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My cob house. Wall thikness and roofing help!  RSS feed

Hugo Ruax
Posts: 1
Location: Bahia - Brazil
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Hey there...
I am new here, hope to make the right question.
My nemae is Hugo and i am building a cob house in Brazil. Actually I am just finnishing the walls.
As a fisrt time builder I am a little worried about the walls thikness and i get myself questioning
if I should use wodden pillars to support the roof or if I could trust on putting the all weight of the
roof direct on the cob walls.

I've started the base of the walls with 60cm at the base and now they
are about 25cm at the top. We are about to start roffing and it would be very king if someone here
could give some words so i can fell a little more secure about staring the roof.

Thanks a lot and I hope to hear from someboby here!

Big hugs!
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Jack Edmondson
Posts: 240
Location: Central Texas zone 8a, 800 chill hours 28 blessed inches of rain
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You have (for common reference to most sources) a 2 foot wall at the base and about 10-11 inches at the top. From everything I have read that is plenty. You should not need to use a post and beam construction for the roof. However, a good 'bond beam' around the top will go a long way towards the longevity of your wall, for cob or any other material. The bond beam could be horizontal posts embedded in the top several inches of wall. How are you planning to attach the roof to the wall?
Glenn Herbert
Posts: 2180
Location: Upstate NY, zone 5
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Have you ever had an earthquake in your area? If so, I would not trust cob walls alone to support the roof. 60cm at the base is good, but 25cm at the top is fairly thin.

Are you planning to have a ridge supported on posts or on the cross walls I see? If a ridge is supported by other means than the outer walls, you will have short spans and the walls can probably take the load.

Do you ever have hurricanes or very strong winds? in that case, I would want a post structure to hold the roof edges down. I wouldn't trust just the weight of 10-20cm of cob to hang onto the roof well enough.
We should throw him a surprise party. It will cheer him up. We can use this tiny ad:
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