Another case of black mold in an Outdoors RV

[bneukam]

Originally Posted by ColoradoRFL

One point and a question,

1. The plastic “barrier” appears attached to the insulation so not meant to be sealed. Maybe use insulation with a paper backing instead of plastic?

2. I don’t know how to reach Matt but has anyone suggested to him heat treatment? Mold survives cold but not heat over 120 degrees. The advantage of a trailer is you can park it inside a paint bay and turn on some outdoor kerosene type heaters. Maybe an RV ready thermal vac would be a great business?

Pest control companies tent houses with bed bugs and other infestations for heat treatment so no reason they can’t tent a travel trailer as well. The trick is to stay below maybe 160 to avoid electronics damage but over 120 to kill off all the mold in one hour.

Not sure what plastic barrier your referring to?If its the bubble foil lined on top, that is not attached to the insulation. It may appear to be from moisture condensing on the foil and the insulation bonding to it. But it’s rolled out separately.

Insulation that is paper faced has a tar/asphalt liner that is a vapor retarder. But the issue here is the improper use of the foil vapor barrier that is on the cold side. Water vapor needs to be held back before getting to the cold surface. That’s why it should be on the conditioned side. For that reason alone you need to be extremely careful when using your trailer in temperatures below freezing. If you do use it, refrain from boiling water, and showers, etc.

They use the foil lined bubble wrap to protect the batten insulation from the radiant heat in the summer.

Besides the proper use of a vapor retarder, it’s also very important that you don’t have multiple layers that trap moisture.

I know nothing about heat treatment of the mold. But Matt’s trailer no doubt needs to have the sheathing removed.

Agree with Mr. D you can have a foam board constructed roof with ducted AC. RV manufacturers have been doing it for 25 plus years. Trusses, and batten insulation is cheap, and that’s why manufacturers use this method of roof construction.

[LarryFabbro]

Just use a 10 percent bleach solution to kill that mold.
Lots of different products to buy, but 10 percent bleach in wate works great

[NeilV]

Originally Posted by egwilly

It would be interesting to see if laminated foam board would work on a trailer with over 240 sq feet of area. Since ORV builds curved roofs, they would have to give up one of their big selling points. Not sure if foam board would hold up under the same conditions as a truck camper.

Never have owned a trailer or motorhome with that construction.

Artic Fox (Northwood) and ORV are sister companies. Very much the same shops and equipment. I am sure they both use the same suppliers.

Laminated stress skin panels are regularly made curved or flat to much greater thicknesses with some even in the 10 to 12 inch thick range. In areas where mold in the attics is a problem they bond Icynene foam insulation to the roof joists and roof deck of home after eliminating the roof vents altogether making the attic part of the conditioned space of the building.

At 3 inches the stress skin panels are rated for wind loads over 100 mph even with just a thin aluminum skin on them and on roofs can support the weight of 2 people over a 10 foot span without additional beams. They have been using these panels in the 6 to 12 inch thick range depending on the span with plywood sub-floor as the top skin for use without other framing as the upper floors in multi-story buildings for some years now. They are even using them in the manufacture of houseboats with fiberglass skins on them.

[TT_TR250RDS]

So a few concerns/questions with tearing a trailer apart to fix the roof insulation/mold.

To perform a spray foam install:

From the interior: to get the spray foam against the interior side of the roof decking plywood.

The luan board that is the interior ceiling board extends to the edge of the exterior walls so there would be no way to just pull that down. Unless I am missing something, you would have to cut it out and then scab it back together. Not ideal.

From the exterior: If you rip the rubber roofing off and pull the roof decking plywood up off. There would be no way to spray foam against the interior side of the roof decking plywood.

I am not seeing the feasibility of doing spray foam.

Another few options I was thinking of are:
1)Rip the roof off from the exterior. Take the silver bubble insulation and maybe glue that down to the luan board interior ceiling, then lay the pink BATs insulation down on top of that, and then put the plywood back down.

2) Rip the roof off from the exterior. Take the silver bubble insulation and glue that to the luan board interior ceiling, then piece in Polyisocyanurate Rigid Foam Insulation Board insulation down on top of that, and then put the plywood back down.

