Ceiling/roof insulation "stay cool"

[CharlieH]

Anyone have this ? Various thicknesses lays on the ceiling in the roof space reflects/prevents heat penetration etc.hence the "stay cool" tagline.

 

Essential fibreglass style matting encased in thick alluminium type cover.

Looks like a giant thick quilt. ????

[Andrew Dwyer]

I don’t, but I’m interested in it .

What’s the ideal thickness ( the thicker the better I suppose ? ) .

[CharlieH]

It has 3 thickness with different ratings. 2,  3, 6 inch.The 6 is 419 baht per 4m x 0.6m strip/roll 

[bankruatsteve]

In cold places thicker is better because it reduces heat conduction (out).  Here the radiant heat reflection is what we want.  Once the heat is reflected, there's not much left to conduct (through the ceiling) so thickness becomes insignificant.  But, for those thicker-is-better folks - go for it.

[Sheryl]

There is a lot of debate about these things - a lot depends on whether the interior is air conditioned all the time or not. If it, is this will help retain the coolness. But if not, while it may decrease heat transfer down from the ceiling it will also prevent heat from rising up and out which of course is what the heat needs to do.

 

A radiant barrier (tinfoil between the roof and the interior of the ceiling space )is far better IMO as it will prevent heat transfer into the ceiling space. While ideally put in when the house is built, it is possible to retrofit by attaching it to the underside of the roof beams (normally one would have it between the cross cross beams; there has to be a space between the barrier and the roof tiles).

 

Also very important is having adequate cross ventilation in the ceiling space.

 

I did this (retrofitted radiant barrier and increased windows to ventilate the ceiling) a few years ago and it has made a huge difference.

 

they sell the radiant barrier in same area as they sell this fiberglass insulation stuff.

[bankruatsteve]

Note:  if reflective bats are laid on the ceiling they MUST have some insulated space (5cm minimum to wit).  Otherwise, they become heat conductors.

Edited June 30, 2019 by bankruatsteve

[NightSky]

I think that a lot of heat is stored in the concrete breeze blocks and in the evening they radiate heat into the house. The roof insulation wont affect this much I expect. A good tip to help keep the house cool is to plant trees on each corner of the house and use those for shade from direct sunlight. Mango trees grow quickly as a temporary measure until something else grows around it.

 

Insulation seems costly although as someone else mentioned maybe if you have air conditioning it will help keep it cool for longer unless you open a window or a door for a minute and the heat just comes in again. 

 

[eyecatcher]

I researched every insulation batt sold in all the big box stores before i bought the stay cool.

Only Home pro and SCG stocked it.

The R38 rating there is the best you will find, the nearest being R27

However it effectiveness depends on the thickness so its rated per inch thickness.

I bought mine about this time, when the sales were on at i think 350 a roll maybe less. ( i bought 15 rolls but they said free delivery only when you spend 6k...so i bought a ladder aswell haha)

 

Used on the top floor ceiling of our business, and made an immediate massive improvement and on going monthly savings on aircon use.

 

At the time must admit i was chuntering about this business expense but two unbearable humid Mays later I am pleased we did it

 

[eyecatcher]

3 hours ago, Andrew Dwyer said:

I don’t, but I’m interested in it .

What’s the ideal thickness ( the thicker the better I suppose ? ) .

Not necessarily, .

The roll pictured above and most rolls i have seen are displayed with the overall R thermal resistance value.

R38 is for that 6" roll so its rating is 6.33 per inch.

You can find some of Globals cheap cheapies which are 2" thick but say R18

At first glance you think the Stay cool is a much better quality but the cheap cheapy is actually R9 per inch, a better quality product but its really too thin to be of any real use.

6" was always the minimum thickness to acieve your 0.3 u values for a roof (going back a fair while) and I would guess even for heat insulation a 6" layer is a minimum.

You can get three rolls of cheap cheapies at 117bt each to get your 6" but its going to cost more than a 6" roll.

 

 

[eyecatcher]

3 hours ago, bankruatsteve said:

Note:  if reflective bats are laid on the ceiling they MUST have some insulated space (5cm minimum to wit).  Otherwise, they become heat conductors.

You are not making this sentence very clear steve. 

can a space be a space if its insulated?

5cm above or below, above will have metres of space surely.

 

It kinda makes sense if you are talking about insulating between rafters..

[Denim]

Got the same sort of thing in our roof space , just a different brand. Just got 2 inches thick because I don't think the 6 inches is worth the extra cost. Certainly very effective at keeping heat out and cool air in.

 

After we had installed it for a couple of years I had to move our wardrobe to get something fallen down behind. Once I was behind the wardrobe I noticed it was warmer than in front of it and the heat seemed to be coming from the ceiling.

 

Got the ladder out and touched the ceiling behind the wardrobe then in front. The former was hotter than the latter.

