New roof advice

[Sheryl]

As  soon as the rains are clearly done with for the year I am going to have a new roof put on - original is now 20 years old, was a cheap sort of fibro-cement no longer even sold and starting to crack.

 

Naturally I would like to do what I can to minimize heat in the house.

 

From what I have read in prior threads in this forum, I should:

 

1 - Use the lightest color tile possible, preferrably white (Question: if this is so, why are red and brown tiles so popular in Thailand?)

 

2- Install reflective foil. I gather it goes under the battens (which are metal). None of the workmen out here are familiar with this so I will have to explain and oversee. Questions:

 

- what is this called in Thai and are there any particular brands I can ask for?

-where can it be found?

-how is it installed/affixed to the battens?

 

Any other tips?

 

I considered insulation but discarded the idea when I read that rats like ot eat it -- I have a huge problem with rats, bats and squirrels getting into the attic area as it is.

 

Likewise considered on of those fan things that go atop the roof, but am concerned it would provide a means of entry for the above creatures. it took me 2 years of pitched battle to get a colony of bats out as it is.

 

Appreciate advice!

 

 

 

 

 

 

 

 

[Crossy]

Does it have to be tile?

 

Bluescope steel roofing is long lasting, light, available in any colour you could ever want and, if you get the type with a thin layer of PU insulation, doesn't sound like you are living in a kettle drum.

 

Worth a look.

 

[kamalabob2]

Plenty of good options with Fiber Cement roof tiles at least 5mm thick. Three brands to consider in Thailand in my experience. One example is Shera brand Cool series Fiber cement roof tiles  in "Pearl White", which are moderate in price. 

[eyecatcher]

Unfortunately you simply cannot chop and change roof coverings without possibly some major structural works.

for example your corrugated sheet tiles are lightweight and the steel battens supporting them may only be at 400/500 centres.

 

concrete tiles come in all manner of sizes and weights and accordingly to set them up you will need steel battens every 150/200/225/250/300 etc etc etc.

 

tiles are also much heavier per m2 so it would be an idea to make sure the roof has adequate and I mean 4x2 steels or 3x2 steel with several purlins.

a contractor setting out with the intention of fitting a lightweight roof will not set up steel capable of carrying tiles.

 

I would say go like for like and opt for the lightweight sheets mentioned above. it makes life easier for everyone with the benefit of integrated foil backed insulation.

 

fully appreciate the vermin quandry, I have them running around our roof despite my best efforts to keep them out.  Squirrels are currently dragging in trees and leaves to make a nest for hibernating, then it will be babies and more squeeling

[Alantct]

Unfortunately you simply cannot chop and change roof coverings without possibly some major structural works.
for example your corrugated sheet tiles are lightweight and the steel battens supporting them may only be at 400/500 centres.
 
concrete tiles come in all manner of sizes and weights and accordingly to set them up you will need steel battens every 150/200/225/250/300 etc etc etc.
 
tiles are also much heavier per m2 so it would be an idea to make sure the roof has adequate and I mean 4x2 steels or 3x2 steel with several purlins.
a contractor setting out with the intention of fitting a lightweight roof will not set up steel capable of carrying tiles.
 
I would say go like for like and opt for the lightweight sheets mentioned above. it makes life easier for everyone with the benefit of integrated foil backed insulation.
 
fully appreciate the vermin quandry, I have them running around our roof despite my best efforts to keep them out.  Squirrels are currently dragging in trees and leaves to make a nest for hibernating, then it will be babies and more squeeling

You should use the shaped plastic edging to seal the openings between your roof tiles and the fascia and then no more gaps for any other minor gaps. We fit them as standard to our builds and never have any issues from vermin.


