Attic Insulation

[sticklee]

I'm looking at options to keep the house cooler, without installing another AC unit. Does anyone have first hand experience with insulating their attic? What about installing roof vents, I notice most homes do not have vents installed. Any recommendations are appreciated.

[clinique]

insullation of all types is available in CM. silver batts, foam batts, foam spray, differing prices obviously.

speak to a home improvements company,, its not that expensive,,

BUT note that even with this insullation, in summer (ie now) you will likely find you still need the additional aircon

[WinnieTheKhwai]

Insulation helps somewhat (slows down the warming up), but with tempearatures of 40 degrees and the sun continuously on the roof, it's still going to heat up. Venting works somewhat in the afternoon in the wet season when the winds pick up, but again, without much wind it doesn't help. And, even if there was wind it would still suck in 40 degree air.

Tall trees in the right places to block the sun work well, though the sun is high this time of year.

Is this a single floor 'bungalow' type home?

[garyh]

Tinting windows will also make a huge difference if you use good film. Each square metre of sunlight coming in is approximately 1KW of heat

[kandahar]

sticklee, tell us about your house. Single level, or multiple? Crawl space underneath or a pad poured on soil? Large attic or small? Lots of windows or few and if few, are they huge or normal? Ten foot ceilings or less than that? What is the composition of your roof?

Edited April 18, 2010 by kandahar

[WinnieTheKhwai]

Tinting windows will also make a huge difference if you use good film. Each square metre of sunlight coming in is approximately 1KW of heat

Ideally you'd want to keep sunlight off any windows, period. So never mind about film. This can be achieved with large roof overhangs, trees, etc.

Seeing that the OP already runs an airconditioner, probably he'd get the most mileage out of insulating the space that is airconditioned through insulating the (hanging) ceiling from the top, make sure sunlight doesn't enter and ideally stays off the walls, etc.

Venting the roof is never bad of course, but not a magic bullet solution especially not this season.

[koosdeboer]

Tinting windows will also make a huge difference if you use good film. Each square metre of sunlight coming in is approximately 1KW of heat

Ideally you'd want to keep sunlight off any windows, period. So never mind about film. This can be achieved with large roof overhangs, trees, etc.

Seeing that the OP already runs an airconditioner, probably he'd get the most mileage out of insulating the space that is airconditioned through insulating the (hanging) ceiling from the top, make sure sunlight doesn't enter and ideally stays off the walls, etc.

Venting the roof is never bad of course, but not a magic bullet solution especially not this season.

very good advice, agree 100%

[sticklee]

sticklee, tell us about your house. Single level, or multiple? Crawl space underneath or a pad poured on soil? Large attic or small? Lots of windows or few and if few, are they huge or normal? Ten foot ceilings or less than that? What is the composition of your roof?

Thanks everyone for input. My house is a small one storey 2 bedroom. Poured concrete slab, 10' celings. Well treed with large trees on south and west side so I have lots of shade. Standard windows, 2 per side of house with sliding entry at front. Roof is terra cotta tile type. Large porch (overhang) at front entry and single car carport at front. Front of house faces south. Currently have 1-9,000 BTU AC in room at ne corner. The interior heats up fairly quickly and cools down slowly. All fairly typical given the current temperatures. I was hoping to slow down the heating up with insulation and with better air circulation through the attic, clear out the hot air more efficiently after sundown....Does that seem sound thinking?

[kandahar]

sticklee, tell us about your house. Single level, or multiple? Crawl space underneath or a pad poured on soil? Large attic or small? Lots of windows or few and if few, are they huge or normal? Ten foot ceilings or less than that? What is the composition of your roof?

Thanks everyone for input. My house is a small one storey 2 bedroom. Poured concrete slab, 10' celings. Well treed with large trees on south and west side so I have lots of shade. Standard windows, 2 per side of house with sliding entry at front. Roof is terra cotta tile type. Large porch (overhang) at front entry and single car carport at front. Front of house faces south. Currently have 1-9,000 BTU AC in room at ne corner. The interior heats up fairly quickly and cools down slowly. All fairly typical given the current temperatures. I was hoping to slow down the heating up with insulation and with better air circulation through the attic, clear out the hot air more efficiently after sundown....Does that seem sound thinking?

I'll throw my two baht out there. You don't have any dead air under the house so that idea is out. Too bad on that.

