Any floor insulation advice?

[RazorCityDen]

Originally Posted by djontz

FWIW, I agree with Smitty...you can't be too careful about insulating and doing whatever you can to stop condensation. You are going to spend a lot of time and hard earned money on this project. You won't want to have to redo parts of it a couple of years from now.

Redo parts in a couple years because the floor doesn't have an R or two of insulation?

That's getting a little carried away IMO.

If the floor is sound now I can't imagine what a skoolie conversion is going to do to it to require it to be replaced in 2 (or 10 years for that matter). The nail heads weren't even rusty in my bus when I pulled up the rubber mat in my bus a year ago and that was after at least 12 years of carrying around Montana curtain climbers, stomping in and and out twice a day in snowy boots with he heater blasting and the humidity probably off the charts (I remember rural bus culture )

I've cut several holes in the floor of my bus and didn't see anything that would concern me between the metal floor pan and the plywood. I'm also not seeing any moisture collecting anywhere inside from condensation. The only time I've even had my windows fog up is when I ran a propane heater before I got my wood stove in.

I can see the benefits of a couple R's under the plywood or on top for that matter, but I think the case is getting a bit overstated. After all that little bit of insulation isn't going to keep the interior heat away from the metal floor pan and moisture could still condensate under the insulation on top of the metal floor pan.

I think the key is letting the floor "breath" to carry the moisture away and not getting carried away with vapor barriers. I definitely wouldn't put any vapor barriers in my bus. I'm not all that excited about them in houses, they seem like a good idea in theory, but they cause as many problems as they solve, if it's breached anywhere the water vapor seeks that channel and you get water mucho hidden water damage.

Take care,
Den

[RazorCityDen]

I'm don't claim to have all the answers Smitty and I'm not taking it upon myself to lay down official internet bus conversion doctrine, I'm just relating my own limited experience with bus converting.

I wonder how all that rot & rust damage takes place in many of the buses we see (that are 10-15 years old)? Look at some of the travel trailers with rotten walls & floors (from condensation).

I have seen all the pictures of the rusty buses and I've helped repair more than a few RV's over the years and maybe your right maybe it is condensation that trashes the floors. I also think it has a lot to do with how much moisture goes though the floor from wet boots and leaking roofs, windows, plumbing and doors and how long it stays there and the quality of the materials it's in contact with till in dissipates.

I haven't gutted enough western buses at this point to know if mine just led a charmed life or if it's representative of what happens in our climate. I know lots of the mid west buses I looked at that had rusty steps and soft floors also had a lot of rust on the chassis. I know that I had no problem pealing back some rubber on the edges to look at the plywood. Mine (Montana School bus) has none of that and neither does my buddy's which was a Sundance, WY School bus. The road salt just plays hell with sheet metal especially if it isn't treated particularly well, I think that's whats happening to lots of the mid west buses, years of slushy boots tracking in the road salt and it's finding it's way to the sheet metal.

I know when I pulled up the rubber mat over my plywood it was stuck tight as hell and came up in little pieces and the edges of my plywood are sealed to beat hell with a large bead of that black caulk Bluebird seals with. I personally don't think much if any moisture got to my plywood and what did find it's way though dissipated before it could do any damage to the galvanized floor pan or the plywood. Who the hell know's at this point? Like I said before, maybe my bus led a charmed life and I'm happy for it, that's what I wanted was a straight unit to build on, hunted all over and paid a premium to get one.

Where did all that condensation (as well as the "off the chart" humidity) go? Condensation isn't a 24/7/365 issue, so simply "not seeing" it doesn't mean you don't have the problem(s).

I'm not convinced there was condensation between the plywood and sheet metal, but I know the area's I've cut into looked fine and I haven't found any rust anywhere on the bus. If I had shaken the dice on a mid west bust I most certainly would have torn the plywood out if for nothing else but a look see and some paint. If I would have had any inkling of drama with my bus I would have torn it out, I've got help when I need it and the materials sitting, but it was sound.

