Ceiling/roof insulation "stay cool"

[GarryP]

15 minutes ago, Denim said:

 

This depends on whether you are buying a new build house or are having your own built. If you are buying a built house then you will get some kind of suspended ceiling. If you are having your house built it is up to you what kind of ceiling you want.

You can have a 2x4 steel frame but of course it will be more expensive and heavier

 

As I said, I had a steel gantry welded down the center of the attic to give me access. well worth the little extra.

 

 

 

In a couple of years I will be having a house built so it is an option I will keep in mind. My current house was part of a project so I had no say in the matter. Also, because I will eventually be selling my current house and moving up country, I will hold off installing insulation as savings in electricity would not cover the cost of the insulation and installation before I sell up.   

[Thainesss]

16 minutes ago, CharlieH said:

You could consider using running boards, get some planks strategically placed between the steel roof frame (assuming you have the height).

 

Just a suggestion. I did that and it worked out well when laying the insulation.

 

I just paid some locals to climb up there and lay it out LOL. Mine was done after the house was bought so there wasn’t any way to get long enough boards up there through the access hole.  

[GarryP]

17 minutes ago, CharlieH said:

You could consider using running boards, get some planks strategically placed between the steel roof frame (assuming you have the height).

 

Just a suggestion. I did that and it worked out well when laying the insulation.

I shall pop up and have a gander this weekend. Your suggestion seems the most appropriate. I just need to do some cleaning up there, but I won't be installing any insulation in my current house. That will be done when I move upcountry and have my new house built.   

[spidermike007]

32 minutes ago, Thainesss said:

 

If it were 2X4’s in the western sense then they go between them. 

 

In the suspended ceiling they go between the ceiling supports in any fashion you can fit them, as close to the gyprock as you can get it. 

 

So, is it impossible to lay down the batting, in a ceiling that is suspended, since it sounds like there is nothing to support the weight of a person doing the work up there?

 

 

[spidermike007]

7 minutes ago, Thainesss said:

 

I just paid some locals to climb up there and lay it out LOL. Mine was done after the house was bought so there wasn’t any way to get long enough boards up there through the access hole.  

And the suspended ceiling was strong enough to support someone crawling around up there, laying down and taping the batting?

[Thainesss]

7 minutes ago, spidermike007 said:

And the suspended ceiling was strong enough to support someone crawling around up there, laying down and taping the batting?

 

They didn’t tape the insulation, it’s all snug together, and they didn’t stand or walk on the ceiling. They just stood on the steel braces and pulled it around with a piece of rebar bent into a hook. 

 

You dont have to stand stand on the suspended ceiling part of it. 

[bankruatsteve]

12 minutes ago, spidermike007 said:

 

So, is it impossible to lay down the batting, in a ceiling that is suspended, since it sounds like there is nothing to support the weight of a person doing the work up there?

 

 

You might be surprised.  I weigh over 100kg and could do pull ups from the rail (well try to).  While I have been up there and use the walls for "travel", I wouldn't use the rails simply because I doubt I could balance.  What did work well for my wife (who ended up laying the bats) is to use 2 boards of about 70cm and (what's the term?) flip-flop around that way.

[Don Chance]

The problem is moisture, assuming you have AC. In a hot, wet climates you want a vapor barrier on the exterior, like a bubble keeping the wet air out of your building.

 

If you put the vapor barrier on the inside like with vinyl wall paper you will create mold, so be careful. This happened with a big hotel chain in Florida.
 

So you want to seal the exterior completely so no air is coming in, your ac will work less.

 

To keep the sun off your structure you need a big umbrella that could be a roof made of palm fauns, insulated roof tiles, clay tiles are also good.

 

The problem with putting insulation on the ceiling is that if you are not running the AC all the time you may get mold - heat and humidity rises. Cold air does not rise it sinks, so it is not necessary to insulate there.

 

Insulate and VB the walls, floors from the exterior and also the roof. Then drywall or ceiling tiles on the ceiling with a vented roof.

