Which Insulation Material under the Roof?

[4MyEgo]

12 hours ago, 4MyEgo said:

The Sisalation worked well, but after 10am in the morning in this Isaan Thai summer, the air cons had to go on, but once I installed the whirly birds, i.e. on the very hottest days, I would crank them on at around 2pm-3pm,

Edit: The above should have read "but once I installed the ceiling batts, as the whirly birds were already in, suffice to say without insulation batts you will notice the heat in the ceiling coming through your gypsum plasterboard ceilings, i.e. in my case, without them I would notice the house getting hot at 10am, with them, I would notice the house getting hot between 2pm-3pm, and yes airflow is important in the ceiling space, but ceiling batts are also as important, even more so from my experience in reducing the heat entering the house for hours on, and keeping the cool air from the air con in, as opposed to escaping up through the gypsum plasterboard ceiling without batts.

[4MyEgo]

4 hours ago, gejohesch said:

Thanks for all this feedback. I have a question re. the whirly birds. My roof ridge from gable to gable, is 7 metres : could I get away with only 1 whirly bird in the middle, or should I rather think of 2 whirly birds, one at each end?

I believe the more whirly birds you have the better, as we have a double gable roof at the front with those wooden slatted saloon type windows and the high clearance within the roof, two whirly birds was enough, however if you only have 1.4, personally I think you will need more, but it's trial and era, so start with two as a minimum and see how you go.

 

4 hours ago, gejohesch said:

The "saloon type windows" : I know what you're talking about. These are the "slatted windows" I mentioned earlier. They are made of wood and can be bought in kits anywhere in Thailand, costs somewhere like 1500 - 2000 THB a piece if I remember right. We have 2 in place, one at each gable. I had them painted with teak colour paint and they look great.

Not sure about kits, although they come as a pair and 1500 - 2000 sounds like a hell of a lot, if I recall the local hardware charged me about 500-750 for the pair. 

 

 

[Kwasaki]

4 hours ago, gejohesch said:

I see recommendations for attic insulation in the USA : What R-value Do I Need? | Johns Manville (jm.com) Obviously, it would not be straightforward to compare between any US state and Thailand, however I find it interesting that the USA recommendations vary between Rt 30 and Rt 60 (increasing from south to north). 

Coming back to the 2 options I described in my OP:  "Material A is SCG "Stay Cool Green-3 Insulation - Rt 27" at 369 THB per roll. Material B is Sunshield "Extra Cool - Rt 37" at 279 THB per roll"

I find it strange that the material with the higher Rt value (A) is also the cheaper. Maybe it's the quality of the material, apart of the Rt value? Maybe I'm missing sthg in the specs? Not knowing better, I would opt for Sunshield at Rt 37 since it is cheaper and has the higher Rt factor.

 

Your thinking to much. 

Any fibreglass /rockwool incased in foil or not less than 10cm is OK for ceiling areas the thicker the better. 

Your vented gable ends are quite adequate if you go for whilibird thingys you risk the problem of leaks disturbing the roof if they are not proffesionally installed. 

 

As suggested already get a reflective underlining material installed to underside of roof and you have done a reasonable job of reducing roof heat. 

 

Lining board to incase the reflective material is OK but not that necessary butp will improve insulation a bit more but at an extra cost.

 

I was working in construction for 34 years and the insulation question was always brought up on many types of roofing designs. 

 

Up to you what you do. 

[gejohesch]

40 minutes ago, 4MyEgo said:

Edit: The above should have read "but once I installed the ceiling batts, as the whirly birds were already in, suffice to say without insulation batts you will notice the heat in the ceiling coming through your gypsum plasterboard ceilings, i.e. in my case, without them I would notice the house getting hot at 10am, with them, I would notice the house getting hot between 2pm-3pm, and yes airflow is important in the ceiling space, but ceiling batts are also as important, even more so from my experience in reducing the heat entering the house for hours on, and keeping the cool air from the air con in, as opposed to escaping up through the gypsum plasterboard ceiling without batts.

All that makes perfect sense. Bottom line is : best is to do 1/batts = insulation + 2/ventilation. Not only one or the other.

[gejohesch]

34 minutes ago, 4MyEgo said:

I believe the more whirly birds you have the better, as we have a double gable roof at the front with those wooden slatted saloon type windows and the high clearance within the roof, two whirly birds was enough, however if you only have 1.4, personally I think you will need more, but it's trial and era, so start with two as a minimum and see how you go.

