Adding a 2nd AAC block inner wall to all perimeter walls

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Re: Adding a 2nd AAC block inner wall to all perimeter walls

Postby Klondyke » Sat Sep 02, 2017 9:56 am

canopy wrote:
Klondyke wrote:In my "up-country" it is the cheapest (5 Baht for 40x20cm), in yours obviously might be different.


This is a common misconception. You have to consider other cost factors than the block cost. q-con blocks are much larger than cinder blocks so think cost per sqm, not cost per block. Second, the cost of building with cinder blocks rises again when you consider they need 10mm of mortar. q-con needs just 2mm mortar AND because they are much wider and taller use less mortar yet again. The time and therefore cost of laying cinder blocks is also higher because you have to lay a dozen or two of them for every one q-con. And so on and so forth. As I mentioned earlier, builders who have used all 3 say the final cost difference in a house is nil. That's why you see some of the poorest people on the tiniest budget using q-cons.


What I have meant was the cost for sqm if with double cinder blocks each for 5 Bht. So, what is the cost per sqm with q-con?

And sorry, I have yet to see 2 mm mortar made by the poorest people...
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Re: Adding a 2nd AAC block inner wall to all perimeter walls

Postby canopy » Sat Sep 02, 2017 10:58 am

Klondyke wrote:What I have meant was the cost for sqm if with double cinder blocks each for 5 Bht. So, what is the cost per sqm with q-con?


q-con is 200Hx600W so 8.3 blocks per sqm. cost is commonly 16 baht so 133 baht per sqm. But again don't forget all the other factors. Block is just one part of the cost picture. For example, q-con is one popular brand, others brands are cheaper.

Klondyke wrote:And sorry, I have yet to see 2 mm mortar made by the poorest people...


lol, i know what you mean. but q-con should always be set with slotted scoup trowels now stocked at most hardware stores yielding a perfect 2mm mortar bed and rapid mortaring with just a single swipe over the block. Also, aac mortar should always be used. Thick mortar and/or using sand & cement is bad in many ways such as higher cost and thermal bridging.
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Re: Adding a 2nd AAC block inner wall to all perimeter walls

Postby Klondyke » Sat Sep 02, 2017 11:30 am

canopy wrote:
Klondyke wrote:What I have meant was the cost for sqm if with double cinder blocks each for 5 Bht. So, what is the cost per sqm with q-con?

q-con is 200Hx600W so 8.3 blocks per sqm. cost is commonly 16 baht so 133 baht per sqm. But again don't forget all the other factors. Block is just one part of the cost picture. For example, q-con is one popular brand, others brands are cheaper.


Cinder blocks 40x20 cm: 12.5 pcs/m2 x 5B = 62.5B/m2, If 6B/block = 75 Baht/m2
So, that's quite a difference.

Klondyke wrote:And sorry, I have yet to see 2 mm mortar made by the poorest people...

canopy wrote: lol, i know what you mean. but q-con should always be set with slotted scoup trowels now stocked at most hardware stores yielding a perfect 2mm mortar bed and rapid mortaring with just a single swipe over the block. Also, aac mortar should always be used. Thick mortar and/or using sand & cement is bad in many ways such as higher cost and thermal bridging.


I do not know the cost for aac mortar, surely much more than the usual cement mortar. And I assume that the workmanship for making mortar plaster is of the same effort whether 2 mm or 5mm or 10mm. And the material, cement and sand is very cheap. Cement = 110 Baht, track ca. 3 m3 = 800 Baht.

