Aereated Wall: Single.Vs Dual

[KunMatt]

I'm in the final design stage of a house in Isaan for my family and would like some advice about using aereated bricks. It's of major importance to me that this house is as cool as possible, and after what I've read on forums such as this one over the last couple of years I've always pre-planned to use a dual wall Superblock with gap setup.

The local architect/building company we have gone with suggest using a single wall of 7.5cm Q-Con brick for all of the exterior walls. They say they have built a lot of farang's houses this way. The fact that this architect not only knew what Q-Cons were but uses them all the time and even had a sample in his office makes me now want to use Q-Cons for ease and peace of mind.

I spoke to another farang in this village and his house was built using the red bricks for exterior walls, a 10cm gap (I think with foam) and the grey breeze block type bricks for the inside of the wall, and his house was very cool (downstairs). The architect said this is the old fashioned way of doing it and has been superceeded by using these Q-Con blocks.

I've done several things to keep the house as cool as possible,

- it's a long bungalow, with high ceilings and high roof.

- the house is raised and has a 0.6m crawl space underneath.

- all sun facing walls are kept in the shade by large overhangs, and I will plant trees to create more shade.

- the south facing side has a 5 meter roof extension for an outside social area

- also the south facing side is the narrowist of the house, and it is a kitchen diner that is isolated to the rest of the living area so that large room (4m x 7m) has to heat up before the rest of the living area and bedrooms can.

Just for reference, my partner's dad's house is built using a single wall of the grey breeze blocks, the same type that they use to build the walls around the land here, and his house is not as hot as I'd expected. Even when we stay here in the hottest month of the year it's still bearable indoors using a small fan. I'm thinking that even just using the 7.5cm Q-Cons and the steps I've made in the layout would be a great improvement over this.

So here are my questions;

Given my layout, would anybody suggest using a single wall of thick (10cm or 15cm) aereated blocks instead of the dual wall? Obviously cost, time, space, weight etc of bulding the double wall are all factors.

Would anyone recommend using Superblocks over the Q-Con, given that this company has never used them before but can get them from BKK for roughly the same price as the Q-Cons? However none of the builders have any training in building with Superblocks.

Given the layout of my house as explained above, would I get a massive improvement using a two wall 7.5cm aereated blocks with air gap for all of the exterior walls, opposed to just using a single 10cm or 15cm aereated brick?

Any advice would be greatly appreciated as there is literally nobody around here who could help me out with this.

Thanks in advance..

[bankruatsteve]

If you have rea this forum, you should already know the opinions/answers to your questions. So, I will just give you my experience:

I found that buying 7.5cm superblock (at about 19 baht) was cheaper than buying say 15cm blocks which would need to be special ordered. I got these from Global. So, I put up double walls with NO gap (ie: 2x7.5). I find that to be the perfect width and the constuction guys just loved working with it. FYI: it takes a LOT less morter and time than the red brick and I'm pretty sure the overall cost is at least equal if not less. As you will know (if you have read other opinions), a gap is suggested by others. I just don't think there is significant added R value in doing that (with the aereated blocks) and it just makes construction more complicated (2 walls vs just 1). After finally finishing the outside painting with a light reflective color, my superblock walls are everything I had hoped. The house stays cool in the now hot weather and retained the heat when it was cold. So anyway, that's what I did.

[doglover]

I spoke to another farang in this village and his house was built using the red bricks for exterior walls, a 10cm gap (I think with foam) and the grey breeze block type bricks for the inside of the wall, and his house was very cool (downstairs).

It must have foam (unless it was during the cool season) and probably mold as well...

Just for reference, my partner's dad's house is built using a single wall of the grey breeze blocks, the same type that they use to build the walls around the land here, and his house is not as hot as I'd expected. Even when we stay here in the hottest month of the year it's still bearable indoors using a small fan. I'm thinking that even just using the 7.5cm Q-Cons and the steps I've made in the layout would be a great improvement over this.

!!! For you the 7.5cm should have you feeling comfortable. Anyone else better at least double that...If it is a typical Issan house with concrete block walls on the bottom level and a wooden upper level I understand more where you are coming from as the heat rises quickly to the upper level leaving the ground level....bearable (with 4 Thai baths a day).

Given my layout, would anybody suggest using a single wall of thick (10cm or 15cm) aereated blocks instead of the dual wall? Obviously cost, time, space, weight etc of bulding the double wall are all factors.

