My home builder is offering me the choice of QCON (AAC) block or large cement block (cinderblock) for the same price installed for all exterior walls.

[Silencer]

When I looked up the cost for each product (20cm think vs 19.5cm thick) it looks like QCON is at least 3 times more expensive. I have read many of the pros/cons of QCON (primarily insulation qualities and workability vs strength in hanging very heavy objects on it and render cracking).  Regardless, all things being equal, wouldn't it be a no brainer to go with the upgraded QCON block or do the large concrete blocks offer some advantages I should consider. Looking for a sanity check before making the decision. Maybe some of you choose one over the other for non cost-related reasons I should consider.

[Crossy]

I think 90% of us would say Qcon, purely for the better insulation properties (lower A/C energy costs).

 

Built correctly there really aren't any disadvantages.

 

[carlyai]

What size are the large blocks, you got a picture?

Those large 8" cement blocks are a good thing.  Not used the Thai ones but in Aus they are used extensively.

[Encid]

We are using the AAC blocks for our build (ThaiCon not QCON... same same), however there is a cinder type concrete block available that incorporates an air gap, which may make them a possible cheaper alternative with some insulating properties.

 

 

They are called "Fast Bricks" and come in different thicknesses from 3" to 8".

 

[Silencer]

45 minutes ago, carlyai said:

What size are the large blocks, you got a picture?

Those large 8" cement blocks are a good thing.  Not used the Thai ones but in Aus they are used extensively.

The large cinderblocks are 39cm length, 19cm height and 19.cm width. Pic below. I have seen homes in the area using double block, these cinderblocks, and AAC blocks.

[Silencer]

9 minutes ago, Encid said:

We are using the AAC blocks for our build (ThaiCon not QCON... same same), however there is a cinder type concrete block available that incorporates an air gap, which may make them a possible cheaper alternative with some insulating properties.

 

 

They are called "Fast Bricks" and come in different thicknesses from 3" to 8".

 

Yes, it appears my builder is offering the WK-8/WK8-1 style or AAC.

[Silencer]

Has anyone found any problems with hanging heavy objects (kitchen cabinets, AC/units, stone wall murals, etc) or adhesion issues with AAC?  I'll need to look up the correct fasteners for heavier loads but if they work well, that eliminates that concern.

[Encid]

Just now, Silencer said:

Has anyone found any problems with hanging heavy objects (kitchen cabinets, AC/units, stone wall murals, etc) or adhesion issues with AAC?  I'll need to look up the correct fasteners for heavier loads but if they work well, that eliminates that concern.

From the QCON handbook depending on the blocks thickness the allowable load in kg/m² is quite high provided that you use the correct fasteners.

 

[Pouatchee]

28 minutes ago, Silencer said:

The large cinderblocks are 39cm length, 19cm height and 19.cm width. Pic below. I have seen homes in the area using double block, these cinderblocks, and AAC blocks.

Never saw those for sale, anywhere. Had I, I might have built my house with them.

I used 15 cm Qcon instead. Cheaper than the 20" and once the concrete is on the walls actually are 20 cm thick. 

[KhaoYai]

I would only use QCON blocks for an interior wall.  Having used them to create an inner wall (cavity) at my house - yes they are very easy to use etc. etc. - however, they are so weak its unbelievable.  It won't be too long before the Thai burglar community realise that they no longer need to break doors down, all they need is a saw and they're in ????. Seriously though, it would be very easy to either cut through a QCON wall or hammer it down with minimal noise.

 

Got to be honest, I haven't checked out what other blocks are available but I'm pretty sure that concrete blocks will be around and if I was building an exterior wall, that would be what I'd go for.

 

If you do go for QCON, make sure your builder is used to using them.  Chasing out for sockets etc is very easy but its also very easy to make a big mess if you're too heavy handed.  If you're drilling into them to mount something, don't use the hammer option on your drill - its not necessary and will just make a mess if you do.

Edited April 29, 2023 by KhaoYai

[carlyai]

1 hour ago, Silencer said:

Has anyone found any problems with hanging heavy objects (kitchen cabinets, AC/units, stone wall murals, etc) or adhesion issues with AAC?  I'll need to look up the correct fasteners for heavier loads but if they work well, that eliminates that concern.

No problems with the correct fastners and spec. load limits.

I hung my pool chlorinator on QCon blocks.