More effort to spend for 2 mm on site, to get such a thin sand thru a fine mesh ca. 1mm, In fact, I have never seen it so thin. They always do the 5 - 7 - 10 mm with normal cement and easy meshed sand, so it is in rural Thailand. And there is always a lot of material found at the bottom of the wall what is sometimes made use of and sometimes not.
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Re: Adding a 2nd AAC block inner wall to all perimeter walls

Postby canopy » Sat Sep 02, 2017 12:02 pm

Saying mortar is cheap fine if you are talking one bag. And we are talking a huge quantity difference here like 5 or 10 to one. Mixing also takes time (and money) and when buying by the cubic meter of material dumped on the ground there will be waste. Comparatively AAC mortar comes in neat 50KG bags, is pretty cheap and different brands are available at different prices. If using the correct trowel there are edge guards, thus there is no wasted slop on the floor and the bed is always exactly 2mm with a single swipe. Doing it right is super fast, not the other way around. No one smart enough to be on this forum should allow a builder to do a job without the right trowel. And since q-con is larger this is less mortar again.

We've only talked about a few differences like mortar and speed of laying, but there are other cost factors. But I think it's all a pretty pointless comparison. Using thick q-con blocks (125mm-250mm) gives a substantial advantage in thermal performance, one of the most critical parts of a house in Thailand. I just can't imagine the up front price difference being a barrier to most people. I don't really buy into always using the cheapest, but those people are out there. God forbid someone comes out with a 10mm thick block. People will build houses with it and claim it is cheaper and therefore the superior choice.
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Re: Adding a 2nd AAC block inner wall to all perimeter walls

Postby Ians » Sat Sep 02, 2017 12:44 pm

Of course all this about thermal insulation for walls, ceilings and roofs is all nonsense when SWMBO throws open all the doors and windows when it's 36c outside because the breeze is cooler, effectively balancing out the inside/outside temperatures and negating any effects from the carefully planned and expensive insulation installed.
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Re: Adding a 2nd AAC block inner wall to all perimeter walls

Postby Sometimewoodworker » Sat Sep 02, 2017 12:47 pm

Klondyke wrote:
I do not know the cost for aac mortar, surely much more than the usual cement mortar. And I assume that the workmanship for making mortar plaster is of the same effort whether 2 mm or 5mm or 10mm. And the material, cement and sand is very cheap. Cement = 110 Baht, track ca. 3 m3 = 800 Baht.

More effort to spend for 2 mm on site, to get such a thin sand thru a fine mesh ca. 1mm, In fact, I have never seen it so thin. They always do the 5 - 7 - 10 mm with normal cement and easy meshed sand, so it is in rural Thailand. And there is always a lot of material found at the bottom of the wall what is sometimes made use of and sometimes not.


The equivalent area of sand and cement (disregarding the time taken if you need to sieve it) is around 5 bags of cement + maybe 200 ~300 Baht of sand. So about 600 Baht, wastage at least 5 to 10%

The equivalent is 50kg bag of AAC glue at maybe 130baht, no extra sand needed so 2mm is simple to do.

Labour for the glue, dump some in a 5 gallon bucket add water and use a paint mixer, so probably 1/5 the time, virtually no wastage.

You really should try AAC yourself, you will never want to to use the expensive cinder blocks walls again.
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Re: Adding a 2nd AAC block inner wall to all perimeter walls

Postby Klondyke » Sat Sep 02, 2017 12:50 pm

Ians wrote:Of course all this about thermal insulation for walls, ceilings and roofs is all nonsense when SWMBO throws open all the doors and windows when it's 36c outside because the breeze is cooler, effectively balancing out the inside/outside temperatures and negating any effects from the carefully planned and expensive insulation installed.


I fully agree with you. The windows - mostly difficult to reach - are the whole year either left open or closed.
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Re: Adding a 2nd AAC block inner wall to all perimeter walls

Postby Andyfteeze » Sat Sep 02, 2017 3:03 pm

Klondyke, you still dont get it? Double blocks is fine if it impedes the flow off heat. If however, the heat is continuous, it eventually finds its way in uncontrollably. Its the nature of the beast. leave all the doors and windows open, and your cinder block soon absorbs what ever latent heat there is. Your aircon use is marginally greater than it needs to be. Sure its better than single skin, but thats just arguing over adequacies. Having the cavity open at the top just doesnt help the insulating properties you want. At best the cinder wall is trying to get to the ambient temp in the shade. Those are facts, you cant twist them. It may be fine for you, but thats not what we are on about.
Your aircon is working to keep the walls cool instead of keeping the air cool. But really, if you dont mind paying the electricity bill, this whole conversation is irrelevant.

