John Seaver wrote:greetings all!
i would like to retro fit my 1800's barn with a living roof.... is this possible, my concern is the weight of soil and plants. has anyone done this?
You need to give WAY more details. Rafter material, spacing, roof deck material, roof pitch, amount of rainfall, etc.
I have seen very few barns that could take that kind of load or had a roof pitch that really would work. Most are better served being guttered for rainwater harvesting.
Growing up, the neighbor built a rainwater catchment off his barn (UNHEARD of in that day) and then pumped it up to the roof and ran soaker hose over the peak. Running the water over the roof made the animals MUCH more comfortable during the summer.
"You must be the change you want to see in the world." "First they ignore you, then they laugh at you, then they fight you, then you win." --Mahatma Gandhi
"Preach the Gospel always, and if necessary, use words." --Francis of Assisi.
"Family farms work when the whole family works the farm." -- Adam Klaus
Tyler could well be right but many buildings, including barns, of that period (and earlier) here in the UK were originally designed to support a thatch roof which represents a fairly significant weight - admittedly, this might not be the case with your barn John. You might be able to get away with a very thin substrate on the roof but that would probably limit you to having sedums up there. Here's a list of weights for different depth substrates taken from 'the DIY Guide to Green & Living Roofs' by Dusty Gedge and John Little (highly recommended):
Loads of various green roof systems:
*Sedum blanket [20mm] 55 kg/m2
*Sedum blanket [40mm] 80-90 kg/m2
*Substrate based system [80mm] 120 kg/m2
*Substrate based system [100-120mm] 140-170 kg/m2
*These are ball park figures based on commercial systems
That'll be wet weight. Dusty Gedge has started recommending a substrate depth of 160mm where possible or, even better, a substrate of varying depths in order to create a more diverse range of habitats. You'd obviously have to determine what load your barn could take and work from there. Might need a structural engineer I guess. Plants are a bit easier, especially on a roof with a deeper substrate - the deeper the substrate the more stuff will survive up there.
"A society grows great when old men plant trees whose shade they know they shall never sit in."