortar due to a lack of gutters and a deck being attached to the brick.

Of these, I suspect #2 is the root cause. Water runs off the roof through a valley on the eave side of the problem area and splashes on the deck, or runs between the deck joists and bricks. Overall this creates a soggy situation in an area that gets no sun six months of the year. The slightest hole drilled for termite treatment or as a weep hole could funnel in water, thanks to that deck.

My step 1 is to fix the wood. Step 2 is installing gutters. Step 3 is to repoint the bricks, spray them with waterproofing, and maybe alter the deck so there’s a gap between the deck and the bricks. That last step is where I’m fuzziest about the details. The deck is only a foot off the ground so IDK why they had to attach it to the bricks instead of making it freestanding.

[ChpBstrd]

Good progress today. I snapped a chalk line on the bottom of the existing subfloor and used a battery skillsaw to cut away only the subfloor. This was ergonomically difficult due to flying sawdust and positioning my body around all the debris. The line wasn't perfect but it's straight enough. It's also 12" from the wall plate, so a 1x12 will fit in that spot just right. Then I broke away the old subfloor, exposing the bottom of the hardwoods. I also used my undercut tool to hack off the ends of nails. Worked great! I sprayed the bricks with rubberized undercoating. This stank so bad I had to evacuate the crawl space, and of course the smell came right into the house so I had to open windows and endure the complaints from the S.O.

I think I'll slather everything in liquid nails when I put the subfloor board in place. That will hopefully take care of the crawl space air leaking into my bedroom problem.

BTW, that last picture shows the other side of the room, where the band joist and much of the sill plate are still hidden behind two 2x10s. You can see how this covered up much of the rot, which is how I, my home inspector, and a couple of termite inspectors all missed it. Oh well, that's what "as is" means on real estate contracts! I'm glad I don't have to pay a contractor a five-figure sum to do this work.

LUMBER IS FREAKING EXPENSIVE. It's 3x the price it was this time last year. $16 per 1x10 board.

Next Steps:
     Continue removing nails, etc.
     Cut sill plate, band joist, and new 1x12 subfloor.
     Apply tar paper between bricks and new wood.
     Install subfloor, then sill plate, then band joist.

Time investment: 9 hours

[ChpBstrd]

Fresh pics!

I cut off the nails from below - some with an undercutting saw, some with a reciprocating saw. Then I gooped up my 1x12 with liquid nails, mashed it into place against the sole plate and hardwoods, and sunk a couple of screws into the sole plate to hold it up. Next I install my new band joist to wedge it in place.

I'm starting to realize the damage extends farther than this one bedroom wall, and probably includes most of the north side of the house (DR and kitchen). Basically anywhere the deck was attached to the bricks. Maybe I should alter the deck so it doesn't hang on the bricks ASAP, so that I can repoint the bricks and make sure the weep holes are uncovered (if there are any weep holes).

Time investment: 18h

[ChpBstrd]

More updates. I had to cut the existing floor joists at an angle so that I could slide in the new band joist and sill plate from under the house. It was a tight fit. After lots of hammering, I gave up and trimmed a half-inch off the 2x10 band joist. Even then it took some major hammering with another large piece of lumber to pop it into place.

Then I installed "cripples" or spliced-on joists onto the old joists so they could sit on the new sill plate. Metal brackets were used to pull it all together.

[ChpBstrd]

What do you all think this job would cost if I was to hire someone to do it?
$5,000?

I'm maybe 20 hours and $500 into it.

[lthenderson]

In my experience, jobs like these are almost impossible to find someone to do and if you do find someone, you will pay through the nose for the privilege. It's not a big project, can quickly spiral as you dig into rot and find other things needing replaced, and not the most desirable work area so most will just pass or give you the "if you'll pay me that much I'll do anything" figure. It is easier to find someone for stuff like this is if it is included in a large scoped project.

[NaN]

So I am kind of confused, what does liquid nailing a subfloor up do?

[ChpBstrd]

So I am kind of confused, what does liquid nailing a subfloor up do?

There’s no good way to install a vapor barrier from underneath, so I figured a few lines of goo would at least keep the wind from blowing through. It’s a half arsed attempt, sure, but that floor won’t squeak either. Perhaps tacking up some tar paper with staples would have been more legit.

[NaN]

So I am kind of confused, what does liquid nailing a subfloor up do?

There’s no good way to install a vapor barrier from underneath, so I figured a few lines of goo would at least keep the wind from blowing through. It’s a half arsed attempt, sure, but that floor won’t squeak either. Perhaps tacking up some tar paper with staples would have been more legit.

So a subfloor does hold some structural purpose and is not just a vapor barrier. Else we would just install our wood floors on top of the joists directly with a thin sheet of vapor barrier underneath. I would not want to stand on the wood floor in that joist bay, or place anything with load in it (bed frame post). I can see someone's leg or something else pushing through the hardwood right at that seam. You solved the wall problem, but you didn't solve the weak flooring problem.

