A mate is renovating/extending al old house and wants to put in a solid stove with boiler. The location he is considering is near the back of the house and it will be low down on the roof ( below 1/3 of the distance between the ridge and the gutter) I was wondering what kind of vent is needed ie can it vent out through a Proprietary vent or would it need to go into chimney. Is there a minimum height the vent has to be above the roof?