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[Kwasaki]

1.  Use whatever roof cover you want the colour like in our village depends on the local authority.

2.  As said see if your roof frame is of sufficient strength to take your choice of roof cover.

3.  Vent gables if you have them for under-roof airflow.

4.  Use a breather membrane under your roof covering.

5.  You can put additional roof insulation under roof cover as well if wanted. 

6.  As said cover seal eave openings vented or otherwise.

7.  Ceiling completely covered with silver wrapped rock-wool will insulate very well.

 

[Sheryl]

Oh dear, more complicated than I thought, and I am having trouble understanding some of the lingo.

 

Kwasaki:  (1) What is a "breather membrane", where does it go, what does it do and how does this relate to a reflective foil?  (2) Are you saying the color has no effect on how hot it will get? (there are no rules where I live as to roof color.) (3)  when you say "Ceiling completely covered with silver wrapped rock-wool will insulate very well" is that the same idea as reflective foil? I am not looking to insulate per se, just to reduce radiant heat coming in from the sun.

 

eyecatcher:  What do you mean by "400/500 centres" ?  Is that distance apart? In cm or what? Likewise  when you say "steel battens every 150/200/225/250/300 etc" is that cm apart?  Please confirm & I'll have someone go up there and measure the distances of what I have. I certainly want to avoid major structural work and it is sounding like this may dictate what sort of roofing material I can use.

 

Crossy: what is the advantage of bluescope steel roofing? I can't buy it locally so would entail a long trip to get, if it is really advantageous could do but if not would rather stick with what I can buy within the province I live. And with it, is it still advantageous to put in refective foil? Or is "PU insulation" the same thing? My impression was that one needed to have reflective foil behind the battens with space between it and the roof material and that insulation was altogether something different?

 

Everyone: I am not sure that what I have now are corrugated sheet tiles and also not sure that what I was thinking to replace with are concrete tiles.  Here are pix, maybe someone can confirm what these are called.  To me the two materials seem the same except that the second has a sort of enamel-like colored coating, but I am told they are in fact different material?

 

Current roof: 

 

 

 

 

 

What I was thinking of replacing it with (but in lighter color)

 

 

 

 

Thanks!!

[simoh1490]

Sheryl,

 

Your house was built in such a way as to allow for a certain type and weight of roof, if you try to exceed those parameters you put the structural integrity of your whole house at risk, simply the extra weight of the new roof may not be capable of being supported, structurally. 

 

You currently have lightweight fibro-cement panels which you could safely and easily replace with more modern steel sheets. Steel roofing is highly effective since it does not retain heat after the sun goes down  the same way that concrete tile does.  But  you will need to insulate the underside of the roof in order to dampen rain noise and protect against radiant heat.

 

Finally, steel roofing comes in many colours and the lighter the colour of your roof the better, lighter colours reflect heat whilst darker colours absorb it.

 

 

[BEVUP]

On 10/28/2017 at 2:01 PM, Sheryl said:

As  soon as the rains are clearly done with for the year I am going to have a new roof put on - original is now 20 years old, was a cheap sort of fibro-cement no longer even sold and starting to crack.

Sheryl, most of these guys would know better then me about what these old tiles may be made of. Doesn't seem to old for what I'm thinking 

Just hoping some of the older members may know

[Sheryl]

Thanks, Simoh.

 

I understand the weight aspect and will be weighing the old tiles and measuring the beams etc.

 

I'm a little confused by the term "insulate" because to me that means keeping temperature in (which I do not want, obviously) , but I gather from what you are saying that insulation can also serve as a reflector against radiant heat? What type of insulation do I need for that?

 

And just how quiet will steel roofing be with insulation? What I currently have is completely quiet -- I don't hear the rain on the roof at all --  and I really don't want to switch to something that is noisier.

 

Any reason why you don't recommend to replace with other  fibro cement panels or similar weight?

 

Lastly, do you know what steel sheets are called in Thai, any brand names and where I might find them?  I don't think they can be found where I live so would likely have to come to Bangkok.

 

Thanks!

[Sheryl]

P.S.  Would this be an example of what you (and Crossy) mean? And does it contain the right sort of insulation or would I have to add something?