I guess the bottom line is I'm not convinced condensation is trashing the floors on it's own, I think a lot of it comes from years of road salt slush tracked in and finding it's way to the sheet metal pan. While I don't think insulating the floor is a bad idea I'm not convinced it's going to keep the floor pan from rusting from condensation and it's really anyone's guess because there's lots of variables at play.

Personally I looked at the condition of my floor installed in 1993 and thought it would serve me just fine another 16 years, but everyone's got to find there own comfort zone. Everyone's bus had a different past life and everyone has there own priorities and budget for time and money. As far as floor insulation making the bus warmer that would be another one hard to prove, but what the hell, whatever makes folks happy.

Take care,
Den

[RazorCityDen]

Originally Posted by djontz

I don't know about the bus being warmer either. Might make my feet feel better on a cold morning though

BTW, where did you get your bus? Private party or a dealer? I live right in the heart of the rust belt, and I am a little nervous about buying one locally...

Could be!

Harlow's Bus Sales from their White Horse, MT bus yard, they had many to choose from at the time, they also got buses up in Libby, MT and a few other states. They ain't cheap, but they are market and in good shape and the folks I dealt with knew buses. Harlow's is a multi-state school bus dealer, they charter and keep buses to contract haul fire fighters and search and rescue folks.

When there's rust eating at the floor it's eating other area's as well, not always so easy to fix as the floor pan. We get lots of folks out here these days from the mid west to work and it's not uncommon to see their mid 90's pick-up's just plain falling apart with rust.......did "condensation" cause the shock mount to break off or the bed mounting brackets to pull though?

Westerners are generally little squeamish about rust!

Take care,
Den

[Seeria]

Might consider that reflectix tech. They come in a variety of types, some sealed insulation R3 to R17 is highest I can see. Home Depot appears to only have one type but if you run a search for reflectix or hmm think it is called prodex insulation you can get an idea for the different types. Bubble wrap to fiberglass sealed barriers etc.

[RazorCityDen]

Originally Posted by Smitty

lol, I wasn't trying to imply you thought you did Den

The major factor in rust issues is location. Western locales are generally known for preserving vehicles for longer periods, lack of snow & road salt does wonders. However, there are still cool nights waking to a hot morning sun, which is the mixins' for condensation. Sure those dozens of little snow-covered feet add gallons of water to a bus floor weekly I'm sure. I got lucky (with my mid-west bus) and have no issues in my bus, floor, steps, window openings, all good. I have 1 small (3-4") area at the back where the rear window sweated and ran down inside the panels, and pooled at floor-level. My bus didn't have plywood under the rubber floor, which I think was a good thing. Even so, there was no rain for several days prior to removing the rubber, and the floor was soaking wet, from condensation.

I would agree with that, between the lack of road salts and low humidity our vehicles stay in pretty good shape. I lived in the mid west for three years (long story ) and remember my kids standing swamper deep in salty slush at school waiting to get on the buses and the white crust in our mud room every winter that all of us tracked in from everywhere.

Agree wholeheartedly, there's no one-way or standard to converting ones bus. If there were, it would be boring! I see some buses where the owners have spent lots of time and money, and ended-up with amazing results...but left the stock windows in place, but, their bus their choice. Same with insulation, matters not to me if someone chooses to insulate their bus, but I will tell you once they regret it, it's too late.

If the bus window's are tight, function good and suit the owner, why not use them? Before I bought my bus I had planned to switch out to RV windows but found the factory windows to be heavy duty and function well. I would imagine other folks made a similar decision. I don't think it makes for a less "amazing" conversion. Personally the first time I sat some lawn chairs where my couch is going and looked out at the 180deg view from my living area I knew I wasn't closing it in with port hole sized windows, I lowered my galley cabinets as well so they wouldn't mess with the view. I plan on backing my bus up into the shelter of tree's with a nice panoramic view of my back trail and if it gets chilly I'll throw another stick in the stove, which will also be drying out any of that pesky condensation (wood heat is the condensation buster) As far as a complete insulation redo, I had mused that as well, but the factory insulation in my bus seemed just fine to me when I started heating it last winter to work in it and this summer in the shade of my yard. Everyone's comfort level and expectations are different though. Myself, I looked at that sturdy ceiling and thought what a wonderful place to attach my framing, cabinets and some thin paneling. Others look at it in horror "MY GOD that ceiling must be at least 12% less efficient! I'm tearing it all down and replacing everything!". Whatever twist their cranks

Condensation can be resolved by insulation & ventilation, be it floors, walls or ceiling, and the extent to which either are done is a decision only the owner can make.