I would forget about the cavity and just go with a thick single wall and you can read alot more about why in this thread http://www.thaivisa.com/forum/topic/432933-how-to-properly-insulate-ventilate-double-blockbrick-walls/. The aerated concrete blocks are super light so I wouldn't be too worried about the weight, but you will lose some interior space of course. You should check out the new wall insulation offered by Chang. I just so a commercial tonight about it and have nothing more to offer about it other than it would seem worth looking in to. The afformentioned thread also discusses where insulation would be best utilized in the wall system.

Your ideas for an optimal layout for the tropics are very smart and will help immensely with comfort in your new home. All the best!

[extexthai]

From what I have gathered....Q-con, Superblock and the others are pretty much the same....AAC block...put together with a glue, not a mortar and be sure to start with a two tiered red brick course on the bottom, especially in bathroom areas, as AAC block can soak up moisture. I did use 7.5cm AAC block on the exterior wall, red brick on the interior and enough dead air gap to make it all cover the beams inside, so the wall came out flush. They will put in connecting beam-like structures where you have windows and doors, connecting the columns for both the sill area where the window will set, and the header at the top of said window or door. It makes for separate compartments. I am beyond tickled pink about the end results of our house as far as being passively cool, that I can't relate enough about using ACC block in the construction process. Using high ceilings with exhaust fans at ceiling level, will aid in eliminating hot air gotten during the day so you can open up early in the morning and get cooler air inside for a more than comfortable temp during the early part of the day. I have also noticed how almost sound proof it is, too. When I close the bedroom room doors, I do not hear the lovely 06:15 public announcements and early get up music they love to play in our village area. I also recommend a double wall. Ever own a thermos bottle? Even good ice chests are all double walled. Happy building....ett

[klikster]

.. be sure to start with a two tiered red brick course on the bottom, especially in bathroom areas, as AAC block can soak up moisture.

Hi extexthai,

Question. Would a reinforced beam, similar to header beams, be a better option? Or maybe excessively expensive?

Also, re: bathrooms (shower area) .. will AAC block with render and tile suffice?

[Soutpeel]

Also, re: bathrooms (shower area) .. will AAC block with render and tile suffice?

most likely not....I would "tank" (bitumen type coating/paint) any bathroom areas because water will migrate through grout/any render eventually through the blocks themselves which would end up with the blocks crumbling...

[powderpuff]

I also recommend a double wall. Ever own a thermos bottle? Even good ice chests are all double walled.

Quite right. Although in case of a thermos bottle a Vacuum is pulled between the inner & outer vessel (normally made of glass).

[lovelaos]

I also recommend a double wall. Ever own a thermos bottle? Even good ice chests are all double walled.

Quite right. Although in case of a thermos bottle a Vacuum is pulled between the inner & outer vessel (normally made of glass).

Double wall wth at least 15mm cavity, no need for foam. Trust me, I was a builder in U.K for 17 years. Done the same out here and house is cool in summer, warm in winter.

[JoePai]

I also recommend a double wall. Ever own a thermos bottle? Even good ice chests are all double walled.

Quite right. Although in case of a thermos bottle a Vacuum is pulled between the inner & outer vessel (normally made of glass).

Double wall wth at least 15mm cavity, no need for foam. Trust me, I was a builder in U.K for 17 years. Done the same out here and house is cool in summer, warm in winter.

Did you 'seal' the wall at the top ?

[extexthai]

I also recommend a double wall. Ever own a thermos bottle? Even good ice chests are all double walled.

Quite right. Although in case of a thermos bottle a Vacuum is pulled between the inner & outer vessel (normally made of glass).

Double wall wth at least 15mm cavity, no need for foam. Trust me, I was a builder in U.K for 17 years. Done the same out here and house is cool in summer, warm in winter.

Did you 'seal' the wall at the top ?

If you have any windows or doors, they will put a beam for both the sill and the header for windows and just a header for doors. They capped both the ACC block and red brick from column to column together, so yes the walls are sealed. I was waiting for the hot season to post just exactly how cool/warm my house is, but it seems like we were skipped over for the really hot days, at least so far up here in the northern part. I am loving that, let me tell you. I guess I will have to wait for next year to find out. But so far, our house has been unbelievably comfortable, hell, I would say way on the cool side of the thermometer. But a lot of that has to do with the wonderful breeze we get here. ett