 

Not sure about kits, although they come as a pair and 1500 - 2000 sounds like a hell of a lot, if I recall the local hardware charged me about 500-750 for the pair. 

 

 

Yeah, maybe I was wrong with the price I quoted. I bought them over a year ago and that was together with a lot of other stuff, so I could not remember precisely. They are a rather simple build and small so not using a lot of wood, so they should be cheap indeed.

[4MyEgo]

5 hours ago, gejohesch said:

I find it strange that the material with the higher Rt value (A) is also the cheaper. Maybe it's the quality of the material, apart of the Rt value? Maybe I'm missing sthg in the specs? Not knowing better, I would opt for Sunshield at Rt 37 since it is cheaper and has the higher Rt factor.

When I did the research before building from scratch, SCG sold me the stay cool for 400 baht per roll of (Rt38), I believe on special, I can certainly vouch for it doing it's job, as for the other one, well, I can't, stay cool is made from glass I believe, recycled material so environmentally friendly, and has a slow combustion rate, e.g. it doesn't burn in case of a fire from say for example of an electrical fire, short circuit and all that.

 

One thing I didn't do when it came to insulation is I did a hell of a lot of research and didn't skim on costs as I wanted what I got.

 

I recall the builder saying you don't need insulation, he was wrong, and the hardware guy selling me some insulation on a small bungalow we first built in 2009, it was c-r-a-p and is now falling apart under the roof tiles, back then I didn't know much and trusted these guys as they live here, nope, lesson learned, research and a few extra quid did it. 

 

Our house is big as we have a big family, now to give you an example, the cost of both the Sisalation and the batts was 120,000 baht, now everyone has a budget and if there is one thing I can't handle being a person who spends most his days in the house, is sitting in a chair doing what I do with sweat running down his face at 10am in the morning, sure I could put on the air conditioner or a fan to blow around the hot air, nope I sit in my wife's cool house that I built her and every time someone walks in, I can hear them say oh, air con uh, when there is no air con on, that said I notice the difference if I go out and come back in, suffice to say there would be a clear 10 degree difference between inside and outside, not to mention when winter comes, it's warm in the house.

 

Not trying to sell you a product or anything like that, but it's a matter of choice of course and the choices that I made paid off, but as mentioned, I can stand up in my ceiling space so have more space for the air to move around, the Sisalation is top grade costing me 60,000 baht and the batts another 60,000 baht (big house), and I reap the rewards of being in comfort as opposed to an oven.

 

Sounds like your on the right track, the only concern I have for you is that it's a metal roof and your clearance is only 1.4, but other with metal roofs can best advise their experiences, that said I don't think there would be that much difference in the roof type.

 

In the video below he used the work reflective, which would be the Sisalation, then you have the batts.

 

 

 

The thicker the better, to me Sisalation is like having a a layer of clothes over your body in the sun, even though you have a layer of clothes on, the heat will still penetrate over time, and the more layers you have, the longer it takes for the heat to come through.

 

I remember when I first came here I said to my wife are these people crazy wearing these clothes in the heat, she said cooler, I though she was mad, but she is right, the top layer is like the Sisalation, any layers under that work as the batts and then the gypsum plasterboard. 

 

That's the best I can explain it, without Sisalation, you will heat up quicker, even thought the batts will provide you with some time of the heat entering the house, Sisalation is the first point of slowing down the heat entering, batts are the 2nd point, but not before the whirly birds moving some of that hot air out. 

 

 

 

 

 

 

[UWEB]

5 hours ago, gejohesch said:

I see recommendations for attic insulation in the USA : What R-value Do I Need? | Johns Manville (jm.com) Obviously, it would not be straightforward to compare between any US state and Thailand, however I find it interesting that the USA recommendations vary between Rt 30 and Rt 60 (increasing from south to north). 

Coming back to the 2 options I described in my OP:  "Material A is SCG "Stay Cool Green-3 Insulation - Rt 27" at 369 THB per roll. Material B is Sunshield "Extra Cool - Rt 37" at 279 THB per roll"

I find it strange that the material with the higher Rt value (A) is also the cheaper. Maybe it's the quality of the material, apart of the Rt value? Maybe I'm missing sthg in the specs? Not knowing better, I would opt for Sunshield at Rt 37 since it is cheaper and has the higher Rt factor.

