green roof

[KLD]

Just starting to think about renewing the roof over the back of the garage. Currently there is a small unused balcony there, but it's started to leak. One idea was to take it all off, and put a green roof on instead.
Can anybody recommend any references to bring me up top speed (typical loads, materials used as in liners, drainage fleezes etc, minimum slope (is 10degrees steep enough?), plants for a relatively shady spot).
The roof will be about 3.6m x 3.6m. A purlin half way would be easy to include.

Klaus

[billi]

Hi Klaus

I used firestone pondliner for our log-cabin , but the last green roof i did ( flatroof ) garage 10x6 metre,  i ordered "Green Roof Elastoseal EPDM " from a company in the UK  called flexibleliningproducts and its a good product

There are attractive  "sedum plants" available that need not more than 50 mm of soil /substrate (also half shade )

There are onlineshops that sell those as very small plants  vor ca 30 cents each , (you should plant about 10 per m2 )

Perhaps email them if they ship to the UK

I donot think you need google translate  or  

http://www.dachstauden.com/Stauden-Sortimente/Dachbegruenungspaket-Halbschatten-I-fuer-4-m%B2::938.html

Billi

Ah nearly forgot  i have groundcover strawberries on my roof as well (nice flower , green foliage , and tough, a few fruits as well  )  i can sent you some bare root plants when you are ready

[AlanM]

Hi Klaus,
On the turf roofs that i build/lay(?), i use Oldroyd Xv membrane. This has dimples like an egg box, although much smaller, which creates a 5mm air gap below the membrane to allow any condensation to escape. The turf, about 6" or sedum 2", goes straight on to this with no need for any different layers of fleece or rubber or drainage etc. I can pm you the supplier if you wish

Alan

[KLD]

Billi and Alan

Thank you very much for your advice! I've had a look at both membranes. Alan, can you remember what the square meter costs were for the Oldroyd eggboxes? Should I put another membrane underneath, maybe just a DPM type like you put under a concrete slab?

One construction detail that I haven't understood at all is the up-stand (or whatever it's called) along the lowest edge. Somehow the surplus rainwater has to get out, while the strawberry plants and soil want to stay put. How do you fix a board along that edge without having to penetrate the membrane? I found a few sites recommending a minimum fall of 1:50?

Klaus

[AlanM]

Hi Klaus,
apologies for not replying sooner, The oldroyd cost was about £100/ 2mx20m roll, so about £2.50/m2. That was over ayear ago and i had bought quite a bit (12 rolls), so it may well be a bit more than that now if you only need a small amount. (Depending where you are i still have several rolls) In addition you need green roof plugs which are a rubber grommet which fits into the dimple and has a nail hole for securing. You need about 200/ roll at about 100mm spacing along top edge. They are about £5/200. Along the bottom and the edges there are upstands. At the sides they are just a timber (6x2) fixed to the sarking/deck and the oldroyd runs up this. At the bottom you fix turf beam brackets, which are a metal bracket which has a small leg  to which you fix a timber beam, (i use larch as it is durable). The oldroyd runs underneath this beam and there is a gap about 20mm or so to allow any water to drain out. In addition i lay stones about 150mm/200mm deep behind the timber beam so that it is free draining, and will improve its longevity. Oh and forgot, yes i put another layer underneath. I used to use 22f underslating felt, but now tend to use wunderlay or something like that as it is much easier and quicker to work with. I can send you a pic of the turf beam if you wish, dont have one at the moment or i would attach.
Not sure about minimum fall, but as long as water can escape from lowest point it should be ok. You could always put a wee bit of perforated pipe in to assist drainage, running from front to back if you think it would be too saturated on its own

Alan

[KLD]

Alan, that's just what I needed, thanks very much. On the Oldroyd web page I found these, I guess that's what you refered to?

Klaus

PS. Just saw in your profile that you're up in the Highlands. Bit far away, sadly, as I'm in Oxfordshire. Thanks for the offer!

[AlanM]

Klaus,
yes that is the bracket I was talking about, They are about £5 each i think, and i usually space them on every second rafter, so maybe 800 to 1200 spacing with a 40x125mm turf beam.
Oh well, oxfordshire is a bit out of my way, but the navitron van is up here once a month or so...........
Can look out my contact for oldroyd if you wish
Alan