Thread: Alternative Roofing Materials

Ben, I also think thatch is good and was just mentioning the pros and con. As I said, I'm not sure what I would use, preferably something sustainable.

Anyone building from bamboo should be concerned about it being eaten. The thatch sheets have split bamboo with the grass tied to it. The pieces of split bamboo can be attacked by insects, sometimes within a few weeks. My worry is that these insects will move into the bamboo structure.

The info about ventilation and insulation is all pretty basic, but thanks anyway.

Ben – I thought my post was fairly straightforward, but perhaps not. Without getting into too much of a theological dispute about this, a couple of points:

1. It’s just not true that cob is rammed. Cob is built up in layers by hand without formwork. Rammed earth is…well…rammed, which is why it’s called rammed earth and not cob. Cob gets its structural integrity from the interplay of straw and earth. Rammed earth gets its structural integrity from being rammed. If you’re confused about this, I’ll post some links explaining the two techniques. I dare say there are hybrid techniques, where people have tried to combine cob and rammed earth, but when people talk about cob they mean something which has NOT been rammed.

2. My comment about termites was with reference to straw/clay (also called light earth), a building technique different to either cob or rammed earth. Walls are largely straw and are therefore at risk of attack by termites (and, no doubt, a lot of other nasties). In Thailand it would be foolish in the extreme not to take this risk seriously. Rammed earth is generally considered termite-proof as the material is too dense for termites to penetrate (This is from what I have read, although I accept this may be incorrect). I imagine cob, being loosely built, would be at risk of termite attack, at least in so much as it may not present a barrier to termites getting into your house and finding something tasty to eat – your doors or windows, perhaps.

3. The point about the differing thermal properties of the building was to distinguish massive structures with high thermal mass (cob, adobe, and rammed earth) from lightweight structures with low thermal mass (straw/clay). Tropical climates, such as experienced in Thailand (both North and South), have low diurnal temperature swings. I live in the North and for more than half the year day-night temperature variations are less than 10 degrees. This means that buildings (well, everything, in fact) cannot lose much heat during the night (low cloud cover prevents long-wave radiation). Houses built with materials which have high thermal mass run the risk of heating up during the day and then staying uncomfortably hot during the night (a common enough experience in modern Thai houses). That is, when heat is absorbed it is also radiated – if it can’t be lost to the sky, it will lost to your body. Not a pleasant experience when you’re trying to get to sleep. To a certain extent, this could be overcome by intelligent planning and design but it would be a more efficient – and safer and more complete and so better – solution to begin with a low-mass material. If you’re planning on building in Thailand (and doubly or trebly so if you’re not going to rely on air-conditioners for your cooling), this is an area which repays study. I’d also take issue with the claim that cob and rammed earth “would give exactly the same fundamental temperature”. As rammed earth can be over twice as dense as loose earth (density being a determining factor in the thermal properties of a material), rammed earth houses and cob houses will have different internal climates.

dan
thank you for the clear up on wording, now i understand what you're talking about!

straw bale construction light earth building are not realistic in Thailand, that is to say by all means build but of course the likely hood is that they will collapse!

Why?

Simply put, climate! Relative humidity is such in thailand that the internally braced straw would disintegrate because of the intense humidity, if you live in northern thailand you are in the worst area for relative humidity, sometimes reaching a peak of 85%, with lows touching around 75%!

With strawbale or straw builds there needs to be a maximum relative humidity of 65% sometimes in very hot conditions 70% is viable, otherwise the above mentioned will likely happen!

This means that straw buildings would not do very well and would be highly risky to undertake in such a climate as we have in thailand!


Secondly have you ever actually built with cob, because all buildings that have been made from the earliest periods in england are rammed they must be compacted! Maybe not in the same compressed form method of actual rammed earth, but the cob mixture( clay 20%, aggregrate 70% straw 10%, this can vary slightly) must be added compacted by a wooden ramming tool or by foot. This must happen and so as i have done it and know a lot about cob i would prefer to go with my knowledge and understanding on this basis!