3) From the factory, they could use an actual vapor barrier fastened against the bottom of the trusses, add the silver bubble insulation on top of that, BATs insulation, and then plywood.

I am not a builder or an expert in roofing but as discussed it would make sense at the very least to have the silver bubble insulation against the conditioned side (luan interior roof).

[Billiam59]

There is no doubt the folks in the video are an extreme case, living full time during the winter. I do not think this happened during their summer travels unless there is an actual roof leak. That said, I may wait on cold weather camping again until this issue is addressed.
Thought - would it be possible to access the attic by cutting say three holes for additional roof vents pictured earlier and use those holes to pull out sections of the foil below breaking up the vapor barrier? It seems pulling out some of the foil in various spots and adding additional ventilation would help. It could eliminate the need to remove the roof. Thoughts on this as a preventative measure?

[NeilV]

In some of the pictures posted showing this problem in other threads it shows that more is at play here than simply vapor barriers or adding insulation as the plumbing fixtures and wiring fed through the roof along with the vents themselves are getting condensation freezing to them which then melts leading to mold blossoming. Those issues would also need to be corrected which is going to be very difficult without some major redesign and tear-out. Not enough thought to thermal breaks and the like. The start of any remediation would have to be with a Trisodium Phosphate or Ammonium Chloride treatment of the attic space to kill the mold spores first with the Trisodium Phosphate being the better choice since in can be applied with a fogger with limited access to the attic space.

Adding a vapor barrier when there currently is none, additional insulation including Icynene, etc should not be done until after the mold spores have been completely eradicated from the area. Adding more vapor barriers though has proven to just make the problem worse in most situations so not the best choice for making these occasional use campers into full time, severe climate, extended stay/full time abodes. Venting in itself can become a major cause of re-infestation since it allows mold spores floating in the air outside to migrate back inside the attic space. When we remediate homes and businesses were there is a high concentration of mold spores in the outside area we have to put powered ventilation with HEPA Filters to prevent re-infestation with positive air pressure being maintained in the living space to prevent/limit mold spores entering when you open a door so that open window ventilation then becomes ill advised. Dehumidifiers also become a critical element in maintaining control.

Conventional attempts to increase efficiency with traditional insulating and ventilating methods has backfired causing all sorts of mold/mildew issues and correcting this can be quite destructive and costly. I've been in situations where its so bad when you open up the walls that you must wear a full DecTam Suit with full faced respirator sealed to the hood along with the sleeves and pant cuffs sealed to your gloves and boots. You can get into situation where everything gets double bagged and thrown away except for the framing and roof decking. In some areas due to building code changes you can't tear it down and build new unless you make it smaller so in those cases enough has to be left standing to qualify as a renovation and you must follow the original plans for footprint and partition layout to the letter.

Mold is a really big problem now due to the building/insulating/ventilation techniques introduced to save energy since the 70's and used into the 80's, 90's and past the year 2000.

[Dave Pelletier]

If I had such a problem and wanted to correct it, my current thinking would be to do this:

- remove the plywood roof deck (remove all items on the roof, the trim pces and the membrane)
- remove the existing insulation
- remove the AC ducting (just allow the AC to blow from the bottom of the unit. Alternatively the duct needs to be wrapped with duct insulation c/w integral vapor barrier.
- poly/tape/bag all ceiling mounted items like speakers and lights
- seal and poly around all penetrations for piping and wiring
- spray closed cell insulation onto the ceiling from the top; perhaps 3" worth - no other insulation put back on top. spray insulation on any pipes extending through and I'd probably build a box around the vents/fans and insulate those too.
- replace the plywood (or treat the original plywood)....new plywood could also be treated with a mould resistant coating.
- I would add a couple plastic residential roof vents, one at the front and one at the back with the openings facing rearward.
- re-install the membrane, trim, etc.

If you really wanted to get fancy a humidity sensor and a dehumidistat hooked to a small 12V fan connected to one of the roof vents would further decrease the likelihood of any future issues. And yes, you'd need to ensure the vents were clear of snow at all times when in use.