 

The interior walls should also be dry wall with a 1/2" gap. Do not just paint the interior concrete walls as commonly done if you can avoid it.

 

The concrete walls will dry from the inward because the exterior side should be completely sealed, ideally with spray foam.

 

In a cold climates we worry about roof and ceiling insulation because again heat rises and the humidity drys out with the mechanical heating.

Edited July 2, 2019 by Don Chance

[bankruatsteve]

I have taken several hits in this thread, some not so nice and most totally unfounded.  I usually don't give a crap but when one poster misstates a scientific fact, I feel compelled to respond:

 

First off, all heat energy is emitted by thermal radiation.  No exceptions.  ALL objects (plant, animal, rocks, particles) on the planet emit thermal radiation.  Probably all objects in the universe as well although not sure about black holes.

 

Heat energy is transferred in basically three ways:  radiation, convection, and conduction.  A fire is an example of all three.  For a roof space (attic), the roofing absorbs heat energy radiated primarily from the sun.  The roofing conducts heat to the attic space.  If there is a reflective "barrier" beneath the roofing most of that heat energy is reflected back to the roofing.  It's not 100% but safe to say most.  In that case, it's pretty much end of story.

 

If not, the heat from the roofing continues to radiate and is also convected throughout the attic space.  I suppose it could reach an equilibrium where convection would stop.  If there is no barrier between the attic space and the ceiling, the heat is then conducted to the living space.  That is what we don't want.  One barrier for both radiated heat and convected heat is reflective foil.  Again, it is not 100% but effective.  Another way is to retard the conduction using insulation.  Insulation absorbs radiated and convected heat but slows down the transmission.  ('R' stands for resistance not blocking)  The higher the R, the longer it will take to conduct but conduct it will.  Both methods degrade when "stuff" (dust, critters, water damage, etc.) affect the effectiveness of the material and could require replacement after a time.

 

Now, unless I managed to misstate something the above cannot be refuted because it is fact.  The following are my opinions that are based on experience and I can't be bothered to research for backup. 

 

In this climate, I find that insulation is not the most cost effective or practical method to retard heat transmission to the living space.  I find that reflective bats resolve most of the issue.  Of course insulation can add to that but, for me, it wouldn't help much, is not worth the cost, and is why I say "superfluous".  This is what you can agree or disagree and, if you have research to the contrary, I would be interested in seeing it but probably won't change my opinion on it.

[CharlieH]

"In this climate, I find that insulation is not the most cost effective or practical method to retard heat transmission to the living space.  I find that reflective bats resolve most of the issue".

 

So based on this statement, the product in the OP has BOTH reflective and insulating values, as the insulation is covered in reflective coating and rated @ R37 . Or have I misunderstood ?

[bankruatsteve]

1 minute ago, CharlieH said:

"In this climate, I find that insulation is not the most cost effective or practical method to retard heat transmission to the living space.  I find that reflective bats resolve most of the issue".

 

So based on this statement, the product in the OP has BOTH reflective and insulating values, as the insulation is covered in reflective coating and rated @ R37 . Or have I misunderstood ?

Yes.  Again, my view is that reflecting most heat energy is "better" than retarding all of it.  Without some insulative gap, reflective foil is likely to become a conductor as well.

[sandmonster]

My house had reflective foil on the underside of the roof as standard. In addition, I chose to add the thickest StayCool insulation during the build. I am SO glad I did. My neighbours who only have the reflective foil are amazed how much cooler my house is especially upstairs. It really is night and day. When I go to my friends house nearby with only the reflective stuff, its like a furness in comparison.

 

Whatever the science, my 5 years real world experience says it works and was well worth it. 

 

 

 

 

[CharlieH]

3 minutes ago, sandmonster said:

My house had reflective foil on the underside of the roof as standard. In addition, I chose to add the thickest StayCool insulation during the build. I am SO glad I did. My neighbours who only have the reflective foil are amazed how much cooler my house is especially upstairs. It really is night and day. When I go to my friends house nearby with only the reflective stuff, its like a furness in comparison.