 

Once everything was back in place I got up into the attic and made it over to the hot corner. Sure enough there was an area about 2 square feet not covered with insulation. Soon remedied and now the corner is no longer a hot spot.

 

During construction I also had the most expensive ( thick ) foil

put just under the ceiling tiles as mentioned by Sheryl. Roof space is also well ventilated all around and at the front and back face. (still hotter than hell up there though )

 

I have been a bit obsessive this year about keeping the heat out as it was a real hot hot season. Put up UV film on all windows ( minor difference ) and just today I was crawling around under the house ( raised on 1 meter posts ) painting the underside of the living room floor white to see if would make any difference reflecting heat up through the floor !!!

[Tarteso]

I bought last year in Home Pro the same sistem for roof and wall of living room and bedroom. Must to say that it works, (covering with palm panels).

Expensive?... yes!.
But make me feel in a very confortable house....with a little help of the aircon.

[Tarteso]

Forgot to mention that it’s a Teak house.

[Thainesss]

Every time I see threads like this I’m always shocked at people questioning the need or “point” of insulation. 

 

First of all, in a basic Thai house with a tile roof and gyprock ceiling - attic temps get up over 60C. I’ve put a sensor up there in mine to check it. 

 

Second, insulation will block most of that heat from radiating downward into your room. 

 

Third, if you use aircon, then it also creates a barrier and keeps the cool air in the room. The aircon doesn’t have to battle the heat radiating down from your attic space - requiring much less BTU’s to cool a space. 

 

Spending 20-30k to put insulation in your roof is beneficial even if you don’t use aircon, and even more beneficial if you do. 

 

 

[CharlieH]

Ok, thanks to those that have contributed so far.

 

Here is the story to date: I was looking for something to assist in cooling the house due to the excessive heat in latter months, more so than previous years, or so it felt. Anyway, I did some research and decided to try this insulation. As a test I did the main bedroom first at 6m x 4m. This room is generally closed up during the day and if entered mid/late afternoon was really hot and uncomfortable, it needed the Air-con opening almost immediately if staying in there for more than a  few minutes.

So, in Homepro I see the above item @425 per roll and bought enough for that room. The result was quite dramatic and saw an immediate drop in temperature during the day of some 4 degrees, and less use of air-con as it achieved set temp quicker and seemed to stay cooler longer.

Having a pleasing result, I then went to Thaiwatsadu who had the same product on sale @ 419 per roll. I then purchased enough to cover the rest of the home. It was easy to lay although really hot up there. It took around 3 hrs to complete the job and total cost for the home around 10k. So far so good.

 

I will now monitor the specific room temp differences / air-con use etc in the coming week and report back on the overall effect this has had for the benefit of those considering a similar project.

[Tarteso]

If you manage to do yourself, be carefull with the handling and cutting the glass fiber...wear gloves and mask!

 

[Lacessit]

5 hours ago, bankruatsteve said:

In cold places thicker is better because it reduces heat conduction (out).  Here the radiant heat reflection is what we want.  Once the heat is reflected, there's not much left to conduct (through the ceiling) so thickness becomes insignificant.  But, for those thicker-is-better folks - go for it.

The thicker the better, BOTH ways. When you are running an aircon below the ceiling, you don't want that nice cold to be leaking out through the ceiling.

Radiant heat implies direct radiation on the foil covering. In a roof space, it's actually heat transfer by convection in the roof space between the exterior roof and the interior ceiling that is the principal mechanism. That's the reason for having soffits or roof ventilators, to allow the heat to escape. If you really want the foil to be reflective, it should be on the roof exterior.

A few reasons for having insulation encapsulated in foil. It's cheap, it's a good marketing gimmick for the credulous, and installers don't get irritation from bare fibreglass.

[Mr Freeze]

Ive used two layers of the 10cm quilting ,the second layer cross lapping the first . Its made a huge difference, you can now touch the ceiling without scalding your hand in the summer . If you like your AC its well worth doing .

 

 

 

 

[Naam]

13 hours ago, Thainesss said:

Every time I see threads like this I’m always shocked at people questioning the need or “point” of insulation. 

 

First of all, in a basic Thai house with a tile roof and gyprock ceiling - attic temps get up over 60C. I’ve put a sensor up there in mine to check it. 

 

Second, insulation will block most of that heat from radiating downward into your room. 

 

Third, if you use aircon, then it also creates a barrier and keeps the cool air in the room. The aircon doesn’t have to battle the heat radiating down from your attic space - requiring much less BTU’s to cool a space. 

 

Spending 20-30k to put insulation in your roof is beneficial even if you don’t use aircon, and even more beneficial if you do. 

 

 

reading thaivisa threads on airons, insulation and related topics for nearly 15 years is still a neck hair raising experience for a physicist. 