I am not sure what else you would do now. Maybe put in some perpendicular blocking? Well, with the old diagonal subfloor maybe perpendicular to the sub floor board direction?

[ChpBstrd]

So I am kind of confused, what does liquid nailing a subfloor up do?

There’s no good way to install a vapor barrier from underneath, so I figured a few lines of goo would at least keep the wind from blowing through. It’s a half arsed attempt, sure, but that floor won’t squeak either. Perhaps tacking up some tar paper with staples would have been more legit.

So a subfloor does hold some structural purpose and is not just a vapor barrier. Else we would just install our wood floors on top of the joists directly with a thin sheet of vapor barrier underneath. I would not want to stand on the wood floor in that joist bay, or place anything with load in it (bed frame post). I can see someone's leg or something else pushing through the hardwood right at that seam. You solved the wall problem, but you didn't solve the weak flooring problem.

I am not sure what else you would do now. Maybe put in some perpendicular blocking? Well, with the old diagonal subfloor maybe perpendicular to the sub floor board direction?

That's exactly what I did @NaN to keep the seam from bowing. Here are pics of the perpendicular blocks going up. Eight of these span the entire wall, about 16" apart. A side benefit is they keep the band joist from moving or twisting despite it only being toenailed into the sole plate and sill plate with 3" screws. Between the perpendicular blocks and the seam between the new subfloors, I put a piece of 1" lumber with more liquid nails and a couple of short screws. This helps seal the seam and provide a little more support between the perpendicular blocks. After the perpendicular supports were installed, I did a little dance on the floor above. It's the least bouncy floor int the whole house - ready for the legs of a bed to sit on it.

The last picture shows tiny holes in the lumber. Those tiny holes are apparently air holes made by termites. So FYI, if you are inspecting a house and see tiny holes like this, don't assume it away. Such boards are or were infested. Apparently the water damage attracted termites to this area at one time in the past, and the PO just did a coverup job by hammering those 2x10s over the rotten band joists. It fooled me, an inspector, and two termite company people. The lumber looked OK for a while because the inside of it was first to dry out, and therefore rotted the slowest.

After completing the right side of the room, I removed the newer board from the left side and noted it was just as rotten. So I repeated the process on that side. It went much more quickly. Now the entire wall looks a lot like that last picture with the perpendicular supports.

Time investment: ~25h
Money investment: ~$500 due to price of lumber tripling

[NaN]

Yeah, that looks good and I guess that should keep anything from punching down through the seam. Great job! Hopefully that works for you, but you definitely saved a ton. Just have to deal with the fallout and time investment. If this is any indication of the rest of the house you might be up into the 100s of hours in no time.

Hope you don't beat yourself up to much over missing that. I know the joys of finding PO gems after purchasing a home all too well. My whole house was a cover up. Inspectors are garbage, but not like it would really help your situation. I hate old homes, but hate building new homes, too.

[theoverlook]

You need gutters big time. We bought a house with lots of water damage, and the gutters not being cleaned caused the majority of the problems. Walls are not meant to contain massive amounts of water coursing over them or splashing on them. Any slabs or decks or protrusions that can catch water are an invitation for moisture incursion and rot and insects. Water is relentless, as are insects.p

I disagree with the rubber undercoating on your bricks. We had a similar product on some bricks on our office building and bricks started spalling and efflorescing due to their inability to breathe effectively. You rapidly age masonry if it can't breathe. It might be OK if you can keep the outside of the wall dry but if you're getting lots of water splash on it still you might notice the brick get white efflorescence on it, that's the salts leaching out of the brick.

[ChpBstrd]

You need gutters big time. We bought a house with lots of water damage, and the gutters not being cleaned caused the majority of the problems. Walls are not meant to contain massive amounts of water coursing over them or splashing on them. Any slabs or decks or protrusions that can catch water are an invitation for moisture incursion and rot and insects. Water is relentless, as are insects.p

I disagree with the rubber undercoating on your bricks. We had a similar product on some bricks on our office building and bricks started spalling and efflorescing due to their inability to breathe effectively. You rapidly age masonry if it can't breathe. It might be OK if you can keep the outside of the wall dry but if you're getting lots of water splash on it still you might notice the brick get white efflorescence on it, that's the salts leaching out of the brick.

Exactly. Gutters have gone up, but I can’t run the spouts until I rebuild the deck so that it doesn’t hang off of the bricks. Also will repoint the bricks while I’m there.

What’s amazing is how this whole issue was caused when someone building a deck decided that masonry bolts were, what? $75 cheaper than deck support blocks and 4x4s as per code. A little mistake like that ended up threatening the structural integrity of the house, and invited in the termites.