In my case, I have even less of a choice. Drilling a well would cost double what my house budget is, so I really need to collect every drop of rain I can.
I do hope to put green roofs on some of my outbuildings, someday.
H Ludi Tyler wrote:
Old roofs might have leaked quite a bit and the building remain "sound" especially if it is mostly built of stone. We have different standards of indoor comfort than folks had in the past. In ye olden days, being indoors meant you were mostly dry and the wind wasn't blowing.
Well, that's true although if a roof is leaking in a climate which has severe winters, even stone buildings will soon show signs of stress if the roof leaks. And most of us today would indeed be unhappy with the occassional dust shower from the ceiling landing in our dinner.
My thought was that there might be some techniques there which could still be helpful, esp if incorporated into the roof with some materials which weren't available in ye olde dayes
They used Birch Bark !!
Makes sense doesnt it?
Birch Bark is amazing stuff.
It was used to make canoes.
As for living roofs, if the old timers has EPDM they would have used it. Its really the best way to waterproof a living roof. They are very expensive, require maintenance and have are very difficult to implement. They tend to be a better choice for areas that are not directly above living space.
It would be sturdy and spread the load well.
Rot-proof with good waterproofing ability.
Jen, in that diagram a liquid asphalt acts as the waterproofing layer. Definitely something better suited for commercial applications. I would never go without a solid liner personally.
I think the .60 thickness is the preferred product for EPDM roofs. Its really not that expensive compared to anything else. PVC is the other option but I dont like what Ive heard about it. The real expense and risk is in the waterproofing details at intersections. All these products are best suited to nearly flat roofs, a rare thing in residential.
The expense of extra structure needed to support living roofs is pretty small in comparison to the other details but it is a concern especially when that extra structural support is interrupting the insulation details.
A friend iwants to build and underground house
but the roof construction is proving to be prohibitively expensive.
He's looking at Ferrocement too , with fiber added to the cement.
I guess your friend has the same concerns as me in that situation of using Polyethelene sheething. It would be very cheap but just not durable enough in my opinion. EPDM in one uninterrupted piece would have to be the waterproof layer to me. Not too pricey but its the structural support of all that heavy soil thats the problem. I have always thought the best way would be commercial grade steel bar trusses which would indeed get expensive.
Pam Hatfield wrote:Does anyone know how they USED to build green roofs? People keep sending me photos of old huts in Iceland and other places, some now heritage sites and there they are standing cheek by jowl with shingled buildings and everything's still looking sound. For sure THEY were built before EDPM pond liner or any other sorts of plastic. I have some pretty good idea but would love to hear from someone who knows for sure how it was done.
I just registered to answer your question I've written a bachelor report on green roofs as it's an interest of mine as I come from a country which has a lot of turf roofs and because I grew up in a house with a traditional turf roof. Here is an example how modern traditional turf roofs are made in Faroe Islands, as well as some comparisons at the end with how it was done before the advent of plastic http://www.kontrast.fo/tidindi/pdf/18.pdf
Today birch bark is only added at the footing of the roof if it's an old building, to preserve the old look. But most modern houses don't have birch bark at all due to cost. But it's said that each layer of birch bark has a lifetime of approximately 10 years, which is only added for each layer... e.g. 5 layers of birch bark and you can expect 50 years of light repairs and maintenance.
NB! The cost of birch bark paved the way for the dimpled plastic method with a fishing/trawler net underneath the turf and sometimes on top of the turf to ensure it stays put (it's very windy in the Faroe Islands)
And the climate has to be able to support the rather water-demanding turf roof, otherwise it's going to be a costly affair to water. For that case a modern green roof with carefully chosen sedum plants would be more suitable for locations where there are more dry periods.