Log store modular green roof using square guttering

What?: Converting the ugly roof of a log store into a green roof.

Where?: Terraced house

When?: 29/05/20

Design and implementation: The roof is approximately 2.2×1. 3m with a
gentle slope.

We were looking at a modular system for ease of implementation. However to ones we found online were heavy and expensive.

As we were going to use house leeks for vegetation, drainage was the main issue. These plants can literally live on a rock, but hate sitting in wet substrate.

We decided to use 100mm square guttering with drainage holes drilled as they are light, waterproof, rotproof, inexpensive and the 2m lengths required no cutting.

  1. Get guttering piece and fit 2 end caps.
  2. Drill about 20 off 5mm drain holes.
  3. Drill 1 4mm fixing hole in the middle for a mounting screw.
  4. Put in place and screw into middle centre to hold in place.
  5. Put a strip of geotextile in base.
  6. Place a layer of pea gravel on geotextile to hold in place and for drainage.
  7. Place a layer of 50/50 compost and perlite.
  8. Put the plants in.
  9. Top up and surround plants in pea gravel. This gives drainage, keeps the leaves off wet substrate and looks great.
  10. Repeat with another row of guttering until the rook is full.
  11. We then boxed in with 25mmx150mm tanalised timber to neaten the edges and form a nicer look, leaving a 2 inch gap at the down slope end for runoff.
green roof case study

As I tend to over engineer when I build, very little strengthening was needed. However, check the strength of the roof as even this light system will add 30-40 kg per square metre.

Benefits and constraints: Pros. Quick, modular, light, inexpensive.

Cons: Waiting for the plants to cover the gaps. But that is also part of the fun.

Further opportunities: As these are modular, the slope angle of the roof is irrelevant. Possibly doing the garage roof next using a support frame.

Costs: £150.

£100 for guttering, end caps and timber. £50 for perlite, compost, gravel and plants.

Who?: DIY