 

You are mixing up two different sizes, both SCG Stay Cool 3" and Sunshield Extra Cool 3" having Rt factor 27, factor Rt37 is for 6"/150mm thickness.

[4MyEgo]

8 minutes ago, gejohesch said:

All that makes perfect sense. Bottom line is : best is to do 1/batts = insulation + 2/ventilation. Not only one or the other.

For top results the bottom line is 1/Thermal reflective Sisalation, 2/Stay Cool batts with an Rt - 38, shop around, get them on special, 3/whirly birds. All 3 should provide you with the extra comfort, but do expect to have less in pocket.

 

I can stay in a 3 star hotel to save money, but will stay in a 5 star if it's on par (sale), but my home is my environment and I want to 5 star comfort for the remainder of my years, so will fork out the difference, 6 years on, not one regret, especially when it comes to summer here, I don't notice the extreme heat until I walk out the door to pick up the kids at 3pm, and can't wait to get back.

[MrJ2U]

19 hours ago, JAS21 said:

Your suggesion #1 can be bad news

JAS21 is right.

Unfortunately thats what we did, "Western" style.  

We're trapping the heat in.

 

#2 is good.

 

Light covered roof tiles with heat reflection will help keep it less hot.

 

Also rats and birds love that roof insulation to make nests.  

 

Next house I'll definitely plan better!

 

[gejohesch]

22 minutes ago, Kwasaki said:

Your thinking to much. 

Any fibreglass /rockwool incased in foil or not less than 10cm is OK for ceiling areas the thicker the better. 

Your vented gable ends are quite adequate if you go for whilibird thingys you risk the problem of leaks disturbing the roof if they are not proffesionally installed. 

 

As suggested already get a reflective underlining material installed to underside of roof and you have done a reasonable job of reducing roof heat. 

 

Lining board to incase the reflective material is OK but not that necessary butp will improve insulation a bit more but at an extra cost.

 

I was working in construction for 34 years and the insulation question was always brought up on many types of roofing designs. 

 

Up to you what you do. 

True, I know, I'm the type to think a lot ???? But is it not better than precipitation with a chance to regret afterwards? Once the whole roof replacement + improvement operation is done - at cost - I certainly would not like having to do more again because the heat insulation problem has not been solved!

 

About the whirly birds, I take your advice. I had been thinking exactly the same : what if the builders do not install them correctly and we get leaks? That's the last thing we want, with the heavy rains we get around here!

 

About the reflective material, I attach a pic showing the roofing sheets we installed somewhere else last year. They have that foam underneath with a metallic shining stuff - probably aluminum? It's called "0.35" which in fact has 5mm thickness. Costs about 280 THB per sq metre. You see that material a bit everywhere nowadays. So my question is : would that fit what you mention as the sort of reflective material required?

 

Finally, many thanks for your contribution - and also my thanks to the others who replied to my OP. Guy like me, I know nearly nothing about building, so it's great to get advice from people who have experience, before going to the shops and struggling with all the options and the difficulties to discuss with the locals.

[Kwasaki]

8 minutes ago, 4MyEgo said:

For top results the bottom line is 1/Thermal reflective Sisalation, 2/Stay Cool batts with an Rt - 38, shop around, get them on special, 3/whirly birds. All 3 should provide you with the extra comfort, but do expect to have less in pocket.

 

I can stay in a 3 star hotel to save money, but will stay in a 5 star if it's on par (sale), but my home is my environment and I want to 5 star comfort for the remainder of my years, so will fork out the difference, 6 years on, not one regret, especially when it comes to summer here, I don't notice the extreme heat until I walk out the door to pick up the kids at 3pm, and can't wait to get back.

If you felt your whilibirds in the 45 degrees hot sun I bet you wouldn't be touching them for long and what good are they on days of hot sun and no wind. 

[4MyEgo]

6 minutes ago, Kwasaki said:

If you felt your whilibirds in the 45 degrees hot sun I bet you wouldn't be touching them for long and what good are they on days of hot sun and no wind. 

Whirlybirds are designed to spin in even in the lightest winds. Whirlybirds extract hot air via two ways; convection and creating a vacuum. The vacuum potential is driven by the wind speed and drawing heat out of the roof space.

