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close this bookFCR: Fibre Concrete Roofing (SKAT, 1987, 185 p.)
View the document(introduction...)
View the documentAcknowledgements
View the documentSummary
View the documentHow to read this report
View the documentIntroduction
View the documentExecutive summary
View the documentTiles or sheets?
View the document10 Key questions
Open this folder and view contents1. Limits of application and acceptance
Open this folder and view contents2. Producer organization
Open this folder and view contents3. Technical rationale
Open this folder and view contents4. Manufacturing technology
Open this folder and view contents5. Installation
Open this folder and view contents6. Costs and economics
Open this folder and view contents7. Knowhow transfer
Open this folder and view contents8. Fallow-up programme
Open this folder and view contents9. The questionnaires
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Tiles or sheets?

This report is about Fibre Concrete Roofing. This includes both of the roofing elements “tiles” and “sheets”, the first being a further development of the latter. The comparison between FC-tiles and FC-sheets is a bit like a comparison between a truck and an oxcart: it is obvious, that the FC-tiles are the most developed product, and in most aspects they are superior to the sheets. Nevertheless, as there are situations where an oxcart is more adapted than a truck, there can be cases, where sheets are the better choice than tiles. In most cases however the FC tiles will be the more appropriate product and cause less problems than the FC sheets.

Sheets

Tiles

FC sheets will be compared to asbestos or corrugated iron sheets; expectations will be difficult to meet.

FC tiles will be compared to clay tiles; expectations are easier to meet.

Only a good workteam will be able to guarantee a good overall esthetic appearance of a finished roof.

Good esthetic appearance is easy to achieve, as minor errors do not show easily.

Moulding needs a very well coordinated team of at least two workers.

One qualified worker can do the moulding .

Tamping or vibrating are difficult to standardize.

Vibration is standardised.

Production is possible without electricity and with very simple equipment.

Production process needs electrical or manual vibration.

Handling of the fresh product is difficult; risk of breakage.

Easy handling; almost no breakage of one day old tiles.

Curing in water tanks is difficult because of the big size of sheets.

Curing in many kinds of water tanks is easily possible.

Transport is rather difficult and risky.

Transport is less difficult.

Lower costs for equipment.

Higher investment for production equipment.

Higher cement content (1: 1 ); therefore more cement per square meter and higher material costs.

Lower cement content (1: 3); therefore less cement per square meter and lower material costs.

Heavier self-weight and less overlaps will withstand stronger wind forces.

Lighter cladding; easier to tee removed by wind if not tied down.

Handling of the sheets on the roof is breakage. difficult and may lead to

Easy handling on the roof.

Traditional craftsmen (used to GCI sheet and clay tile roof laying) need special training for FC sheets installation.

Where clay tiles are common, most craftsmen will be able to install FC tiles.

Bad supporting structure or warping of timber leads often to leakage.

Uneven parts of the roof structure can be absorbed to a certain extent by the tiles.

Replacing of sheets on the roof is difficult; other sheets may brake in the process of replacement.

Replacing of tiles is easier though not without problems.

Training is essential and has to be done by a qualified instructor. Minimum training time 2 to 3 weeks.

Initial training can be achieved in a shorter time but follow-up is required at initial stage of technology.

The stresses within the sheets are higher than in the tiles. Sheets are therefore more susceptible to cracking.

Due to its smaller size the stress within a tile is smaller and less cracking occurs.