Load bearing, cavity brickwork.

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Re: Load bearing, cavity brickwork.

Postby canopy » Sat May 16, 2015 10:28 am

MGV12 wrote:The minimum width allowed here is 20cm [as all blocks sold as AAC are not necessarily up to standard] however in other countries with more stringent codes 10cm AAC is accepted as being load-bearing


On the contrary, other countries can be more stringent than Thailand. Take for instance Hebel, the parent company of q-con. Their spec for Australia is as follows:

Generally, the minimum recommended wall thickness is:
250mm for external walls
150mm for internal load-bearing walls
100mm for internal non-load bearing walls
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Re: Load bearing, cavity brickwork.

Postby MGV12 » Sat May 16, 2015 12:12 pm

canopy wrote:
MGV12 wrote:The minimum width allowed here is 20cm [as all blocks sold as AAC are not necessarily up to standard] however in other countries with more stringent codes 10cm AAC is accepted as being load-bearing


On the contrary, other countries can be more stringent than Thailand. Take for instance Hebel, the parent company of q-con. Their spec for Australia is as follows:

Generally, the minimum recommended wall thickness is:
250mm for external walls
150mm for internal load-bearing walls
100mm for internal non-load bearing walls


"On the contrary" :)

I don't see from the literature online that Hebel Germany are directly specifying what the Australian manufactures/purveyors should recommend for the minimum thickness of AAC blocks in load-bearing walls. When referring to other AAC block manufacturers [under licence or not] and Government sites there does not appear to be anything more specific let alone a consensus. Even the Australian Hebel site only recommends "External walls are typically constructed using 250mm thick Hebel PowerBlock+" Why quote 'typically' if that is the minimum specification/code? It could as easily be due to a combination of structural and insulation properties. Based on whose opinion? I would be very interested to see a link to the parent company's current thinking and whether that applies to all territories to which they export or grant licences.

General footnote: Specifications demanded by building control authorities and those who manufacture building-related products are in a constant state of flux ... therefore it always pays to check out the current situation or engage a professional to do so on your behalf; should such person exist/be available at affordable rates where you are looking to build.

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Re: Load bearing, cavity brickwork.

Postby canopy » Sat May 16, 2015 12:35 pm

True, and even other things like fire resistance, seismic and acoustics could be factors in the recommendation. But the important thing is block size should not be chosen arbitrarily, especially if they are load bearing. It is wise to stick with the manufacturers instructions. Realistically, there are just not going to be many people here who can prove a smaller size would be ok for their purposes or pay a qualified person to perform a proper analysis to determine if it is feasible.
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Re: Load bearing, cavity brickwork.

Postby MGV12 » Sat May 16, 2015 2:40 pm

canopy wrote:Realistically, there are just not going to be many people here who can prove a smaller size would be ok for their purposes


No point in arguing with that.

However ... where are manufacturers instructions posted that specifically specify the minimum width for an AAC block to be deemed as load-bearing?

Surely the load that is being supported should have a bearing on it.

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Re: Load bearing, cavity brickwork.

Postby FT10toLOS » Sat May 16, 2015 5:29 pm

pipoz wrote:They look good. Could easily use them for a BBQ area

pipoz

True, but I'm exploring the possibility of using them as a cavity (2 skins) load bearing wall and doing away with the column//beam thai method totally.

I'm wondering if any forum members have any knowledge / experience in their use.
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Re: Load bearing, cavity brickwork.

Postby Ians » Sat May 16, 2015 5:35 pm

Why, any good reason over cavity wall with columns and beams considering it us something most builders are good at / happy to do etc.
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Re: Load bearing, cavity brickwork.

Postby Sometimewoodworker » Sat May 16, 2015 6:05 pm

FT10toLOS wrote:
pipoz wrote:They look good. Could easily use them for a BBQ area

pipoz

True, but I'm exploring the possibility of using them as a cavity (2 skins) load bearing wall and doing away with the column//beam thai method totally.

I'm wondering if any forum members have any knowledge / experience in their use.

You seem to be heading for a world of hurt. Getting Thai builders to construct in the way they know (column and beam) without mistakes is often a challenge. Getting them to build something they have never experienced is much more fun, if you are a masochist :lol:
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Re: Load bearing, cavity brickwork.