The next thing I see, based on your description, is the ceilings. I had the same problems that you speak of. However, the attic WAS vented, passive, on both ends of the house. The kitchen was the hottest room, even though we didn't cook. The refrigerator was causing that room to get warmer than the rest of the house. That motor, compressor and the cycle do produce a lot of heat outside of the refrigerator. So, I cut a large rectangular hole in the ceiling, built an nice frame with screen and made some decorative louvers to hide the screen. Instant success when I cut the hole. I was standing on a ladder, sweating bad and the instant I removed the large piece that I had cut out, the breeze began to cool me down. The hot air rising caused a great draft and that continued until the hot season was over. So, you can use convection to overcome a lot of your problem.

The ends of the attic do need to be vented. The hot air needs to be able to get out and rise. That is a cheap project.

Once the kitchen problem was solved, I noticed that the rest of the house really wasn't much cooler. I also noticed that with the 10 foot ceilings, the hot air at the tops of the rooms could not get out of the rooms because the tops of the walls were solid all of the way down to the tops of the room doors. So, any heat trapped up there, stayed trapped. So, same thing. I vented each room into the attic and went through the same discovery each time. That hot air just needs a place to go. Up and out. I didn't want to vent each room. It would have been better to cut a vent at the tops of the walls so they could vent from room to room and then into the kitchen. But the interior walls were six inch concrete. It was just easier to vent them all into the attic.

So, try removing one ceiling panel in a hot room in your house and see how much draft you get. That alone may get the temps down enough to make you happy.

Edited April 18, 2010 by kandahar

[sticklee]

sticklee, tell us about your house. Single level, or multiple? Crawl space underneath or a pad poured on soil? Large attic or small? Lots of windows or few and if few, are they huge or normal? Ten foot ceilings or less than that? What is the composition of your roof?

Thanks everyone for input. My house is a small one storey 2 bedroom. Poured concrete slab, 10' celings. Well treed with large trees on south and west side so I have lots of shade. Standard windows, 2 per side of house with sliding entry at front. Roof is terra cotta tile type. Large porch (overhang) at front entry and single car carport at front. Front of house faces south. Currently have 1-9,000 BTU AC in room at ne corner. The interior heats up fairly quickly and cools down slowly. All fairly typical given the current temperatures. I was hoping to slow down the heating up with insulation and with better air circulation through the attic, clear out the hot air more efficiently after sundown....Does that seem sound thinking?

I'll throw my two baht out there. You don't have any dead air under the house so that idea is out. Too bad on that.

The next thing I see, based on your description, is the ceilings. I had the same problems that you speak of. However, the attic WAS vented, passive, on both ends of the house. The kitchen was the hottest room, even though we didn't cook. The refrigerator was causing that room to get warmer than the rest of the house. That motor, compressor and the cycle do produce a lot of heat outside of the refrigerator. So, I cut a large rectangular hole in the ceiling, built an nice frame with screen and made some decorative louvers to hide the screen. Instant success when I cut the hole. I was standing on a ladder, sweating bad and the instant I removed the large piece that I had cut out, the breeze began to cool me down. The hot air rising caused a great draft and that continued until the hot season was over. So, you can use convection to overcome a lot of your problem.

The ends of the attic do need to be vented. The hot air needs to be able to get out and rise. That is a cheap project.

Once the kitchen problem was solved, I noticed that the rest of the house really wasn't much cooler. I also noticed that with the 10 foot ceilings, the hot air at the tops of the rooms could not get out of the rooms because the tops of the walls were solid all of the way down to the tops of the room doors. So, any heat trapped up there, stayed trapped. So, same thing. I vented each room into the attic and went through the same discovery each time. That hot air just needs a place to go. Up and out. I didn't want to vent each room. It would have been better to cut a vent at the tops of the walls so they could vent from room to room and then into the kitchen. But the interior walls were six inch concrete. It was just easier to vent them all into the attic.

So, try removing one ceiling panel in a hot room in your house and see how much draft you get. That alone may get the temps down enough to make you happy.

I like your idea. DIY, simple, minimum of expense and easy to get by the landlord. I can't help going back to roof venting...allowing that airflow from down below to get up and all the way out. As an insurance assessor/inspector in Canada, I always noted roof venting on large areas or exposed roofing. Along with proper soffit venting it is supposed to work. I'm not HVAC trained or a building inspector tho'.

[mogoso]

I grew up with an attic fan, seemed pretty good idea in Florida. pulled air from the whole house and while not aircon it made it somewhat comfortable

[WinnieTheKhwai]

sticklee, tell us about your house. Single level, or multiple? Crawl space underneath or a pad poured on soil? Large attic or small? Lots of windows or few and if few, are they huge or normal? Ten foot ceilings or less than that? What is the composition of your roof?