 

http://www.bluescope.co.th/wp-content/uploads/2017/05/leaflet_zacs_color_2017.pdf

[simoh1490]

15 minutes ago, Sheryl said:

Thanks, Simoh.

 

I understand the weight aspect and will be weighing the old tiles and measuring the beams etc.

 

I'm a little confused by the term "insulate" because to me that means keeping temperature in (which I do not want, obviously) , but I gather from what you are saying that insulation can also serve as a reflector against radiant heat? What type of insulation do I need for that?

 

And just how quiet will steel roofing be with insulation? What I currently have is completely quiet -- I don't hear the rain on the roof at all --  and I really don't want to switch to something that is noisier.

 

Any reason why you don't recommend to replace with other  fibro cement panels or similar weight?

 

Lastly, do you know what steel sheets are called in Thai, any brand names and where I might find them?  I don't think they can be found where I live so would likely have to come to Bangkok.

 

Thanks!

In cold climates most people associate the term "insulate" with keeping warm, aka, keeping the heat in, as you suggest, but the obverse is true also in that it also means keeping the heat out.

 

The same principles apply in either case, a layer of insulation, the thicker the better and that will stop the heat transfer, a layer of traditional fibreglass batts, covered in aluminium foil will work, six inches is better than three and nine inches even better still. HomePro has the six inch rolls for about 369 baht  a roll and it needs to be laid on top of the ceiling, under the roof so that when the steel roof does get hot it doesn't radiate that heat onto the ceiling of your living space.

 

Noise is slightly more tricky. The insulation described above will help deaden the sound of rain on the steel roof but it may not be as quiet as your existing roof since that is made of a material that naturally doesn't amplify sound. The perfect answer is to use spray on insulation on the underside of the roof which will reduce noise considerably and also aid slightly in heat transfer but this is quite costly.

 

Finally, steel roofing material is widely available, go into any Home Mart, Homepro , Global House or similar and there will be lots of displays set up and information and prices readily available. It's worth noting that most locals will favour a steel roof over the alternatives because it doesn't retain heat after sunset plus it's a cheaper alternative., most foriegners however will prefer concrete roof tiles thinking they are more robust and that steel roofs look cheap. I think the locals clearly have the edge on this one but each to their own.

 

 

 

[Sheryl]

Thanks, very helpful and I am slowly getting the picture.

 

So even if there is insulation on the steel roofing material I should also lay down the material you mention?  Placing it on the floor of the ceiling would be very difficult as it is covered with wiring (encased in PVC). Can it be put on the underside of the roof beams instead? If so, how to affix?

 

And any ideas re the product below? It seems to already contain some sort of insulation

http://www.bluescope.co.th/wp-content/uploads/2017/05/leaflet_zacs_color_2017.pdf  page

 

My local HomePro does not carry any roofing materials and there is neither Home Mart nor Global House in my province, and the local shop which does have roof materials has only fiber cement tiles (and no information to be gotten from anyone there, to put it mildly). So either way I am going to have to travel and if someone can name a specific store & location where I can be sure to find this, would appreciate it.

 

 

[simoh1490]

32 minutes ago, Sheryl said:

Thanks, very helpful and I am slowly getting the picture.

 

So even if there is insulation on the steel roofing material I should also lay down the material you mention?  Placing it on the floor of the ceiling would be very difficult as it is covered with wiring (encased in PVC). Can it be put on the underside of the roof beams instead? If so, how to affix?

 

And any ideas re the product below? It seems to already contain some sort of insulation

http://www.bluescope.co.th/wp-content/uploads/2017/05/leaflet_zacs_color_2017.pdf  page

 

My local HomePro does not carry any roofing materials and there is neither Home Mart nor Global House in my province, and the local shop which does have roof materials has only fiber cement tiles (and no information to be gotten from anyone there, to put it mildly). So either way I am going to have to travel and if someone can name a specific store & location where I can be sure to find this, would appreciate it.

