CLC vs. AAC bricks

[CLW]

Currently in the process of planning our house in Bangkok together with an architect and general contractor.

I would like to insulate the house according to western standards.

Cavity wall seems to be red tape for most contractors and they can't or don't want to do it.

Therefore I might opt for insulated wall bricks such as CLC (cellular lightweight concrete) or AAC (autoclaved aerated concrete) blocks.

 

On the paper CLC seems to have several advantages over AAC such as better cracking resistance under humid conditions, closed surface avoiding mold issues inside the bricks, use of regular anchors for furniture or wall TV mount, use of regular mortar and plaster/rendering.

They only thing I haven't researched yet is the price difference.

 

AAC are offered from several companies like SCG or through home stores such as Thai Watsadu or even local building supply stores.

CLC from what I've found are only offered from a company called DCON https://www.dconproduct.com/en/products/dcon-block/

 

Anyone has used either one of the bricks and can tell about his experience? Thank you

 

[OneMoreFarang]

A couple of general comments.

 

This is a place where you can easily research prices, what's available, etc.

https://www.onestockhome.com/

 

What you use should be very much related to what the builders know. Don't try to ask Thai builders to use material which they don't know. I don't know how many builders know each material. But as you said, there are differences, and don't trust your builders to know those differences...

 

And from my current inside renovation I suggest: Don't use too thin blocks/walls. If you have a pipe on one side  or a wall and another pipe on the other side of the wall, then you have suddenly a hole in the middle...

[sometimewoodworker]

4 hours ago, CLW said:

Currently in the process of planning our house in Bangkok together with an architect and general contractor.

I would like to insulate the house according to western standards.

Cavity wall seems to be red tape for most contractors and they can't or don't want to do it.

Any builder who is throwing up red flags with cavity walls is someone I don’t want working for me.

 

4 hours ago, CLW said:

On the paper CLC seems to have several advantages over AAC such as better cracking resistance under humid conditions, closed surface avoiding mold issues inside the bricks, use of regular anchors for furniture or wall TV mount, use of regular mortar and plaster/rendering.

None of those are any different between AAC (widely available and used) and CLC (never heard of it) 

As to wall anchors, they are both lightweight blocks so you need exactly the same anchors.

 

For mortar AAC is very inexpensive due to using 3mm thickness. With plaster/render the AAC base coat is less expensive that the regular topcoat.

4 hours ago, CLW said:

Anyone has used either one of the bricks and can tell about his experience? Thank you

Yes I have as have many others you can find my building story on the board designed for building and advice on cool Thai houses, the build has just under 400 posts.

[Tropposurfer]

If your commissioning an architect then why not try to see if this option is available? A decent progressive architect can select a builder who will work to your spec's not his own. There are some really cool Western/Thai build style fusion architects in BKK.

 

https://becowallform.co.uk/insulated-concrete-formwork-icf-system/

 

I can't say whether this is available in LOS but this modular brick-like polyurethane system is filled with concrete and reo and is used in Europe a bit now as an alternative to heavy 'form shutter' systems and is amazing.

 

The foam system (link supplied) is simple and fast to erect, trim, and fill with crete and allows for waterproofing and rendering fastening systems that are super easy. Many of these products are eco-friendly too.

Its super insulating as well with an amazing thermal mass index.

 

If you're going to use a hollow reo filled block system than go for a wide block not the thin ones so often used here. Lateral, vertical compression strength, with thermal mass and sound insulation being far better than the thinner blocks.

Make sure for all structural walls the architect uses 12 mm reo bar throughout too not the rubbish 4mm to 7 mm they use everywhere here. 

7mm mesh minimum in all floor slabs AND properly 'chaired and tied' where necessary. Simply pulling up mesh with the hands as crete is poured does not work as the mesh will sink to the bottom/lower part of the slab, and weaken it, and if exposed underneath will invite rusting - BAD!

[LukKrueng]

I built my house using CLC blocks. They are light and easy to work with. The only mistake I did was using the thin blocks (7.5 cm). Insulation is still good in most days, not so good in very hot\cold days. The blocks and special mortar needed are more expensive, but as the blocks are bigger and need a very thin layer of mortar the total costs are not much higher.