 

I look at it this way, they are cheap enough at say 1,500 baht each to have there for when there is the slightest wind to extract the hot air out of the roof space, that said, it's also a wise decision to have air conditioning in your car for those hot days, can you imagine driving around without air conditioning ?

[Kwasaki]

6 minutes ago, gejohesch said:

True, I know, I'm the type to think a lot ???? But is it not better than precipitation with a chance to regret afterwards? Once the whole roof replacement + improvement operation is done - at cost - I certainly would not like having to do more again because the heat insulation problem has not been solved!

 

About the whirly birds, I take your advice. I had been thinking exactly the same : what if the builders do not install them correctly and we get leaks? That's the last thing we want, with the heavy rains we get around here!

 

About the reflective material, I attach a pic showing the roofing sheets we installed somewhere else last year. They have that foam underneath with a metallic shining stuff - probably aluminum? It's called "0.35" which in fact has 5mm thickness. Costs about 280 THB per sq metre. You see that material a bit everywhere nowadays. So my question is : would that fit what you mention as the sort of reflective material required?

 

Finally, many thanks for your contribution - and also my thanks to the others who replied to my OP. Guy like me, I know nearly nothing about building, so it's great to get advice from people who have experience, before going to the shops and struggling with all the options and the difficulties to discuss with the locals.

So you have reflection to underside already so to improve you could line with boarding or plasterboard to improve a bit at cost. 

With the venting draw through effect of vents in gable ends roof that all you can do other than do extra venting in ridge but again at extra cost. 

To put 150mm or 200mm insulation on ceiling areas is about as good as you can go. 

Advice is always difficult online forum the solution is to be able for someone who knows what his doing to see your build and then access a suitable insulation applicantion at a reasonable cost. 

Unless your building is in a windy location whilibirds are a waste of time. 

[Kwasaki]

4 minutes ago, 4MyEgo said:

Whirlybirds are designed to spin in even in the lightest winds. Whirlybirds extract hot air via two ways; convection and creating a vacuum. The vacuum potential is driven by the wind speed and drawing heat out of the roof space.

 

I look at it this way, they are cheap enough at say 1,500 baht each to have there for when there is the slightest wind to extract the hot air out of the roof space, that said, it's also a wise decision to have air conditioning in your car for those hot days, can you imagine driving around without air conditioning ?

As long as your happy OK. 

They are not something I would recommend unless you lived by the coast. 

[sezze]

IMHO , since heat rises , but you do not want the heat of the roof going down .

Forget about the spray insulation and put the same money in the ceiling insulation . Ceiling insulation makes the heat not come down , everything up has to cent its way out .

[gejohesch]

47 minutes ago, UWEB said:

You are mixing up two different sizes, both SCG Stay Cool 3" and Sunshield Extra Cool 3" having Rt factor 27, factor Rt37 is for 6"/150mm thickness.

I checked again : you're right!

[4MyEgo]

1 hour ago, Kwasaki said:

As long as your happy OK. 

They are not something I would recommend unless you lived by the coast. 

Extremely happy with them, suffice to say just got off my back side at the time of replying to your comment, walked out to see what they were doing and they are spinning like crazy, noting that there is only a slight breeze and we are nowhere near the coast.

 

I did mention in an earlier reply to another poster I believe, that I can stand in our ceiling space and we have two gable roofs at the front with those salon style looking fixed panels on either side allowing the air in, and with the whirly birds acting like a vacuum, the results are evident to me. Also in Queensland Australia which has a similar climate to Thailand, they can be seen installed in houses that are nowhere near the coast.

[BigT73]

18 hours ago, pagallim said:

Agreed, here it's typically galvanised steel frame and cement tiles.   I had spray foam installed in our place some 7 years ago and it's proved excellent.   We had no previous leaks anyway, but the foam has effectively locked the tiles in position.

 

What I like about your design is you can have recessed light fittings. The batts in my ceiling had holes cut in them for my inset lights.  I noticed a difference  after the holes were cut.  In hindsight either your option or do some drop down ceiling just for lighting.

[unheard]

On 2/4/2022 at 2:38 PM, gejohesch said:

Hmmm, thanks for the feedback. Have to ask again the factory, and our builder (we have a very good one, based on past experience) if they think there could be a problem with the "ungluing" you mention.