Wood heat drys me and the bus out when I'm working in it all day (not kidding I come in with chapped lips and can see it in my wood handles tools)). I can't imagine water vapor isn't being ventilated though the 1/4 opened windows fore and aft.

Bottom-line, if I were not going to insulate the entire bus, about the only purpose insulating the floor would serve would be to cut-down on road noise. Other than that, it will do little to cut heat gains & losses.

I agree, but not all "insulation" comes from pink foam under plywood.

I'm of the thought at the end of the day it's still a big, steel bodied truck that offers a lot of utility and value, hell that's why I bought it! And as such comes with certain trade-offs I would no sooner try to turn my SCHOOL BUS into a Holiday Rambler than I would try and turn a good pack mule into an English park horse.

Take care,
Den

Smitty

[RazorCityDen]

It must be a combination of wood heat and our environment because I don't seam to have all these moisture problems with my factory insulated/partially insulated floor Bluebird. It takes about 30 minutes to go from stone cold to t-shirt warm in it when it's zero outside if the wind isn't howling. A little longer when the winds whipping. Within an hour the ceiling and walls are warm to the touch and then I throw in a couple/three more 2X4 scraps and throttle the stove back and it keeps it toasty for several hours before I have to mess with it again.

Wood heat is the way to go IMO.

My windows have only fogged up once when I was running a forced air propane heater.

For kicks I have tried a couple "storm windows", Bluebird windows have a nice ledge inside the frame that allows a piece of plexi-glass to fit inside and be held in place with the metal snap closures I'm using for my screens. I'm not sure it would be necessary, but it wouldn't take hardly anytime to do and I have the plexi-glass.

I also plan on some type of low amp fans to help move air in and out of the bus, right now I use the low tech method of cracking a window fore and aft and it seems to work good enough. I work all day in the bus don't have any moisture problems and I don't suffocate, I call that a success

I'm not suggesting that no consideration be given ventilation or insulation issues I just think the concept gets over played, there's lots of simply converted buses out there that are serving there owners just fine with factory insulation. I think it's a little silly to imply all those projects and experiences aren't a success because they used the factory windows or didn't tear out all the factory insulation looking for that last theoretical 10% of efficiency.

One of the charms of a school bus conversion is value and simplicity, it doesn't have to be complicated or expensive to be effective IMO.

Take care,
Den

[bhaley51]

Originally Posted by turtle

Hey there! I'm new to bus conversion, and am looking to get my floor installed on my 1978 International Harvester Loadstar (about the size and shape of a short school bus). So far I have the basic metal floor of the bus and roughly 3/4" wood covering that. The wood that's there came with the bus and seems a little like plywood, it may be more dense, but pretty close. Some holes are drilled in the flooring here and there. I want to have a full time life on this thing and am in a commonly wet and cold place. I'm in Washington, but plan to travel in a couple of years. I'm interested in what to use to prevent mold, keep clean, and insulates. I've had suggestions about using more wood. There is a little leakage from the back exit door, so I need something to keep water from getting into the floor and not trap it. I'm interested in your suggestions!

Thanks!
Turtle

Remove the wood n treat the floor or you’ll be sorry. Lots of rust by doors n stairs. I was supper surprised too. Treat floor paint with por15 then paint. I’m inquiring as to best insulation to put down too

[weboughtabus]

Originally Posted by bhaley51

Remove the wood n treat the floor or you’ll be sorry. Lots of rust by doors n stairs. I was supper surprised too. Treat floor paint with por15 then paint. I’m inquiring as to best insulation to put down too

Easy mistake to make, but you just replied to a post from 2009 in a thread that hasn't seen any activity in over eight years