[TigerandDog]

We used to AAC bricks to build our house last year. As stated by an earlier poster you need to ensure that the builder you choose knows how to work with them. When obtaining quotes from builders we asked them had they ever worked with AAC bricks previously. Most answered yes, but when we questioned them on mortar thickness and render etc they would say the same as if they were using red bricks or the cement bricks with the hollow center (similar to those in the pic in Tropposurfer's post), and if they managed to answer those questions correctly we then asked to see a current construction site where they were using AAC bricks. Some were using them, but not correctly so they did not get hired. Even with the company we eventually chose we had to get them to replace one of the brickies as he was not using the correct quantities of mortar and he was just smashing bricks the same as they do with red bricks instead of cutting them to size with a hacksaw. We have air con installed but so far have only had to use it for 1 hour at night during the hotter months in the upstairs bedroom. The house stays cool in the hot weather and keeps warm in the cold weather. They also do an excellent job of reducing the amount of external noise (village, temple & school loudspeakers that blare out morning and evening), We used the 7.5cm bricks. Some wall sections have double bricking, but most are single brick. Also make sure that after rendering and BEFORE painting that the builder applies a protective plastic skin. The stops teh render from absorbing the moisture from the paint, which means that the paint will last longer before a repaint needs to be done.

[sometimewoodworker]

21 minutes ago, TigerandDog said:

Also make sure that after rendering and BEFORE painting that the builder applies a protective plastic skin. The stops teh render from absorbing the moisture from the paint, which means that the paint will last longer before a repaint needs to be done.

That is something that is neither standard nor recommended and is completely incorrect. The correct recommendation is to thin the first coat by about 50% if the render absorbs moisture from the paint makes zero difference to the lifespan of the paint. Your idea of putting a plastic skin first will block moisture from escaping from the substrate. House paint is not waterproof, it will shed liquid water but allow vapour to pass. So the plastic will allow the fabric of the walls to gain more and more moisture, as the humans and animals are transpiring litres of water vapour per day, that unless you are running AC to extract that, has to go into the fabric of the house and usually transpires through the largest surface (the walls)

 

Just try living in a plastic bag if you don’t believe me.
 

The rest of the post is certainly sensible.

[The Theory]

18 hours ago, CLW said:

Cavity wall seems to be red tape for most contractors and they can't or don't want to do it.

I built it my way, cavity wall filled by 1.5 inch rigid foam between walls that get sun. I wanted to build cavity walls by red bricks, but the type was not available in my area. Walls remain cool with sunlight over (also it blocks noise with my type of windows, no sliding). I installed an exhaust fan for under the roof that works    with a thermostat (manual control too). It kicks when it go over 40 degree, it it reaches that hot since I used insulated metal roof. 

 

[paul1804]

I have used Q-Con blocks which are a light weight L= 600 x H = 200mm with vary widths from 75 - 250mm. They also do lintels up to 3.6m in length so great for most windows and doors. 

They are fantastic but you have to know and follow the correct construction procedures, they have a web site which is very informative. They are more expensive than your old style concrete blocks but so easy to use and so much better for almost everything from construction to noise, sound and insulation. I would absolutely use them again if I were building a house. 

[TigerandDog]

2 hours ago, sometimewoodworker said:

That is something that is neither standard nor recommended and is completely incorrect. The correct recommendation is to thin the first coat by about 50% if the render absorbs moisture from the paint makes zero difference to the lifespan of the paint. Your idea of putting a plastic skin first will block moisture from escaping from the substrate. House paint is not waterproof, it will shed liquid water but allow vapour to pass. So the plastic will allow the fabric of the walls to gain more and more moisture, as the humans and animals are transpiring litres of water vapour per day, that unless you are running AC to extract that, has to go into the fabric of the house and usually transpires through the largest surface (the walls)

 

Just try living in a plastic bag if you don’t believe me.
 

The rest of the post is certainly sensible.