With regards to interior thermal temps. mass will of course absorb more heat and indeed radiate it out at cooler periods, like night time! With this in mind and the fact that straw buildings are not feasible, then good design as mentioned so that natural cooling is adhered and maximised should be sufficient to allow comfortable day and night time temps. Again there are actual building like this in and around chiangmai, that dont use aircon, and by all means to their apparent detriment are not high in mass and also not designed for maximised natural ventilation but they are cool! So in light of this actual model a house with high mass walls and good design and natural ventilation all combined to increase overall internal temps, then i would think that this would be efficient enough, and yet still the best method for sustainable building!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

i hope the rest as also been cleared up for you!

To add i think that just in the same way that theological has no meaning in this topic, clearly some words and their meanings are beyond you or at least for sake or argument misused or interpreted as used!

maybe you meant theorised discussion of building, or something of that like,

please remember im just having a bit of a poke at you and no hard feelings are meant, i am interested and thank you for your discussion there-in, and im sure its giving others an insight into the world of sustainable building!

I was only trying to contribute to the discussion, building sustainably doesn't mean rebuilding every few years. Trying to make the place as durable as possible is very much in line with sustainability.

By including the negative aspects of thatching I was hoping people could discuss solutions, I didn't expect to be told that sustainable building is 'more than I can handle'.

I've already renovated one house that uses bamboo and thatch extensively, so I'm familiar with these materials. I also have many publications on building and preserving bamboo, as well as a background in building/construction and considerable knowledge of design.

I would be interested in discussing sustainable/alternative roofing materials. Does anyone have suggestions for controlling the beetles that eat the split bamboo in the thatch?

Originally Posted by Dan

^ Found a bit more on the school on the internet - what a fantastic building. I think I may shamelessly copy some of their ideas. Thanks for the lead.

Have you found a way of preserving your bamboo yet? I saw some of your posts (or at least I assume their yours) on other forums.

Regarding the preservation, I've found the method I want to use and have a sourced for the bamboo. It's important to get everything right as building a home is quite an investment of time and money. I'm now waiting for the dry season as this is the time to harvest.

We have 3.5 rai of land next to Khao Yai, with really nice views. The house we've fixed up there is very simple but comfortable. I would really like to build something nice, but have trouble justifying this if I wasn't living there full time.

Regarding bamboo and termites/bugs, I think the bottom line is you need to be using the house daily. Termites hate noise and vibration, so they aviod places that are lived in. The house we rented had termites, the spare room was full of them, with hardly any in our room.

Do you have firm plans to build and will you definetely use mud?

Dan - okay, okay........so you agree with me on the principal of cob and rammed earth though, having very similar comparisons of technique and build.........no im only pulling your leg!

intelligent folk can be eccentric and humorous and if i have a flaw being asinine it is thankfully something i can cope with, and amongst many not the worst!

posted by Dan
However, one word of advice: Don't make asinine remarks such as "clearly some words and their meanings are beyond you" and then follow this immediately with the equally fatuous comment "im just having a bit of a poke at you and no hard feelings are meant".

i shouldnt have said the top point, but theology is a long explanation away from point, and so maybe in typed dialog best not used unless can be understood or easily self-explained!

anyway enough of semantics!



straw slip hey(by the way i wasnt being obtuse i was just missing what you meant in terms of technique), that is interesting, mainly because i would have thought quite laborious and labour intensive? i know that this is sometimes the preferred choice in filling walls, i have one question which is what do you plan to do with filling the ceilings?

more to follow

Originally Posted by Dan

However, one word of advice: Don't make asinine remarks such as "clearly some words and their meanings are beyond you" and then follow this immediately with the equally fatuous comment "im just having a bit of a poke at you and no hard feelings are meant".

Don't worry Dan. I think he doesn't like to be made to look stupid. I thought he'd be used to it by now.

dan

bamboo is great for practically everything, i wouldnt go by what smithson makes of its destructibility, as this material is widely used through out many 3rd/2nd world countries and is becoming ever more popular with commercial and western world architecture!

There are numerous books and websites on this building technique!

To be honest with you, personally if you are worried about internal temps with cob or rammed earth i would say these arent actual real life reflections and more so seem to be from a third person perspective, unfounded reasonable doubt!