My new build still has no doors or windows but is very noticeably cooler all the time. My anticipation is that electricity running costs ( mainly aircon ) will be very small a long way into the future. A cheap and comfortable existence is what i was after.

Another cost factor with Qcon is total life efficiency. Your power bills can be halved by using qcon instaed of cinder. Over a long period of time, Qcon will actually be saving money. Its like saying I am going to buy a V8 cause they are cheap to buy then pay everytime you fill up!

PS moderator " TIHS" isnt "terrible", woeful would have been a better description. Good to see you on the job anyway. I could have used PARC, but then it may have fallen foul of ................... lol <original post amended :D - Mod>
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Re: Adding a 2nd AAC block inner wall to all perimeter walls

Postby Sometimewoodworker » Sat Sep 02, 2017 3:54 pm

Andyfteeze wrote:
My new build still has no doors or windows but is very noticeably cooler all the time. My anticipation is that electricity running costs ( mainly aircon ) will be very small a long way into the future. A cheap and comfortable existence is what i was after.


That was exactly our experience, we are a few months ahead of you, but it will warm up quite a bit with doors and windows. Though the AC cools everything down very quickly.

Are you going with LED's everywhere? That will also help reduce heat gain and power costs.

Ps QCon is already cheaper than cinder blocks just for the build.
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Re: Adding a 2nd AAC block inner wall to all perimeter walls

Postby Klondyke » Sat Sep 02, 2017 4:21 pm

Andy,
you might be right for the different materials with different heat accumulation ability. However:

We do not have the cavity open on the top, the walls are fully encased.

For 6 working days we are not at home, only evenings, the house is closed, therefore cool, the walls are not much over 30. Evenings, after 18.00 the outside air is already down around 30 and later night dropping down to 24 - 26.

We do not run a/c most of days. E.g. now, for last month when evenings daily raining it hasn't been switched on. During the high summer April - July, we run just few hours before we go to bed, up to early morning switched off at 4 am, the temperature selected to 26 deg.

And evenings, we swim. Once staying half an hour in the water (28 - 30deg), then another 2 -3 hours we do not feel overly hot. When evenings sitting I put on socks, sometimes long Johns and a shirt with long sleeves (some laughs :D ).

My electricity bill is suffering not because of a/c but because of my 6 pumps (well pump, river water pump, house aut. pressure pump, pool filter pump, fish pond recirculation pump, rainwater tank forwarding pump).

In November, December, January, February, evenings, sometimes also Sunday morning I light up my fireplace, enjoying the flames and warmth.

Image
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Re: Adding a 2nd AAC block inner wall to all perimeter walls

Postby Andyfteeze » Sat Sep 02, 2017 8:58 pm

i like your line, the walls are cool, not over 30 degrees. lol. classic.
Yes bought a whole stack of 7w and 10w phillips leds. Flatish with no external Tfr. Even outside lights, bought some pretty solid led units.

Klondyke, my point is with qcon blocks your aircon cools the air, not the walls. I consider 25degrees comfortable, 30 , is still rather warm for sleeping.
My design specs demanded that the walls absorb as little heat as possible thus allowing the aircon to more effectively cool the air and reduce the humidity. Thus it will be on for short periods of time only, saving on power. The new inverter technology does it well.
To test this, does the room warm up if you turn the aircon off? If so, the blocks are radiating heat and your aircon is cooling the walls. Qcon blocks dont radiate what they dont store. its all part of construction industry culture here - monkey see and monkey do without a single thought about how and why.
Anyway, as i said if your happy its a mute point. This is really about understanding why some products should be left on the shelf. I am not here to convert people, but when i read misconceptions I have to reply.

Cinder blocks/red bricks are not suitable for home construction. they are used through ignorance or cost. What was suitable 5 years ago is now not, even in Thailand.
some may think thats a big call, i think its a logical position.
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