[Strawbale] Rammed Earth and Strawbale

Tue May 2 10:22:14 CEST 2006

I am not sure I understand what is being asked...but I do know a combination
rammed-earth SB house which is being finished this summer in Spain.  There
they used rammed earth in the south--as thermal mass to collect heat in the
winter and stabilize the temperature.  They have prepared the wall with
vents so as to add on a Trombe Wall to add additional heating in the winter.
I have pictures if anyone is interested. Of course where they live it is
cold (even snows sometimes) in winter, but generally sunny!

It is a very dry climate.

They have insulated the foundations with natural corch pannels...if that
answers the insulation question.

Rikki Nitzkin
Aulás, Lleida, España
rikkinitzkin at earthlink...
(0034)657 33 51 62 
www.casasdepaja.com (Red de Construcción con Balas de Paja)

> -----Mensaje original-----
> De: strawbale-bounces at amper....muni.cz [mailto:strawbale-
> bounces at amper....muni.cz] En nombre de strawbale-
> request at amper....muni.cz
> Enviado el: miércoles, 19 de abril de 2006 12:00
> Para: strawbale at amper....muni.cz
> Asunto: Strawbale Digest, Vol 7, Issue 3
> 
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> Today's Topics:
> 
>    1.  combination rammed earth / strawbales (Ben Albu)
>    2. RE:  combination rammed earth / strawbales (Patrick FRD)
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Tue, 18 Apr 2006 23:56:13 +0200
> From: "Ben Albu" <ben at albu...>
> Subject: [Strawbale] combination rammed earth / strawbales
> To: "European strawbale building discussions"
> 	<strawbale at amper....muni.cz>
> Message-ID: <op.s774jzii5wtkfj at pc400mhz>
> Content-Type: text/plain; format=flowed; delsp=yes;
> 	charset=iso-8859-15
> 
> Dear strawbalers,
> 
> These days I have been thinking about some things concerning the
> construction of strawbale walls.
> I also had a look at the construction of walls with the rammed earth
> technique.
> 
> Traditional, breathable strawbale wall : loam / strawbale / loam
> 
> disadvantages of this "sandwich" construction :
> 
> walls are difficult to finish straight, the same problem for the corners.
> setting up of a strawbale wall goes fast and easy, but loaming is a lot of
> work
> a loadbearing wall can shrink over time, and loam will crack.
> 
> advantages of a rammed earth wall :
> 
> construction is easy and goes fast (?)
> cheap (in materials, but it requires more loam)
> straight and beautiful result
> good loadbearing capacities
> 
> disadvantages of this type of wall :
> 
> poor isolation (for cold climates)
> 
> 
> I was wondering if somebody has some experience in making a combination of
> rammed earth / strawbale / rammed earth
> 
> If yes ....
> 
> Would the isolation properties be the same for this kind of construction
> compared to a classical strawbale wall ?
> 
> What about the fire resistant ? Is it advisable to put the bales in
> between without loamfinish ? In Austria they finished a strawbale wall
> completely with wood, but they dipped it in loam before construction.
> Would this also be a requierement if the straw is set up between 2 layers
> of rammed earth ?
> 
> Which advantages/disadvantages do you see for this type of construction ?
> 
> What about he foundation ?
> 
> I am also wondering if the time required to loam a strawbale wall would be
> +- equal to the construction of a rammed earth wall ?
> 
> Are there other techniques to isolate a rammed earth wall ? (Not with
> foam, rockwool, etc ...)
> 
> Thanks for your help.
> 
> Ben Albu
> Belgium
> 
> ben at albu...
> 
> 
> 
> 
> ------------------------------
> 
> Message: 2
> Date: Wed, 19 Apr 2006 10:46:10 +0100
> From: "Patrick FRD" <patrick at frdata....uk>
> Subject: RE: [Strawbale] combination rammed earth / strawbales
> To: "'European strawbale building discussions'"
> 	<strawbale at amper....muni.cz>
> Message-ID:
> 	<!&!AAAAAAAAAAAYAAAAAAAAAHH18cgDB5RBolOS93rTwYnCgAAAEAAAAGOG7NBCTGxO
> l+eUPaNSbYoBAAAAAA==Afrdata....uk>
> 
> Content-Type: text/plain;	charset="us-ascii"
> 
> As a nwebi I don't know if this is the most appropriate way to reply but
> ......
> 
> I have also wondered about increasing the U value of rammed earth walls.
> 
> The shuttering for cavity or double rammed earth walls could be very
> complicated and time consuming.
> 
> A viable option would be to build a single wall having 3 vertical layers
> rammed together.  This could be
> 
> 1050mm wider shuttering with a 450mm bale wall built in the middle and