I think rammed earth or cob would look amazing, if we take into consideration the pic i posted earlier in the thread. Lofty ceilings mass walls and good design technique will insure a minimal thermal heat leak maintained within the house. In mostly all hot countries earth is used to great effect. Its true to say we dont have extremely cold nights, but i still cant see this being anymore then facilitating a fan in the bedroom. It would be a shame to not conduct the potential of this building into realisation for there is not alternative in any material that i could understand to better overall in most areas that we have discussed.

Of course using a traditional wood teak design would be the next effective design and model, but this seems to be not as popular as bamboo or soil, so will not discuss further.

Originally Posted by Dan

Very coy answer!

Definitely have firm plans to build (near Lampang so the arse-end of nowhere) and will definitely not use brick/cement/block but I'm unsure about what I will use. I love the look of rammed earth but I'm worried about heat problems so am currently 70% swung towards straw/clay. However, now I've seen the Bangladeshi school I'm starting to think again. Perhaps more importantly, my wife saw it and said "I want that one" which is why I'm trying to find out something more about bamboo. I've done a lot of research on earth building but, until now, nothing on bamboo.

Didn't mean to be vague, the bamboo in the picture may not get attacked by termites, but it's flying bugs that mainly eat bamboo.

Also, much of the bamboo is exposed to the weather, so this will shorten it's life, because bamboo should never get wet. The frame of that building is bamboo, it has been used on the lower levels.

I doubt this bamboo was even preserved, as it looks quite green in some of the pics.

If you're in the north and want to build with bamboo, the hill tribes are very good at that. There are also ppl teaching mud building near Chiang Mai. I understand a Thai can attend the course for a 'donation' so if you have a potential builder maybe you can send them there? Might be better than you doing the course yourself, as you would then have to explain it to others.

Personally, I think building here really need a different approach to the west. I really don't think that many walls are necessary, look at the Thais, they spend most of their time sitting in the shade. If you reduce the amount of walls it's cheaper, easier and you don't have all those headaches about thermal mass. Take a look at some of the bali style houses.

oh no marmite stop, c'mon now, your a grown man and frankly bitching doesnt suit you!

what difference is my stupidity, to me telling a story or giving information???

maybe im just abit more realistic about myself (as much as on ecan be on this type of forum)!

anyway where were we before fat mama interrupted us


clay slip mix
This is a mix that will be left raw on the wall to give a more naturalistic aesthetic if you can see the doors it is in this case not a nice effect, but when done well looks good and has great potential





It seems that most straw clay slip that i have ever seen is traditionally combined with strawbale building, with the straw bale slip being used to fill internal walls and external fascia walls. I havent seen much clay slip only building, dan this could be something to look into more about???????

Originally Posted by benlovesnuk

dan

bamboo is great for practically everything, i wouldnt go by what smithson makes of its destructibility, as this material is widely used through out many 3rd/2nd world countries and is becoming ever more popular with commercial and western world architecture!

There are numerous books and websites on this building technique!

The joints you've show in other pics would allow insects to eat to enter the soft inner parts of the bamboo. If the bamboo was not treated it would deteriorate very quickly. Using thatch would cause concern, due to what I said earlier.

Bamboo is an incredible plant is widely used around the world. It has many fantastic properties, but natural durability isn't one of them. There several websites and books focusing on bamboo, they all discuss the importance of preservation.

yes, indeed preservation is key which means that if you do it right and preserve the bamboo in your house there should be no problem......

i think thatch is something that worries you and as such maybe not worth your consideration, maybe another material whether it be sustainable or not would be better to ease your mind.

as stated before any natural material will need constant care and updating

This is an article about the negatives, although to me they sound uninformed, but see what you think, personally a lot of misconstrued opinions do tend to be caught and held in regard. maybe going to see some bamboo buildings with your partner and asking some builders what they think!!??????