2 cents

Dave-

[NeilV]

Once you bond foam insulation to the roof underlayment and fill the cavity you generally do not install conventional roof ventilation. When we remediate a problem structure and bond foam insulation to the underside of the roof, any existing ridge and attic vents get removed and the openings plugged. If there is any space between the ceiling and an insulated roof you usually want to make that area part of the conditioned living space.

You do not want to create a situation where you have 2 vapor barriers either as once condensation gets in-between them you will most likely need to remove the materials in order to dry them out and treat them.

[Dave Pelletier]

Agreed; using your method, you'd need to ventilate the attic space below the insulation to keep it the same temp as the living space....my method would just be more practical since there is no way to get 100% coverage on the plywood without completely dissassembling the ceiling and cabinetry

[Billiam59]

Reading comments above it sounds like several posters believe this is a design issue, that other owners with the same roof system may be at risk. If we own campers where this problem does not yet exist what would be the best way of preventing it from occurring?

[Dave Pelletier]

Originally Posted by Billiam59

Reading comments above it sounds like several posters believe this is a design issue, that other owners with the same roof system may be at risk. If we own campers where this problem does not yet exist what would be the best way of preventing it from occurring?

IMO;

- make sure you have adequate ventilation always, especially when cooking or showering - run the range fan and bath fan whenever those things are going on (and for a period of time afterwards) and keep at least one window cracked.
- if your plugged in, you can run a humidifier but clearly that isn't a fail safe; can't hurt though.
- long term use in low ambient temps can be problematic, especially in high humidity environments. Full time winter use would be a big concern to me.
- check your attic periodically so that if there is any moisture, it can be caught before there is a significant problem.
- you could also install a humidity sensor in the attic space

There may also be some value in sealing off openings into the attic where wiring and pipes go through the ceiling. .....likewise you could seal around other penetrations like lights, speakers, AC vents, fan housings, etc.

While I don't think humidity is going directly through the ceiling panelling, one could also use a waterproof membrane coating and paint the entire ceiling with it.

I live in a relatively low humidity area and I don't intend to use my trailer from around Novermber to April so I seriously doubt I'll have any problems but being who I am, I can't help but to consider improvements - it's a character flaw!

....just some thoughts.

Dave

[bneukam]

This has absolutely nothing to do with outside environment, and it’s humidity levels. But everything to do with the build up of water vapor levels INSIDE the trailer, especially during periods of greater temperature difference.

Anyone who tells you different doesn’t have a clue what they’re talking about.

Nobody knows if the Luan interior board has a vapor retarder layer. If I owned an ORV that would be the first call I would make.

Agree with sealing any cracks or voids that lead to the attic space. But that alone is not sure bet.

There are videos out there how to remove the interior ceiling in an RV, it’s not difficult, and is the method our friends used to treat there mold.

[Dave Pelletier]

Removing the ceiling is relatively easy; getting full coverage from below using spray foam without removing all the cabinetry, etc is impossible IMO.

2 cents

[ColoradoRFL]

Originally Posted by bneukam

This has absolutely nothing to do with outside environment, and it’s humidity levels. But everything to do with the build up of water vapor levels INSIDE the trailer, especially during periods of greater temperature difference.

Anyone who tells you different doesn’t have a clue what they’re talking about.

Nobody knows if the Luan interior board has a vapor retarder layer. If I owned an ORV that would be the first call I would make.

Agree with sealing any cracks or voids that lead to the attic space. But that alone is not sure bet.

There are videos out there how to remove the interior ceiling in an RV, it’s not difficult, and is the method our friends used to treat there mold.

Our Outdoors RV doesn’t appear to have any luan or “seal barrier” in the attic. The top of the attic is plywood (looks like pine) along with insulation that has a bubbly plastic side which is placed against the plywood.

The attic areas are not sealed from the living area but there is insulation between the two making the attic much colder.

As I mentioned before, warm air traveling up into that attic space drops water vapors as it gets colder since humidity levels they are taking about are relative to the temperature of the air.

Here is a picture of the plywood not luan.