Here’s a project that I recently completed. The brief was to build storage for bikes, logs, tools, a large car bicycle rack and 3 wheelie bins. The space available was over 8 metres long x 80cm. I suggested that the bins didn’t need a sedum roof, this was agreed so we tucked them out of the way next to the entry gate. This reduced the length of the shelter to just under 6 metres. Here’s how it went:
- How to manage the levels on a sloping uneven concrete surface. In the end I built identical size vertical frames and two roof frames all with 3” x 2” timber. I used screw plates to attach the vertical frames to the roof frames and joined up the roof frames with some hefty screws.
- I cut 80cm strips of 18mm 1220x 2440 exterior grade ply to form the roof. I screwed this onto the roof frames.
- On the standard 225mm decking, I first trimmed off lengths from one side about 25mm. I fixed the remaining plank to side of the roof timbers to form the edge of the tray to hold the epdm liner and the sedum.
- I attached the frame to the concrete fence posts. (My cordless drill driver was simply not up to it – I had to buy an SDS drill – and a cordless impact driver). I used strips of old tile lying around and gripfill adhesive to make up simple footings for the vertical frames. This got the levels right and helped drainage – ie the timber would not be sitting in water.
- I then used the rest of the ply to create the panels and to make up the shelves. I used 20mm quadrant beading to protect the edges of the ply from weather damage – and of course to make it look good. I also had leftover strips from the decking to face the front edges of the ply shelves.
- The EPDM rubber liner. It does seem to have a bit of a life of its own. They advise you lay it out to leave it to rest for 30 minutes before doing anything (‘a natural product’!). To glue it down I used an exterior grade contact adhesive, I would suggest less is more here. The trouble with contact adhesive is it is tricky to adjust once you have put it down.
- Once stuck down I then fixed the remaining 25mm strips of decking onto the top clamping the EPDM into place. I put mastic down first.
- The sedum roof. Never having done anything with sedum before, I ended up ordering it as a package from Green Roofs Direct in Larne – they seemed to know what they were talking about. In the event this was very straightforward – indeed very satisfying – a living green roof!
- I was not sure how this would work. The expert advice I received was contradictory: (a) not much will drain off the roof, or (b) you’ll get a lot of water draining off the roof. As it turned out the latter was true. Fortunately, I had thought about it and I drilled 3 x 50mm holes in the ply, before putting down the epdm. I then carefully cut two diagonal lines in the liner over each hole. I also glued a strip of rubber around the inside of the hole from underneath. We then fixed guttering draining the water into a waterbut. On the top I bought some aluminium mesh, folded it up so that it would lay over the drainage holes and hold back the substrate and the sedum. I covered that with pebbles.
- I then painted the whole lot using Cuprinol Garden Shades, Black Ash. I like it as an exterior paint.
Client very happy with the result.
52 –The space
53 – The timber frame.
54- Plywood in place also the decking tray
55- The laying of out the EPDM rubber liner. I went for the thicker 1.5mm
56- Laying of the protective membrane and the substrate.
57- Substrate levelled out, foreground drainage channel created with aluminium mesh and pebbles
58 The sedum rolls go down. – later than planned hence the lack of daylight!
59 The finished bike shelter. Woodwork finished off with at least two coats of Cuprinol Garden shades, black ash. Design includes two bays for bikes with security anchors; a log shelter; shelves for tools, cycle gear and a compartment with giant hooks for the bike rack.