House Building Using Brick Cavity

[Vegemite]

Recently on a bus to Bangkok from upcountry I spoke briefly with a bloke from Belgium.

He had built his house using 2 walls with a cavity between them.

Basically the same as a standard Thai house using colums and a concrete floor.

He said that he had no need for air conditioning or insulation as there was a constant flow of air through the cavity.

" The same as in Belgium" he said.

Does anyone have any info on this system?

Hope I got the country right. Belgium I mean.

Thanks.

[tyler2uk]

Ive been in a house where a there was a cavity and to be honest i could tell no difference...

we didnt bother, we did however use a raised raft foundation and put vent bricks under this so air could flow under the house.

we also used gable end vents opposed to soffitt vents and put no insulation at ceiling level so the warm air can raise out of the rooms...

I personally think that if you can keep the warm air from building up in the roofspace then it wouldnt radiate down into your rooms. And the way to do that is let it escape..

We also used good shaded doors and windows and i probably think this helped a lot..

Even in the midday heat now we have no need for aircon...in fact we are thinking of taking it out..

[Dave the Dude]

Ive been in a house where a there was a cavity and to be honest i could tell no difference...

we didnt bother, we did however use a raised raft foundation and put vent bricks under this so air could flow under the house.

we also used gable end vents opposed to soffitt vents and put no insulation at ceiling level so the warm air can raise out of the rooms...

I personally think that if you can keep the warm air from building up in the roofspace then it wouldnt radiate down into your rooms. And the way to do that is let it escape..

We also used good shaded doors and windows and i probably think this helped a lot..

Even in the midday heat now we have no need for aircon...in fact we are thinking of taking it out..

Hi

In uk building trade we only use twin walled building system except for internal non-loadbearing walls, I also opted for traditional home like above,but with a GRANITE floor layed thruoghout which keeps rooms cool and very easy to clean

Edited April 23, 2006 by Dave the Dude

[Asian Frog]

It is well known that air is one of the best insulator. It works well in Europe, so why not in Thailand? However, you have to be careful about the "heat bridges" like lintels, doors and windows and ceiling. I have built an house using "SIPOREX material"with a professional architect advising me: you can loose all the advantages of insulation if you are not consistent and forget an appropriate treatment for details like lintels...

Regards

[Vegemite]

It is well known that air is one of the best insulator. It works well in Europe, so why not in Thailand? However, you have to be careful about the "heat bridges" like lintels, doors and windows and ceiling. I have built an house using "SIPOREX material"with a professional architect advising me: you can loose all the advantages of insulation if you are not consistent and forget an appropriate treatment for details like lintels...

Regards

Thanks for your reply.

The man that I was speaking to new what he was talking about and said that the system worked very well in Thailand. He had designed several houses for Thai conditions.

As far as lintels over windows and doors go, if the walls are not load bearing as is a typical Thai style concrete floor and column house, the lintels dont need to be substantial as they are only supporting the cladding. The roof as I understand is supported, basically, by the columns.

Where I live, if a brick cladding is used you only need an angle iron to support the bricks above the openings but the structural walls are timber and hence have lintels to suit.

Thanks for your input ( what is SIPOREX )

All the best.

[Asian Frog]

First SIPOREX (from my memory) is a brand which has given its name to a block of "autoclaved aerated concrete": concrete mixed with aluminium powder, a reaction between cement and aluminium produces a very light white block which is full of tiny air bubbles, Siporex block are very light, expansive, must be glued with special glues and protected by a special coating, but it is one of the best insulating material. The quality of the coating is fundamental because the SIPOREX is spongious and can deteriorate rapidly with humidity.

I have built an house in the vicinity of Paris, 20 years ago with this material.

Secondly, I was not talking about the strength of lintels, windows... but of their thermal properties!

The search done, 20 years ago with this very good professional architect was showing that if you spend a lot of money by doubling your walls in order to get the best insulation, you have to avoid what we call in french " les ponts thermiques" (I translate literally by "Thermal bridge". For example I remember that a non corrected lintel can loose up to 20% of the effect of your insulation. You have to find the way in your design to trap " the heat path". It means that you have to use material like wood or to build-in an insulating material your lintel. Your ceiling is also one of the main "heat bridge" (something like 30% / 40%), you have to find a proper way for its insulation. and your windows have to be "doubled glasses". Your search is interesting, but you must not stay half way because the final result can be very different.

The Roman were already using double walls as a way to insulate the houses.

Regards

[citizen33]

Has anybody any experience of foil-backed insulation rolled out in the roof space? I have read abut this and seen a similar system used in some large retail buildings (e.g. the new Plaza in Kalasin). The upstairs floor of our Thai house is rather hot at this time of year and I wish now I had insisted on a concrete floor in the attic, which would not have added that much to the costs. However, the foil insulation may be a fairly cheap alternative. I think that cavity walls as used in the UK would be a good idea, but I also think the concrete ceiling might provide more benefit for less expense.

[Dave the Dude]

Has anybody any experience of foil-backed insulation rolled out in the roof space? I have read abut this and seen a similar system used in some large retail buildings (e.g. the new Plaza in Kalasin). The upstairs floor of our Thai house is rather hot at this time of year and I wish now I had insisted on a concrete floor in the attic, which would not have added that much to the costs. However, the foil insulation may be a fairly cheap alternative. I think that cavity walls as used in the UK would be a good idea, but I also think the concrete ceiling might provide more benefit for less expense.

Hi (again) Citizen33

If you are thinking about the same foil insulation as used in UK,it is EXTREMELY expensive but a great timesaver.It has many layers and is as efficient as a huge thick amount of 'oldstyle' loft insallation.Sorry I can't be more specific as I'v never used it,just seen it in others houses

[Farma]

Hi Citizen 33,

There are a couple of types of the roofing insulation you mention. One is fitted under the roof tiles and the other on the ceiling.

The one I used is known as Staycool and quoted to me by Homemart as 270 Baht for 2.4 Sq meter packs.

My house has been a noticeable cooler since installing it. It's also reduced the outside traffic noise.

[Dragonman]

Recently on a bus to Bangkok from upcountry I spoke briefly with a bloke from Belgium.

He had built his house using 2 walls with a cavity between them.

Basically the same as a standard Thai house using colums and a concrete floor.

He said that he had no need for air conditioning or insulation as there was a constant flow of air through the cavity.

" The same as in Belgium" he said.

Does anyone have any info on this system?

Hope I got the country right. Belgium I mean.

Thanks.

Unless they have different Building Surveying concepts in Belgium to the UK, the idea of good insulation in tropical climates is to prevent hot air flowing into the building, not encouraging a constant flow ,as air travels from warm to cold. An air cavity helps, but will certainly not prevent the need for air con or insulation! It is still possible for the cavity to be breached by convection and radiation, and well installed insulation will allow for only small passage of warm air by reducing the flow.

All these methods only reduce energy costs! Good insulation everywhere will probably reduce temperature by 2 or 3 degrees, a fan aimed at you will reduce skin temp.by about 5 degrees.

It depends of course if you find an in house temp. of 30 OK, when at 33 you need air con