Thanks everyone for input. My house is a small one storey 2 bedroom. Poured concrete slab, 10' celings. Well treed with large trees on south and west side so I have lots of shade. Standard windows, 2 per side of house with sliding entry at front. Roof is terra cotta tile type. Large porch (overhang) at front entry and single car carport at front. Front of house faces south. Currently have 1-9,000 BTU AC in room at ne corner. The interior heats up fairly quickly and cools down slowly. All fairly typical given the current temperatures. I was hoping to slow down the heating up with insulation and with better air circulation through the attic, clear out the hot air more efficiently after sundown....Does that seem sound thinking?

I'll throw my two baht out there. You don't have any dead air under the house so that idea is out. Too bad on that.

The next thing I see, based on your description, is the ceilings. I had the same problems that you speak of. However, the attic WAS vented, passive, on both ends of the house. The kitchen was the hottest room, even though we didn't cook. The refrigerator was causing that room to get warmer than the rest of the house. That motor, compressor and the cycle do produce a lot of heat outside of the refrigerator. So, I cut a large rectangular hole in the ceiling, built an nice frame with screen and made some decorative louvers to hide the screen. Instant success when I cut the hole. I was standing on a ladder, sweating bad and the instant I removed the large piece that I had cut out, the breeze began to cool me down. The hot air rising caused a great draft and that continued until the hot season was over. So, you can use convection to overcome a lot of your problem.

The ends of the attic do need to be vented. The hot air needs to be able to get out and rise. That is a cheap project.

Once the kitchen problem was solved, I noticed that the rest of the house really wasn't much cooler. I also noticed that with the 10 foot ceilings, the hot air at the tops of the rooms could not get out of the rooms because the tops of the walls were solid all of the way down to the tops of the room doors. So, any heat trapped up there, stayed trapped. So, same thing. I vented each room into the attic and went through the same discovery each time. That hot air just needs a place to go. Up and out. I didn't want to vent each room. It would have been better to cut a vent at the tops of the walls so they could vent from room to room and then into the kitchen. But the interior walls were six inch concrete. It was just easier to vent them all into the attic.

So, try removing one ceiling panel in a hot room in your house and see how much draft you get. That alone may get the temps down enough to make you happy.

This all very nice, but will NOT work in combination with air conditioning; those nice vents would be like leaving all doors and windows open. So if you can go without aircon in 40 degree heat: great. If not, then insulation is better than venting.

[Hog Head]

Vent the attic using louvers in the gable ends, assisted by a thermostatically controlled barn fan if necessary. I wired my house for the fan but found it is not necessary in my situation. No point in having air out if there is no air in, so you need to let air into the attic space via vented soffits. You will have seen these vented soffits in Canada as part of the building code.

Roof turbines are a good idea if you do not mind the look and have a good place to install them, but you still need air in.

Once the attic is vented, then you should think about insulating the ceiling. Spray foam on the roof tiles is a great idea, but you will get more bang by doing the ceiling first. Foil encased fibreglass bats while a low R value, are easy to install and as effective as the R factor would indicate. Foam has a higher R value, but if installed on the ceiling you will need to take care that it can support the weight.

Windows are the next thing to do, and short of replacing them with double pane low-E glass, you are limited to UV film.

New construction offers many more possibilities but given that this is an existing structure, your choices are limited.

[chiangmaiexpat]

There are many types of roof vents. Simple louvered openings in the gables do a fine job for gabled roofs. With a hipped roof, you can install a vent on the surface. They come in many styles and shapes. We have a dutch gable roof with white tiles that reflect a part of the radiation. In addition, there is a silver foil above the 2nd floor ceiling, which also reflects radiation. All exterior walls are double brick walls with an air gap (for thermal insulation) and the house is designed to allow a natural draw along two axes if the windows and doors are opened. We use sliding windows and doors to control the air flow. It's quite effective. Even now (in April) we hardly use air conditioning. We have installed ceiling fans in all rooms. Instead of tinted glass, we use curtains and blinds to block the sunlight, because the tinted glass would take away too much light on darker days. What I'm saying is that a single measure is unlikely to bring substantial improvement, but several combined measures for passive cooling are quite effective.

Cheers, CMX

[seesip]

I've read that having a light colored roof can reduce the heat from direct sunlight substantially, does any one have any experience with light or white colored roof tiles... or painting existing ones? Also what about the wooden slats that seem to enclose many of the more modern buildings and houses--it looks like it would help by giving some shade to the sides of the house, but would like to hear from anyone who's tried it?