 

Whatever the science, my 5 years real world experience says it works and was well worth it. 

 

 

 

 

Well I have to agree with this, thank you for adding your experience.

 

Also, regardless of any scientific comment etc, my experience is that the test bedroom showed a marked improvement, that led to the whole house 120m2 being done and so far I am delighted with the obvious reduction in heat, the reduced use of the air-con, amd the rooms staying cooler longer after a/c use.

 

My experience and opinion on this product is that it was well worth the cost for the end result achieved.

[GarryP]

The problem with reflective bats is that while they enjoy sleeping and meditation during the daytime, they can get quite noisy once the sun has set.  As such, I think I will stick with reflective batts which are much quieter as they seem to be uninterested in moving about and screeching.  I'll get my coat.

[bankruatsteve]

6 minutes ago, CharlieH said:

Well I have to agree with this, thank you for adding your experience.

 

Also, regardless of any scientific comment etc, my experience is that the test bedroom showed a marked improvement, that led to the whole house 120m2 being done and so far I am delighted with the obvious reduction in heat, the reduced use of the air-con, amd the rooms staying cooler longer after a/c use.

 

My experience and opinion on this product is that it was well worth the cost for the end result achieved.

There used to be a Thai guy who posted on this forum (IMHO?) whose family are/were builders.  He commented often on how many builders would either use the wrong type of material or installed the under-roof reflective improperly.  I also have the product on my ceiling and the 2" of insulation is just right.

[geoffbezoz]

11 minutes ago, CharlieH said:

Well I have to agree with this, thank you for adding your experience.

 

Also, regardless of any scientific comment etc, my experience is that the test bedroom showed a marked improvement, that led to the whole house 120m2 being done and so far I am delighted with the obvious reduction in heat, the reduced use of the air-con, amd the rooms staying cooler longer after a/c use.

 

My experience and opinion on this product is that it was well worth the cost for the end result achieved.

Did you affix it to the underside of the roof or lay it flat on top of the ceiling ?

[CharlieH]

Just now, geoffbezoz said:

Did you affix it to the underside of the roof or lay it flat on top of the ceiling ?

I just rolled it out and let it lay flat on the ceiling, some what similar although not as pretty as the image further up the topic.

[geoffbezoz]

2 minutes ago, CharlieH said:

I just rolled it out and let it lay flat on the ceiling, some what similar although not as pretty as the image further up the topic.

Have you had any condensation problems in the loft area or is the loft void ventilated ?

[Thainesss]

59 minutes ago, bankruatsteve said:

In this climate, I find that insulation is not the most cost effective or practical method to retard heat transmission to the living space.  I find that reflective bats resolve most of the issue.  Of course insulation can add to that but, for me, it wouldn't help much, is not worth the cost, and is why I say "superfluous".  This is what you can agree or disagree and, if you have research to the contrary, I would be interested in seeing it but probably won't change my opinion on it.

 

If this logic was true then they wouldn’t sell insulation worldwide and incorporate it into building codes and require it for energy saving strategies in the west, both for cooling AND heating. 

 

And I mean even refrigerators have insulation on all sides, not just foil. 

[CharlieH]

1 minute ago, geoffbezoz said:

Have you had any condensation problems in the loft area or is the loft void ventilated ?

The loft has 4 gable ends, all of which have slatted vents allowing cross flow ventilation, the soffit boards also vented around the roof perimeter.

[bankruatsteve]

4 minutes ago, Thainesss said:

 

If this logic was true then they wouldn’t sell insulation worldwide and incorporate it into building codes and require it for energy saving strategies in the west, both for cooling AND heating. 

 

And I mean even refrigerators have insulation on all sides, not just foil. 

The logic is my opinion of the most cost effective method to reduce heat infiltration to the living area of a house built in Thailand.  What is there to be "true" or not?  I am well aware of the requirement and advantages of insulation per se.  What does a refrigerator have to do with anything I have said?