You can lay the foil encased insulation (bats) on top of the electrical PVC pipes as long as they are complete and no wires are exposed.

 

As long as the insulation sits between the surface of the roof (tiles or metal sheets) and the floor of the roof void/attic then you'll be fine, the idea is to prevent the roof from radiating heat onto the attic floor and into the living space so however you can make that work is up to you and will depend on the design of the house.

 

A radiant barrier is nothing more than heavy duty aluminium foil which sits under the surface of the roof, it's purpose is to convert radiant heat into convected heat (hot air) which can then be vented. It's cheap to buy and easy to instal when the roof is being replaced but there are some rules that must be followed: there must be an air gap between the radiant barrier and the roof; there must be adequate ventilation in the roof void for the hot air to escape; there must be a source of air into the roof void to replace the hot air being vented, preferably at a lower and cooler level and the two vents, inbound and outbound must be similarly sized. In practise, a roof vent in the gable or ridge of the roof (hot air out), AND perforated eves boards on the lower part of the roof (cooler air in) will work well.

[Sheryl]

Thanks. I am a little unclear if the foil-encased insulation you are talking about and then the radiant barrier in your third paragraph are one and the same thing? If not does one install both or just one and which is better and why?

 

There are some exposed wires, I also have a lot of ceiling fans and would prefer not to try to lay anything directly on top - in addition to fire concerns, would make electrical repairs difficult. My understanding was that aluminum foil radiant barriers could be applied directly below the battens (while the roof material is on top pf the battens, thereby some space between. Any reason this can't be done with the foil-encased insulation? (assuming those are 2 different things?) And in either case - aluminum foil radiant barrier or foil-encased insulation - how does one attach it to steel battens?

 

Lastly what form does steel sheet roofing material come in? Does it come in discrete panels or is it a large roll? And how does it affix to the batten? I am concerned that the workmen I had arranged (who did a good job on roof of garden shed for me recently) would not know how to affix it if it is in a large roll or affixes in a very different manner from the tiles they are used to.

[simoh1490]

4 hours ago, Sheryl said:

Thanks. I am a little unclear if the foil-encased insulation you are talking about and then the radiant barrier in your third paragraph are one and the same thing? If not does one install both or just one and which is better and why?

 

There are some exposed wires, I also have a lot of ceiling fans and would prefer not to try to lay anything directly on top - in addition to fire concerns, would make electrical repairs difficult. My understanding was that aluminum foil radiant barriers could be applied directly below the battens (while the roof material is on top pf the battens, thereby some space between. Any reason this can't be done with the foil-encased insulation? (assuming those are 2 different things?) And in either case - aluminum foil radiant barrier or foil-encased insulation - how does one attach it to steel battens?

 

Lastly what form does steel sheet roofing material come in? Does it come in discrete panels or is it a large roll? And how does it affix to the batten? I am concerned that the workmen I had arranged (who did a good job on roof of garden shed for me recently) would not know how to affix it if it is in a large roll or affixes in a very different manner from the tiles they are used to.

Radiant barrier comes in a roll, just like Reynolds Aluminium foil except it's very heavy duty and wont easily rip or tear - a radiant barrier must be installed at 90 degrees to the roof rather than laid on the attic floor.

 

Foil encased fibreglass insulation is constructed as such to prevent the absorption of moisture and dust. The foil encasing is made of coated paper and is easily torn and nowhere near the sturdiness of the radiant barrier material.

 

By all means use both, a radiant barrier protects against radiant heat penetration whereas rolled/encased fibreglass insulation protects against convected heat or hot air penetration. (note: a radiant barrier converts radiant heat to convected heat).

 

Radiant barrier (Reynolds wrap) is laid across the rafters on the outside of the house, and new battens put on top, the new tiles or roof is then put on top of the battens. The batten (is a spacer) is important so that the Reynolds wrap doesn't actually touch the roofing tiles/sheets (very important, there must be an air gap, even if only small). Note: rafters are the beams that slope and meet at the peak of the roof and extend all the way down to the eves or tops of the walls of the house.