Green Home Building Jun 13, 2008
Building A Bamboo Home

Negatives of Bamboo Home Construction

By Jennifer Chait
In my last post we looked at the Pros of Bamboo Building. What are the negatives? Well, yesterday I mentioned the look; which like I said is a little too tropical for me, but it might suit you. Visual issues aside (that's so personal), there are some other bamboo negatives to consider before you dive into building an entire bamboo house.
Green Home Building notes that joinery can be an issue since, "Its strength comes from its integral structure; it cannot be joined with many of the traditional techniques used with wood." You can get around this issue by working with a bamboo building expert though.
Bamboo can dull your tools due to large amounts of silica found in it.
Wet and bamboo don't go as well together as you might think. If you stick bamboo into wet soil it can cause big problems. Special care needs to be taken during the building process.
Bamboo will go up in flames super quick. I.e. it's a highly combustible building material. Uh oh.
Bamboo is unique. This is why I love some bamboo floors and furniture pieces so much - it's unique. However, that's not so great for home building. Because sizes of bamboo vary so much it can cause building problems.
You'll need to use chemicals to protect bamboo from weather extremes.
Bamboo is not as straight as timber or even logs. It can taper. It's hard enough to build with perfectly dimensional lumber so, it's going to take extra care and skill to build well with wood that won't always stay flat.
As with any material, you should research bamboo fully before deciding to build with it.

Harvesting

Bamboos are useful for different things at different ages. The recommended age to harvest for bamboo construction is 3-6 years. To select culms that have the greatest strength for building purposes it is important that the culms are at the right age. If the culms are older than 6 years they may have been subjected to insect damage on the interior of the plant but it will be difficult to assess.
When harvesting it is best to cut just above the node at the base and to carry out the harvest immediately after new shoots have started to grow. At this time the plant will have given all it's starch to production of the new culms leaving less in the harvested culms.
To create special shapes or effects, bamboos can be bent or straightened through a process of heating and clamping until cool.

Originally Posted by Smithson

If you're in the north and want to build with bamboo, the hill tribes are very good at that. There are also ppl teaching mud building near Chiang Mai. I understand a Thai can attend the course for a 'donation' so if you have a potential builder maybe you can send them there? Might be better than you doing the course yourself, as you would then have to explain it to others.

Yes - I think we exchanged posts about this another site! I may well go up there this winter.

Personally, I think building here really need a different approach to the west. I really don't think that many walls are necessary, look at the Thais, they spend most of their time sitting in the shade. If you reduce the amount of walls it's cheaper, easier and you don't have all those headaches about thermal mass. Take a look at some of the bali style houses.

Again, you're right. It just takes quite a shift in how one thinks and I haven't quite got there yet.

I'll respond to your message when I get to the magic 20 posts.

Originally Posted by benlovesnuk

yes, indeed preservation is key which means that if you do it right and preserve the bamboo in your house there should be no problem......

I thought the destructibility of bamboo wasn't an issue?

Originally Posted by benlovesnuk

i think thatch is something that worries you and as such maybe not worth your consideration, maybe another material whether it be sustainable or not would be better to ease your mind.

I've used thatch on my house and like it, I mentioned it's neg points as I thought it was worth discussing.

Originally Posted by benlovesnuk

This is an article about the negatives, although to me they sound uninformed, but see what you think, personally a lot of misconstrued opinions do tend to be caught and held in regard. maybe going to see some bamboo buildings with your partner and asking some builders what they think!!??????

The article is very good, the author is informed. It's important to realize the negatives and constraints before going ahead. The main problems with bamboo are durability, joinery and combustibility.

You seem to be doing a lot of googling and cutting and pasting. In fact it reminds me of the another thread started by "Eco Warrior". He also enjoyed the smart arse comments and superior attitude.

Do you have any experience building or have you just been reading stuff on the net?

Dan, when do you plan to tell your Mrs you plan to have the hill tribes build you a bamboo house!

Regarding the lack of walls, it does take a shift in attitude. Same with the Thais, after building the western style concrete box, they still spend most of the time sitting under a tree.

Originally Posted by Smithson

Dan, when do you plan to tell your Mrs you plan to have the hill tribes build you a bamboo house!

Regarding the lack of walls, it does take a shift in attitude. Same with the Thais, after building the western style concrete box, they still spend most of the time sitting under a tree.

To give her due credit, she's been very amenable to my suggestions, particularly as she's from a boringly middle-class Bangkok family, for whom I might as well have suggested moving to Pluto when I expressed an interest in alternative building. Like I said, she's the one who got really excited about the look and layout of the school and gave me instructions to find out how to build it. As long as it's unique enough to get a spread in the Thai Homes & Garden, she (sadly) will be happy.