Postby Roger Ramjet » Sat May 16, 2015 9:35 pm

FT10toLOS wrote:True, but I'm exploring the possibility of using them as a cavity (2 skins) load bearing wall and doing away with the column//beam thai method totally.

I'm wondering if any forum members have any knowledge / experience in their use.


It would depend on how many floors you intend going up. I would not place another slab on top of a load bearing Superblock wall, even if it was double thickness. You would have too many forces working against you here with the heat, let alone the fact that Thailand is regarded as a earthquake prone area. Thai builders tend to like columns so they can tie in the steel for the roof onto something. You would need to anchor a lot of steel along both load bearing walls and then you run into expansion again. Don't forget that Superblock do not expand, but steel does.
You would also have to consider how you would keep the wall straight for any length. Even with columns lazy Thai builders have a bad habit of not being too particular about straight walls, claiming the render will cover their mistakes.
You would have to be on the job the whole day.
There is a reason why load bearing Superblock walls vary in thickness and the maker will not make recommendations. If you look at places like Darwin Australia, that now use Superblock as load bearing walls, you'll find the width is different to say Melbourne Australia. The reason behind that is Darwin is subject to cyclones and Melbourne is not.
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Re: Load bearing, cavity brickwork.

Postby canopy » Sun May 17, 2015 8:29 am

I don't get posts like this Roger. I could be wrong, but it sure sounds like a lot of uninformed blabbering without any factual basis. People come here I think to get reliable information. Let me reply to some of this from a spec. "Depends on how many floors"? No it doesn't. "I would not place another slab on top"? The spec describes how to do it safely so why would one care what you would or wouldn't do. "Need to anchor a lot of steel along both load bearing walls?" Several completely different anchoring methods are recommended and that is not one of them.

However, I agree with the consensus that a huge problem with load bearing walls is not being able to find a Thai builder who is capable of doing it correctly. What you will often find is they don't follow specs, but instead make things up like Roger. This can result in areas that are already strong get beefed up resulting in wasted material doing nothing. And areas that are weak get overlooked and can fail. On a load bearing wall that isn't worth the risk. Just making a properly engineered supporting slab for load bearing blocks is way beyond the common builders capabilities. Even given a spec they may choose not to follow it or do their best only to make lots of errors with bad cement mixing, rebar touching earth, etc.
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Re: Load bearing, cavity brickwork.

Postby Roger Ramjet » Sun May 17, 2015 10:17 am

canopy wrote:I don't get posts like this Roger. I could be wrong, but it sure sounds like a lot of uninformed blabbering without any factual basis.

canopy wrote:What you will often find is they don't follow specs, but instead make things up like Roger.

canopy,
You naughty boy you, you haven't read my build and certainly not Max and Bee in Chiang Mai because that's where it was raised as Max started ahead of me. Max built an observatory that was more than two stories.....but it's all discussed on those pages because Max is in an earthquake area..... and he had problems with his workers. But that's just rehashing what's already written.
To be honest I was answering the original posters question without knowing the specifics, which is why it was addressed to him and asking for more details.
canopy wrote:The spec describes how to do it safely so why would one care what you would or wouldn't do.

Could you please point me to the site in Thailand in an earthquake area that gives those specs?
canopy wrote:"Need to anchor a lot of steel along both load bearing walls?" Several completely different anchoring methods are recommended and that is not one of them.

Please point me to the website in Thailand that shows the different anchoring methods for double skinned Superblock?
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Re: Load bearing, cavity brickwork.

Postby canopy » Sun May 17, 2015 1:17 pm

I at times need to reference things like seismic, soil and wind loading information for a particular site. The answers to these get a lot more specific than "Thailand" just so you know. When I get the numbers I provide them to an engineer or plug them into the table of the building specifications and follow the recommendations. Pretty simple. Maybe you should try it.
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Re: Load bearing, cavity brickwork.

