Flooring
I think the final layers will look like:
Insulations we considered include:
- roxul (brand name for rockboard, mineral wool, whatever)
- rigid foams (all need to be rated to 25-psi). Some people call for as much as 50–75 psi for trafficked areas (some construction code), but I saw a data point that I trust that suggests that 25-psi is sufficient.
— polyiso (the stuff that is tan and typically foil-faced)
— EPS (class IX — 25 psi) (glorified white styrofoam)
— XPS (that dense stiff foam that is typically pink or blue)
- cross-linked polyethylene (xlpe… glorified yoga mat, camping pad, )
- cork
Reasons some options got nixed:
- Roxul… too much of an unknown for moisture performance, unclear if it’s available in the right 10% compressive strength. I actually think it could have worked, but just saw it as a bit riskier w/o a ton of reward.
- Polyiso… r-value degrades over time and degrades at low temperatures. Foil-faced versions are not permeable.
- XPS… r-value degrades heavily over time and does not do nearly as well as EPS in a 15-year below-grade study.
- Cross-linked polyethylene… vapor permeability = 0 perms. I’m not looking to trap moisture in between the van skin and the insulation indefinitely.
- Cork… rather expensive and worried about moisture performance. I take it very serious and will consider it if EPS doesn’t work out for some reason.
Winner:
EPS… r-value does not degrade with time, extremely light and cheap, no HFCs like XPS, excellent vapor permeability, excellent moisture performance over time… see this study.
Caveats:
EPS needs to be class IX with a density of 2 pounds per cubic foot in order for it to have a high enough compressive strength of 25-psi or greater. An added benefit of the more dense stuff is it goes from about R-4 to R-5 per inch.
We were able to source
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It seems the forums are oddly missing really solid information on flooring… it just seems like people assume “things will work out” regardless of what path they choose.
Two links from Gary / Builditsolar.com are the best I’ve found thus far.
I’m pretty warm to his approach, but I’m mostly debating between what kidn of underlayment / insulation to use:
Polysio like Gary
Closed-cell foam made specifically for going under flooring… more dense / heavy?
Some form of cork?
What are the underlayment options?
What are the finish options?
Need to run the:
Wires
Pipes
L-tracks
(Potential) Punctures through it. Tank fill, city water, and shore plug might go on the side of the van… stealth / clean look vs. getting messy / rusted out down there?
Heater fuel, intake, exhaust
Water tank inlet
City water inlet
Shower drain
Sink drain
Electrical shore plug
Flooring
What are the underlayment options?
What are the finish options?
Need to run the:
- Wires
- Pipes
- L-tracks
(Potential) Punctures through it. Tank fill, city water, and shore plug might go on the side of the van… stealth / clean look vs. getting messy / rusted out down there?
- Heater fuel, intake, exhaust
- Water tank inlet
- City water inlet
- Shower drain
- Sink drain
- Electrical shore plug