[Donnyboy]

I've read that having a light colored roof can reduce the heat from direct sunlight substantially, does any one have any experience with light or white colored roof tiles... or painting existing ones? Also what about the wooden slats that seem to enclose many of the more modern buildings and houses--it looks like it would help by giving some shade to the sides of the house, but would like to hear from anyone who's tried it?

worth a read (URL removed..some issues with the link)

[keemapoot]

An absolutely fantastic new ceiling insulation product is called Stay Cool Green 3’ insulation by the Siam Cement Group SCG. It is sold at all Home Marts and also Homepro.

I recently installed it and it was a radical improvement. Comes in a couple of grades.

[JohnC]

I had my roof interior sprayed with a foam agent in January and the temperature difference in the house now is very noticeable plus it fixed my water leaks and made the roof more secure from break in's. Anyone interested is welcome to pm me for further details.

[kandahar]

sticklee, tell us about your house. Single level, or multiple? Crawl space underneath or a pad poured on soil? Large attic or small? Lots of windows or few and if few, are they huge or normal? Ten foot ceilings or less than that? What is the composition of your roof?

Thanks everyone for input. My house is a small one storey 2 bedroom. Poured concrete slab, 10' celings. Well treed with large trees on south and west side so I have lots of shade. Standard windows, 2 per side of house with sliding entry at front. Roof is terra cotta tile type. Large porch (overhang) at front entry and single car carport at front. Front of house faces south. Currently have 1-9,000 BTU AC in room at ne corner. The interior heats up fairly quickly and cools down slowly. All fairly typical given the current temperatures. I was hoping to slow down the heating up with insulation and with better air circulation through the attic, clear out the hot air more efficiently after sundown....Does that seem sound thinking?

I'll throw my two baht out there. You don't have any dead air under the house so that idea is out. Too bad on that.

The next thing I see, based on your description, is the ceilings. I had the same problems that you speak of. However, the attic WAS vented, passive, on both ends of the house. The kitchen was the hottest room, even though we didn't cook. The refrigerator was causing that room to get warmer than the rest of the house. That motor, compressor and the cycle do produce a lot of heat outside of the refrigerator. So, I cut a large rectangular hole in the ceiling, built an nice frame with screen and made some decorative louvers to hide the screen. Instant success when I cut the hole. I was standing on a ladder, sweating bad and the instant I removed the large piece that I had cut out, the breeze began to cool me down. The hot air rising caused a great draft and that continued until the hot season was over. So, you can use convection to overcome a lot of your problem.

The ends of the attic do need to be vented. The hot air needs to be able to get out and rise. That is a cheap project.

Once the kitchen problem was solved, I noticed that the rest of the house really wasn't much cooler. I also noticed that with the 10 foot ceilings, the hot air at the tops of the rooms could not get out of the rooms because the tops of the walls were solid all of the way down to the tops of the room doors. So, any heat trapped up there, stayed trapped. So, same thing. I vented each room into the attic and went through the same discovery each time. That hot air just needs a place to go. Up and out. I didn't want to vent each room. It would have been better to cut a vent at the tops of the walls so they could vent from room to room and then into the kitchen. But the interior walls were six inch concrete. It was just easier to vent them all into the attic.

So, try removing one ceiling panel in a hot room in your house and see how much draft you get. That alone may get the temps down enough to make you happy.

This all very nice, but will NOT work in combination with air conditioning; those nice vents would be like leaving all doors and windows open. So if you can go without aircon in 40 degree heat: great. If not, then insulation is better than venting.

And you are very right about that. I had AC in the bedroom only, in the situation that I described and I did not vent that room. If the OP is providing AC to the entire house, then it won't work for him.

Now that I see that he is renting or leasing, I'm not sure if any of the advice given is going to help him. I didn't catch that before. He needs to buy more window unit air-conditioners. When he moves, he can take those with him. If he pays to insulate the place, the insulation will stay behind.

[Naam]

Insulation helps somewhat (slows down the warming up), but with tempearatures of 40 degrees and the sun continuously on the roof, it's still going to heat up. Venting works somewhat in the afternoon in the wet season when the winds pick up, but again, without much wind it doesn't help. And, even if there was wind it would still suck in 40 degree air.

no wind needed with forced electric ventilation. cost of energy a fraction of the savings.

[jaideeguy]

3 comments [for 2thb].....

1] beware of donnyboy's 'hot roofs' link.....it tried to force my computer to dwonload a pdf that I didn't want and then locked my pc up so I had to reboot.

2] beware of that fiberglass insulation sandwiched between 2 foils........makes perfect nesting for rats, birds, and all kind of critters. and it's a mess to remove.

3] I have two spinners on my roof and they spin all day long....the hotter the faster and I opened a couple of celing tiles and could see the upbreeze pulling air from below, but it was hot air from outside.....so no improvement. Maybe if I opened it when the outside air cools it would be more effective. My next step will be reflective paint or maybe a sprinkler on roof>>??