[sometimewoodworker]

1 hour ago, bankruatsteve said:

If there is a reflective "barrier" beneath the roofing most of that heat energy is reflected back to the roofing.  It's not 100% but safe to say most.  In that case, it's pretty much end of story.

A generally accurate assessment apart from the point that most silver foil just under the roof tiles/metal or glued to the thin insulation that is glued to the metal is actually a radiant barrier and functions by not radiating heat down into the roof space.

 

Sometimes it can't reflect (glued to the insulation or in direct contact with the roof material).

 

Sometimes while initially it can reflect due to dust buildup on the upper surface any reflective capability is degraded, though the underside (radiant barrier) will continue to perform (not radiating much heat) with virtually no reduction in performance ( dust not sticking well to that side.

 

This is a point that seems to be the one that is the most challenging for some people to understand, I don't suggest that @bankruatsteve is one of them

[CGW]

1 minute ago, bankruatsteve said:

What does a refrigerator have to do with anything I have said?

Maybe its time to reconsider your logic & look at how insulation actually works? your a long way off the mark at present.

[bankruatsteve]

11 minutes ago, CGW said:

Maybe its time to reconsider your logic & look at how insulation actually works? your a long way off the mark at present.

Jeez.  OK - where have I been a long way off on how insulation actually works?  Quote please.

[Thainesss]

10 minutes ago, bankruatsteve said:

The logic is my opinion of the most cost effective method to reduce heat infiltration to the living area of a house built in Thailand.  What is there to be "true" or not?  I am well aware of the requirement and advantages of insulation per se.  What does a refrigerator have to do with anything I have said?

 

I not trying to be rude here but just because a house is built in Thailand doesn’t mean it’s some foreign planet in another galaxy where heat transfer principals don’t apply. I’m from a climate just as hot as Thailand and probably more humid, the same principals apply and are written into building codes and energy saving procedures because they work. 

 

The reverse of what you’re saying is that basically the west is doing it wrong regarding insulation and the only thing that’s needed is reflective foil & everything else is superfluous. 

 

And we both know that’s not right. 

 

Regarding fridges - you’re cooling a space (inside the fridge) and the outside is hot (same as a room/roof/walls) and if your logic was sound then they wouldn’t insulate the fridge on all sides - just a foil barrier and plastic. But they don’t. Because you’d need 2 or 3 times the cooling power to do the same job. Because insulation is working. 

[CharlieH]

Ok, I am going to call "time" on this topic, it was about fixing a specific type of product and its usefulness etc.

 

It seems to have devolved into repeated argument of thermodynamics and physics of insulation and heat transfer.

 

I would suggest those that wish to debate that further open a topic specifically about that and argue until your hearts content there.

 

CLOSED.

 

 

[bankruatsteve]

4 minutes ago, Thainesss said:

 

I not trying to be rude here but just because a house is built in Thailand doesn’t mean it’s some foreign planet in another galaxy where heat transfer principals don’t apply. I’m from a climate just as hot as Thailand and probably more humid, the same principals apply and are written into building codes and energy saving procedures because they work. 

 

The reverse of what you’re saying is that basically the west is doing it wrong regarding insulation and the only thing that’s needed is reflective foil & everything else is superfluous. 

 

And we both know that’s not right. 

 

Regarding fridges - you’re cooling a space (inside the fridge) and the outside is hot (same as a room/roof/walls) and if your logic was sound then they wouldn’t insulate the fridge on all sides - just a foil barrier and plastic. But they don’t. Because you’d need 2 or 3 times the cooling power to do the same job. Because insulation is working. 

I generally appreciate your posts but what in the hell is going on here?  I am not a insulation denier.  I am not trying to take away anybody's insulation.  I never said heat transfer principles don't apply here.  I suspect codes are what they are in the states because it also gets COLD.  My one and only point in this thread was my first one:  IMO reflective insulation (in these circumstances) beyond say 2" does little to help and is not cost effective.  That's it.  How all this other stuff comes up is befuddling to me.