Foam Insulation Under Cab for heat??

[campingfig]

Hello Campers! Took my RV to a local HIGHLY recommended shop to get their opinion about the poor airflow in my 2007 Ford E450 Winnie Outlook. He said that he has seen rigs come in with Spray Insulation under the cab area...under the cab. He said he sees it once in a while when he puts the RV up on the rack. WHAT A GREAT IDEA! SPRAY FOAM INSULATION 'UNDER' THE CAB AREA - UNDER THE FLOOR BOARD THAT GETS SO HOT! Question is now, what type of business do I call regarding that type of work? Does anyone out there have info or experience spray foaming the underside of their cab area for engine/header heat insulation? I would love to know!

[Kit_Carson]

MountainAir05 wrote:
This is what I have. Pricy but it does work.


http://www.dynamat.com/

Did you have this installed by an upholstery shop or RV shop? I have considered having this done on my Class C.

[pnichols]

campingfig wrote:
By the way...we DO have those same heat shields around our pipes. EXACT same shields. They just dont' do the job and shield enough area.

Hmmm ....

Our Itasca floor has fairly heavy carpeting and heavy padding under it as delivered by Winnebago. Our floor does of course get warm during hot weather driving, but nothing overly disagreeable about it. The MIX A/C pretty much takes care of what heat there is just fine. However when set to MIX, one must have the temperature control all the way into the blue (cold) position and use a fan speed of 3 or 4 for it to be effective. A fan speed setting of only 1 or 2 will not be strong enough to counteract heat coming up through the carpeting. And as I said, I have never seen a need to stop using as much A/C as we want regardless of how hard we thought the engine might be working relative to outside ambient temperatures and road grades. I assume the temp gauge will move if we're ever operating outside safe engine or transmission heat limits and so far it hasn't come anywhere near indicating showing too hot of a condition ... including pulling up long grades outside Death Valley.

However our E450 is carrying around only an 11,800 lb. Class C and we rarely tow anything except a small aluminum boat, so maybe that helps a bit to keep heat buildup lower in the cab floor area.

[campingfig]

By the way...we DO have those same heat shields around our pipes. EXACT same shields. They just dont' do the job and shield enough area.

[campingfig]

pnichols wrote:
We use the MIX setting "a lot" in our E450 motorhome's cab to keep cool air coming out at our feet at the same time as cool air coming upward and flowing down over us from the front windshield vents - this is far superior to the air conditioning blasting directly out at our face and body from the dash vents.

However, our motorhome's floor does not get that hot anyway ... because for some reason there are heat shields installed underneath in the front blocking heat transfer from the V10's exhaust up to the cab floor. Here are photos of the driver's side heat shield (upper photo) and passenger's side heat shield lower photo):






A Ford mechanic said that the shields were not standard Ford cutaway van items, so I assume that Winnebago had them custom-installed by Ford or some third party before building the motorhome (Itasca) onto the E450 chassis.

By the way, our Ford E450's temperature gauge has never moved into it's high temperature area under any conditions - so I assume that means that the engine and transmission temperatures are staying within safe operating zones. We run the air conditioning as much as we want as high as we want in the MIX or other settings whether pulling up long mountain grades in scorching temperatures or sitting idling on the blacktop in fast food parking lots for minutes on end in scorching temperatures.

I consider the E450's engine/transmission cooling system as outstanding and definitely one of it's strong points. As a indication of this, the E450's transmission cooling system actually takes about 5 more quarts of fluid than that of the E350 transmission's cooling system.

I would recommend that the OP first look into getting metal heat shields installed above the exhaust pipes under the cab floor and then using the MIX air conditioning vent setting much more - then maybe trying heat insulation schemes only as a last resort.

True...the engine runs AWESOME and has never overheated. We love its performance! However, wife and I would really like to improve the ride - espcially the driver - since there is no where else to sit with the gas pedal and steering wheel. 😛

[pnichols]

We use the MIX setting "a lot" in our E450 motorhome's cab to keep cool air coming out at our feet at the same time as cool air coming upward and flowing down over us from the front windshield vents - this is far superior to the air conditioning blasting directly out at our face and body from the dash vents.

However, our motorhome's floor does not get that hot anyway ... because for some reason there are heat shields installed underneath in the front blocking heat transfer from the V10's exhaust up to the cab floor. Here are photos of the driver's side heat shield (upper photo) and passenger's side heat shield lower photo):





A Ford mechanic said that the shields were not standard Ford cutaway van items, so I assume that Winnebago had them custom-installed by Ford or some third party before building the motorhome (Itasca) onto the E450 chassis.

By the way, our Ford E450's temperature gauge has never moved into it's high temperature area under any conditions - so I assume that means that the engine and transmission temperatures are staying within safe operating zones. We run the air conditioning as much as we want as high as we want in the MIX or other settings whether pulling up long mountain grades in scorching temperatures or sitting idling on the blacktop in fast food parking lots for minutes on end in scorching temperatures.

I consider the E450's engine/transmission cooling system as outstanding and definitely one of it's strong points. As a indication of this, the E450's transmission cooling system actually takes about 5 more quarts of fluid than that of the E350 transmission's cooling system.

I would recommend that the OP first look into getting metal heat shields installed above the exhaust pipes under the cab floor and then using the MIX air conditioning vent setting much more - then maybe trying heat insulation schemes only as a last resort.