 

The rolled fibreglass aluminium can go anywhere between the floor of the attic (this is the ceiling of your living space, bedrooms etc) and the rafters but putting it just under the battens wouldn't work. Simply,  that wouldn't meet the needs of either a radiant barrier or of fibreglass batt insulation since it would leave the steel rafters exposed to radiate heat onto the attic floor plus it wouldn't protect the attic floor from convected heat generated by that steel.

 

Your roof tiles.sheets AND the steel rafters are exactly like a UK storage heater which absorbs and stores heat during the day and releases it (before and) after the sun goes down, the idea is to put a barrier between that heat source and your living space. I'm sorry but I can't advise a creative solution for this without actually seeing the roof void, can you post a picture of the attic and underside of the roof?

 

Finally, the metal sheet roof comes in rigid panels that are not dissimilar to your existing roof and are affixed in the same way.

 

 

 

 

 

 

 

[simoh1490]

Regarding your link here - http://www.bluescope.co.th/wp-content/uploads/2017/05/leaflet_zacs_color_2017.pdf

 

It's hard to tell but it does look as though the product contains some sort of insulating layer but it would almost certainly be totally useless when it comes to insulating against heat, that would require an insulating layer that is really quite thick, several inches. BUT that insulating layer may be useful in deadening the sound of falling rain which on a bare metal roof can be quite loud. If you think of a metal sink it usually has a thin piece of insulation underneath it and its purpose is to dampen the noise of water hitting the steel.

 

If the above is correct and the product is otherwise good, it would be a good potential candidate since it would solve the noise transfer problem. Perhaps that solution and a radiant barrier combined would be sufficient to solve most of the radiated heat issue although you would still have to contend with the convected heat or hot air which may or may not be a problem.  

 

From what I've seen I think Colorbond is pretty much the number one in Thailand for coloured metal roofs: http://colorbond.com/products/roofing

 

Lastly, if you let us know a rough location in Thailand where you leave perhaps we can come up with a source for the product.

[Ahab]

46 minutes ago, simoh1490 said:

Regarding your link here - http://www.bluescope.co.th/wp-content/uploads/2017/05/leaflet_zacs_color_2017.pdf

 

It's hard to tell but it does look as though the product contains some sort of insulating layer but it would almost certainly be totally useless when it comes to insulating against heat, that would require an insulating layer that is really quite thick, several inches. BUT that insulating layer may be useful in deadening the sound of falling rain which on a bare metal roof can be quite loud. If you think of a metal sink it usually has a thin piece of insulation underneath it and its purpose is to dampen the noise of water hitting the steel.

 

If the above is correct and the product is otherwise good, it would be a good potential candidate since it would solve the noise transfer problem. Perhaps that solution and a radiant barrier combined would be sufficient to solve most of the radiated heat issue although you would still have to contend with the convected heat or hot air which may or may not be a problem.  

 

From what I've seen I think Colorbond is pretty much the number one in Thailand for coloured metal roofs: http://colorbond.com/products/roofing

 

Lastly, if you let us know a rough location in Thailand where you leave perhaps we can come up with a source for the product.

Radiant barrier contains a thin layer of foam with a metal (normally aluminum) reflective layer attached to the underside. The insulating value of the thin foam is not much, but the purpose is not so much insulation as to decouple the reflective layer of metal from the metal of the roof (to prevent a path for heat conduction, metal to metal).

