vivienz

Green roof

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Does anyone have any experience of a green roof?  We're considering incorporating an element of this into the new build.  Still very much at the pondering stage and everything is dependent on cost (of course) but we'd like to do it if possible.

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I was mulling this over if I do a garden room. Sedum's the thing apparently.

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Green roofs can be good.

 

Green walls are anathema. And lots of maintenance.

 

They did a big green roof on the Timbrel Arch Grand Design in Kent, and showed some detail. The video will be around somewhere.

Quote
9 "The Eco Arch: Revisited" (Revisited from Series 9: Episode 4) Kent 9 November 2011
Kevin McCloud revisits an arch-shaped home made of clay tiles in the Weald of Kent, built by Richard Hawkes, who designed the property, and his wife Sophie. It was intended to be self-sufficient in energy and supply some to the national grid but serious problems occurred when the arch collapsed during construction, so the presenter returns to see if their innovative home has lived up to its promise.

 

Ferdinand

Edited by Ferdinand

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sedums and sempervirens are both good as they can cope with dryness.  A lot depends on whether you want a roof that stays green or one that changes with the seasons.  I think there are quite a few companies that provide advice.  But I havent done one myself.  I like the idea though.

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Posted (edited)

Just picking this thread up again after more than a year. Pondering a green roof for my coming build.

 

@vivienz did you get anywhere with your idea? 

 

Has anyone currently got a green roof? Anything good or bad to say about them? Cost? Maintenance? Do they play well with roof lights?

 

Complete beginner here.

Edited by Dreadnaught

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@dreadnaught

We didn't in the end. We were thinking about it over the single storey garage but as it's north facing and heavily shadowed by the 2 storey house, we didn't take the idea any further, I'm afraid.

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Our planning was for a green roof. We went back and got it changed.  I have never seen one that looks good long term and you do have to do maintenance and I certainly wasnt getting up on the roof to weed out the wind blown seeds etc.

 

My bro in law commercial roofer also does green roofs, he gave me a very realistic view of them which confirmed my feeling that they were more trouble than worth to me.

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The best one I've seen in real life is in Brittany and belongs to the office building of a garden landscape company!  The roof is a wave shape and covers quite an area, but one would imagine that it would be in good nick, given their line of business.  It's certainly been there for at least 8 years and still looks pretty good.

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in our submission I have a small green roof. (eco credentials)

It will be the last thing we do and it will the cheapest and most low maintenance I can find...as money runs out a Green roof does not get us in through the door.

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I have to for planning, and want to anyway.

They are not ‘fit and forget’ so if you’re not keen on gardening I’d suggest not burdening yourself.  That said, they aren’t necessarily too demanding on maintenance.....depending on what look you want.

Sedum  can look pretty dead in winter......people think it’ll give constant year round green appearance.

Wildflower won’t offer much in winter.

Meadowgrass is pretty good, but needs more growing medium depth....means more roof build up, more weight... 

We want a roughty toughty mess so wont worry about weeds, but if you wanted well manicured you’ll end up weeding just like a garden.

You’ll half run-off so reconsider any rainwater harvesting ideas.

Ballpark £7k for my 150sqm flat roof....but that’s the ‘green’ element, materials only....the roof also had to be engineered for the weight and the membrane had to be specific.  There’s an ‘approved’ approach to creating a green roof which you’ll need to follow if you want any waterproofing guarantees from your roofer....this makes it difficult to diy a cheap alternative.

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I'm doing a DIY one on a 15% pitched  50m2 roof. I've built an OSB floating roof on battens over the original one (which apparently needed ventilation above its roof membrane) and covered this with a massive EPDM membrane. Planning to use Cellweb type stuff to retain the growing medium, which will will  be pearlite or similar and compost. 

I've no intention of doing lots of maintainance so to going to seed it with sedums etc and let natural selection take over. Something will grow there and it'll probably be green some of the time! Some of the matt forming sea cliff campion type plants might be worth a try too.  And whatever blows in on the wind and likes it there.

The SE has okayed it in weight terms.

 

Main issue to overcome is designing a border at the lower end which retains the green stuff whilst allowing drainage through into the gutter below. And doesn't rot/rust. Some kind of ACO drain cover might work.

 

Any other ideas on what to use for this welcome?

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Landscape fabric over a solid retaining upstand. You'd only need drainage along the base so leave a gap?

 

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32 minutes ago, dnoble said:

I'm doing a DIY one on a 15% pitched  50m2 roof. I've built an OSB floating roof on battens over the original one (which apparently needed ventilation above its roof membrane) and covered this with a massive EPDM membrane. Planning to use Cellweb type stuff to retain the growing medium, which will will  be pearlite or similar and compost. 

I've no intention of doing lots of maintainance so to going to seed it with sedums etc and let natural selection take over. Something will grow there and it'll probably be green some of the time! Some of the matt forming sea cliff campion type plants might be worth a try too.  And whatever blows in on the wind and likes it there.

The SE has okayed it in weight terms.

 

Main issue to overcome is designing a border at the lower end which retains the green stuff whilst allowing drainage through into the gutter below. And doesn't rot/rust. Some kind of ACO drain cover might work.

 

Any other ideas on what to use for this welcome?

 

Most suggest using a coarse gravel or stone at the edges with fabric to stop the fines getting into the guttering. Will see if I can find a pic. 

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2 minutes ago, PeterW said:

 

Most suggest using a coarse gravel or stone at the edges with fabric to stop the fines getting into the guttering. Will see if I can find a pic. 

That's a thought. there would still need to be some kind of barrier to stop the coarse stone falling off into the gutter or to support the fabric though wouldn't there? Unless I'm misunderstanding,  pic might make it clearer.

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