The straw does eventually rot but it takes a long time. Because of the steep angle the water runs off. As for insects, the straw contains no food so there is no reason for them to be attracted to the roof. Same for microbes, I'm guessing here, they probably live off the bird droppings like any other roof. Moss can grow on old thatch like it can on any surface but it is slow growing so doesn't really cause a problem. The thatch is replaced or covered with new straw every 25 years or so (another disadvantage of a thatched roof as it is not cheap).
Regular maintenance is required. The ridge is most vulnerable to weather and bird damage and may need replacing every 10-15 years. it is recommended that the roof is inspected after every winter. Small areas of damage can be patched without having to repair the whole roof though. It is important that the roof can dry out after it gets wet so overhanging trees must be removed and moss and lichens which hold moisture must be kept under control. The straw can be brushed as part of the maintenance and the straw can be knocked back and have its fixings (hazelwood staples) resecured to tighten any thatch which has become loose. The straw should be tightly packed to stop water penetrating. Modern buiding regulations state that, when completely stripping down to the timbers for a re-thatch, a fire resistant barrier is placed between the timbers and the thatch. This is usually in the form of boards. The thatch itself can also be treated with fire retardant sprays. Owning a thatched house is no longer for poorer members of society. Generally you will have to buy cash as mortgages are virtually impossible to get and insurance and maintenance costs are high. They do provide good insulation but the main reason for wanting one is aesthetic, They look fantastic (in good condition) and even some modern buildings use thatch. Traditional buildings can be stunning.
This picture of a roof having a new layer added gives you a good idea of how thick the thatch is laid, the steep angle and how it is secured. The wooden pegs you see in the foreground are green hazel and bent in half to resemble large staples.
Except for Spanish tile a roof has basically one purpose.Hardly ever aesthetic. I wonder what Frank Lloyd Wright thunk.His architecture was To Die For. A roof is for structural Integrity.Like a solid foundation.Building a good quality home should never focus on the aesthetics of the roof.Yes,a house using dormers is very attractive as windows ARE more often for aesthetics. Like a Bay window for a Picture window.My Mom had a Bay window in her bedroom.Plus a really nice adjoining bathroom.And she had to have a spiral staircase.It was a custom built home using stone.She went and let her bridge party friends { the Women } talk her into selling it after Dad died.A huge mistake.She lived to regret it.Because she ended her days in an Old Folks home.She could easily have afforded and maintained a private maid and caretaker.I couldn't believe what her Old Folks home cost.The Trust officer said $ 10,ooo a month. Today metal roofs are all the rage.But they're ugly.And my neighbor got one in Red.Really stupid color choice.But he put it up himself and did a mark-up job.I don't have the gall to tell him what a stupid color it is. A Biker friend of mine around the block had a Green metal roof put up around 7 years ago.He loves to keep his yard looking nice.But his roof shows every speck of dirt and his large trees shed on it. I have seen thatch homes in Germany and Ireland that looked scrumptious.But then they also look like trouble.Like when Bales of Hay are left outside and get wet.Moldy.Not Goot.
The main purpose of a roof is to keep water out of a house, Straw has been doing this successfully for thousands of years. Straw is not hay and a thatched roof is not a bale on the ground. Tiled and slate roofs also need replacing due to frost damage and other factors. The difference is that they last for longer. You may not value aesthetics but many people do.
So what happens to yer Thatch roof when hit by lightening or a fallen tree.Or like you said Bird Droopings.Too much snow. Excess weight won't be a problem.? My favorite architecture design is a nice Craftsman style roof and front porch.With one large bay window { Dormer } in the middle of the roof.Can't Thatch that.
The biggest misconception I had to overcome when getting building permits was the Straw vs Hay confusion. Straw is a cellulose which is inedible and extremely durable, whereas Hay is a foodstuff for many creatures and easily biodegradable. Straw is also hollow and hold a lot of air which is an excellent insulator. Thatch has been in use since building were first introduced and is a time proven roof material. There are Nebraska style houses still standing from the days of western expansion in the U.S. http://thesustainablehome.net/the-original-nebraska-straw-bale-buildings/
All those situations will effect a roof no matter what it is constructed from. Roof beams on thatched houses are far stronger than modern roofs. They are generally thick oak beams rather than the puny pine of tiled roofs. Like I said, thatched roofs have been used successfully for thousands of years. They have disadvantages, many of which I've already outlined but they also provide a continuity of tradition and are part of the culture of many nations around the world. They may be old fashioned and have no tradition in the new world but they still have a place in the old one. There is room in architecture for all kind of options. Like you I find metal roofs ugly and industrial in appearance but that does not detract from their function of keeping the weather out. Thatch may be expensive to maintain but it is still a viable material with advantages in appearance and the continuity of tradition. It also provides employment in highly skilled trades and farming traditions going back centuries. It is a sustainable and ecologically sound solution to the need for a waterproof roof.
If people think about it, old medieval style timber framed buildings are the ultimate in sustainable housing construction. They mostly consist of locally sourced natural materials. Wood, straw, clay. stone, lime mortar etc. They contain almost no energy intensive man made materials. Even nails are sparingly used as mortise and tenon joints are the traditional (and far stronger) technique. Floors were often compacted earth and cobbles rather than energy intensive tiles or high CO2 concrete. Glass wasn't readily available with shutters being the solution to letting in light and air and many of the materials used have high insulation values. They also employ highly skilled craftsmen and are very individual in appearance.
The first house in the photo is fabulous! So many obstacles to having thatch that you’d have to love the look of thatch. A longterm commitment with maintenance and hefty costs. When we built our house, we specified an iron roof so that we could hear the rain. Slightly scuppered in this owing to insulation and deafness, the sound of the rain is muffled.
We obviously need, Synthetic Thatch in the world. Why not? Really. Recycled plastic straws comes to mind. Or just recycled plastic created and colored into Syn-Straw or Syn-Thatch (Moi should patent & copyright) Interested investors; - - - message / conversation Moi621
Not Syn-Thatch. It should look like thatch but, not made of straw. That stuff on the video look so, "plastic". No bulk Single layer thatch look doesn't do it.
Trouble with plastic for roofing is that it degrades faster than straw. That Palmex palm frond lookalike stuff is only guaranteed for 20 years. UV light destroys plastic, otherwise we would have light weight recycled plastic roof tiles by now.
“One of the first was an 1886 school house, which suffered an ignominious fate. Unfenced and unstuccoed, by 1902 it was reported that the building had been eaten by cows” Something to beware of!
That’s mind boggling. The labour involved would be costly I think. That looks so lovely. Is it finished with anything or just left to weather?
I think cedar is naturally resistant to rotting. Very oily wood. That is probably very new, it will go grey in colour over time. Hell of a lot of nails though.
LOL Have to be a very hungry cow to eat wheat straw though. Barley straw is fed to cows over winter sometimes but it's not their favourite.
I found where that shingle picture came from. https://www.customshingles.com/false-thatched-roof A Florida company.
