Sedum Green Roofs - Vegetation Blankets - can a house extension incorporate such green features?

Yes but it is not yet commonplace nor is it easy no matter what the ‘strap lines’ say within the glossy architectural press. I have yet to see a house extension that has incorporated a sedum green roof using the pre-grown vegetation blankets (although I expect there are a few).

Although this roof design and market for green roofs is fairly high on the agenda for new commercial developments and even for a few select new homes, it is not widely recognised as being a design solution for residential or domestic house extensions.

This, I think, is mainly down to cost and the interconnection between the existing and new roofs. If a property was proposing a simple but fairly large flat roofed house extension then this may become an option but for most two storey house extensions that have an existing house roof pitch of over 20 degrees then the sedum green room using vegetation blankets is really a non-starter.

The house extension designer or architect could alter the roof of the extension to be more suitable for a green sedum roof but the final effect and its interrelationship with the existing property would probably appear very awkward, out of keeping and appear very incongruous.

However, it does appear that many Planning Departments are willing to accept these design irregularities as acceptable as incorporating green elements within a building design can override external appearance issues.

I am seeing this more often now especially for these so called ‘contemporary’ design of buildings where it seems that the only way of attempting to make a building more energy efficient and green is to make it look like a randomly stacked set of multi-coloured storage boxes from Ikea and thrown together by Tracy Emin. Seems like that only radical modern design can achieve an energy efficient or green building? - Hog wash!