When Valerie Cappell and her family decided to build their dream home, they determined “to do the right thing” by making it as ecologically-friendly as possible.

But the “Grand Designs-esq” adventure turned into a nightmare when she discovered the highly sustainable wool she had chosen to insulate the four-bed property was hosting a moth infestation of “biblical proportions”.

Despite being reassured that treating the organic substance with pyrethrin would be sufficient to ward off insect invaders, she had to rip apart swathes of the wave-shaped house.