Thread: Mud, bamboo and alternative building materials

another question....what is the least angle possible for a thatch roof and still work properly and be waterproof ??

I notice the front section of your little verandah roof is relatively low pitch.

Hey Nawty, I'll try and answer your questions.

Bamboo will last the shortest time if it's untreated, outside and exposed. We've used some around a veggie patch and after a year it's pretty much had it. Thailand is tropical and Khao Yai has heaps of rain, so it's super humid.

Regarding the suspension bridge, I've wondered about that myself, you'll see on most of the bamboo structures the poles are protected from the rain.

I'm guessing the roof would keep a lot of rain off, depending on how much wind there is. If it did get wet, then maybe due to it's design it would dry quickly - the problem isn't so much getting wet, but staying wet. Bamboo in damp areas will rot, even if it's undercover.

If you built a carport and covered it with a vine, not only would it get wet, but the vine would slow down the drying. It would also add weight to the structure, making it collapse faster once it weakens.

Why don't you build a carport with a tin roof, then grow the vine over roof? This would work fine and be much cooler than the tin by itself.

Regrading the thatch, if it's new enough and thick enough I don't think the angle has to be that great, but it may not last so long.

The higher the pitch and thicker the thatch the longer it'll work/last - but a higher pitch requires more materials (incl. thatch).

I think 35 degrees would be fine. For this shed I did 45, because it was easier to work everything out. For the house I might do 35, to stop the roof getting to high.

Cheers,

Hmmmm...sounds sadly correct.

I shall take a pic of the structure near our house made of small bamboo and has a vine growing over it....not much mind you.

Passionfruit growing a treat....looking good.

^ Good to hear about the Passionfruit, don't be shy with the chook shit, they love it.

One idea I was thinking about for your place was to cut the bamboo just after the rains, then sink it in the river for up to 1 month. This is a traditional form of preservation. You could then build small structures like salas, sheds etc, which could be easily rebuilt in 10 yrs or so.

Interesting.....can these then be used outside, or still have to be covered ?

Why does the water soaking protect them ?

The water removes the starch, which is what the borers are after. It is a traditional method, not as effective as chemical treatment but simple, especially as you have bamboo growing close to a river.

However it doesn't mean the bamboo can be used outside, even borax treated can't be used outside because it's water soluble and will leach.

There are ways to treat bamboo for external use, and while I don't know much about them, I think they are pretty toxic and not something that could be easily applied. Best bet is to do a search for 'bamboo fencing' and see what comes up.

When exposed to the sun, bamboo will crack, allowing water to enter the inner culm, which will make it rot even quicker. There are UV resist finishes that could help prevent this, but it's all going to be a lot of work.

You could always plant some bamboo and park your car under that.

Now thats an idea, I could bend it over to the other side, plant 4 clumps and tie them to each other and create my archway carpark.....

We spent the beginning of the year treating bamboos using the Boucherie method. The idea is to use pressure to force borax through the culm at the basal end. This pushes the sap out the other end and even for long, large diameter culms, the process is complete in a few hours.

Altogether we have over 50 large 'Pai Trong' poles and over 100 x 50mm 'Pai Liang' poles. They are now drying and will be used to build our house in about 6 weeks.

We put the poles in under cover to dry. The bamboo had a strong smell and it had recently rained which bought out the bugs. They started crawling on the bamboo and even chewing, however they died.

I made a short video which is on youtube, unfortunately my battery ran out before I could film more. You can see the sap dripping from the pole, which hopefully gives you the idea.

Originally Posted by benlovesnuk

Originally Posted by Dan

Other than the obvious risk of termite infestation, I can't see any problem with that, or why cement would be preferable to earth. If it's got the wide overhangs and it's on a stem wall, earth would, I think, be fine. Adding sand or organic fibres to your clay will reduce the risk of cracking. Also, working in several thin layers will do the same. Why not make a small panel, plaster it with earth and see what happens? It shouldn't take long.

Where did you get your info or understanding that termites like earth buildings, is this personal experience or hear say, internet etc etc????

Its just that From quite a wide source i understand that termites have no interest in adobe or cob for any purpose, especially compacted soil mixed in this fashion its simply not a food source or even possible for them to generally borough through! I believe termites that come from the ground can be stopped by adding a sand barrier i think of about an inch thick when compacted down as they cannot get through.

Secondly termites that fly which there are some in chiangmai, have to be dealt with in other ways, but like i said im pretty certain that they have no interest in adobe cob or any other earth mix for building....only wood!

Termites don't normally eat adobe or cob, but can move through it easily and get to any shelves or window/door frames you have. Rammed earth or earthbag is better, although they can probably still get through it. In Sa Kaew there are several earthen buildings built using soil cement adobe bricks (not compressed). They appear to be resistant to termites and moisture, but are not hygrosopic, so lose the air quality benefits of earthen architecture.

Originally Posted by Smithson

Regrading the thatch, if it's new enough and thick enough I don't think the angle has to be that great, but it may not last so long.

The higher the pitch and thicker the thatch the longer it'll work/last - but a higher pitch requires more materials (incl. thatch).

Cheers,

In the tropics they normally keep the layer of thatch quite thin - it rots more quickly if it's too thick.

Nawty, there's a great bamboo carport with a living roof here:
Bamboo garage with sod roof - James Elkis - Bamboo Forums

Originally Posted by Smithson

They are now drying and will be used to build our house in about 6 weeks.

I am looking forward to seeing pics of your build

the bamboo houses I have stayed in have been fairly primitive but they seem to last a few years without chemicals

with your protection, it should last decades