Damp-proofing Tiny House on trailer


Just wondering how people would suggest damp proofing the floor blocks? We are going to use it as a tiny house and set it on a trailer so there’ll be some airflow underneath but I would be worried that it may not be enough. Going to be using Proctor Wraptite on the external face.

Pretty much any DPC you can find at the builder’s merchant will do. Stick it to all surfaces on the trailer that will be in contact with the Wikihouse/timber sole plates (for simplicity I’d just fit it everywhere below the footprint of the building).

Given that it’s going on a trailer I expect it’ll be quite far off the ground; providing ample ventilation. 150 mm off the ground is the minimum. Anything above 300 mm is high and will result in more than enough ventilation. Make sure you have adequate drainage beneath too; channel water around the perimeter if it’s on a slope.

Wikihouse guidance recommends a 50mm sand blinding, a polyethylene membrane laid over for damp-proofing and then a 50mm stone blinding over that, below the footprint of a suspended floor. But for a Wikihouse on a trailer, sitting quite high above the ground, that’s probably overkill.