Corrugated Bamboo Roofing Sheets

SUBMITTED BY-

UTKARSH DWIVEDI

B.ARCH SEM III-B

ENROLMENT NO.-A8304013046

What are Corrugated Bamboo Roofing Sheets?

Corrugated bamboo roofing sheets (CBRS)

are an excellent alternative to corrugated

metal, plastic or asbestos roofing sheets.

They are produced from a natural and

sustainable resource and can be used to

cover homes, storage facilities, animal

pens and many other temporary or

permanent structures.

How are Corrugated Bamboo Roofing Sheets Made?

• CBRS is made from several layers of

woven bamboo mats. These woven mats

are impregnated with an adhesive resin

and pressed together between two

specially designed corrugated pressing

plates. The sheets can be produced in a

range of sizes to suit particular

requirements and can easily be trimmed

for special applications.

• The main materials used are bamboo slivers to produce the mats, and adhesive resin in which to soak the mats. A resin applicator is needed, and a drying chamber is optional. Corrugated pressing plates for the hot press are of course essential.

The process of producing CBRS involves 6 steps:• Bamboos are split into thin slivers.

• Slivers are woven into mats.

• Mats are soaked in adhesive resin.

• Mats are allowed to drain and dry.

• Mats are glued together under high temperature and pressure.

• Sheets are trimmed to shape.

PRECAUTION

• An important precaution to be taken in

making mats for BMCS production is that

slivers with the glossy (epidermal) layer

should be avoided as they are resistant to

bonding. Such slivers can however be

used in basketry etc.

• The moisture content (m.c) of freshly

woven mats is in the range of 40% -50%.

On drying them in sun, the m.c is

generally about 12% - 15%. If transport

and or storage is more than one month it

is advisable to undertake prophylactic

treatment. The simplest and significantly

effective treatment for mats, provided

they are not exposed to drying, is

spraying with 1% solution of mixture of

boric acid and borax in the ratio of 1:1.

Spraying can be done by hand or

knapsack sprayer. This will not have any

adverse effect on bonding. The mats

should be dried after prophylactic

Joinery details

BMCS are anchored to bamboo purlinsUsing J bolts

Detail showing how BMCS are joined to bamboo purlins using J bolts at the crest

BMCS should be bolted at crest not trough. Detail showing overlap of

BMCS .

Accessories can be used to resolve corners and joints problems.

Complete house with BMCS roofing

Main advantages of CBRS

• Bamboo roofing sheets are

environmentally friendly and a safe

alternative to plastic, zinc or corrugated

asbestos roofing panels.

• They have the same standard

measurements as conventional

corrugated roofing sheets.

• Bamboo roofs are quieter in the rain and

cooler in the sun than conventional metal

or plastic sheets. A study has shown that

cows in sheds roofed with bamboo yield

more milk than those under corrugated

zinc sheets because of the cooler

environment.

• Bamboo sheets are durable and strong

with excellent internal bond strengths and

a high resistance to weathering, fire or

insect attacks.

• They have an attractive and natural

appearance and are easy to work with

Comparing CBRS Materials

How do bamboo corrugated roofing sheets compare to zinc, plastic or asbestos roofing sheets? The following study compares the mechanical properties and performance differences between the four different

materials.

1. Thermal Transmission Performance

Bamboo has the highest thermal

resistance and the lowest thermal

transmission coefficient, therefore,

bamboo has the best thermal

isolation properties compared to the

other three materials.

MATERIAL THERMAL RESISTANCE(m²K/W)

Coefficient of thermal transmission W/(m²K)

Bamboo 0.030 5.2

Zinc 0.012 6.2

Plastic 0.007 6.4

Asbestos 0.019 5.9

2. Density and Water Absorption Properties

Bamboo has the lowest density and the

highest water absorption ratio compared

to plastic and asbestos which may

influence its durability in exterior use.

However, this characteristic is easy to

overcome when using better resins in

the production process or by applying

a coated outer layer.

Material Density (g/cm³) Water absorption ratio (%)

Bamboo 0.71 36.7

Plastic 1.56 1.7

Asbestos 1.60 21.1

3. Bending StrengthBecause zinc and plastic sheets are too thin

to determine its strength properties, the

determination was done with bamboo and

asbestos sheets only.

The results have shown that bamboo has a

higher bending strength than corrugated

asbestos board, and would be greatly

superior to plastic sheets. This means that

corrugated bamboo roofing sheets can

endure larger long-time loads in employment.

Material Flexural strength(MPa)

Bamboo 39.72

Asbestos 31.91

4. Impact strength

Corrugated bamboo roofing sheets

have an excellent impact strength.

They bare a much higher instant

striking force compared to asbestos

sheets.

Material Impact strength(MPa)

Bamboo 9.93

Asbestos 2.55

Building Materials & Technology Promotion Council (BMTPC)

• Under a project funded by BMTPC a technology for manufacturing BMCS has been developed at IPIRTI(indianplywood industries research and training institute) where pilot scale/experimental BMCS production facility has also been established and commercial scale of production has been established at M/s. Timpack Pvt. Ltd., Byrnihat, Meghalaya.

• More than 2000 BMCS made at the pilot facility at IPIRTI have already been used

Some of them are;-

• a rain shelter at the National Zoo, New

Delhi;

• specially designed terrace café at the

DFID India office, New Delhi;

• pantry near Glass House at Karnataka

Raj Bhawan, Bangalore; (Ar.neelam

Manjunatth)

• Bamboo houses constructed at

Bangalore under DFID funded project

“Bamboo Shelter Demonstration of

Best Construction Practices”

implemented by IPIRTI in

collaboration with TRADA Technology

of UK.

.