Flood Barriers

[gregs]

FWIW this started off about waterproofing plywood, thats all. I appreciate all the suggestions. Since its gone far deeper than the initial question I will offer up another piece of information about the house that has me going the direction I am.

The bottom floor is concrete construction with smooth stucco finish. All of the exterior door openings are flush. What I mean by this is the door and framing is inset from the face of the exterior wall by about 4" or so. There is no exterior sill or ledge and the openings are above grade and incorporate a separate step or landing. That allows me to install a flat panel over the opening with no interference from the bottom or sides. The bottom area before the step is around 4"-6" which I think is a good width to create a seal with a neoprene gasket material.

Attaching them to the wall is still not locked in. But I am thinking at this point to use stainless threaded rod epoxied into the wall. Then I am thinking either plain nuts and washers or large knobs to make it tooless. The other option is a female threaded insert also epoxied in place with a similar fastener idea.

The Flexseal is also part of the equation. I will have it on hand and use it If we where to have the time and the forecast suggested a similar path that would cause the storm surge.

Again this is just one part of the flood mitigation plan I have been developing. Its taking time on the front end but expect it to save time and money when it happens again. So far most things have been good planning and picking appropriate materials and construction techniques to mitigate the amount of damage.

 

[DGersic]

Overall, I like your idea. By itself, it won’t stop everything, but if it slows down the water intrusion enough to allow other things to work, it may be ok. You’ll get some water, but maybe slow enough to allow pumps to eject it back out.

 

[CraigStu]

I think the studs would be the way to go. We have all been there on something where we are trying to manuever something around so we can stick a bolt through it to get it to thread into a threaded hole that we can't really see. A good way to cross thread it right at the start. Usually it is much easier to kind of hang the board on a protruding stud. Maybe a large wingnut on the stud? I bet you can find some kind of decorative cap to slip over the stud between floods.

 

[pcmeiners]

"I am considering using 3/4" plywood for the panels and thinking about what to coat it with to keep them from absorbing water."

Marine plywood with an oil based primer. If you use latex primer on ANYTHING the paint will peel if submerged, latex top coat is OK. Went through Sandy, interior walls were under water for >24hrs, I had used oil based primer, and was the only house in the area where the taping/paint did not lose adhesion; basically the wall dried out and only needed repainting, but no repair.

 

[Youngandfree]

At my church, they turned a picnic pavilion into an enclosed utility building of sorts by closing it in with blocks. There's a drainage creek that runs near it that can flood. They installed aluminum c channel on the edges of the door jambs and slide a sheet of aluminum into the c channel as the flood barrier. Looks like it has foam strips to help seal it. Never seen it in action to know how effective it is.

 

[Flatkansas]

I am considering using 4x8 sheet of clear polycarbonate hurricane shutter panels around and up against the perimeter of my manufactured home (25'x46'). I plan to install a 1-1/4 aluminum angle with anchors and sealant on the concrete slab around the home to support the bottom edge of the panels. I will use heavy duty tape (water proof) to seal the bottom sections to the aluminum angle and the vertical seams between the panels. These panels are hurricane impact rated, UV stable on one side, and weigh 8 pounds. I will have these cut to size and ready to deploy prior to a flood event.

https://www.lowes.com/pd/Storm-Busters-48-in-x-96-in-Clear-Polycarbonate-Hurricane-Shutters/3041437

Whoops, we couldn't find that.

www.grainger.com

For my application I will have the panels with the 4 foot section running vertical, 8 foot section horizontal. This should provide 4 feet of flood protection.

I am also considering installing two each 1 hp sump pumps under the home that can provide 5640 gallons each at 5 foot lift to handle leakage past the flood protection barrier.

Stay tuned....

"Engineers are a solution in search of a problem......."

​

 

[DGersic]

I am considering using 4x8 sheet of clear polycarbonate hurricane shutter panels around and up against the perimeter of my manufactured home (25'x46'). I plan to install a 1-1/4 aluminum angle with anchors and sealant on the concrete slab around the home to support the bottom edge of the panels. I will use heavy duty tape (water proof) to seal the bottom sections to the aluminum angle and the vertical seams between the panels. These panels are hurricane impact rated, UV stable on one side, and weigh 8 pounds. I will have these cut to size and ready to deploy prior to a flood event.

https://www.lowes.com/pd/Storm-Busters-48-in-x-96-in-Clear-Polycarbonate-Hurricane-Shutters/3041437

Whoops, we couldn't find that.

www.grainger.com

For my application I will have the panels with the 4 foot section running vertical, 8 foot section horizontal. This should provide 4 feet of flood protection.

I am also considering installing two each 1 hp sump pumps under the home that can provide 5640 gallons each at 5 foot lift to handle leakage past the flood protection barrier.

Stay tuned....

"Engineers are a solution in search of a problem......."

​

Impact rated is good, but different from the pressure that water exerts as it piles up around your inverted swimming pool.

Moving water is even worse.

 

[PopcornSutton]

Water pressure is not to be taken lightly. Many years ago I did a project on the National Zoo, and it was in the flood plain near Rock Creek. Heavy rains from the north would surge down, and the staff would have plenty of time to prepare. Flood gates were specified for the two openings, manufacturer and models. This was a poured concrete building, at these openings we had the cast-in frames for the flood gates. These frames and the gates themselves were welded aluminum with a radius at the bottom both sides. The gates were about 3 feet high. The frames had a substantial "stop" welded on the inside at support the gate. The gates had heavy slide bolts that would lock them in place to the frame and there was a heavy seal in the gate that was to be inflated with air pressure when installed, both sides and bottom continuous.

I was told they cost a fair amount of money, but we had to purchase them, no substitutions were allowed. But it sure impressed me what kind of load they were designed to hold by their construction. Just want to pass this along when folks talk about a piece of 3/4 plywood and such.