[spidermike007]

I have only a small crawl space, to get into the attic. So, I think rolls any larger than 2" would be impossible to get up there. I am going to try the 2", and install a few exhaust fans in the attic. I expect it will make a big difference, as the house gets ridiculously hot, without the AC on. 

[CharlieH]

Just now, spidermike007 said:

I have only a small crawl space, to get into the attic. So, I think rolls any larger than 2" would be impossible to get up there. I am going to try the 2", and install a few exhaust fans in the attic. I expect it will make a big difference, as the house gets ridiculously hot, without the AC on. 

In my experience, its around 2 inches when you roll it out, then as its left laid flat it opens up,/expands so in your case it would fill the void nicely, I suggest.

[Laza 45]

18 hours ago, bankruatsteve said:

In cold places thicker is better because it reduces heat conduction (out).  Here the radiant heat reflection is what we want.  Once the heat is reflected, there's not much left to conduct (through the ceiling) so thickness becomes insignificant.  But, for those thicker-is-better folks - go for it.

Interesting.. I have foil/foam insulation attached to aluminium roofing.. above ceiling similar ..reflective foil and foam backing.. from what you are saying it wouldn't make much difference if I were to put  insulation batts above the ceiling insulation.. I have been thinking of doing this as I want to put air con in the room.. 

[Retfed50]

We used this to insulate the addition we put onto an older home. 6" in the attic and also 3" in the east and south facing walls. Works very well. The only time we use the air conditioners is in the bedrooms when we sleep.

[Formaleins]

Unless you can get virtually an hermetic seal around the ceiling / roof area between the top of the matting and your underside ceiling then it is not much good. If you imagine the hot air and cold air being exactly like water, you will see just how tight a seal you need in this heat to make much difference. There are some excellent videos on YouTube that address the insulation of ceilings and roof spaces.

There was a company in Chiang Mai a while back that would spray that expanding poly foam chemical on the inside of your roof. I would have thought that you would get a much more effective seal using that method.

 

I have also used the reflective silver type foil from SCG and it is pretty much useless.

Edited July 1, 2019 by Formaleins

[Dumbastheycome]

Our house has reflective barrier foil under the roof, over the gib ceiling and inside hollow spaced exterior walls.

All rooms that remain closed are always relatively cool most noticeably for cool floor tiles. for  However the living area daily becomes quite warm due to absorbed heat from ambient air flow.

We have ac only in the  bedroom but even during recent extreme hot weather rarely have needed to use it.

While products are now widely available for reducing heat transmission the concept of double/triple window glazing seems to so far not been recognized as an important factor. Even in a closed room the window glass transmits heat in quite efficiently.

 

[Old Croc]

In Australia, a country where extreme temperatures are the norm in summer, virtually every house is insulated with these "batts". It is a normal part of a house build, and there is over whelming evidence that they are effective. (During the GFC the Government there made the supply and instillation of them free in an effort to keep the economy going) 

For maximum efficiency they should cover the entire roof space including  the eaves.

 

 

Edited July 1, 2019 by Old Croc

[millymoopoo]

Yes, have it in house in CM but there's more to it than just this insulation.

How well the house is insulated relates to how well you prepare it.

!: Roofing has insulation layer incorporated under it from new (it alone is not very effective)

2: Large 'whirly bird' style roof vent fitted to roof at top of apex.

3: Several wall vents added to outside walls at ceiling level, to allow circulation of air through the ceiling cavity, to exit out the 'whirly bird'.

4: Then finally this insulation laid ontop of the ceiling and covering over the walls that protrude through the ceiling, this is important as the exposed walls that protrude into the ceiling cavity become heat conductors if left exposed.

Now we don't melt during songkran and the A/C uses half the electricity.

[BobBKK]

Well this has inspired me to get this done. Great info thank you.

[chilly07]

Always check the fire resistance of any insulation! We had a neighbours house burn out when the insulation caught fire. Failing all else put a lighter to it!

[Lacessit]

33 minutes ago, Formaleins said:

Unless you can get virtually an hermetic seal around the ceiling / roof area between the top of the matting and your underside ceiling then it is not much good. If you imagine the hot air and cold air being exactly like water, you will see just how tight a seal you need in this heat to make much difference. There are some excellent videos on YouTube that address the insulation of ceilings and roof spaces.

There was a company in Chiang Mai a while back that would spray that expanding poly foam chemical on the inside of your roof. I would have thought that you would get a much more effective seal using that method.

 

I have also used the reflective silver type foil from SCG and it is pretty much useless.

That expanding poly foam chemical is a potential death trap. If there is a short in any of the wiring running through the ceiling, it's a major fire hazard. No way I would want to sleep under that.

Hot air rises. The best way to get rid of it, and increase the efficiency of the insulation lying on top of the ceiling, is to have soffits or roof ventilators.