[stubblejumper]

When I said earlier most foams are not flame proof I was thinking that the OP was talking household foams such as GreatStuff or Tiger Foam. Check with Icynene (H.O. Cleveland) they are the worlds largest manufacturers of spray foam insulation and have a non-flammable foam for home and industrial use but it is intended to reduce flame spread and does melt down. Whether it would work at those temps and that close to the heat source ?????????

Another source is Unifrax that manufactures a ceramic fibre spray for use inside boilers and furnaces. Their H.O. is in New York. As near as I could tell with a quick read this product is something like the old (now banned) asbestos spray.

Just google "high temperature foam spray" there are lots of sources, it's just a question of what meets your needs and of course $$$

[campingfig]

I already had Dynamat installed behind the doghouse and under the footboard and mostly under the chairs. It did help alot but I still have significant heat coming up by my foot and under the floorboard, under the chairs, turning my cab into an oven on hot days. The doghouse has been checked and is sealed properly. We do run the mix air once in a while but as most would understand, you don't want to run your air alot when the engine is pulling and working really hard in high temperature outside going up mountains and hills. I have two issues I want to improve:

1)Poor airflow on this 2007 ford Chassis design. :E The front air intake panel/grill is restrictive, poor design - hence the new Ford grills that came out in 2008 with ALL their truck models - HUGE 'breathable" intake grills. After looking a mulitple options over several years with many shops unanimously agreeing the engine compartment is TOO tight for any inside additions/modifications. Hence the need to increase airflow in the engine. I have a friend who will make two custom air scoops for my hood to force air in the engine and over the top of the back doghouse area. They will be customed made and painted to match Ford hood. It is a VERY different idea and will probably look cool too! 🙂

2) HEAT coming up from underneath...under the floor panel.:M I have Dynamat installed but I am considering doubling the layers. Yesterday a muffler shop told me they have seen a few rigs come in with some type of sprayed-on insulation UNDER the cab area...adhered to the metal floor ON THE OUTSIDE under the cab area. They had NO idea what type of companies do this. This makes GREAT sense if I can figure out who and where I can have this done. The shop told me it makes sense to try and stop the heat BEFORE it passes through the metal cab.

Therefore, the inquiries to see if anyone out there has experience with spray insualtion UNDER the cab area...and if so, does anyone know what type of business does this work? Is it even feasable? I have spoken to so many RV shops, Muffler shops, etc and ALL of them have told me to NEVER EVER wrap your exhaust pipes,header areas with wraps, muffler wraps,muffler 'blankets' or otherwise even though these products exhist.(wrapping on race cars, etc, they say is a different situation. I have been told several times wrapping will hold the heat in the pipes and over time over stress the metal and cause cracking, exhaust leaks and other horrible costly damage. The exhaust system needs a place to release it's heat naturally. So, wrapping the exhaust anywhere is out of the question. I have been told I just need better air circulation and better heat barriers. I already have the heat shields underneath, but of course, the shields are only a certain size where heat easily moves around the edges and up elsewhere.

[mlts22]

First thing I'd recommend would be Dynamat. Unlike the spray foam, it is easily pulled out if you need to service something. I'd definitely have this at least for the doghouse, if not under the carpet/vinyl for the entire cab so you can drive with bare feet without issue.

[JohnnyT]

Moved from class A forum

[wny_pat1]

Find the area near you, like the local farmers market, where there are lots of trucking businesses around. Usually you will find one that does spray foam insulation on cabover class 8 trucks.

[wildmanbaker]

Try your local airport. Call companies that do airplane repair/maintenance and explain what your problem is, and what might be done to correct it.

[MountainAir05]

This is what I have. Pricy but it does work.


http://www.dynamat.com/

[bsinmich]

You might find people with similar problems & MH on the Class C forum. I seem to remember similar problems when we had a couple of Cs.

[Golden_HVAC]

Hi,

My buddy has a 1987 Ford based class C, and it also has foam applied to the underside of the Box portion of the RV. Not under the cab itself.

As long as you stay about 3" from the exhaust, then spraying on the foam to the cleaned sheet metal should work find. You need to prep it properly, according to the material being applied. In other words, if they say to not using rubbing alcohol to prep the metal, don't use it. If they say must be cleaned with rubbing alcohol, then that is the stuff to use, and the foam is compatible with it.

They do make higher than average temp rated foams, used to fireproof buildings, but still it might not hold up well next to the 1,100 F exhaust system, so check the ratings on the products. You might also consider wrapping a small section of the exhaust system, where it is closest to the chassis metal, and also the doghouse. This will reduce the amount of heat radiated into the drivers area.

My buddy replaced the factory fiberglass insulation with some cheap foam aluminized insulation - it did not work worth a darn, still transmitted more heat than the factory insulation, and caught fire while driving in 95F weather on the way to Las Vegas. So we tore that out, and went without insulation until I replaced it with some 1.5" thick air duct insulation. I don't know how fireproof it is, but it is rated to not promote flame spread, and putting a BBQ lighter to the fiberglass for about 30 seconds did no damage to the material. So it has been in place for about 6 years now, with no damage yet.

I put some 1/2" thick foam pads on the floor of my RV, and it really helped cut down on the heat transfer into my class A motorhome.

Fred.