The method you are advocating is so out of date. I would say that you have not kept up to date with the latest STANDARD practice when it comes to cement render and the painting thereof, especially by quality builders. The skin/sealer is applied the same as an undercoat, viz it's painted on (2 coats) before the undercoat and the top coat of paint are applied. I was made aware of the process by a mate of mine, back in oz, who works in the paint industry, and as previously stated, it is now STANDARD practice with the most of the top end builders in Thailand too. The sealer is readily available at stores like Global Warehouse, SCG etc.

[CLW]

On 3/3/2023 at 10:21 PM, sometimewoodworker said:

Any builder who is throwing up red flags with cavity walls is someone I don’t want working for me.

 

None of those are any different between AAC (widely available and used) and CLC (never heard of it) 

As to wall anchors, they are both lightweight blocks so you need exactly the same anchors.

 

For mortar AAC is very inexpensive due to using 3mm thickness. With plaster/render the AAC base coat is less expensive that the regular topcoat.

Yes I have as have many others you can find my building story on the board designed for building and advice on cool Thai houses, the build has just under 400 posts.

Get your point of using less mortar between the AAC blocks. But the special AAC plaster / render is definitely more expensive than for regular brickstones, concrete or CLC.

[CLW]

On 3/4/2023 at 8:47 AM, LukKrueng said:

I built my house using CLC blocks. They are light and easy to work with. The only mistake I did was using the thin blocks (7.5 cm). Insulation is still good in most days, not so good in very hot\cold days. The blocks and special mortar needed are more expensive, but as the blocks are bigger and need a very thin layer of mortar the total costs are not much higher.

DCON (manufacturer of CLC blocks) says, that regular mortar and plaster / rendering can be used since they are concrete based bricks with foam agent and closed cell structure (vs open cells with AAC).

Yes, definitely not using those tiny 7.5 cm wall thickness. Already twenty years ago, when energy savings were not a concern, in Germany you used air cavity brickstones with at least 11,5 cm or even more for load-bearing walls (24 cm or more)

[CLW]

On 3/4/2023 at 12:23 PM, The Theory said:

I built it my way, cavity wall filled by 1.5 inch rigid foam between walls that get sun. I wanted to build cavity walls by red bricks, but the type was not available in my area. Walls remain cool with sunlight over (also it blocks noise with my type of windows, no sliding). I installed an exhaust fan for under the roof that works    with a thermostat (manual control too). It kicks when it go over 40 degree, it it reaches that hot since I used insulated metal roof. 

 

Where to find rigid foam for insulation? Almost not existing here (same as rockwool by the way...)

[CLW]

On 3/4/2023 at 9:48 AM, TigerandDog said:

We used to AAC bricks to build our house last year. As stated by an earlier poster you need to ensure that the builder you choose knows how to work with them. When obtaining quotes from builders we asked them had they ever worked with AAC bricks previously. Most answered yes, but when we questioned them on mortar thickness and render etc they would say the same as if they were using red bricks or the cement bricks with the hollow center (similar to those in the pic in Tropposurfer's post), and if they managed to answer those questions correctly we then asked to see a current construction site where they were using AAC bricks. Some were using them, but not correctly so they did not get hired. Even with the company we eventually chose we had to get them to replace one of the brickies as he was not using the correct quantities of mortar and he was just smashing bricks the same as they do with red bricks instead of cutting them to size with a hacksaw. We have air con installed but so far have only had to use it for 1 hour at night during the hotter months in the upstairs bedroom. The house stays cool in the hot weather and keeps warm in the cold weather. They also do an excellent job of reducing the amount of external noise (village, temple & school loudspeakers that blare out morning and evening), We used the 7.5cm bricks. Some wall sections have double bricking, but most are single brick. Also make sure that after rendering and BEFORE painting that the builder applies a protective plastic skin. The stops teh render from absorbing the moisture from the paint, which means that the paint will last longer before a repaint needs to be done.

Most of it makes sense, but how can 7,5 cm bricks reduce heat or even noise? 