 

I are putting the thickest Colorbond white roof I can buy with the best radiant barrier (attached to the roof underside) that Colorbond offers. The workers put the roof on my work shed first, and on a hot day at noon you can hold your hand right next the underside of the roof and not feel any radiant heat from the sun. This stuff works by reflecting the heat from the sun and keeps the heat out of the attic space, keeping the attic space much closer to the ambient air temperature, it really works. The good quality product from Bluescope is a bit pricier than what most Thai's are willing to pay so you may have to special order (we did), but the warrantee is better and the product is much better. White is the absolute best color for reducing heat absorption, even a light color like grey or tan absorbs significantly more heat. 

 

We are also installing two solar powered attic fans to ventilate the attic (drawing cooler air from under the eaves). Good luck with your build. If you have any questions you can send me a PM. This is the second radiant barrier roof we have put on a house (the first was in Hawaii).

[Ahab]

9 hours ago, simoh1490 said:

 

A radiant barrier is nothing more than heavy duty aluminium foil which sits under the surface of the roof, it's purpose is to convert radiant heat into convected heat (hot air) which can then be vented. 

This statement is not true or perhaps not worded correctly. Concur that radiant barrier is nothing more than heavy duty aluminum foil.

 

Heat can be transferred into the air of the attic by three mechanisms.  Conduction, convection, and radiation. Properly installed radiant barrier sheathing reduces or eliminates heat entering the attic via conduction (roof material heating up and transferring that heat into the attic space), and radiation (suns energy transferring into the attic).

 

Conduction: The transfer of energy between objects that are in physical contact. Thermal conductivity is the property of a material to conduct heat and evaluated primarily in terms of Fourier's Law for heat conduction.

 

Convection: The transfer of energy between an object and its environment, due to fluid motion. The average temperature is a reference for evaluating properties related to convective heat transfer. (Basically warm air rises and cool air doesn't)

 

Radiation: The transfer of energy by the emission of electromagnetic radiation.

 

Radiant barrier sheathing is normally mounted to the underside of a metal roof, (separated by a thin layer of foam "insulation", this thin layer of foam prevents heat from the metal roof directly conducting to the radiant barrier foil and then directly into the attic) or suspended below other types of roofs (e.g. cement tiles). 

 

The purpose of the radiant barrier is not to "convert" heat. The purpose of a properly installed radiant barrier on the underside of a metal roof is to prevent radiant heat (and conductive) transfer from the sun/roof material from entering the attic space to begin with, thus keeping the space much cooler from the get go. Proper ventilation will enhance the effectiveness of keeping the radiant barrier heat out of the attic, and a cooler attic will reduce the amount of work A/C has to do to keep the house cool (if it has to be used at all).

[Kwasaki]

15 hours ago, Sheryl said:

Kwasaki:  (1) What is a "breather membrane", where does it go, what does it do and how does this relate to a reflective foil?  (2) Are you saying the color has no effect on how hot it will get? (there are no rules where I live as to roof color.) (3)  when you say "Ceiling completely covered with silver wrapped rock-wool will insulate very well" is that the same idea as reflective foil? 4. I am not looking to insulate per se, just to reduce radiant heat coming in from the sun.

Firstly my personal choice would be composite roof sheet which is best to use in Thailand it's what they use on cold store buildings.

1.  A covering that goes under roof tiles to weather any ingress of rain or for metal roof sheets to deal with condensation. 
Not much relation to reflective foil claims.

2.  Doesn't matter what colour with roof tiles but the lighter the better especially with a metal coloured roof sheet, you can use aluminium.

3.  No just a covering keeping the insulation from creating dust and breaking down.

4.  Your Quote :-  I am not looking to insulate per se, just to reduce radiant heat coming in from the sun. unquote.   Well insulation can do that as well as a ventilated roof area with airflow. 

Edited October 30, 2017 by Kwasaki

[Kwasaki]

15 hours ago, Sheryl said:

Everyone: I am not sure that what I have now are corrugated sheet tiles and also not sure that what I was thinking to replace with are concrete tiles.  Here are pix, maybe someone can confirm what these are called.  To me the two materials seem the same except that the second has a sort of enamel-like colored coating, but I am told they are in fact different material?

