Thursday, January 19, 2006

Thatch and Grab

According to this story from the Cape Gazette, a master roof thatcher from England is hoping to use common reed (Phragmites australis) to thatch roofs here in the U.S. As his website indicates, Colin McGhee thatches roofs for both historical and aesthetic purposes, and even sells thatched sections for movie sets. McGhee wants to use phragmites reed for the thatched roofs of the houses at Historic Jamestown National Park in Virginia, but has had actually some difficulty locating a good source of the plant, since many towns already have programs in place to burn or spray herbicide on invasive stands.

If any master (or apprentice) thatchers out there know whether the tops of the reed inflorescences are used in the thatching process or are removed, please comment below. I am interested in finding out if the seeds might be spread through this pathway.


Tim Abbott said...

I've done a bit of research into this and my understanding is that Phragmites thatch needs to be harvested from stands that contain only new growth and no dead reeds.
Essentially, a wetland or moist field is managed for a phragmites crop. The tops are not used, but whether they are cut and disposed of on or off site is not clear to me. I've resourses I can consult though, and if I find more I'll repost.

Aside from the invasive species concerns, I'm a big fan of thatch as a modern roofing material. There is a great publication by a British group called Intermediate Technologies called Thatching, a Handbook that lays out the pros and cons of various thatching materials and techniques, including the use of common reed. I'm not sure if it is still in print but i bought my copy in southern Africa in 1997.

Tim Abbott said...

According to Thatching: A Handbook by Nicolas Hall(Intermediate technology Publications, 1991 reprinting); "Phragmites australis is the most commonly used grass for thatching material in Europe primarily because it is durable, but also because it grows in dense stands where other crops are not viable...(Harvesting) is done either annually or biennially during the winter months after the frosts have loosened leaf growth. Cutting is done by machine, and the stems are cleaned with a hand-held side rake before being bundled for the thatcher."

According to Hall, leaves are removed from the culm and thatch is bundled in lengths of between 1 and 2.5 meters in length. I strongly suspect inflorescences are removed, although in my experience there is just as much risk of phragmites spreading from culm fragments - and even more so from the rhizome- as they do from seed,which while copious are not outstandingly fertile.