Subfloor idea

[spenceadventures]

Originally Posted by Ercflyer

Has anyone used or thought about using the Dricore R+ one step subfloor and insulation panels in their skoolie. Just saw them at Home Depot. Roughly $8 for a 2’x2’ panel but by the time you figure total cost on plywood, foam insulation and lumber for the underside of the plywood it is about the same cost.

I am using this exact product for my skoolie. Even talked with a company rep over the phone and asked lots of questions about install. Long story short, they recommended to NOT fasten DRICORE to skoolie floor via glue, as many do with bigger sheets. Will cause insulation and plywood to separate from stresses. They recommended to keep it a floating type subfloor and "friction fit" it around perimeter, with a little give for expansion/contraction of the plywood. It goes together like a charm. Only hiccup is finding good ones from the pile at my local HD. Most of it looks like someone bought it, used it for temp job and then returned it. LOTS of the T/G joints were shot.

Since my Skoolie is a short one, I have less floor to cover. I am liking it so far!

[zen builder]

Spence, So you are installing this over your metal flooring? Any moisture barrier ? This sounds like a good product. I grew up a little west of you ( Cumberland) in western NC now , nice to hear from " locals". Take care. jeff

[spenceadventures]

Originally Posted by zen builder

Spence, So you are installing this over your metal flooring? Any moisture barrier ? This sounds like a good product. I grew up a little west of you ( Cumberland) in western NC now , nice to hear from " locals". Take care. jeff

No moisture barrier inside. I plan on cleaning up underside and spray foaming beneath the bus, to help with insulation/noise factors. We only plan on using this as a weekend/longer trek vehicle, not a "live in it full time" vehicle. So freezing/sub-feezing temps will not be issue, most of the time.

Cheers!

[kidharris]

Originally Posted by musigenesis

Wood is about R-1 per inch, so even 3/4" doesn't add much. Rubber is similar and even thinner, typically. Carpet and foam padding are also thin and don't add a whole lot of insulating value.

Lets see...R2.5 (insulation) + R.5 (1/2" plywood- OSB) = R3. Nope, the manufacturer is not rounding up for marketing purposes, you are not doing your calculations correctly. You have to consider the whole system in your calcs.


How is rubber similar to wood? "Thin" What is thin? Is that a physics term?

There are a lot of sheep that would argue with you. Besides that, the major use of carpets and rugs has traditionally been to keep your feet from getting so cold. How can that be?

Other points about carpet and.or rugs. Some types of "fluffy" carpets/rugs provide a thicker dead air space (insulation) right up till you step on it, at which point it gets thinner and provides more headroom. Rugs have the advantage of being removable when not needed or doubled up when needed.

I have found that it is that first bit of insulation that matters the most. This was dramatically driven home to me around 50 years ago during my hitch hiking years. When you are cold enough, a 1/8 inch thick cardboard box can feel like a heated room. HVAC is about comfort, not refrigeration.

It is the hollow cells, aka dead air spaces that provide the insulation values in most insulation products. Lack of air (vacuum) and reflectivity are also important methods in preventing the transfer of heat. Installation methods can increase/decrease the effectiveness of insulation systems. Design matters too. IMHO, insulation in and of itself is over rated as a design consideration, but it is easy to design and makes a lot of $$ for manufactures. It is a fairly recent trend in construction along with high energy using automated HVAC systems. You don't even have to get dressed in the winter as long as you stay indoors, you can be as lazy as you want. Maybe put some socks/shoes on for that little bit of floor. Or a rug?

In a typical RV/skoolie the whole floor and walls don't contribute equally to the thermal transfer. Most of the floor (2/3 - 3/4?) is covered by permanent cabinets, appliances, beds & other furniture which should be installed so as to provide much more insulating properties than the floor, same is true for the walls. If you are parked, putting temp or permanent siding around the underneath to cut off the wind (air movement) would help immensely .... starting to ramble, gonna stop now.

[zen builder]

Spence, Thanks for the update. jeff

[kidharris]

Originally Posted by zen builder

Spence, So you are installing this over your metal flooring? Any moisture barrier ? This sounds like a good product. I grew up a little west of you ( Cumberland) in western NC now , nice to hear from " locals". Take care. jeff

I just took a second look at the pics and reread his post. The rectangular channels in the foam are probably meant to channel any vapor to the outside edges to escape the system. Any adhesive that could block these channels would block the escape of the vapor. I first saw this type of vapor handling system maybe 25-30 years ago in substrate products for re-roofing commercial flat roof systems to avoid tearing off the old roof. Just put down the vapor channeling substrate and some vents every so often (commercial roofs can be very big) to allow moisture trapped in the old roof to escape. A lot of people didn't understand the way the system was supposed to work and improper installation was common (adhesive aka hot asphalt) blocked the channels and trapping the vapor. I wouldn't be surprised if this is the real reason for making it a floating system. If de-lamination occurred it would still be a floating system (maybe float too much).

