cavity walls

[highlander]

possibly a silly question, my house seems to be like other houses i see being built in issan either of wood construction or with the concrete post and infill walls does nobody ever build up here or in thailand anywhere with cavity walls filled with insulation or have their roofs insulated, would it be a cost thing or is there a problem with say ventilation or insects ?.

curious scotty

[Thetyim]

Qcon blocks are the best compromise for Thailand

[Ciaphas]

I've got a wooden house and when building it I brought this reflective thermal sheeting a bit like massive rolls of alaminum foil that should have been placed under the roof tiles to reflect the heat back. The first lot of builders didn't put it in so when the second lot of builders arrived they used it to insulate the walls. The only room the builders recommended putting cavity wall insulation in was the room with air con and you can buy foam blocks for that. I think that most thai builders don't even think about insulation the first lot I had didn't have a clue and it wasn't until the second lot came that they understood what I was talking about.

[DrAndy]

does nobody ever build up here or in thailand anywhere with cavity walls filled with insulation or have their roofs insulated,

they certainly insulate the roofs, when they have the money

cavity walls do not seem to be common but, as was said, Qcon is a good alternative. I am sure you could build using cavity walls if you made sure the builder understood what you wanted

[fremmel]

The standard local builder can build with insulated roofs and cavity walls with insulation if you explain in enough detail what you want. A couple of years ago I built a house using a local independent contractor using a labor only contract where I bought all the materials. I used the standard concrete tiles, put foil underneath them, good ventilation in the attic, 4" fiberglass on the ceiling, and double thin concrete block walls with 2" of fiberglass in the cavity. I originally thought about using QCon type blocks but the double walls with fiberglass costs about the same and gave 3 times the R-value. And I have nice thick walls so I don't have columns visible on the outside walls.

The insulation works well. I live outside Udon where we've had temps in the high 30's to low 40's for the last month or so and yesterday was the first time I've needed to turn on the AC. Before then nights would get down into the low 20's and I could just open the windows at night to cool the house down, close them in the morning, and the house would stay pleasant all day. But this week the night time temps are getting into the high 20's so by late afternoon the house has warmed up enough to warrant turning on the AC.

[Norton]

does nobody ever build up here or in thailand anywhere with cavity walls filled with insulation

Yes. Common if the house is a wood structure. Usually wood frame studs with gypsum on interior side. Cavity filled with 3 or 5 inch fiber insulation.

have their roofs insulated

Reflective foil directly under roof tiles. Fiber insulation on top of drop ceiling.

Fiber insulation and reflective foil not that expensive and effective.
Insulation approx 200 baht/square meter.

[BKKBILL]

When building next year planning on using double insulated blocks with air gap, foil at roof tiles and insulation above ceiling. As fremmel said no columns visible and with all wiring and plumbing installed in the cavity. These blocks have dropped in price making this a good option IMHO. I think with the recent price increases of oil even in Thailand electrical prices will be rising fast soon.

[Norton]

Thailand electrical prices will be rising fast soon.

Already on the up swing. Electrical wiring insulation and copper prices driving it up.

[Thetyim]

^
I thought he meant the price of Kilowatt hours

[Norton]

He probably did. That too.

[crippen]

Nuclear Power being planned though.. That will bring the price down!

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Allegedely.

[Norton]

Nuclear Power being planned though.. That will bring the price down!

No question about it. Everyone will glow in the dark.

[DrAndy]

low cost lamps

[BKKBILL]

True I did mean electrical kilowatt costs. Don’t think nuclear power will be here in my lifetime. So no worries there.

[fremmel]

BKKBill - If you're going with the QCon type block in the double wall primarily for insulation have you thought about the thin concrete block with fiberglass inside instead? Much cheaper and gives a better R-value. Or, if you really like the QCon, by putting fiberglass in the cavity you can about double the R-value for less than 50 baht a square meter.

These are some R-values I've pulled off the net that, as best I can tell, match up with the materials and walls we have here in Thailand.

Single concrete block - 1.0

Single ACC block - 3.25

Double concrete block with air - 2.8

Double ACC block with air - 7.5

Double concrete block with fiberglass - 9.5

Double ACC block with fiberglass - 14.2

[Old Monkey]

BKKBill - If you're going with the QCon type block in the double wall primarily for insulation have you thought about the thin concrete block with fiberglass inside instead? Much cheaper and gives a better R-value. Or, if you really like the QCon, by putting fiberglass in the cavity you can about double the R-value for less than 50 baht a square meter.

These are some R-values I've pulled off the net that, as best I can tell, match up with the materials and walls we have here in Thailand.

