Teardrops n Tiny Travel Trailers

What are some options for roof insulation? I see sliced foam being used, seems like a pain. Anyone used fiberglass? Foil/bubble? Other ideas?
Would need to be 1.5" thick and light weight.

Hard to beat EPS for insulation 3.85 R per inch. We have 1.5 inch roof and sides.

I used 1.5" foam board in the roof of my current build with no problem. I used a box cutter with a couple of passes on each side of the cut line and it broke clean. I've seen people cut it with a power saw but that really makes a mess.

Use rigid foam board to insulate your teardrop. Three kinds are readily available.

1) Expanded Polystyrene (EPS) is the least expensive with R values of 3.6 to 4.0 per inch of thickness.
2) Extruded Polystyrene (XPS) has R values of 4.5 to 5.0 per inch of thickness.
3) Polyisocyanurate (polyiso) is the most expensive with R values of 7.0 to 8.0 per inch of thickness (which may degrade to R 6 to 6.5 with aging). It is often foil faced.

links:
https://www.homeconstructionimprovement ... on-values/
https://www.finehomebuilding.com/2009/0 ... d-i-choose

I'm using 1.5" of polyiso for the roof and 1" of polyiso for the cabin walls.

If you have one, a track saw with dust collection makes for an easy no-mess way to cut insulation board.


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I see sliced foam being used...

I use my table saw with a dust system and it's clean and fairly quick. I ballpark where the kerfs are.



The advantage of hard foam is that it adds superb strength to a roof that is sandwiched in two layers of 1/8" Baltic birch. Stiff and strong.



Tony

A tape measure, a utility knife and a 48" drywall square are handy tools for measuring and cutting rigid foam board to size. A table saw is useful for repeated cuts and kerfing. I often cut the foam board to snugly fit into openings. Then use a drywall spatula or drywall knife to help fit/persuade the cut-to-size piece of foam board into place between the roof spars, wall or floor framework, etc. To create a rigid strong and lightweight torsion box effect the foam boards are glued to the inner and outer plywood skins with construction adhesive.

When I cut the voids in the walls and bulkheads I didn't bother to necessarily make the cuts all that straight--just what I could do quickly with the jig saw. I rough cut the foam with a utility knife snapping it clean, then put the piece behind the wood and traced the void with a Sharpie. Found I had no trouble following the outside of the Sharpie line with my band saw. Gaps between the wood and foam were usually less than 1/16" or so. (Only reason for the rough cutting was for the pieces that didn't clear the 12" clearance of the band saw.)

The foam dust was pulled down into the saw just like saw dust, but the foam dust charged electrically and stuck nicely to the painted metal sides of the saw until I vacuumed it off. Not much in the air, and little on the floor even. This is in New Mexico with single digit humidity. Your atmospheric conditions may vary!

Tom

The fiberglass will sag over time I've try a little foam . Make sure you stop any air getting around it

I found that a half-moon blade on an oscillating multi-tool made quick work of cutting the rigid foam insulation. Used a drywall t-square and Sharpie to draw the line and was able to stay very true to the line even moving fairly quickly. The thinness of the blade helped cut down on the amount of dust as well.