AAC Blocks

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Re: AAC Blocks

Postby MGV12 » Fri Jan 04, 2013 11:36 am

fredlk wrote:
MH2 wrote: how long I should wait before I can apply wall tile to the Q-con block in my bathrooms and kitchen.

It is not recommended to use Q-con in bathrooms. I have Q-con everywhere but the bathrooms are all built in red brick. Pattayapope has Q-con in his bathroom and has some issues with it.


Within my sphere of knowledge in the use of AAC blocks here in LOS: The only time AAC block becomes unsuitable for bathrooms is if the walls are not waterproofed first and the tiling is not installed correctly ... the same with any wall construction ... as standards in Thailand are often not what you might call 'best practise' it is wise to be cautious if you are unable or unwilling to ensure the job is carried out correctly :roll: However, if the wall is sealed first, as all bathroom walls should be whatever the construction, and the tiles laid using swimming pool grade adhesive and grout there will be no problem. After all stud walls and plastered/rendered walls are not waterproof either. I have seen many bathrooms tiled here and, unless instructed otherwise [and watched] the workers pay little or no attention to the waterproofing need. Even when using swimming pool grade grout it's a good idea to seal the grout surface when it's dry ... this also makes cleaning easier/more effective and keeps the grout lines looking good for longer.

In response to the question by MH2:

With the exception of the very rare stud wall, all walls here have a significant moisture content when constructed; block and red brick being the highest due to the thick beds of mortar used; whereas AAC uses thinset adhesive which is by its very nature thin and therefore introduces a very low water content. With temperatures as high as they are excessive moisture is not usually the problem ... it's often the opposite where the blocks/bricks absorb the moisture from the render and dries out too quickly ... thus causing poor adhesion/cracks. A completely dry wall is more susceptible to cracking and other problems than one that has a [low] moisture content.

An aside and not applicable to AAC block walls: I have done a lot of work on 'Black & White Thatch' houses in the UK and they can have very serious problems if the walls are not allowed to absorb moisture from the air. That's why a lime render is employed ... a customer bought an old house without having a full survey and subsequently had to have all the walls stripped and re-rendered as a cement render had been used which caused the walls to dry out; a very expensive mistake.

I would be interested to know where you found the comment "If sealed, the moisture will lower the R-factor of the block and shorten its lifespan." and what the climatic conditions were where this occurs and the levels of moisture they were referring to. A very high moisture content can without doubt cause issues but so can a very low one ... causing the walls to be less resilient to absorbing the micro-movements due to changing climatic conditions, passing traffic etc.

As always ... just my opinion and discussion input ... I don't profess to be an AAC block expert. I find that there are many varied opinions on many such subjects these days [mostly due to content found on the internet] and they can't all be right; or wrong.

No problems whatsoever with any of my AAC walls, including shower areas, after nearly three years.

“Some days I am an optimistic pessimist ... other days I am a pessimistic optimist”
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Re: AAC Blocks

Postby Sometimewoodworker » Fri Jan 04, 2013 1:25 pm

MH2 wrote:I now have another AAC/Q-con question that I have not seen addressed here. The recommended way to finish exterior walls is to use a "breathable" stucco plaster. This means that although the stucco should repel water it will allow small amount of moisture trapped in the block to evaporate back out through the stucco layer. The recommendation for interior finishing is similar. The recommended finish is a breathable latex or mineral paint. I've also seen reference to breathable acrylics.

Apparently the reason for requiring "breathable" finishes is that all AAC block contains moisture (as high as 18%) when freshly produced and it takes several months for this moisture to dissipate even when the block is unfinished.

I don't know where you got that idea from as far as I can discover, unless badly stored, AAC block contains little to no moisture. They do need slight wetting when laying and the "glue" like all cement based mortar contains some water. For more information the link under may help.
http://citadelecobuild.com/index.php?option=com_content&view=article&id=88&Itemid=328
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Re: AAC Blocks

Postby cooked » Fri Jan 04, 2013 4:34 pm

I used 'breathing plaster' 30 years ago, my BIL next door used 'non-breathing' plaster for rendering outside, in Switzerland. Can't see any difference yet. I also built the bathroom with these blocks and finished off with wood instead of rendering. Still Ok last time I looked.
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Re: AAC Blocks

Postby MGV12 » Fri Jan 04, 2013 7:36 pm

Sometimewoodworker wrote:For more information the link under may help.
http://citadelecobuild.com/index.php?option=com_content&view=article&id=88&Itemid=328


Personally I would not follow the Indian standard [as per the link] for construction using AAC blocks. Just one example is they quote a 10mm bed thickness when laying ... whereas the adhesive used here and in Europe is a thin set [type] with a nominal thickness of 3mm as applied and 2mm when compressed by laying the block. The notched applicators available make this a simple process.

The following link may be of interest ... it also briefly addresses the installation of tile on an AAC wall in shower areas.

http://masonrymagazine.com/6-08/autoclaved.html

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Re: AAC Blocks

Postby MH2 » Sun Jan 06, 2013 2:58 pm

I would be interested to know where you found the comment "If sealed, the moisture will lower the R-factor of the block and shorten its lifespan." and what the climatic conditions were where this occurs and the levels of moisture they were referring to.