Single concrete block - 1.0

Single ACC block - 3.25

Double concrete block with air - 2.8


Double ACC block with air - 7.5

Double concrete block with fiberglass - 9.5

Double ACC block with fiberglass - 14.2

Four years ago, because air cond will make my wife sick, I was building and I tried this for the walls : 2 thin blocks with 4" 10 cm empty space. On the inside, 6 blocks with holes in the first row. On the outside wall, third and fourth row, 5-6 holed blocks with mosquito net on the inside. The higher roof in the middle of the house and the openings will let warmed air rising out, creating a negative pressure, this will suck new air which will have to travel downward inside the cavity, cooler, this will mean a small draught of cool air at floor lever.
4-5 degrees gained when the door stays closed.
The blocks were cheap, 2,10 tb.

[highlander]

sounds like roof insulation is a must, both under the tiles and on the drop down ceiling, guess the ceiling insulation will be easy as i have already done this with my house in scotland, but the under tile might be a bit different fitting this retrospectivly,

looks like if i was building from scratch then double blocks with insulation would be the best idea, also old monkeys idea would be ok if no aircon is going to be installed..

cheers guys scotty

[Thetyim]

have you thought about the thin concrete block with fiberglass inside instead

Never seen them
Any one got a picture or link ?

[Ciaphas]

but the under tile might be a bit different fitting this retrospectively

As far as I'm aware you can't fit the foil under the tiles retrospectively, this is what caused us all the grief with the first builders, even though they knew I wanted it before the build began and the second builders said it couldn't be done with out pulling off all the tiles.

[DrAndy]

have you thought about the thin concrete block with fiberglass inside instead

Never seen them
Any one got a picture or link ?

I think he meant double thin concrete blocks built with a cavity. The cavity gets filled with insulation

[Thetyim]

^
Thanks

[fremmel]

Thanks DrAndy, yes, that's what I meant. I guess it would have been clearer if I'd said "thin concrete block with fiberglass in the cavity instead of an air gap".

[PomMichael]

XXXXX - Closed Top
XX YY
XX YY
XX YY
-- YY
XX YY
XX YY
XX YY
XX YY
XX YY
XX YY
XX --
XX YY
XX YY
XX YY
XXXXX – Bottom Foundation

XX = Outer Wall, YY = Inner Wall.

Some questions regarding the benefits of using a double wall with cavity fill insulations in Thailand (BKK Metro area).

Venting (--) is required from what I'm reading - but how high up on the wall?
The gap should be 4 cms -is this standard?
Options for fill (blown, foam, etc)?

Besides cost - any negatives about using a double exterior wall?

[fremmel]

From what I understand, vents in double walls were originally about moisture buildup inside the cavity from leaking, unsealed exterior walls. I come from Florida where a "cavity wall" is simply a wood stud wall with a veneer on both sides. Generally brick or exterior paneling on the outside and sheetrock on the inside. The cavity was filled with insulation. With air conditioning the cavity was never vented and, in fact, usually sealed with a vapor barrier to keep the hot air out and to keep the moisture from condensing on the cooler inside the walls.

When I built my house I made sure to seal both the inside and outside layers of my double wall because I did not want any air infiltration. With outside temperatures hitting 30° by 8 AM and continuing on up to 40°+ the last thing I wanted was to let that hot air into the house. If you live in more a moderate area of Thailand and want the outside air inside then why not just open the windows? Old Monkey's system works for him but there must be enough heat gain from somewhere, maybe sunny walls or hot roof and ceiling, so that the inside air is warmer than the outside air. But wouldn't just opening the windows work as well as venting the walls?

In answer to you other questions, I used fiberglass as my cavity fill because it was cheap, effective, and easy to install. I'm very happy with my double walls and haven't found any negatives about them yet.

[aussie chris]

has anyone considered using dry rice husks as insulation in wall and ceiling cavities and even building timber floors with a cavity,all filled with rice husks,the studies I have read on it's insulation qualities have been very very good indeed,it ha s a very high silica content,which means it's very resistant to mould,insect and vermin infestation,the R value is higher than fibro batts and almost everything else that I have compared it to.
there have been serious studies done on it,
And the really good thing about it in thailand is that you can get it pretty much for the price of having it delivered to your door as it is considered as a waste product.
could be very worth while looking at very seriously when building !!!!
anyone can get the info on the web just by typing in rice husk insulation.
hope someone can use this to there benefit and living comfort and save probably several thousand baht, without the need for air con except maybe in the most extreme weather.