First for us: One of our water connections gave way at the fixture. The good news is that It was caught within an hour, but boy, was there a lot of water in that time! It overflowed to the adjacent room with wood floors, and literally poured through the ceiling below… The ceiling below is plaster, and appears to be ok (except for minor staining). The water found every crack (and light fixture) to make it’s way to the floor below. It is an older (drafty) home, and we’ve set up fans and a dehumidifier. No carpet affected. No drywall (only plaster). My concern is whether or not we need to take more drastic steps to dry out the cavity between the floor/ceiling. Would it be sufficient to simply drill holes to be patched after a significant dry out period, or would the entire plaster ceiling need to be removed (what a mess as it is a large room below!). We haven’t called insurance (yet) until we determine the extent of problem, but also concerned we may not know the full extent right away. I prefer to not involve insurance (rates always rise after a claim), until we know if necessary. Thanks in advance!
I don’t think just drilling holes will provide adequate airflow for quick drying unless you can pump warm air directly through those holes into cavities. So I think you need to cut bigger holes so you can get significant airflow up there. And it needs to be soon before mold can get established.
I feel like your bigger problem may be the room with the wood floors. When they get wet the floor boards can swell and cause the floor to buckle. And when they dry out they don’t "un"buckle. Then you have a significant floor repair… it has happened to me. 
You might consider calling a flood mitigation firm like Floodbusters or the equivalent, they will have the equipment to get stuff properly dried out and treat for mold if necessary.
I don’t have any experiences with this but just giving you my sympathy for dealing with this mess and want to mention that ServiceMaster is another nationwide service that deals with this stuff with heavy duty fans, humidifiers, etc.
I would call a company like Serve Pro or others mentioned above to at least get a look and estimate. You don’t want to risk any potential mold issues. Something similar happened to us to and we had to have part of ceiling cut out and fan dried for days by a pro before new dry wall put in.
Absolutely contact Serve Pro or an equivalent! You need to deal with this immediately. You also should call your homeowners insurance. It is likely to cost more than you think to get everything back into its original shape.
We had a shower over-flow issue that ended up with all sorts of floor and ceiling work. Wowza. I was able to find individual people to handle each of the issues after the insurance company sent out Serve Pro, so I did keep the total repair job under the insurance settlement.
Yup you’ll want to call the pros immediately. We had a few water incidents when we first moved in and called out the pros each time. Even where I am in AZ with 20% humidity it took several days of big industrial fans and a dehumidifier to get things dried out. The pros use some sort of moisture meter than can tell if the walls and baseboards are still damp. You really don’t want to go on gut instinct.
On the downside IIRC it can get pricey very fast. I seem to recall it generally taking 3 fans for 3-5 days, at a cost of around $25 per fan and $50 per dehumidifier per day. They math gets scary very fast.
The nice thing I noticed is how collegial all the various water remediation companies were that I talked to. A few times the first company I called wasn’t able to send someone immediately and they always referred me to a couple of their competitors. I was impressed with their customer ethic as an industry (from my tiny personal sample).
From my experience ServPro is opportunistic and overpriced. We recently had a water leak that caused a fair amount of damage. The plumber’s insurance covered everything, so I didn’t really care who they used, but what ServPro charged was ridiculous. Basically they tore out some drywall and brought in some fans and dehumidifiers for a week or so to dry things out, and submitted a bill for over $8,000.
Later I saw the same fans available for rent at Home Depot. I could have done the dry out myself for under $1000.
@kjofkw - If you’re comfortable doing what you’ve done so far, I see no need to bring in the “professionals”. If it were me, I’d remove the ceiling below to allow the fans and dehumidifier to thoroughly dry out the cavity, and then hire a drywall contractor to replace the ceiling.
Pulling out the plaster is a heavy messy job. But that plaster might have a paper/ drywall type backing or it might only be true plaster on chicken wire. Either way, you have wood ceiling joists up in there that can get mold also if not dried out properly. The joists are placed every 16 or 24 inches apart and they can prevent air flow between the joists.