[carlyai]

Maybe at the end of the day it comes down to what the contractor is familiar with laying.

Those 8" cement blocks are heavy  and if the bricklayers are not used to them it could be a problem. They need the 10mm (if I remember) mortar joint etc.

With vertical reabar they can be filled with concrete for a super strong construction. When layed, render on the outside and finished render on the inside.

To get the same insulation properties with QCon you would need 2 rows of blocks and an air gap. (My guess).

Even trying to lay the QCon blocks as per the manufacturers instructions, we still had cracks. 

 

[sometimewoodworker]

1 hour ago, Silencer said:

Has anyone found any problems with hanging heavy objects (kitchen cabinets, AC/units, stone wall murals, etc) or adhesion issues with AAC?  I'll need to look up the correct fasteners for heavier loads but if they work well, that eliminates that concern.

This question has been asked often, use saw steel plugs and you can hang anything on them

these plugs

 

these are a few things using them

[Silencer]

Thanks for all the replies/experiences provided. I'll talk with the builder next week and see what he recommends, his crews experience level with each, hear him explain the installation process, and go from there. I don't use AC much (however, will have several installed) but maybe I'll get grumpy as I age and be happier with a cooler interior.  ????

[timendres]

8 hours ago, Silencer said:

When I looked up the cost for each product (20cm think vs 19.5cm thick) it looks like QCON is at least 3 times more expensive.

This would be my one concern. Why is the contractor offering this at the same price?

[spidermike007]

Stay away from cinder blocks and Thai brick, if at all possible. Zero benefit. Qcon has multiple benefits. Easier to build with, great insulation, lightweight, easy to hang shelves, artwork, etc. It is 2023. Cinder and Thai brick are yesteryear.

[Silencer]

1 hour ago, timendres said:

This would be my one concern. Why is the contractor offering this at the same price?

My original plan was Qcon but I was not committed to it, he knew that, and he wanted to confirm with me before ordering. He said the labor was a bit lower for Qcon and they would be "about the same" overall cost when materials and time factored in, so either was ok for him from the financial side. He's not nickel and diming me, letting me make last minute adjustments (two staircases, window/door sizes, even a small extra interior space added) with no cost impacts so far.  I need to stay on top of the work but no complaints. Most of the concrete work completed now.

[jim234]

Those fastbricks seems to insulate better than Qcon. They are not just random concrete bricks.

 

Anybody on here who have used them before?

 

[sometimewoodworker]

1 hour ago, jim234 said:

Those fastbricks seems to insulate better than Qcon. They are not just random concrete bricks.

 

Anybody on here who have used them before?

 

There is no exact comparison with AAC blocks, (QCon is just one brand of AAC) specially since the water absorption of AAC is 12- 15% by the total volume

and what is the price for 7.5cm 

Edited May 3, 2023 by sometimewoodworker

[jim234]

Do different brands of aerated bricks differ a lot in their properties? 

 

Are AAC bricks the same as aerated bricks? If not, what is the difference?

 

In their comparison they use 10cm bricks and those fastbricks seem quite a bit cheaper.

 

I understand that they use this comparison to promote their product (so might not be 100%), but it does look interesting to me.

 

 

 

[sometimewoodworker]

19 minutes ago, jim234 said:

Do different brands of aerated bricks differ a lot in their properties? 

There are different things called aerated bricks, so the answer is probably yes.

21 minutes ago, jim234 said:

Are AAC bricks the same as aerated bricks? If not, what is the difference?

Your post, your information, so you need to answer your question.

22 minutes ago, jim234 said:

In their comparison they use 10cm bricks and those fastbricks seem quite a bit cheaper.

You haven’t given prices for the individual blocks/bricks, all other bricks or blocks are priced individually, though with minimum quantities for those prices. Also there are delivery costs involved 

25 minutes ago, jim234 said:

I understand that they use this comparison to promote their product (so might not be 100%), but it does look interesting to me.

You haven’t given availability or places that stock them.

 

From experience there are great claims made for different building materials, these usually turn out to be cherry picked data that once an accurate independent analysis is performed show that in the real world the material is not nearly as much or even any better than others. Also the cost benefit, if any, is either without delivery or near to the single plant making them.

 

So if you can discover all the missing information, which includes mortar thickness and type, then you can have a sensible decision on the benefits, if any, involved.