Heat maybe, since air inside the bricks is a good insulator.

But noise blocking only possible by pure density or weight of the stones (or resulting thickness).

Just the law of physics....

[sometimewoodworker]

2 hours ago, CLW said:

But the special AAC plaster / render is definitely more expensive than for regular brickstones, concrete or CLC.

Incorrect. AAC requires a special plaster/render skim coat, that is true. However that skim coat is cheaper than the regular plaster/render so the cost is less. Also as AAC produces a much flatter surface than any other normal wall material so the thickness of render is less. So sorry but false.

2 hours ago, CLW said:

rendering can be used since they are concrete based bricks with foam agent and closed cell structure (vs open cells with AAC).

Not completely correct 

 

2 hours ago, CLW said:

Where to find rigid foam for insulation? 

Almost not existing here (same as rockwool by the way...)

Every school supply shop has it (expanded, polystyrene) in 600 x 1200 panels, so it is that you are not asking the correct questions from the correct people 

 

2 hours ago, CLW said:

Most of it makes sense, but how can 7,5 cm bricks reduce heat or even noise? 

A single skin of 750mm AAC does a very good job of heat insulation and noise reduction, add a cavity and second skin and the second skin, if on the inside doesn’t have to do much, it is probably going to allow the cavity temperature to rise quite a bit if the brick is on the outside but I don’t know if there is going to be a significant difference in performance either way.

 

2 hours ago, CLW said:

But noise blocking only possible by pure density or weight of the stones (or resulting thickness).

Just the law of physics....

You are missing quite a few factors that have significant effects on noise reduction, density of material is just one of many factors 

 

The target price of AAC is ฿14.5 for a 7.5 block (pallet quantities), since CLC is a lower quality product (compressive strength, weight (heavier), side variation, and less good sound reduction you should be able to get them for less than that.

[TigerandDog]

16 hours ago, CLW said:

Most of it makes sense, but how can 7,5 cm bricks reduce heat or even noise? 

Heat maybe, since air inside the bricks is a good insulator.

But noise blocking only possible by pure density or weight of the stones (or resulting thickness).

Just the law of physics....

I don't know the why's and wherefores about the noise reduction, but I do know that the daily noise from the village loud speakers is considerably less, and no the volume of the speakers has not been turned down because when we go outside they are just as loud as always.

[The Theory]

16 hours ago, CLW said:

Where to find rigid foam for insulation? Almost not existing here (same as rockwool by the way...)

It's available at "Do Home" (perhaps Thai watsadu) or online. I got some from Do Home and local construction shop. This foam is not hard much like those i used to buy from Home Depot in the US, but still useable. There are 2 types I found on Lazada. The link is an example, but if you some more search you will find more options about price, size and hardness. 
https://s.lazada.co.th/s.RrGFD

 

[The Theory]

16 hours ago, CLW said:

Most of it makes sense, but how can 7,5 cm bricks reduce heat or even noise? 

Not by a single 8 or 9 cm wall won't stop noise (especially with sliding aluminum windows), must be a cavity wall (with rubber sealed windows preferably push out windows.  

[sometimewoodworker]

1 hour ago, TigerandDog said:

I don't know the why's and wherefores about the noise reduction, but I do know that the daily noise from the village loud speakers is considerably less, and no the volume of the speakers has not been turned down because when we go outside they are just as loud as always.

That is absolutely correct. If you have good windows and doors with IGUs you can get some very goo sound reduction 

 

[Encid]

On 3/4/2023 at 9:48 AM, TigerandDog said:

Also make sure that after rendering and BEFORE painting that the builder applies a protective plastic skin. The stops teh render from absorbing the moisture from the paint, which means that the paint will last longer before a repaint needs to be done.

That is also supported by this website as AAC blocks are very porous:

 

"Where mortar has been used between each brick, you should wait for 4 to 6 weeks to cure properly before applying the paint system. The curing process for mortar is important as it allows the alkalinity content to drop to a level where it won’t affect paint adhesion. It also ensures the moisture content in the mortar falls below 10%, and the time allows efflorescent salts to migrate out of the mortar. There are ‘green render sealer’ products that are available to minimise this curing period, but allowing the mortar to fully cure is recommended for best performance of the paint system.