20 years old roof for Thai the existing roof sheets are probably what's called in  UK 3" profile asbestos cement corrugated roof & side elevation sheeting.

The other roof sheet type with a coating is familiar but the name escapes me after all these years there use to be many different profile shapes.

They may well what's called a non-asbestos fibre cement roof sheet which is as they say a different material.

Goodluck with your choice of roof there are so many roof cover choices, my qualified advice to you would be go with roof tiles pan or profiled because of your house roof design they will work well & be aesthetically pleasing with them in place.

 

 

 

[carlyai]

If you were happy with your old roof, and no noise problems, why not install a modern version of your fibro cement tiles you already have?
If you can get the tiles locally, just take one along with you and order the same, newer versions.
If you need foil insulation in the roof, purchase the highest R rating foil you can, a lot more expensive.
You should leave a 2" gap between the foil and the roof tiles. I installed my foil on the bottom side of the batterns, thus allowing the 2" gap.

I am not a builder, and may be corrected.

Sent from my SM-J700F using Tapatalk

[Sheryl]

55 minutes ago, carlyai said:

If you were happy with your old roof, and no noise problems, why not install a modern version of your fibro cement tiles you already have?
If you can get the tiles locally, just take one along with you and order the same, newer versions.
If you need foil insulation in the roof, purchase the highest R rating foil you can, a lot more expensive.
You should leave a 2" gap between the foil and the roof tiles. I installed my foil on the bottom side of the batterns, thus allowing the 2" gap.

I am not a builder, and may be corrected.

Sent from my SM-J700F using Tapatalk
 

1. Installing a modern version of what I have was exactly my original thought, but then several posters suggested that it couldn't be done without major structural work because it would be too heavy for the existing battens (?purlins?).

 

I now have some data:

 

Battens (?purlins) are 1 meter distance apart and measure 3 x 2 inches.

 

Old tiles weigh 4.5 kg, are 120 cm x 50cm and about 4 mm thick

 

The newer tiles I had in mind were same diemnsions except 1 mm thicker due to paint layer. I don't know the weight but workers whi handled them (I already did this replacement on a small garden shed) state it is the same or lighter. I will try to get spoecific though.

 

Question:  from the above, does it sound like installing a newer fiber cement tile would be an issue?

 

2. What is an R rating and what would be a high one? Can you give me a name or brand? (I think you are referring to radiant foil not insulation, or am I wrong?)

 

Thanks!

 

[Sheryl]

3 hours ago, Kwasaki said:

Firstly my personal choice would be composite roof sheet which is best to use in Thailand it's what they use on cold store buildings.

1.  A covering that goes under roof tiles to weather any ingress of rain or for metal roof sheets to deal with condensation. 
Not much relation to reflective foil claims.

2.  Doesn't matter what colour with roof tiles but the lighter the better especially with a metal coloured roof sheet, you can use aluminium.

3.  No just a covering keeping the insulation from creating dust and breaking down.

4.  Your Quote :-  I am not looking to insulate per se, just to reduce radiant heat coming in from the sun. unquote.   Well insulation can do that as well as a ventilated roof area with airflow. 

Thanks Kwasaki. 2 questions:

 

1. . What are "composite" roof sheets? So far I have heard if fibre cement and metal, is this the same as fiber cement or is it something different?

 

2. What would a "breather membrane" be called in Thai? Can you give me a brandname?

[Sheryl]

10 hours ago, simoh1490 said:

Radiant barrier comes in a roll, just like Reynolds Aluminium foil except it's very heavy duty and wont easily rip or tear - a radiant barrier must be installed at 90 degrees to the roof rather than laid on the attic floor.

 

Foil encased fibreglass insulation is constructed as such to prevent the absorption of moisture and dust. The foil encasing is made of coated paper and is easily torn and nowhere near the sturdiness of the radiant barrier material.

