drying out after a flood

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Bob Hammond
Posts: 629
Joined: Sun Jul 22, 2012 4:13 pm

drying out after a flood

Post by Bob Hammond »

Hi

Last week a large amount of rain fell, and the city's sewer pumping system failed. Water (mostly stormwater?) bubbled up out of the floor drains of my basement shop much faster than my pump could handle it. So I took off for the hardware store and bought expansion plugs and plugged the floor drains and then the pump gained. What a mess, but fortunately I have insurance for this.

The shin-deep water was lightly seasoned, and luckily I'd done more than a cursory sweep of dust a couple of days earlier. Some MDF forms and a fair amount of other materials were ruined, but most things had been off the floor. It was still necessary to move all of the machinery and remove many plastic tubs of material (I was smart enough not to use cardboard boxes for storage.) so that the professional cleaners could come and steam/disinfect the floor and walls. They left an industrial dehumidifer and three massive axial fans to run continuously for 3-5 days. I also had to saw out the bottom 6 inches of some wood partition walls.

Here's a recommendation for you:

If you can, have a backflow check valve installed on your main sewer line if possible. If you can't, then you can buy check valves ($20 ea) that fit in the floor drains that allow drainage out, but not backflow, by means of a floating seal. >This could have saved a huge amount of work and annoyance, and a $500 deductible.<

Also, below is a link to an online relative humidity calculator that you can use with a digital thermometer. Take a dry temp reading, and then wrap the temperature probe in a wet paper towel (room temp water) and place at the intake hose of a shop vacuum (not the exhaust port). Record the lowest wet-bulb temperature and then enter the dry & wet temps into the calculator along with the current barometric pressure (from a weather website). The calculator will cogitate and give you information. At this moment, the shop humidity is 48.5% RH, which is a nice number to see.

http://www.vaisala.com/humiditycalculat ... l?lang=ger

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Peter Wilcox
Posts: 1187
Joined: Sun Jan 08, 2012 1:31 am
Location: Northeastern California

Re: drying out after a flood

Post by Peter Wilcox »

Also, below is a link to an online relative humidity calculator that you can use with a digital thermometer. Take a dry temp reading, and then wrap the temperature probe in a wet paper towel (room temp water) and place at the intake hose of a shop vacuum (not the exhaust port).
A lazy man's sling psychrometer. :lol:

But very sorry to hear about the damage and the work involved in cleaning it up. Best of luck in getting the shop back to its former state.
Maybe I can't fix it, but I can fix it so no one can fix it

Bob Hammond
Posts: 629
Joined: Sun Jul 22, 2012 4:13 pm

Re: drying out after a flood

Post by Bob Hammond »

Peter, this happening is not a completely bad thing. After 20+ years, the place needed a good cleanout and refreshing anyway. At least the insurance will cover the cost of new flooring and paint, and I can do some reworking of the dust collection and electric service after I mull over the floor plan of the tools and benches.

As for the thermometer & shopvac trick, I'm pretty sure that it was Mario who developed the technique. I only found the website. I'll check the RH against the cleaning company's certified instruments on Monday. My Honeywell hygrometer was off by about 10 percentage points, but it was located at a different height and location from where I took the temp readings.

Dave Sayers
Posts: 35
Joined: Thu Dec 19, 2013 2:32 pm

Re: drying out after a flood

Post by Dave Sayers »

We had a blocked drain that flooded the kitchen and that was bad enough. Hope it all goes back ok. One thing I do about 4 monthly is to use Armour All wax on all metal surfaces. It can get pretty damp in my wooden workshops but so far nothing has even started tarnishing, not even the shiny beds on the planer and the drill. Good stuff Armour All and quick and cheap to apply.

Bob Hammond
Posts: 629
Joined: Sun Jul 22, 2012 4:13 pm

Re: drying out after a flood

Post by Bob Hammond »

Dave,
So far, I've not had a significant problem with rust. I think part of that is because of the quality of the steel, but mostly because the cleaning company has left a monster sized dehumidifier and fans.

Maybe you know this already, but as I recall, some Armour All products have silicone compounds in them, e.g. the automotive products. I understand that this can cause problems with finishes if the wood is contaminated with the stuff.

Hmm, somebody told me that canola cooking spray is acceptable. Does anybody know if that's true?

Steve Senseney
Posts: 673
Joined: Fri Jan 06, 2012 2:45 pm

Re: drying out after a flood

Post by Steve Senseney »

The website for Amour All wax indicates no silicone.

I don't know about the canola cooking spray.

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