I spent a few days building a new roof in South London. We used gabion cages filled with a mixture of large stones and logs to create habitat.
I also used a time lapse camera for the first time to try and capture building the roof. I have divided it into 3 sections, first the set up, including adding some insulation. We used gabion cages from Devoran metals for the edges https://devoran-metals.co.uk/
Edges and protective fleece in place
After this we added a drainage layer of aerated clay pebbles, these also add to the insulation and help to reduce overheating.
Drainage layer is added
I struggled a bit with the speeds and lapse times for the videos but slowly getting better. The next step for the roof was to top up the gabion cages and add the soil, we were using Shire substrates who supply an excellent green roof mix.
Soil goes on
Finally planting and seeding. I worked with Rotherview nurseries to get an excellent selection of plants that are growing well at this time of year, including several sedums, campanula and Armeria. We also added lots of wildflower seeds that will start to show their heads in spring or before.
Planting
Overall, we were pretty pleased with the roof as was the client. Looking forward to seeing it develop over the next few years.
I put together another roof in Dulwich recently and thought I would share a few pictures and details.
This one started out with a visit to the clients to have a look at the roof. They had initially asked about a sedum roof and possibly even a cartridge system so I hadn’t been that keen. However when we met they were open to a more interesting type of green roof with a wider range of plants and a roof that develops over time.
We also looked at the skylights in the roof and decided that it would be better to build the roof with something more adaptable than the tray system. We settled on an expanded clay pebble drainage layer that flowed around the obstacles with some gravel borders and the usual Shire Green Roof Substrate for the plants.
I got an excellent selection of plants from Rotherview Nursery near the south coast.
They have a wide range of green roof plants and have been really quick to deliver, the plants including sedum reflexum gold, campanula pusilla, Erigeron, saxifraga scenic red, sedum schoebusser blut, sempervivums, thymus minimus, stops pony tails, armeria splendens, chaenorrhinum, erosion flore pleno, frankaenia thymifolia, and sedum pachyclados. I also added in a selection of alium and armeria bulbs, the client will be putting in crocus bulbs come the autumn. Finally we topped it off with a selection of wild flower seeds including Field Poppy, Red Campion, Black Meddick, Common Knapweed, Ox-eye daisy, Ribwort Plantain, Yarrow, Lady’s Bedstraw, Bulbous Buttercup, Cowslip, Salad Burnet Grasses: Browntop Bent, Strong Creeping Red Fescue, Crested Dogstail, Meadow Fescue, Sheeps Fescue. Hopefully most if not all of them will find a space that suits them on the roof. I expect all the plants to develop and grow over the next few years finding their place on the roof. Not all of them will find that and not all of them will thrive every year but we should get a great selection finding their place.
Finally I made a bench from the pallets left behind by the delivery of the substrates and soils.
After we built the roof I was left with a couple of pallets and some wood I used to create straight lines on the gravel. After a bit of online research I found a design for this bench and we need some garden furniture so I spent last weekend putting this together. A bit cold to sit outside at the moment but I think it will come in useful later in the year.
For more details and to get a quote for your roof send me a message.
This green roof on an extension in Welwyn Garden City is nearly 10 years old and has been thriving. This was the first green roof I made so I was a little cautious about the loading, the middle are is sedum on a foam drainage mat with very little soil. The edges have more soil and substrate so they are able to support wildflowers, grasses and self seeded local plants. Nowadays I would add a lot more substrate but it is still going strong and the recent rain and sunshine combination has got it growing beautifully.
The sedums are quite persistent and even managed to self seed and create a little patch of growth on the gravel driveway which looks great and offsets the potted plants.
This one was retrofitted which encourages caution, you don’t want the roof to fall down but you can find a combination of plants and sedums that will work on almost any flat or gently sloping roof. Even better if you are building a new extension you can specify the roof to take any depth of soil you want for a really fabulous roof with the plants of your dreams. Drop me a line if you want to know more alex@ecoalex.com
This was a really cool extension using reclaimed materials in Hackney. The green roof was a bit tricky to photograph but you can see the effect of the plants blowing in the wind above the skylight.
This was a tiny green roof built as part of a refurb a friend was doing in Stoke Newington. Some nice plants from New Covent Garden and great to have some builders on site to carry all the soil upstairs.
This is a project I completed back in October, secure cycle storage and a green roof. The client wanted secure storage in the front garden without having a big ugly box taking up all the space for planting and we came up with this elegant solution.
Still flowering in March
As the shed is on the way into the house we planted a number of different herbs which can be easily picked when you are on the way home and also release a scent if you brush past. These were combined with some flowering plants (it was October so not much available) and sedums. The whole roof was also sown with wildflower seeds so should be quite productive in the spring. There are saffron crocus bulbs underneath which may start to appear in late summer.
This type of roof can be more easily accessed by the householder so we can try and create a slightly more formal garden than I would on a normal green roof as you can change the plants around and water and feed them if it is necessary.
The green roof itself has a fleece at the bottom then a drainage layer of aerated clay pebbles before the soil, here to about 125mm depth but the sheds are pretty tough so this could be bigger if required. The sleepers look really good but an alternative would be cobbles in gabion cages depending on what would fit with your front garden. Order page.
Dry air in the house is a good achievement but I have also been worrying about the pollution levels. Two of the three air intakes are located above the back garden and the front one has some good tree coverage between it and the road but it is still a busy traffic area. This made me look at some alternative ways of cleaning the air, I did some googling and came across the NASA research project on houseplants and their impact on air quality. Now before I go any further I do realise that these were controlled tests and we would also need a very large number of plants to get a big impact but I figure it can’t hurt and what I made looks great.