My bad, the following reference only mentions R-factor, not lifespan...

http://www.cement.org/HOMES/expert_AAC.asp
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Re: AAC Blocks

Postby MH2 » Sun Jan 06, 2013 3:04 pm

I don't know where you got that idea from as far as I can discover, unless badly stored, AAC block contains little to no moisture. They do need slight wetting when laying and the "glue" like all cement based mortar contains some water. For more information the link under may help.


See the following link...

http://www.cement.org/HOMES/expert_AAC.asp
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Re: AAC Blocks

Postby Sometimewoodworker » Sun Jan 06, 2013 3:29 pm

MH2 wrote:
I would be interested to know where you found the comment "If sealed, the moisture will lower the R-factor of the block and shorten its lifespan." and what the climatic conditions were where this occurs and the levels of moisture they were referring to.


My bad, the following reference only mentions R-factor, not lifespan...

http://www.cement.org/HOMES/expert_AAC.asp

Both the reduction in lifespan of unfinished AAC block and the concern over the water content are from states like Illinois, U.S.A.where there is a freezing element to the weather.

The water content is similar to that of wood that has been air dried and is unlikely to be significant here given the fact that ambient humidity levels are seldom less than 50% and in the rainy season over 90%. However of course like any other wall material it should be suitably finished and protected from continuous driving rain if possible.

The reduction in lifespan comes from ice expansion, not a usual problem in Thailand :roll: :roll: :lol: :lol: :lol:

With a suitable finish it is perfectly OK to use in bathrooms
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Control joints in ACC Block walls

Postby Kiwi65 » Fri Jan 24, 2014 2:32 pm

Hi,
Some design guides recommend the use of control joints in ACC block walls to avoid cracking due to differential movement in dissimilar materials and foundation movements etc.
Has anyone considered the use of these, or alternatively, not used them and now wishes they had!!
thks
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ACC block walls - design constraints

Postby Kiwi65 » Fri Jan 24, 2014 2:38 pm

on one of the Thai ACC web sites, it recommends wall stiffeners.
For example, a 75,, block wall 3.0m high has a max horizontal length 2.5 m before a column stiffener is required.
Or alternatively, a 150mm wall 3m high has a design span of 4.5m

Has anyone got first hand experience with these design constraints. and therefore some helpful advice??

thks
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ACC block walls Tie downs

Postby Kiwi65 » Fri Jan 24, 2014 2:48 pm

Hi
In all the Thai literature reviewed, they do not use any method to tie the first and second tiers down to the floor slab. In other countries, there are clear methods.

Has anyone considered the need for such methods here in Thailand and if so, what method have you used and with which block??

thanks
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Re: AAC Blocks

Postby edvrijmoet » Fri Jan 24, 2014 6:11 pm

if you want to know about construction methods with AAC blocks look at the PDF files provides on the page link below.

http://www.xella.co.uk/en/content/details_1210.php
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Re: AAC Blocks

Postby Mike Judd » Sat Jan 25, 2014 7:04 am

I used Q-con blocks at my house near Khon Kaen 2 years ago and found that it evolved quite a lot of running around , mainly because of the usual "Not wanting to loose face" syndrome, but I got there in the end. I am repeating myself here from other posts, but here goes. First you can't go far wrong if you use Q-Con blocks, they are licenced by Hebel of Germany and although there are copies that you could be O.K. with , Q-Con have the back up that I might have been lucky to get at the time. Their Rep came out ,brought the necessary tools, showed my guys how to lay them /put the ties in to the columns etc; left a detailed instruction booklet in Thai and organised a delivery from Maha Sarakham as Khon Kaen were out of stock. I put a plastic damp course under the first layer of blocks that has a normal cement bed so as to level them before going onto the glue method . The Orange booklet has everything that you would want to know in it for building walls the Thai way. (I.E. Non load bearing.) I only paid B24 per 100m.m. thick block ,but prices seem to have gone all over the place since then. You really have to search around with most things in Thailand because as we all know (Or should) Thais have a habit of saying anything if they don't know or think you will accept an inflated price, being a Farang ? As other's mention the blocks can be used anywhere but need to be rendered with the correct water resisting material then tiles or paint. What thickness you use is entirely up to you and how much you want to spend, 75m.m. being the minimum.
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Re: AAC Blocks

Postby Psychic » Sun Mar 02, 2014 11:11 am

So you would still use posts with Q-con? The 20cm blocks are load bearing so you could, I guess, eliminate the posts. But would Thai builders have problems with the roof structure without having the posts to tie into? I'm considering 20cm blocks for my house and would love to eliminate the posts if it didn't become a major issue.
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Re: AAC Blocks

Postby pattayapope » Sun Mar 02, 2014 1:38 pm

A friend built a bungalow without using columns and it is ok after several years, if you cast a ring beam with decent rebar it should be OK. My house is using twenty cm blocks but has columns but I am sure it culd of been built without them, just remember use all the correct products for rendering etc as these blocks like to soak up water and the wall paint will come off line mine in places. Also if you use a light weight roofing system this will also reduce the load.
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Re: AAC Blocks

Postby Psychic » Sun Mar 02, 2014 5:12 pm

Great thanks, would it make any sense to cap the walls with Q-Con lintels before putting a steel ring beam for the roof?
I'm just trying to get my head around the things you have to consider with AAC like the special render/ mortar. There seems to be two views on them sucking up water but I guess if you do everything right they're fine. Are your blocks fine for supporting shelving/cupboards? I've read somewhere that you need special supports.
Someone said there are no stupid questions. I can probably disprove that :-)
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