[kidharris]

Originally Posted by musigenesis

A reflective layer is only useful against radiative heat transfer, and the problem is that at 70°F, effectively no heat transfer occurs via radiation - it's almost all due to conduction and convection, which reflective foil is useless against.

I don't understand.


First. Would/could you point me to a resource to help me understand what you said/meant?. "at 70°F, effectively no heat transfer occurs via radiation"


Second. Why would we be concerned with heat transfer at 70 degrees F for HVAC purposes?


Third. How do you get that degree symbol ("°") to print. (I just copied-pasted)


Fourth. When did you get so interested in insulation or heat transfer? before or during your build?


Thanks.

[HamSkoolie]

Originally Posted by MNbusboy

It says it has an R value of 3, in a 1 inch product. Is there a better option for higher R value in a small measurement, for those of us trying to save headroom?

https://www.homedepot.com/p/DRICORE-...0003/205505261

Owens Corning (Pink Panther) Fomular 150 is R5 for a 1" thickness, comes in 4x8 sheets for $20. It has a compress-ability rating of 15# per square foot so you don't need to put any framing under it if you top it with 1/2" plywood to spread out the load. Just glue it down to the metal floor then glue the plywood down to the fomular and secure at the edges with something snug against the side wall.


1" of Fomular + 1/2" ply + 1/4" for finish floor will cost 1 3/4" of headroom while giving you a complete thermal break on the floor and probably a total of R6 of so with the plywood and finish flooring. (1/2" ply is appx R0.63).

[HamSkoolie]

Originally Posted by musigenesis

...This is why roof raises are so common in the skoolie world (I feel very fortunate that I've managed to get away without doing it, but I was prepared to do it if it had proven necessary).

We were also planning a roof raise as I'm 6'1" and didn't want to be stooped all the time. One of the reasons we bought the bus we did is that it's an AmTran and had 6'5" clearance before we pulled to original floor (about an inch thick). Not needing a roof raise, new tires, alloy wheels, and auto snow chains were enough to accept a DT444E engine (the same basic engine as in my F350) over a wet sleeve design.

[HamSkoolie]

Originally Posted by BeNimble

Do you have any links for this data? Because polyiso is used in freezers and fridges. Also, for the most part, its going to be 75F if you are heating or cooling living space. I don't know anyone who sets their thermostat to 15F

As was already said, there will be a gradient through the insulation. However, it's not about what temp is set on the inside. Insulation R values are about slowing the thermal exchange fro one side to another. If the 15 degree temp outside reduces the effectiveness (the R value) of a particular material, then transfer is going to be higher and thus you will lose more to the outside. That doesn't mean you'll be cold inside, just that you'll be expending more energy to replace the additional lost heat over a higher R rated material.


You can spend your time, money, and effort on effective insulation ONCE, NOW......or yo can spend your time, money, and effort on providing additional energy for heating for the life of the bus (or home).



The same with high temps..... keeping the heat out reduces the energy needed to cool the interior of your bus. Higher R values slow the transfer of outside heat to the interior.


Like the old commercial said....you can pay me now or you can pay me later.

[kidharris]

Originally Posted by HamSkoolie

Owens Corning (Pink Panther) Fomular 150 is R5 for a 1" thickness, comes in 4x8 sheets for $20. It has a compress-ability rating of 15# per square foot so you don't need to put any framing under it if you top it with 1/2" plywood to spread out the load. Just glue it down to the metal floor then glue the plywood down to the fomular and secure at the edges with something snug against the side wall.


1" of Fomular + 1/2" ply + 1/4" for finish floor will cost 1 3/4" of headroom while giving you a complete thermal break on the floor and probably a total of R6 of so with the plywood and finish flooring. (1/2" ply is appx R0.63).

Since you are gluing everything and there are no spans and the foam does have some compressive strength I would think that you could even use thinner plywood as long as you do not need to fasten to it. Thinner plywood has next to no strength against fastener pullout aka fastener holding ability, but it would still spread the load to prevent impressing the foam.

[HamSkoolie]

Originally Posted by kidharris

Since you are gluing everything and there are no spans and the foam does have some compressive strength I would think that you could even use thinner plywood as long as you do not need to fasten to it. Thinner plywood has next to no strength against fastener pullout aka fastener holding ability, but it would still spread the load to prevent impressing the foam.

Thinner ply would spread the load but less so than thicker. We originally planned a 2/2 framework (1.5" actual) with 1.5" fomular between the frames and 3/4 ply on that (to avoid bounciness between frames). After more research (thanks BEAP) we dropped the 2x2 frame and reduced the plywood to 1/2" as there would be no "between frame" areas and the floor should feel sufficiently solid while giving sufficient attachment strength to other elements of the build.