If it was significant water damage you will have to strategically cut big holes or tear off the ceiling. It’s almost impossible to repair old thick plaster because it is thicker than standard drywall. It will be less expensive in the long run to tear off the ceiling and it will increase your chances of saving wood floor above
I won’t comment on Serv Pros or professional companies. They use scare tactics and are used to charging big pocket insurance companies for their services. Start running big dehumidifiers and fans asap. You can rent heavy duty equipment at your local tool rental place.
We had an issue years past and we did call out insurance agents for advice --and made sure they understood
that we were not making a claim at that point. They did guide us to what needed to be done to make the
situation whole again step by step. We never did make a claim and they never made an issue of that call.
We also wanted super paperwork in place for any future sale of our home where we will need to disclose
a water leak.
Take a lot of pictures before you do anything. If you are a dedicated DIY’r you need more advice than most people here can give. I think it sounds like you need to tear out some plaster and treat with a mold preventer such as Concrobrium. Leave it open for a couple of weeks. You can purchase a moisture meter for about $15 from Amazon. You will also have to replace buckled wood floors after moisture in the subfloor subsides.
The fans Servicemaster charges $25/day for only cost $89 to purchase. http://www.northerntool.com/shop/tools/product_200604585_200604585?cm_mmc=Google-pla&utm_source=Google_PLA&utm_medium=Fans%20%3E%20Air%20Movers%20%3E%20Air%20Movers%20%2B%20Carpet%20Blowers&utm_campaign=XPower&utm_content=35438 We actually just purchased three $19 box fans and left them going for a couple of weeks. Home Depot has huge pallets of them right after hurricanes.
I have had flooding twice from hurricanes. My observation is that the remediation companies charge an arm and a leg. They know they will be paid by insurance companies so their prices reflect it. We were able to tear out walls and repair our house for less than $1,000 while a neighbor’s insurance was charged $20k. I watched the Servicemaster workers pile up all their belongings to be thrown out without any attempt at saving anything.
What type of plumbing fitting failed? Do you have the old gray pipe (polybutylene 1978-1995) that is known to fail at fittings? If so you need to call insurance and get your house repiped because more fittings will fail.
I had a similar situation. Water from an upper floor destroying and flooding the floor below. My first call, after shutting off the water, was to my insurance company. They sent a specialist to my house (within the hour), to take care of it. The company collected all destroyed wet items and carted them off (including ceiling tiles and rug), wet vacced up all the standing water, put in heavy duty drying fans to dry what was left, and I never saw a bill for any of it. It was in the insurance companies best interest to dry things up rather than pay for mold damage later on. The joke was that by the time my daughter got home from school at 3 pm the room had been professionally cleaned and all there was to see were the big fans.
I ended up filing an insurance claim for all the repairs, the insurance company then filed against the plumber (whose newly installed end cap had failed), and the plumber then filed against the pipe manufacturer I think in the end the manufacturer footed the bill. It was no fun getting everything fixed but the insurance company did cover it all (except for my small deductible) and were quite reasonable about things like the small area which was damaged connected to a larger area and repairs had to be done to the entire space (for stuff like painting, ceiling and rug replacement.
Call the insurer. This is what they handle. Don’t think you can DIY or wait it out. Especially not when light fixtures and wiring are involved. Many of us have seen what an overflowing bathtub or ceiling leak in a rainstorm can do and this sounds much more expansive. Don’t assume the insurer will jack up your rates, let them deal with the pros.
We had the unfinished basement flood, that was fun. A couple of wet vacs, fans, and lots of cat litter did the trick. But it’s an open area, concrete floor.
THANKS all! Plaster walls have all been on metal lath – we’ll see about the ceiling. Plumbing break was at a valve between supply and toilet. Been there 15 or 20 years. Rest of house is copper (built in 50’s) and PVC if/when something needed replacement, so I don’t think the grey piping is an issue. Sounds like Insurance call may be first step ;-(
Again, you can ask for advice without making a claim with your insurance company.