07(12)schacher bhatar handout

8/3/2019 07(12)SCHACHER Bhatar Handout

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SDC Bhatar constructionAn illustrated guide for craftsmen

forrev

isio

n

12April

2007

Bhatar (pl. bhateri) is a Pashtoo word for a beam

with a cross section of 3 to 4 inches which iscommonly used to reinforce stone walls.


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1. Site selection and form of house

1. Dont build toonear to asteep slope:stones mightfall on your

house2. Dont build too

near to aprecipice: itmight breakoff during anearthquake.

3. Dont build toonear to aretaining wall:it might break

away duringan earthquake

4. The house musthave a simpleform. If necessary,subdivide it intorectangular parts

5. The house mustnot be longer than3 times its width.

6. A light pitched roofis better for

earthquakes thana heavy flat roof.

7. Dont build higherthan 2 floors.Second floor can

be made in Dhajji.

1

2

3

4

6

YES NO

Better

Max.

2

floors

Lessgood

Max. 3 W

W

5

7


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2. Basic rules

1. No wall must be

longer than 12feet without beingconnected toanother wall.

2. Wall elements

must be at least 3feet long.

3. Windows must besmaller than 3 ft.

4. Walls must be at

least 1 feetthick.

5. Walls must not behigher than 10feet.

6. Choose Blue Pine(pavich/biar) orCedar (deodar) forthe beams. Toprotect forests,take what is more

frequent in yourregion.

Max. 12 ft 1

Max.

12ft

2

Min3ft

Max 3 ft 3

Min 3 ft

Max.

10feet

1 feet

5

4

6

7. The beams(bhatar) in thewalls act asseismic bands.

8. All walls must beconnected to

each otherthrough stonemasonry andtimber beams.

9. Place throughstones every twofeet. They makethe wallstronger.

10. Use flat ordressed stones

for yourmasonry. Dontuse round rubblestones.

11. Use galvanized

nails for all workexcept inside thehouse.

YES NO

Connectingstones

10

Beams =Seismicbands

7

8

Throughstones

9


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3. Foundations and first seismic band

1. Build your houseon soil that is allof the samequality. Dontplace one part ofthe house on infill

soil.2. Foundationsshould be 2 1/2feet large and 3feet deep.

3. First seismic bandshould be placed1 foot above thefoundation (1 footabove ground).

4. The first seismic

band will alsopass under thedoor!

1

Infill soil

will sag

3 ft

3

2 ft

1 ft

2

4

Timberbeam

5. It is better tomake the firstseismic band inreinforcedconcrete insteadof wood. It will

resist better tohumidity.

6. Take care tocross the cornerrebars correctly

7. Make sure that allrebars arecovered with 1 inch of concrete.

Right rebarto the left

Left rebarto the right

6

1 rebarout - out

2 rebarsin - out

Stirrups

every 8

5Concreteband

4

1

1

7


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1. Place the wall beamsevery 2 feet, except forthe first band which isonly one foot aboveground level.

2. Its better to make thelowest band inreinforced concrete to

make it more resistant towater.

3. Place cross pieces at amaximum distance of 3feet from each other.

4. If your beams are tooshort, connect them witha long lap joint (see nextpage).

5. Dont connect the beamsall on the same verticalline, but spread theconnection points.Equally, dont connectthe inner and outerbeam in the same place.

6. Avoid continuous verticaljoints in the stonemasonry.

1 ft

2 ft

Min. 1 ft

Max. 10 ft

Max. 3 ft

Max. 12 ft

First band

in concreteis better

12

3

6

To avoid verticaljoints, raise allwalls together

First band in

timber is alsoallowed

4

5

4. Walls


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5. Connections 1. Minimum size of beam is3 high by 4 large.

2. Beams must be hookedtogether in the corners.Cut a notch of 1 inch intoall four corner beams. Addnails for more security.

3. Keep 4 inches of woodafter the notch forstrength.

4. Cross pieces: you neednotches only on the crosspieces, but not on the

main beams.5. The same for the middle

walls: Notches only on thebeams sticking out, butnot on the main beams.

6. Lap joints must be 1 footlong. Use four 3 nails tosecure each joint.

7. Its important that you useGALVANIZED nails. Theywill not rust and keep yourhouse save for a longtime.

44

Crosspiece

4

53x4 inch

1

4

2 1

3

1 ft

6

Lap jointat least 1

foot long

7


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6. Retaining walls

Inclined walls:

4. Incline the retaining wallstowards the slope with a ratio of1 to 5, that is 1 ft back for every5 ft of height.

5. Incline the layers according toinclined face of the wall.

6. If you can slightly curb theretaining wall towards the slope,it becomes even stronger.

Stepped walls:

1. Dont make the stepshigher than 2 feet. Thehigher you go, thesmaller the steps should

be.2. End each step with a

reinforced concrete band.

3. Dont make the wallshigher than 8 feet.

Long rebars

(4 sutar)

Stirrups (2 sutar)

every 8

4

2

RCbands

max. 2 ft

2 ft

3 ft

max. 8 ft

1

5 ft

1 ft

3 ft

Inclinelayers

min. 2 ft

max. 8 ft

4

53

You can choose

6


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7. Retaining back-wall

1. Build the retaining wall

together with the housewalls.