 

Oil-based prepcoats should be avoided on masonry surfaces even after curing, as the alkalinity of the surface reacts with the alkyd resin of the paint and affects adhesion.

 

The Australian Standard AS/NZS Guide to the Painting of Buildings specifies only two coats of a quality acrylic exterior topcoat is required for exterior brick, FC sheet, concrete, masonry, cement render or AAC blocks (Hebel). It also states that additional prepcoats, topcoats or both may be required depending on the substrate colour, texture or porosity. For this reason we recommend a 1 x Prepcoat and 2 x Topcoat system as best practice."

 

The article makes good reading and goes into more details.

[sometimewoodworker]

48 minutes ago, Encid said:

AAC blocks are very porous

Compared to what??? A block of steel? Of course, a block of expanded polystyrene? Of course.

concrete blocks? Absolutely not.

Red bricks? Absolutely not.

 

You keep making claims unsupported by the evidence 

important note. The CLC block you are so enamoured of is heavier than an equivalent AAC block so the volume of water held is naturally greater.

and here is a demonstration if the above points.

And another, incidentally it includes a drive by illustration of how difficult an AAC block can be to break 

 

 

48 minutes ago, Encid said:

Where mortar has been used between each brick, you should wait for 4 to 6 weeks to cure properly before applying the paint system. The curing process for mortar is important as it allows the alkalinity content to drop to a level where it won’t affect paint adhesion.

You conveniently forget to mention that AAC blocks use a glue at about 3mm thickness so the cure time is in hours or possibly a day or two.

you also don’t mention the paints formulated to resist alkalinity that are easily available.

 

EDIT the poster who is mostly confused is CLW sorry Encid 

[Encid]

2 minutes ago, sometimewoodworker said:

important note. The CLC block you are so enamoured of is heavier than an equivalent AAC block so the volume of water held is naturally greater.

I think you have me confused with someone else... I have never mentioned CLC blocks in any post in any topic on this forum. 

 

4 minutes ago, sometimewoodworker said:

You conveniently forget to mention that AAC blocks use a glue at about 3mm thickness so the cure time is in hours or possibly a day or two.

The Q-CON Handbook calls it a mortar, not a glue... and in any case if you read my post again you will see that I quoted that information from the website I referenced (and linked to).

 

 

You want to argue?

Take it up with the website I referenced.

 

[sometimewoodworker]

4 minutes ago, Encid said:

You want to argue?

Take it up with the website I referenced.

The website is not specifically addressing AAC blocks, they are included, but is also talking about  other wall materials 

Quote

Brick and block are masonry building materials used for constructing walls. Bricks are generally made from fired clay or concrete. Mortar is the cement used between each brick to bond one brick to another. 

So you have material used between blocks/bricks that varies between 3mm and 15mm, so since it’s a site for paint they will recommend a time that is good for any material not for AAC specific walls

[Encid]

 

13 minutes ago, sometimewoodworker said:

The website is not specifically addressing AAC blocks, they are included, but is also talking about  other wall materials 

So you have material used between blocks/bricks that varies between 3mm and 15mm, so since it’s a site for paint they will recommend a time that is good for any material not for AAC specific walls

That is just being pedantic and deflective... the point I was trying to make (which you seem intent on derailing) is in support of @TigerandDog's comment where he said  "Also make sure that after rendering and BEFORE painting that the builder applies a protective plastic skin" to the wall blocks, regardless of type ie. an acrylic based primer before the topcoat(s) (of paint)... a viewpoint well supported by the website I referenced.

 

[sometimewoodworker]

3 minutes ago, Encid said:

 

That is just being pedantic and deflective... the point I was trying to make (which you seem intent on derailing) is in support of @TigerandDog's comment where he said  "Also make sure that after rendering and BEFORE painting that the builder applies a protective plastic skin" to the wall blocks, regardless of type ie. an acrylic based primer before the topcoat(s) (of paint)... a viewpoint well supported by the website I referenced.