Postby Roger Ramjet » Sun May 17, 2015 1:53 pm

canopy wrote:I at times need to reference things like seismic, soil and wind loading information for a particular site. The answers to these get a lot more specific than "Thailand" just so you know. When I get the numbers I provide them to an engineer or plug them into the table of the building specifications and follow the recommendations. Pretty simple. Maybe you should try it.

canopy,
You didn't answer one question. It was posted earlier by a number of people that information changes from location to location.
I did try it, I built a double skin Superblock house at viewtopic.php?f=3&t=1864 and Max's build is at viewtopic.php?f=3&t=1970
When I also get the numbers I go and see the Or Bor Tor engineer because local conditions do apply and he's the only one qualified to tell you what is allowed and what's not because he has to stamp every page of the plans and sign off on them.
If you had cared to look at the building regs for the two places I posted, Darwin and Melbourne regarding load bearing superblock you'll find they are totally different.
And as you will see from Max's build there was a huge amount of steel used because he went with roof tiles and had a cavity Superblock wall.
I'm just saying, I've been there and done that, which is why I posted in the first place.
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Re: Load bearing, cavity brickwork.

Postby FT10toLOS » Sun May 17, 2015 2:06 pm

Roger Ramjet wrote:
FT10toLOS wrote:True, but I'm exploring the possibility of using them as a cavity (2 skins) load bearing wall and doing away with the column//beam thai method totally.

I'm wondering if any forum members have any knowledge / experience in their use.


It would depend on how many floors you intend going up. I would not place another slab on top of a load bearing Superblock wall, even if it was double thickness. You would have too many forces working against you here with the heat, let alone the fact that Thailand is regarded as a earthquake prone area. Thai builders tend to like columns so they can tie in the steel for the roof onto something. You would need to anchor a lot of steel along both load bearing walls and then you run into expansion again. Don't forget that Superblock do not expand, but steel does.
You would also have to consider how you would keep the wall straight for any length. Even with columns lazy Thai builders have a bad habit of not being too particular about straight walls, claiming the render will cover their mistakes.
You would have to be on the job the whole day.
There is a reason why load bearing Superblock walls vary in thickness and the maker will not make recommendations. If you look at places like Darwin Australia, that now use Superblock as load bearing walls, you'll find the width is different to say Melbourne Australia. The reason behind that is Darwin is subject to cyclones and Melbourne is not.


Hi Roger,
Excuse my ignorance, but "Superblocks" is the name of the bricks I posted pictures of ?
As far as specfications/standards go, I'm a retired builder from Australia, so I'm currently just applying Aussie requirements at this prelim stage. This should well and truly cover local requirements until final tweaking for local requirements closer to build commencement.
Regards Rod
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Re: Load bearing, cavity brickwork.

Postby canopy » Sun May 17, 2015 4:08 pm

Roger Ramjet wrote:You didn't answer one question


Yes, but I did describe how you can can get reliable answers to these or other questions. Personally, I don't care about your questions and I am not going to bother to answer any of them even should I already know some or all of the answers. Instead, try to focus on solving these things without my intervention. Only then maybe you will see your post made little sense and could be a detriment to others.
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Re: Load bearing, cavity brickwork.

Postby FT10toLOS » Sun May 17, 2015 4:27 pm

Ians wrote:Why, any good reason over cavity wall with columns and beams considering it us something most builders are good at / happy to do etc.


Hi Ian,

I did go a little way for reasons in my original post. My reasons for exploring possible local techniques for a load bearing wall structure are;

1) It's a building method I'm very familiar with.(I'm also familiar with column/beam construction, with a stressed concrete background, so I understand how easy it is to get it wrong, ie concrete strengths, rebar cover, pour joints etc)
2) I feel I can keep control over quality and costs more so than with a column/beam technique.
3) It's faster and less labour intensive.(although labour is cheap here)
4) Allows for a "raft slab" construction for footings/slab on ground.(advantages as above)
5) It is possible for me to be on site for the duration of the build.

I also realise that the locals are very familiar with their techniques but that is something I'll consider when I finally make my decision which way to go.
As pointed out by other posters, there are others factors such as geotechnic, earthquake, cyclonic, thermal etc to consider.
At this stage I'm mainly fact finding and the input by posters as yourself is invaluable.
I want to check the "build" threads on this site as time allows, as I'm sure many of my questions will be answer there.

Regards
Rod
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