Thatch building lunchlecture tu delft

Thatch Naturallya short introduction

Joost KreugerVakfederatie Rietdekkers

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Vakfederatie Rietdekkers• branche organisation• knowledge and expertise• education• quality control• mediation

• www.riet.com

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contents• short history• waterreed• thatching technique• durability• key features• examples• questions

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Short HistoryThe natural roofing material

• in search of shelter• local materials• variety of materials

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thatch survived• most durable• specialism• 100.000.000 € industry in Holland

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WaterreedAnual so renewable

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Thatching techniqueHard labour craft

• minor changes in craft over the years

• some different and more durable materials• construction changes• change in design

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• Building details roof

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• Building details wall

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• Please visit www.riet.com for all details

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DurabilityEnter architect

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Moisture determines life expectancy• slope• construction• detailed engineering• Surrounding of building• orientation• craftsmanship• quality of thatch• maintenance

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Moisture determines life expectancy• slope > enter architect• construction > enter architect• detailed engineering > enter architect• surrounding of building• orientation• craftsmanship• quality of thatch• maintenance

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Moisture determines life expectancy• slope > enter architect• construction > enter architect• detailed engineering > enter architect• surrounding of building• oriëntation• craftsmanship• quality of thatch• maintenance

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slope• minimum 30° for short distances (gable etc)• minimum 45° for longer distances

Zo hoort het !

Grotere hellingshoek? de combinatie plat dak en riet

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Nog beter !

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Moisture determines life expectancy• slope > enter architect• construction > enter architect• detailed engineering > enter architect• surrounding of building• oriëntation• craftsmanship• quality of thatch• maintenance

• Traditional construction• No R value• Fire risk

Het moderne “schroefdak”

• Modern construction• R=1,5 min• No fire risk

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constructioneither:• open > sheds, barns• closed > homes, public buildings

• different kinds of insulation possible

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Moisture determines life expectancy• slope > enter architect• construction > enter architect• detailed engineering > enter architect• surrounding of building• oriëntation• craftsmanship• quality of thatch• maintenance

less details > less moisture > higher life expectancy

every detail means:

• turning of thatch (less slope)• increase in thickness (less slope)• less sun and wind (less drying capacity)• less drain of water

gedraaid

Rietpakket dikker + overmaat aan water

Recreatieproject 80 woningen, 160 killen

Dak: dikte = 24 cm helling riet = 30°Kil : dikte = 46 cm helling riet = 14°

Life expectancy of a thatched valley

• slope = 75% of optimal• thickness = 75%• oriëntation (north) = 75%• Water volume = 75%• drying capacity= 75%

life expectancy: 75% x 75% x 75% x 75% x 75% = 24%

Life expectancy of roof +/- 32 yearsValley > 0,24 x 32 = 8 jaar.

oplossing

Make it open…• slope = 75% > 100%• thickness = 75% > 100%• oriëntation (north) = 75% > 100%• Water volume = 75% > 100%• drying capacity = 75% > 100%

Life expectancy increases from 8 years to 32

Nog beter !

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key featureswhy thatch survived

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thatched roof• renewable and natural• warm and soft• easily adapts in every surrounding• distinguished• pliable• high degree of formability• firesafe even without fire-retardant• high R values possible

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Examplesthatch is a modern building material

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veiliger !

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Questions ?joost@riet.com

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www.riet.comLearn even more !