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Topic: Bulkhead - minor leak mitigation? (Read 481 times) previous topic - next topic

Bulkhead - minor leak mitigation?

On a recent trip, I noticed a small amount of water on the ground under the tank drains.  At 1st it appeared to be a leaky tank drain valve but, after opening the water heater/water pump bay, there was also water on the floor of the bay.  I discovered that the leak was from the back side of the water heater, where a plumbing finger nut was loose.  I was able to tighten the nut and the slow drip stopped.  I don't think it had been leaking more than a couple of day's, but some water obviously got into the subfloor and escaped around the caulking at the drain tubes.  The drip on the ground stopped within minutes of shutting off the water, which suggests it might have stayed fairly localized in the subfloor.  In fact, it's possible that the water entered from the top side of the tank drain hole and passed right through and out the bottom.  I have not had any extensive bulkhead inspections but there is no indication of existing issues & Rance at Xtreme blessed it as clean only a couple of months ago. 

My question is, does this 1-time issue warrant any extreme measures for drying out the bulkhead structure, or am I safe to let it dry out on it's own?  Is bulkhead damage caused by a single incident like this, or does it typically require more water over a longer period of time?  For those that have had the issue, what would you do?

Thanks.

Re: Bulkhead - minor leak mitigation?

Reply #1 –
I am not aware of any way for the basement structure to "dry out on its own".  Once the insulation is soaked, it stays wet. Guess it might be worth drilling a couple of access holes (sized for waterproof plugs).  And break up/remove the wet insulation, then use a hair dryer or just dry air to finish the job.  You would have to continue to remove until dry insulation is found. 

Then, if much cold-weather camping planned, perhaps use a moderate-expanding spray foam insulation to re-insulate.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Bulkhead - minor leak mitigation?

Reply #2 –
Bdale,  I just went around with that very same fitting it will continue to come loose and finally crack. Do yourself a favor and go ahead and change both of the water heater fittings
Bruce, Linda, and Macy
Zoey RIP 1/20/19
1999 U295 40' build #5400
2017 silver Jeep Wrangler, 1260 watts of solar on top
Moving around the country

Re: Bulkhead - minor leak mitigation?

Reply #3 –
What exactly is used for the insulation?  Is it a closed cell foam board? Open cell foam?  Fiberglass batting?

Re: Bulkhead - minor leak mitigation?

Reply #4 –
Quote from: bdale –
What exactly is used for the insulation?  Is it a closed cell foam board? Open cell foam?  Fiberglass batting?
Rigid styrofoam board. This stuff doesn't actually hold water like fiberglass batting, but if water is trapped between the frame and the edge of the board, it doesn't have anywhere to go and can be held against the frame since it can't evaporate. Far worse than the insulation as regards the frame rusting out, are the four areas in the utility bay where there is two layers of ¾" plywood (to create in effect an inch and a half of plywood matching up with the 1.5" square tube framing) filling the voids. The plywood gets soaked and disintegrates into a black mush, which will do a number on the steel frame. These squares of plywood are placed in the four corners of the utility bay near the outer edge. I believe these were put there to support accessories like hose reels and fresh water pumps etc., even if the coach didn't have that option. You will certainly find the wood in the area where the drains exit the basement floor. If you drill a plug size hole near the bulkhead joint six or more inches from the outer trim (be sure use a magnet to trace out the steel frame), don't be startled to see saw dust...
Edit: Seeing sawdust would be a good thing! What you hope not to see is black mush. Also, be aware that on the street side, there is some doubled up square tube framing about 18" in from the outer trim along the rear bulkhead joint. There are differences between the years, floorplans, an sizes. The above holds true for late 90's coaches and early 2000's, I don't know about earlier or later. Knowing where the framing ends and the insulation or plywood ends is important and why before you start any work down there, clean of the fiberglass skin and use a marker or grease pen to draw out the border of the framework with magnets and a straight edge.
Don
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Don & Tys
1999 U270 3602 WTFE #5402
Xtreme Stage 1 w/Headlight, Step Conversion, etc.
2009 Honda Fit Sport with Navi
Freedom is NOT "just another word for nothing left to lose"... with apologies to Kris Kristofferson

Re: Bulkhead - minor leak mitigation?

Reply #5 –
To clarify what Don said, the insulation is styrofoam but not the white stuff that is composed of small 1/8" diameter beads that crumbles away and makes a mess when it breaks.  The rigid stuff Don speaks of can be found at Home Depot and is usually blue or pink.
John Fitzgerald
1991 U300 (SAI) Side Aisle Island Bed 40'
Detroit 6V92 with Allison Retarder
Meridian (Boise), Idaho

Re: Bulkhead - minor leak mitigation?

Reply #6 –
Quote from: JohnFitz –
To clarify what Don said, the insulation is styrofoam but not the white stuff that is composed of small 1/8" diameter beads that crumbles away and makes a mess when it breaks.  The rigid stuff Don speaks of can be found at Home Depot and is usually blue or pink.
Got it.  My main reason for asking was to determine if it absorbs water or not.  Sounds like it does not.

Re: Bulkhead - minor leak mitigation?

Reply #7 –
While the insulation itself may not absorb water, is is certainly involved in trapping water and leaving the box beams exposed to water.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Bulkhead - minor leak mitigation?

Reply #8 –
Quote from: wolfe10 –
While the insulation itself may not absorb water, is is certainly involved in trapping water and leaving the box beams exposed to water.
Understood, but potentially gallons of water trapped in soaked insulation is an entirely different matter than cups of water between the insulation and box beams.  Knowing which one I'm dealing with helps decide how aggressive I need to get with it.
 

Re: Bulkhead - minor leak mitigation?

Reply #9 –
If the plywood is soaked, you could be dealing with a serious problem. Drilling some small holes next to the box beam where the plywood is can tell you that without being too destructive. I would be tempted to do do some exploration, after drawing some frame boundary lines, with a ⅛" drill bit. If the wood is solid, a number 8 or 10 stainless truss head screw with a bonded stainless washer and a bit of caulking would seal up the hole. If the wood isn't firm, then it won't hold the screw and you have bigger problems. Of course this idea presupposes that you know or can discover where the wood pieces are, because the styrofoam insulation won't hold a screw well either. If you make a mistake with the hole placement, there are any number of ways to seal a small hole permanently. There are pictures on the forum of the bare basement framing from my project and others that can help you visualize the structure. For instance, the picture below is the street side view of the area in front of the water tank which is next to the bulkhead in our floor plan. This is an area where the reels would have been located if our coach had had them.
Don.
Quote from: bdale –
Understood, but potentially gallons of water trapped in soaked insulation is an entirely different matter than cups of water between the insulation and box beams.  Knowing which one I'm dealing with helps decide how aggressive I need to get with it.
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Don & Tys
1999 U270 3602 WTFE #5402
Xtreme Stage 1 w/Headlight, Step Conversion, etc.
2009 Honda Fit Sport with Navi
Freedom is NOT "just another word for nothing left to lose"... with apologies to Kris Kristofferson