[eek]

...

1] beware of donnyboy's 'hot roofs' link.....it tried to force my computer to dwonload a pdf that I didn't want and then locked my pc up so I had to reboot.

Have removed the link for the time-being and pmed Donnyboy. There does seem to be some issue of it locking up the pc. I have a pretty decent pc and a good net connection, but it froze up firefox.

Donny, can you have a recheck on that link please. Tnx.

[Donnyboy]

...

1] beware of donnyboy's 'hot roofs' link.....it tried to force my computer to dwonload a pdf that I didn't want and then locked my pc up so I had to reboot.

Have removed the link for the time-being and pmed Donnyboy. There does seem to be some issue of it locking up the pc. I have a pretty decent pc and a good net connection, but it froze up firefox.

Donny, can you have a recheck on that link please. Tnx.

sorry guys, it was something i found when i googled. It worked ok for me

[Naam]

3 comments [for 2thb].....

1] beware of donnyboy's 'hot roofs' link.....it tried to force my computer to dwonload a pdf that I didn't want and then locked my pc up so I had to reboot.

2] beware of that fiberglass insulation sandwiched between 2 foils........makes perfect nesting for rats, birds, and all kind of critters. and it's a mess to remove.

3] I have two spinners on my roof and they spin all day long....the hotter the faster and I opened a couple of celing tiles and could see the upbreeze pulling air from below,

1. but it was hot air from outside.....so no improvement. Maybe if I opened it when the outside air cools it would be more effective. My next step will be reflective paint

2. or maybe a sprinkler on roof>>??

1. incorrect assumption JDG as there is improvement. if your attic is not ventilated temperatures can reach surprising values. years ago i did a test in my Florida home which was ventilated by several thermostat controlled electric roof fans. on a sunny day in july -ambient air temperature 34ºC- i switched off the fans at 11.00 hrs and measured 4 hours later 72.6ºC (163ºF)!!!

2. a sprinkler on the roof would definitely cause a lower attic air temperature but not lower than the ambient temperature and that with much more energy input than forced ventilation.

[WinnieTheKhwai]

Question on active fans: would those be placed in the ceiling to push air out to the roof space, or near the gable vents to blow air out?

[MESmith]

Question on active fans: would those be placed in the ceiling to push air out to the roof space, or near the gable vents to blow air out?

I would think the problem with pushing air out from the rooms into the roof space is that air has to be replaced from somewhere, & if that means pulling air in from outside through gaps under doors etc that is warmer than the air in the rooms, you will be defeating the object.  This would only be viable in evenings when temps outside have dropped below those in the house.  That's how I try to keep temps in the house down - close all windows during the day as temps rise outside the house, then open as the sun goes down, turning on extractor fans in ceiling.  It's not great, but it keeps temps in house bearable day & night, with assistance from fans.

[WinnieTheKhwai]

Yeah, that's exactly what I do. Somewhere around 9am I close all the doors and windows downstairs. Keeps remarkably cool even without aircon. (though on some of the 40 degree days I did run the airconditioner)

[Naam]

Question on active fans: would those be placed in the ceiling to push air out to the roof space, or near the gable vents to blow air out?

ideal is placement in the roof, like the passive turbines, sucking hot air out of the attic. that there has to be free airflow to replace the sucked out air goes without saying.

[uptoyoumyfriend]

lots of confusion here!

but all the bits and pieces necessary are mentioned.

shade.

air at night -get the place cool -close it in the day keep the cool inside.

have the kitchen and the fridge separate ,windows open, or even better outside.

install roof turbines -they keep the attic at reasonable temps at low cost.

with roof tiles there is enough air coming into the attic-

with corrugated cement roofing (lighter colors are better)you need soffit vents for that.

the ceiling needs to be insulated against hot air and radiation.this is very difficult after construction with the products offered here because of the wiring and the wires used to hang the sheet rock panels from the rafters.it is a mess up there .go have a look.

best would be fill in or blown in insulation which i haven't seen here (yet) .

if yo need it cooler use fan or aircon.

i seriously thought of starting a business with locally (cheaply)made insulation for that matter,like blown in stuff from recycled (paper) products for example available in europe and the us that is environmentally friendly and cheap.

all the products available here now are priced out of range for the average thai or useless or both.

anybody interested ?

Edited April 21, 2010 by uptoyoumyfriend

[Hugh Jarse]

Very helpful info. here about this important matter. About to build a house so reading these threads and the inputs greatly appreciated.