I think he's talking about the thin 2.5 mm glued-on thin silvery plastic-like material.

That's not the kind of insulation you have in mind.

In your case it is a 25 mm (or thicker) polyurethane "PU" insulation that doesn't "unglue" itself after a few years, provides excellent thermal qualities and significantly reduces rain noise.

Also, the ceiling insulation is the way to go.

If combined with properly vented roof ridge (not the whirlybirds - very little air flow), it will allow you to keep the ceiling temps under control.

Walls and windows would be another contributor to heat, but it's a topic for a different conversation.

[unheard]

On 2/5/2022 at 10:49 AM, 4MyEgo said:

the whirly birds acting like a vacuum, the results are evident to me

Whirlybirds do not provide any vacuuming effect - it's a prevalent misconception.

I'm not going to argue with your "evidence" here, just trying to warn others from spending money on a myth.

[unheard]

On 2/5/2022 at 9:02 AM, gejohesch said:

About the reflective material, I attach a pic showing the roofing sheets we installed somewhere else last year. They have that foam underneath with a metallic shining stuff - probably aluminum? It's called "0.35" which in fact has 5mm thickness. Costs about 280 THB per sq metre. You see that material a bit everywhere nowadays. So my question is : would that fit what you mention as the sort of reflective material required?

This material is glued on, will probably fall off withing a few year, doesn't provide much of insulating properties compared to PU - in short, skip it.

Opt for the PU insulation, it normally starts with the 25 mm thickness and usually offer thicker options (the thicker, the better).

PU insulation comes with either silver foil or plastic liner (better looks if left exposed).

Opt for the silver liner option that provides less of the heat re-radiation.

[4MyEgo]

6 hours ago, unheard said:

Whirlybirds do not provide any vacuuming effect - it's a prevalent misconception.

I'm not going to argue with your "evidence" here, just trying to warn others from spending money on a myth.

I remember when I installed two whirly birds in Sydney, I stood under each one and could feel the air being sucked out of the roof, that is enough proof for me, that said, I also see my whirly birds here constantly spinning and the house is cool, so believe what you will, and I will believe the so called myth.

 

https://vertecroofing.com.au/do-whirlybirds-work/#:~:text=The answer to the question,the room or space below.&text=Whirlybirds work to effectively remove,sucking out the hot air.

[gejohesch]

17 hours ago, unheard said:

I think he's talking about the thin 2.5 mm glued-on thin silvery plastic-like material.

That's not the kind of insulation you have in mind.

In your case it is a 25 mm (or thicker) polyurethane "PU" insulation that doesn't "unglue" itself after a few years, provides excellent thermal qualities and significantly reduces rain noise.

Also, the ceiling insulation is the way to go.

If combined with properly vented roof ridge (not the whirlybirds - very little air flow), it will allow you to keep the ceiling temps under control.

Walls and windows would be another contributor to heat, but it's a topic for a different conversation.

Thanks for the clarification.

 

Ventilation : our roof is multi-pitched, i.e. it flattens out half-way down from the ridge. One issue, we now realise, is that the end section (the one that "flattens out"), lies too low on the walls and ceiling.

As a result, there is near direct heat transmission from the roof down into the house.

As we are going to replace the roof sheets, we think it will be best to change the roof shape and make it single-pitch. It will add volume under the roof which can only be a positive when it comes to ventilation. The extra volume can be seen clearly on the attached picture (done with Trimble / Sketchup), especially on the left side.

 

The current gables are dressed up with "mai-sera", the "ceramic-wood" that can be found everywhere in Thailand - as shown in grey on the attached picture. We will have to redo them. 

What I'm now thinking is that we could leave a few cms below the new roof not totally closed up but finished off with a solid metal mesh. Obviously not the type of metal mesh one sees around gardens, or to keep animals penned in, but a very tight mesh that would not allow birds, mice etc to get under the roof (see the picture). Such a mesh would allow extra ventilation and would make whirly birds unnecessary. With the roof sheets extending out from the house by a metre, and the metal mesh being only a few cms, I don't think there would be any problem with rain getting in under the roof and over the habitation.

 

[unheard]

12 hours ago, 4MyEgo said:

I remember when I installed two whirly birds in Sydney, I stood under each one and could feel the air being sucked out of the roof, that is enough proof for me,

If you remove the whirlybirds and just leave the holes open (with some rain covers), the airflow would stay exactly the same.