> 300mm
> of earth rammed on each side.  This is a very thick wall.  The bale will
> move and be compresses during ramming so you will need a well coordinated
> team of rammers.  With experiment the rammed earth could possibly be
> reduced
> to 250mm?  You may need horizontal ties to stop it all falling apart
> possibly layers of chicken wire.
> 
> As an alternative you could use expanded clay beads as the middle
> insulation
> layer.  The beads could be mixed with clay or lime to keep some structural
> integrity. If you used 4-500mm shuttering and carefully separated the
> layers
> with temporary separation boards while filling and initial ramming then
> remove the temporary boards for final ramming.  This will give a
> homogeneous
> insulated wall.
> 
> Alternatively just remove all stones over 5mm in the earth and replace
> with
> expanded clay beads which will probably give the almost the same
> insulation
> benefit as a separate layer of beads and will be much quicker.
> 
> Alternatively use a spray machine to apply the render and edge bead.
> Assuming you intend your building to be permanent the embedded energy and
> the CO2 emissions, involved in using a hired spray machine, will be
> trivial
> over the life of the building will be trivial and probably less that the
> energy involved in excavating the earth.  Rammed earth walls particularly
> double ones, use a lot of sub-soil and unless you are going to do it by
> hand, removing topsoil, excavating and mixing the subsoil, replacing the
> topsoil, moving material to site involves a lot of energy.
> 
> Having said all of that I think that rammed earth looks wonderful my best
> option is Bales with sprayed render for the outer wall and rammed earth
> for
> floors, internal wall, fireplaces and the bottom half or stairs.
> 
> Warning ... none of this is tested just ramblings.
> 
> On a point of clarity the word LOAM seams to have a Varity of meanings it
> is
> often used in Europe to describe inert sub-soil which would be suitable
> for
> earth walls, but in the UK it is used to describe top-soil particularly
> top-soil with lots or organic matter which would be a disaster if
> incorporated in earth walls.
> 
> Patrick
> 
> -----Original Message-----
> From: strawbale-bounces at amper....muni.cz
> [mailto:strawbale-bounces at amper....muni.cz] On Behalf Of Ben Albu
> Sent: 18 April 2006 22:56
> To: European strawbale building discussions
> Subject: [Strawbale] combination rammed earth / strawbales
> 
> Dear strawbalers,
> 
> These days I have been thinking about some things concerning the
> construction of strawbale walls.
> I also had a look at the construction of walls with the rammed earth
> technique.
> 
> Traditional, breathable strawbale wall : loam / strawbale / loam
> 
> disadvantages of this "sandwich" construction :
> 
> walls are difficult to finish straight, the same problem for the corners.
> setting up of a strawbale wall goes fast and easy, but loaming is a lot of
> work
> a loadbearing wall can shrink over time, and loam will crack.
> 
> advantages of a rammed earth wall :
> 
> construction is easy and goes fast (?)
> cheap (in materials, but it requires more loam)
> straight and beautiful result
> good loadbearing capacities
> 
> disadvantages of this type of wall :
> 
> poor isolation (for cold climates)
> 
> 
> I was wondering if somebody has some experience in making a combination of
> rammed earth / strawbale / rammed earth
> 
> If yes ....
> 
> Would the isolation properties be the same for this kind of construction
> compared to a classical strawbale wall ?
> 
> What about the fire resistant ? Is it advisable to put the bales in
> between without loamfinish ? In Austria they finished a strawbale wall
> completely with wood, but they dipped it in loam before construction.
> Would this also be a requierement if the straw is set up between 2 layers
> of rammed earth ?
> 
> Which advantages/disadvantages do you see for this type of construction ?
> 
> What about he foundation ?
> 
> I am also wondering if the time required to loam a strawbale wall would be
> +- equal to the construction of a rammed earth wall ?
> 
> Are there other techniques to isolate a rammed earth wall ? (Not with
> foam, rockwool, etc ...)
> 
> Thanks for your help.
> 
> Ben Albu
> Belgium
> 
> ben at albu...
> 
> 
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> End of Strawbale Digest, Vol 7, Issue 3
> ***************************************