I have been keen to do something with reclaimed wood and also to add some extra insulation to the flank wall in the kids bedroom so I got a bit carried away here and produced this wall made from old pallets with 50mm of woodfibre insulation behind it. I was a bit nervous about this project as it has a bit more of a design impact than some of the other projects, it’s been in a while now though and I am so pleased with the outcome visually.
Insulating the wall and adding pallets
The first thing we did was tour the streets collecting abandoned pallets. I found that ones that were slightly broken already were better as they are easier to dismantle than really well built ones. The kids really enjoyed the collection process and I also got them to stain some of the planks we extracted to add some variety to the wall.
Next step was to get hold of some wood fibre insulation, not so easy for small quantities but thanks to https://phstore.co.uk/ for arranging it for me, delivery costs almost the same as the insulation in small quantities but cheaper than elsewhere and charming service too. I then fixed some 50mm battens to the wall at 600mm and push fitted the insulation between.
The next bit involved a nail gun so was great fun managed to charm the lady at Travis Perkins into giving me a discount and I was off. I fixed them in an offset pattern and tried to group similar widths of board together so it wasn’t too bumpy.
Then we had to make shelves for the plants to grow on. I used the ‘dice’ from the pallets (technical term for the square bits that go in between the pallets) screwed into the wall to support shelves made from more pallet boards. These dice are pretty tough and tricky to drill through, one of them still has half a drill bit in it where it snapped.
Once it was all up we put in the plants, I used Chinese evergreen, peace lily, some snake plants and a cutting from an old spider plant. I also put in a watering system! Well, I bought some globes that you fill up and they drip out over a couple of weeks, they are a bit inconsistent but a lot cheaper than some automated system. I top them up with waste water from kids water bottles and they are still growing nearly a year later.
It’s taken a little while to share this new green roof I built in Herne Hill recently.
There were a number of challenges here particularly the height of the roof with no edge protection, we used a harness to install the edges.
The edges were built using gabion cages filled with cobbles. This created a more natural edge and ensured the stones didn’t roll off the edge of the roof and shatter the tiles below, I think they look pretty cool.
I used aerated clay pebbles for the drainage layer again, really like these rather than the plastic sheets and carrying a bag makes you feel really strong as they are so lightweight. We then put in a protective membrane and covered with ultra lightweight green roof substrate from Shire Substrates.
The roof has been seeded with a mixture of wildflowers and grasses with more to be added in the spring. In the meantime I put in some grasses, sedums and also Cyclamen. I wasn’t really sure about the cyclamen but not much else is flowering this time of year a month later and they seem to have settled in well.
I will add further updates in the spring. There are lots of bulbs in there which should appear soon.
Not all my green roofs are in London, you can see one of my early ones in Welwyn Garden City and this magnificent roof on a garage in Spring Gardens in Marlow
Lots of wildflowers growing here
The roof was installed early this year using Shire substrates and materials from Optigreen. I used expanded clay for the drainage layer and large cobbles to create a more natural looking border.
Wildflowers and sedum
The roof had loads of really nice seeds in it and was also planted with some sedums, aliums and stipa grasses and it has really blossomed tremendously.
This is one I did last year that has been growing really well. The roof was on a new extension so the clients were able to design in extra big joists so we could support a good depth of soil on the green roof.
They managed to get a 5m extension so we had a good size to work with even with the skylights. It was waterproofed by the contractor ready for installation.
Roof cleaned and prepared for installation
The team and myself laid out a protection fleece made from recycled material on the roof, then we added a drainage layer and put a filter fleece on the top to stop roots growing into it. Then we added the substrate, a special mixture of soil, lightweight aggregates, brick chippings etc, this is designed to keep the weight down, drain easily and also stop the plants growing too tall and need maintenance.
The team lay out the substrate
We put a gravel barrier round the edge of the roof and the skylights to assist drainage and add a firebreak. We also put extra gravel under the downpipe from the main roof of the house so the roof can absorb all the water from the roof rather than have it fill up the drains.
Moving materials is always a problem in London and we had to carry all the green roof substrate through the house and up on to the roof. Luckily Ecoalex has some good strong assistants so I didn’t have to do too much lifting. Once we had put out all the green roof substrate at varying depths we were ready to plant.
Roof ready to be planted
For this roof I had a mixture of mature plants and seeds. I included some Stipa tenuissima (the grassy stuff in the foreground) for the first time to see how it would grow and although it browns a bit in the dry periods it seems to be thriving. We also put in a few varieties of sedum to get some ground coverage including house leeks. Other plants included sea burnet and Sempervivum. I picked up all these plants at New Covent Garden Flower market in the morning a great place to pick up plants in London. But these are just to start the roof, the main coverage will develop over the next three years with all the green roof seeds we have planted I used a couple of mixes of native wildflowers including this one from Scotland that has 20 wildflowers and 3 grass species in the mix . Not all these will thrive initially but over time they should each find their own niche on the roof and grow nicely. Gary Grant likes to describe these seed mixes as an orchestra with all the instruments waiting for the conductor to call them in at the appropriate time in the green roof’s own symphony. Below are some pictures of the roof planted and how it has developed this year. More will be added over time.
Sun just appearing
We planted the roof in the heatwave last year so it had to be watered regularly to establish itself