[CapraIbex]

How about solar operated fans for ventilating roof cavities installed to both sides of the gable roof?

[unheard]

2 hours ago, gejohesch said:

What I'm now thinking is that we could leave a few cms below the new roof not totally closed up but finished off with a solid metal mesh.

Probably won't make much of a difference - the air volume in the attic will remain stagnant.

Should only make some difference (maybe) on windy days.

What you really need is to try to create conditions for a constant air flow.

Hard to achieve without a higher roof and a vented ridge(s).

Even on a low pitch roof a vented ridge still could make a significant difference - the hotter, lighter air would want to move to the highest point of the structure (ridge) and escape if there's an opening, if not then it will just seat there, gradually gaining temperature.

[4MyEgo]

39 minutes ago, unheard said:

If you remove the whirlybirds and just leave the holes open (with some rain covers), the airflow would stay exactly the same.

When I built this place, I didn't put in the whirly birds or insulation, I wanted to see if the Sisalation was enough, which I knew it wouldn't be, the following summer the whirly birds went in, there was a drop in the temperature within the house, same temperatures as the previous temperatures outside previous year, then the following summer in went the insulation batts, that said from my experience, and having some knowledge and background in the building game, I can see all three are beneficial, not one or the other, add to that vented eaves of at least 600mm.

 

The above said, as I said before the whirly birds work as a vacuum, helped along with those fixed saloon style looking window panels under each gable (two) gables roofs, meaning I have 4 of those fixed saloon style looking window panels in total, up to you whether you believe it not as I am sitting here enjoying the coolness of the house at 11am with the outside temperature being 28 degree and the whirly birds spinning.

 

That said as I said before, I also researched this topic for a long time before I put them in and saw studies on the efficacy of whirly birds, that and have experienced there contribution to cooling the house by them extracting the heat in the roof space.

 

Now unless you can provide a credible study in a link that states otherwise, I have moved on.

[Saanim]

Insulation as much as possible is the solution. Of course, openings in the gable will contribute to the hot air escape.

However, what does it bring if forcing the air through by any means when the ambient air is 40 deg and more? 

   

[4MyEgo]

36 minutes ago, unheard said:

Probably won't make much of a difference - the air volume in the attic will remain stagnant.

Should only make some difference (maybe) on windy days.

What you really need is to try to create conditions for a constant air flow.

Hard to achieve without a higher roof and a vented ridge(s).

Even on a low pitch roof a vented ridge still could make a significant difference - the hotter, lighter air would want to move to the highest point of the structure (ridge) and escape if there's an opening, if not then it will just seat there, gradually gaining temperature.

If you value a more subtle look, the ridge vent wins in that category. ... Still, despite running the entire length of your roof, ridge vents are static and won't move air the same way turbines do. As long as there's a healthy amount of wind to power them, turbine vents will provide superior ventilation for your attic.Jul 21, 2564 BE

[Kwasaki]

10 minutes ago, 4MyEgo said:

When I built this place, I didn't out in the whirly birds or insulation, I wanted to see if the Sisalation was enough, which I knew it wouldn't, the following summer the whirly birds went in, there was a drop in degrees within the house, same temperatures as the following year outside, then the following summer in went the insulation batts, that said from my experience, and having some knowledge and background in the building game, I can see all three are beneficial, not one or the other, add to that vented eaves of at least 600mm.

 

The above said, as I said before the whirly birds work as a vacuum, helped along with those fixed saloon style looking window panels under each gable (two), meaning I have 4 of them in total, up to you whether you believe it not as I am sitting here enjoying the coolness of the house at 11am with the outside temperature being 28 degree and the whirly birds spinning.

 

That said as I said before, I also researched this topic for a long time before I put them in and saw studies on the efficacy of whirly birds, that and have experienced there contribution to cooling the house by them extracting the heat in the roof space.

 

Now unless you can provide a credible study in a link that states otherwise, I have moved on.

I would say many will agree with your findings nothing wrong with that,  you have achieved what you like. 

 

You can justify them as much as you like and they are beneficial.

 

As I have said personally from architectal and aesthetic point view and the type of house design they will look ugly in many cases and there are many other alternative ways to achieve house heat insulation.