Fitting out your motorhome: All the trades
 #98746  by nannyngaio
 Thu Aug 27, 2015 10:19 am
Hi would love to hear from any body who has ideas on underfloor insulation on a horse truck ( we have turned into motor home)
 #98750  by Bearcraft
 Thu Aug 27, 2015 10:31 am
Buy some sheets of polstyrene and attach them under the floors. Make up some plywood washers and screw through the polystyrene into the floor.

 #98753  by nannyngaio
 Thu Aug 27, 2015 10:39 am
thanks Rob thats sim' ideas to what we have been thinking and if we covered the polystyrene with a cover of some kind of aluminum flooring insulation material ( for extra heat,fire risk etc)do you think it will sweat? Do you know if the polystyrene can be against the under floor or would we need a gap?
Last edited by Mark on Thu Aug 27, 2015 11:49 am, edited 1 time in total. Reason: Redundant quote of immediately prior post.
 #98757  by Bearcraft
 Thu Aug 27, 2015 12:31 pm
I did this to the bus I had and just screwed the polystyrene direct to the underside of the floor.

 #98758  by NeilV
 Thu Aug 27, 2015 12:57 pm
I did the 40mm poystyrene on top of my bus floor as the underside is kinda cluttered, but just layered another ply layer on top... works well for me.

Id say its cheap enough that if a couple bits broke off over time (more likely ground/sticks scraping than wind in my opinion) you'd easily/cheaply be able to replace them, and only a hard layer like ply would protect them from the bottom anyway?

Fire is only a hazard if you cover a heating element like the exhaust or bad wiring anyway, so silver foil wouldn't help there either?
 #98761  by Derb
 Thu Aug 27, 2015 2:35 pm
Only issue I can think of with poly is sponge effect causing rot/rust issues further down the track.
 #98781  by vansvilla
 Fri Aug 28, 2015 7:24 am
The guys who instal underfloor heating lay down a 5mm or less layer of polystyrene for insulation, then the heating element then grout the whole thing in place.

That thickness of polystyrene may well be enough on the floor. Would go on top of the flooring and under any coverings. At that thickness would provide warmth and a soft under foot feeling. Perhaps a layer of hardboard over that will prevent it crushing under foot.

The other thought is that cork tiles will provide a level of insulation as well, I can recall being pleasantly surprised at the difference when I laid them in a bathroom in a house many years ago.
 #98783  by Neddy
 Fri Aug 28, 2015 8:23 am
Whatever else you do, laying thick carpet inside will help a lot.
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