2. Put reinforced concretebands into the retainingwall, at the same levels

as in the house.3. Let the concrete band

enter 3 feet into thehouse walls.

4. Prepare notches 1x4

into these concretebands to lodge the timberbeams.

5. Cut notches in all 3pieces of timber.

6. Make the house walls 1 fthigher than the retainingwall so that the roofbeams will not touch theground.

1

4

4

3 ft

3

6

1 ft

3 ft

Long rebars

(4 sutar)

Stirrups (2 sutar)every 8

2

Caution:A retaining back-wallis less save than anindependent

retaining wall!

5

Notches inevery piece


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8. Drainage of retaining back-wall

1. Retaining walls must have

holes to let the water fromthe mountain come out.

2. If the retaining wall is alsothe back wall of thehouse, this is not possible

because you dont want tohave water in the house.

3. Then you have to make achannel behind theretaining wall, with slopestowards outside.

4. Plaster the backside of thehouse with mud to make itwatertight.

5. Fill the space betweenhouse and slope withstones to let water godown into the channel.

3 slope

slope

4 5

21

Holes 4x4every 2 feet


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9. Windows and doors

1. Wall parts mustbe at least 3 feetlong.

2. Windows anddoors must not belarger than 3 feet.

3. Place thewindows betweenthe beams.

4. If you need abigger window, letthe beams gothrough.

5. Place anchorpieces on bothsides of windows

and doors.6. Dont cut the ends

of the beams toplace your door,but place the door

frame againstthem. Fill theremaining gapswith mortar.

4

5

Openingsmax. 3 ft

2

Wallsmin. 3 ft

1

3

6


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10.Pitched light roof with CGI sheets

1. Attach the lastpair of beams withboards to thesecond last pair ofbeams.

2. Add the rafters ortrusses and nailthem down withlong nails.

3. You can alsoplace the

complete trusseson the second lastpair of beams andfill up the wallafterwards.

4. Take care to linkthe last andsecond last pair ofbeams with nailedboards. The sameyou must do on

top of the wall.3

1 2

Pitched roofwith CGIsheets

2 ft

3

4

Placetruss first

Completewall

afterwards


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35

4

6

11. Flat heavy roof with earth cover

1. Let the top beams

(bhateri) stick out of thewall 1 foot on each side.Connect them with nailedcross pieces

2. Add the 4x6 roof beams

and let them too stick out1 ft on each side (alsoover the retaining back-wall if there is) to protectthe wall against rain.

3. Nail the planks on the roofbeams leaving a half inchgap between each.

4. Place flat stones alongthe edge of the roof tocontain the earth.

5. Add twigs and smallbranches in a layer 4 to 6inch thick.

6. Cover with earth 4 to 6inch thick.

7. Avoid to make the earthcover thicker over theyears!

Flat roofwith earth

Ask an experiencedbuilder to help you

build the roof cover.

1 to 2 ft4x 6

Max. 10 ft

1 ft

1 ft1 ft

1

1 ft

1 ft

2

1

Cut slopeto drainawaywater


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12. Flat heavy roof for big rooms

1. If you want to cover a big

room, you dont need anindependent timber structure.

2. Place a beam 5x7 throughthe middle of the room andsupport it in the centre with a

post.3. Dont plant the post in the

ground, but put it on a flatstone.

4. If the central beam is not long

enough, join it on top of thebeam with a long lap joint

5. Add a capital underneath andfix it to the beam with pegsand straps.

6. Add 4x 4 top beams if youplace them 1 feet apart, or4x 5 if you place them at 2feet.

1 NO !

6

Max. 6 ft

Max. 6 ft

4x 4 at 1 ftor

4x 5 at 2 ft

1 or 2 ft

3

2

5x 7

5

Pegs

Straps

Lapjoint

1 ft4

YESNO

Place the

beamsvertically


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13. Adding a second floor

1. It is better to make a

second floor with theDhajji method. Dhajjiconstruction is lighterand better against anearthquake.

2. Make the connectionswith great care. Theresistance toearthquake dependson them.

3. You can subdivide thewalls in different ways.

4. Fill the walls withstones and mud.

8

1

2

3

4

All beamsand posts

4x 4


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14. Adding a room

1. Dont make continuous

vertical joints. Yourhouse will fall apartduring an earthquake.

2. Open the corner whereyou want to add a room.

3. Connect the newbeams through notchesand nails.

4. Fill up tightly with stone,taking care to make

them go also into thenew wall.

5. If the beams go theother way, overlap thenew beams by 2 ft andnail them together.

2 3

4

Connectingstones

Dotted line:

Old corner

4

2 ft

Nails

1


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15. Think for your children

Dont forget:

1. For every tree youcut for your house,plant 5 new onesso that yourchildren will also be

able to build theirhouse one day.

2. Trees also protectyour land againstlandslides: theroots of the treesare like anchors inthe ground.

Guidebook prepared by theSwiss Agency for Developmentand Cooperation SDC(Tom Schacher, technical advisor)

In collaboration with:

French Red Cross and Belgian Red Cross(technical research and development)

UN Habitat, NSET and NESPAK(revisions)

French Red Cross (Translation into Urdu)

Mansehra, NWFP, April 2007

1 tree cut

5 trees planted1

2

07(12)schacher bhatar handout

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