 

There seems to be rather a confusion about exactly what is the meaning of “a plastic skin”

 

The majority of painting systems for exterior walls are acrylic, acrylic is a plastic, using an acrylic undercoat is a, possibly the, recommended painting system.

 

I have never heard of anyone describing an acrylic undercoat as a plastic skin and the wording used specifically excludes paint as the plastic skin being referred to.

[TigerandDog]

19 hours ago, Encid said:

 

That is just being pedantic and deflective... the point I was trying to make (which you seem intent on derailing) is in support of @TigerandDog's comment where he said  "Also make sure that after rendering and BEFORE painting that the builder applies a protective plastic skin" to the wall blocks, regardless of type ie. an acrylic based primer before the topcoat(s) (of paint)... a viewpoint well supported by the website I referenced.

 

Encid , not quite correct. I did say "Also make sure that after rendering and BEFORE painting that the builder applies a protective plastic skin" but please don't selectively edit what I said. I also said that the skin/sealer was painted on (2 coats) THEN the undercoat/primer followed by the topcoat.

[CLW]

I want to revive this topic because I found this interesting concrete brick stones from CCP brand.

 

https://www.ccp.co.th/product/9621-9619/บล็อกก่อผนัง-hollow-block-มอก57-2560-มอก58-2560-มอก57-2533-มอก58-2533-astm-c177 (simply translate with Google translate)

 

They're categorized into non-load and load-bearing, which can eliminate the one or another reinforced concrete beam normally used in abundance in Thailand.

 

They're available in 19 cm wall thickness and seem to have a good K-value with K-Value (W/mk) 0.1133+-0.047 R-Value(M2.K/W ) 1.676.

 

I guess the price is also cheaper than CLC or AAC bricks. 

What are your thoughts?

[sometimewoodworker]

3 hours ago, CLW said:

 

I guess the price is also cheaper than CLC or AAC bricks. 

What are your thoughts?

They are available from every building materials supplier, manufactured locally and of varying quantities, cost about 4 ~ 6 baht each and have the worst characteristics of any build material.

 

Have you ever looked at any buildings in Thailand? From your questions it seems not, as they are probably the most commonly used for low cost building.

[CLW]

15 hours ago, sometimewoodworker said:

They are available from every building materials supplier, manufactured locally and of varying quantities, cost about 4 ~ 6 baht each and have the worst characteristics of any build material.

 

Have you ever looked at any buildings in Thailand? From your questions it seems not, as they are probably the most commonly used for low cost building.

Have you looked at the provided link? I don't think these concrete bricks from CCP are comparable to locally made "grey stones" that you describe.

They're made in a factory under a standardized and certified process.

You're comparing hand mixed concrete by unskilled labor vs. ready-mix concrete from a dedicated plant.

[sometimewoodworker]

1 hour ago, CLW said:

Have you looked at the provided link? I don't think these concrete bricks from CCP are comparable to locally made "grey stones" that you describe.

They're made in a factory under a standardized and certified process.

You're comparing hand mixed concrete by unskilled labor vs. ready-mix concrete from a dedicated plant.

Naturally I looked at the link. That the amount of cement and grade of aggregate used is somewhat better that used by skilled workers in every building company in Thailand doesn’t change the facts that the bricks (usually known as concrete blocks), whatever grade of aggregate and amount of other materials are borderline the least good material for insulation, both sound and heat, of any wall systems used in Thailand. The only materials that are going to be worse are planks or wood/metal sheeting 

“made in a factory under a standardized and certified process” just means that they are standardized and certified low quality (from a sound and heat viewpoint) building blocks. Lipstick on a pig is a phrase that comes to mind.

 

Now you have identified another material that seems to be a revelation to you, what is the cost per block delivered to your building site? Of course it needs to be in pallet or truck quantities.

 

They can be perfectly good from a structural viewpoint and if there’s no requirement for sound and heat insulation they are a reasonable to good material, I use them in the wall panels of our perimeter walls.