[Strawbale] CRTEZ ZIDA - MOJE MISLJENJE JE DA NISTE DOBRO RAZUMELI KONCEPT GRADNJE SLAMOM

Thu Nov 25 18:38:19 CET 2010

Postovani Jure,

Ko god da je nacrtao ovaj poprecni presek zida, pogresio je. Ovo nije dobar nacin i ovako ce vam malter spolja sigurno popucati.. Bale slame ne treba da posmatrate kao zamenu za termoizolaciju, vec kao gradevinski blok od koga se obicno zidaju zidovi unutar neke konstrukcije (armiranobetonske, celicne ili drvene). Ovaj crtez meni lici na dodatnu izolaciju na montaznoj kuci.

Instalacije se pruzaju unutar zida izgradenog od bala slame - u balama se iskopaju kanali brusilicom koja ima disk kao motorna testera ili motornom testerom, kablovi i cevi se poloze u te kanale pa se sve izmalterise.

Ne znam kakav zavrsni izgled hocete da postignete, ali ako i spolja i iznutra radite clay render - OSB ili druge ploce su apsolutno nepotrebne. Posle veoma malo prakse u ravnanju zida ozidanog balama slame dobicete veoma urednu povrsinu za nanosenje glinenog maltera.

Sto se tice sleganja, konstrukcija objekta treba da obezbedi krutost, ne zid od slame. Kada balama ozidate zid unutar konstruktivnih elemenata, nema straha za pucanje od sleganja. Bale se nalaze unutar nekakvog rama, dobro uglavljene, poravnate i izmalterisane. Na karakteristicnim mestima se postavljaju ojacanja od rabica (pletene pocinkovane mreze) da ne bi doslo do pucanja maltera (bez obzira koje je on vrste.

Stegnutost bala slame se regulise prilikom baliranja i zato je dobro ugovarati slamu direktno sa polja, a onda sa nekim ko ce je balirati posebno pogodite zategnutost vanila (kanapa kojima je bala svezana).

Ne znam da li ste procitali moje prethodne poruke, ali u meni mozete naci veoma koristan izvor informacija. Sledece godine pocinjemo da gradimo nasu fabriku od 4.400 m2, ciji ce svi zidovi biti od bala slame. Jedina smo firma u Srbiji koja je sertifikovala zid od bala slame na protivpozarnu otpornost od 120 minuta (jer po nasim propisima ne treba duze).

Izucavam profesionalno (kao gradevinac) gradnju slamom vec godinama i slobodno mogu da kazem da sam dosta daleko odmakao u tome.

U zelji da pomognem, ne da se nametnem, srdacno Vas pozdravljam i stavljam se na raspolaganje za svako Vase pitanje.

Bane M. Prvanovic

GPB Solutions d.o.o.
Celopecka 8
11000 Beograd

t / f +381 11 386 23 29
m + 381 60 711 0 211
www.dragongpb.com
www.housefasade.com
  ----- Original Message ----- 
  From: Sport Hotel, Jure Pozar 
  To: European strawbale building discussions 
  Sent: Wednesday, November 24, 2010 7:58 PM
  Subject: Re: [Strawbale] Europe's largest strawbale building

  Dear fellow straw balers,

  I appreciate help of all who replied to my previous posts so far, which have helped me a lot with planning my first straw bale house. I have been able to put together a house plan for post & beam with straw bales outside and now when it is finished I would like to ask you for an opinion. I am attaching wall intersection and want to hear your say. If you consider that your replies are too valuable to share freely, please give me number and I am willing to pay a certain amount if it will help me with my planning (reasonable answers with theoretical explanation why should it be done so and so)
  The questions that are still crossing my mind are:
  1.  are OSB plates really better than wooden boards on the inside of the post & beam structure. Timber guys told me the wooden boards breathe too much which make the clay plaster break. I know wooden boards would be cheaper and more natural but I don`t really want to have cracks on my walls. They tell me OSB plates breathe enough. Is it true? The same question with the OSB plates on the outside of the structure: do they breathe enough or will they make moisture on the straw bales when warm air will go from outside to the inside? Or is the lime plaster enough to suck up all the moisture from the straw bale? And how much moisture can really go through the lime plaster? If it is low, than I guess it shouldn`t be a problem. What happens when warm air goes through the wall from the inside to the outside? Will it condense? 
  2.  Another question is what percentage of straw bale can be pressed for every meter? If the straw bale wall is 10 meters high, how much should it be compressed that it won`t fall down/compress any further in the future?
  3. as far as I know it is necessary to compress the straw bale wall, to avoid settling/compressing in the future which would also make the lime plaster crack. How do I compress the walls where I have windows and doors? Is it better to use board frames or are boards above the openings sufficient? 
  4. I am planning to do floor and roof isolation with straw bales as well. I can remember a discussion from Belgium that it is not best to put straw bales in the floor, but can`t remember the explanation why not. I think it was professor Minke who opposed the straw bale floor isolation but there wasn`t enough evidence to prove this theory.
  5. I am also a bit concerned about the straw bales on the roof. We are planning to do the continuous straw bale layer with only screws in the middle to fix the roof laths so there shouldn`t be no problems with the thermal bridging. The thing that concerns me is the classical vapor foil which will be laid above the straw bales. It is supposed to be breathable, but I am afraid it will make condensation in the straw bales. The foil is necessary if the rain gets under the roof tiles - so it slips down the foil. Would it be maybe wise to put another foil below the straw bales, or would it be better to put dip the straw bales in clay before putting them on the roof, so it would such the moisture out of them?

  I appreciate your knowledge, as there are only a few people in my country who know something about straw bale building and they have very little experience as there are only a few straw bale houses in Slovenia and they are all done with infill design which is suitable for certain regions, but not for where I live where we have big temperature differences. If everything goes right the house will be standing till the next ESBG, which I plan to attend. I will start working with straw bales professionally next year in September and will also initiate straw bale association of Slovenia to share the knowledge of straw bale building.

  With best wishes to you all,

Jure Pozar, SLOVENIA STRAWBALE BUILDING

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