Grass Roof

Bryankayak

Hi Everyone,

I'm considering using a grass roof for a hillside house in order to reduce the potential visual impact but I am finding it hard to find info and examples of this in Ireland.

has anyone done this? is there big cost considerations? Thanks for any advice given

BryanF

Yes, I'm a big fan,

Lots of examples on internet

Cost last time I looked was circa 100€/m2

Try google 'green roof ireland', Search by images

ht9zni1gs28crp

Go for it, they look fantastic and are the way forward.

Curious Geroge

Looks great but the sedum roof costs are in the region of €80/100per sqm plus the added cost of reinforcing the roof and having a suitable membrane laid which runs you well over 10k for a reasonable size roof.

ht9zni1gs28crp

How much for the Sedum roofs though?

Curious Geroge

Mike Tender Vane wrote: »

How much for the Sedum roofs though?

Its the in region of €80/100per sqm just for the sedum which comes in trays and are placed on your roof (which may be fibreglass or trocal or alike) but to carry the weight, the roof should be reinforced and its best to have an engineer calculate the weight bearing of wet soil, pitch etc.

Tifosi

Haven't seen many houses with Grass roofs, apart from the telly tubbies. Many a commercial building and my opinion they are not great.

As noted above the grass roof will impose additional structural load. While grand in the rainy season the few days of summer you may have to water the roof, seen many a sorched roof. You will require access for maintenance, more so that a traditional roof.

Some form of mesh for the birds is required, not too fine that they get stuck and you end up raking off dead birds.

Trust there are easier ways of masking the house for visual impact.

BryanF

Tifosi wrote: »

Haven't seen many houses with Grass roofs, apart from the telly tubbies. Many a commercial building and my opinion they are not great.

As noted above the grass roof will impose additional structural load. While grand in the rainy season the few days of summer you may have to water the roof, seen many a sorched roof. You will require access for maintenance, more so that a traditional roof.

Some form of mesh for the birds is required, not too fine that they get stuck and you end up raking off dead birds.

Trust there are easier ways of masking the house for visual impact.

What? how did we get from grass roofs to dead birds?

ht9zni1gs28crp

BryanF wrote: »

What? how did we get from grass roofs to dead birds?

Naysayers....anything different and the naysayers are out:D

Fairdues

I've often wondered about a grass roof as I've seen a number on the programme 'Grand designs' in the UK. Certainly would help on the visual impact on the landscape but often wonder about the maintenance, long term.

Bryankayak

All very interesting points, thanks for the feedback so far. I am still interested in the idea. With regards to watering it in the summer, that is not a problem. Happy to do it.

The common message I am getting is that "Weight of roof " is a concern. Surely the architect will consider this in the design.

ht9zni1gs28crp

Bryankayak wrote: »

All very interesting points, thanks for the feedback so far. I am still interested in the idea. With regards to watering it in the summer, that is not a problem. Happy to do it.

The common message I am getting is that "Weight of roof " is a concern. Surely the architect will consider this in the design.

Yes of course, used to structural engineer specifying hollowcore slabs at first floor. Similar process.

BryanF

Mike Tender Vane wrote: »

Yes of course, used to structural engineer specifying hollowcore slabs at first floor. Similar process.

Not necessarily concrete. This is an evenly spread 'dead load' - an Eng will calculate and determine what's required. Select soil thickness and factor for deep water retention tray.

OP
A Grass roof can protect roof membetane form sun damage.
Act in some part as a water retention system rescuing the impact on urban drainage systems

Etc etc

ht9zni1gs28crp

BryanF wrote: »

Not necessarily concrete. This is an evenly spread 'dead load' - an Eng will calculate and determine what's required. Select soil thickness and factor for deep water retention tray.

Bryan, I never said it was concrete so no need to jump on that point. I was responding to the OP's question of whether the Architect would be used to this sort of calculation. Hence my answer making it simple to show similarities that Architects wont find this uncommon and deal with it accordingly.

Bryankayak

Forgive my ignorance, but how much more should I budget for this, compare to a conventional roof for a new build?

tradesman

don't forget to factor in extra costs for the gardener wanting more for mowing the grass! Lol.

ht9zni1gs28crp

Im pretty sure there are options for certain plants and vegetation that require less maintenance than others.For example IIRC Wildflower gardens only have to me slashed twice a year and the batch removed.

Fairdues

Mike Tender Vane wrote: »

Im pretty sure there are options for certain plants and vegetation that require less maintenance than others.For example IIRC Wildflower gardens only have to me slashed twice a year and the batch removed.

I have no doubt you are right but I seriously wonder about the long term viability of a grass roof and the fear of it collapsing, over time, as it would become increasingly heavier?

Lumen

Use sedum not lawn grass.

It's not going to collapse if it's designed right.

Jamesgrace

A friend has one, the pond liner was the most expensive part but it wasn't mad money and there's no maintenance on it, he's away for long periods and it's doing fine.

looksee

Other than the cost of the sedum plants, how would the cost of a green roof compare with the cost of a standard struts and slates roof on a new build?

Poor Uncle Tom

looksee wrote: »

Other than the cost of the sedum plants, how would the cost of a green roof compare with the cost of a standard struts and slates roof on a new build?

Very approximately €52/m2 more than an EPDM roof over equivalent house area of 240m2.

looksee

So the green roof is cheaper than the strut roof?, getting it to the waterproof level.

I am not too worried about the planting as I can keep the cost of that down, and most of the pricings use preplanted sections in containers, which seems like an expensive (and plastic using) way of going about it. I am thinking in terms of sedums and sempervivums which need less soil than grass or meadow plants.

Effects

I looked at a green roof. Apart from the other half hating the look of it, it turned out more expensive compared to a paralon roof.
I've put a beehive up there recently so I'm covered from an environmental point of view!

looksee

Can I ask what aspect of it turned out to be expensive? What kind of green roof did you put in? Beehive is a great idea!