 

By all means use both, a radiant barrier protects against radiant heat penetration whereas rolled/encased fibreglass insulation protects against convected heat or hot air penetration. (note: a radiant barrier converts radiant heat to convected heat).

 

Radiant barrier (Reynolds wrap) is laid across the rafters on the outside of the house, and new battens put on top, the new tiles or roof is then put on top of the battens. The batten (is a spacer) is important so that the Reynolds wrap doesn't actually touch the roofing tiles/sheets (very important, there must be an air gap, even if only small). Note: rafters are the beams that slope and meet at the peak of the roof and extend all the way down to the eves or tops of the walls of the house.

 

The rolled fibreglass aluminium can go anywhere between the floor of the attic (this is the ceiling of your living space, bedrooms etc) and the rafters but putting it just under the battens wouldn't work. Simply,  that wouldn't meet the needs of either a radiant barrier or of fibreglass batt insulation since it would leave the steel rafters exposed to radiate heat onto the attic floor plus it wouldn't protect the attic floor from convected heat generated by that steel.

 

Your roof tiles.sheets AND the steel rafters are exactly like a UK storage heater which absorbs and stores heat during the day and releases it (before and) after the sun goes down, the idea is to put a barrier between that heat source and your living space. I'm sorry but I can't advise a creative solution for this without actually seeing the roof void, can you post a picture of the attic and underside of the roof?

 

Finally, the metal sheet roof comes in rigid panels that are not dissimilar to your existing roof and are affixed in the same way.

 

 

 

 

 

 

 

 

Thanks, Simoh, I really appreciate your patience.

 

I was hoping not to put in any new battens but rather use the existing, is there any reason why I can't do that? They are 2x3 inches and spaced 1 meter apart. Picture of the attic void below.

 

I live in Prachinburi. Nakorn Nayok is 45 minute drive, Sakeo is 1 hour plus.

 

Can you tell me a brand name in Thailand for the radiant barrier? I think I now understand how it should be installed but am concerned about sourcing it.

 

Thanks!

 

 

 

 

(The yellow lighting is to deter bats)

[Kwasaki]

8 minutes ago, Sheryl said:

Thanks Kwasaki. 2 questions:

1. . What are "composite" roof sheets? So far I have heard if fibre cement and metal, is this the same as fiber cement or is it something different?

 

2. What would a "breather membrane" be called in Thai? Can you give me a brandname?

1.  Composite roof panels are as the picture in my post !  they consist of a metal coated top sheet an underlining and and foam infill.

They come in long lengths to cut down on lap joints on roof construction.

No need for breather or further insulation.

The insulation is the the roof panel.

2.  If you choose the same roofing that you have on your out building with the glazed profile fire-cement you will need a breather.

There are many types of brand breather underlay for roof tile/metal/ fibre-cement materials you can see them e.g. Global House or similar home building supply shops. 

[Kwasaki]

19 minutes ago, Sheryl said:

Finally, the metal sheet roof comes in rigid panels that are not dissimilar to your existing roof and are affixed in the same way.

 

Whow let's not jump ahead too much we don't know that.

[Sheryl]

5 minutes ago, Kwasaki said:

1.  Composite roof panels are as the picture in my post !  they consist of a metal coated top sheet an underlining and and foam infill.

They come in long lengths to cut down on lap joints on roof construction.

No need for breather or further insulation.

The insulation is the the roof panel.

2.  If you choose the same roofing that you have on your out building with the glazed profile fire-cement you will need a breather.

There are many types of brand breather underlay for roof tile/metal/ fibre-cement materials you can see them e.g. Global House or similar home building supply shops. 

Do you mean a metal top sheet that is coated with something or another substance top sheet that is coated with metal? Sorry, still not clear on what this is.

 

I have found specs for a metal roof sheet that comes with EPE foam insulation  that has "embossed aluminum foil with bubbles" under it, is that the sort of thing you mean? (made by SKC).

[Kwasaki]

52 minutes ago, Sheryl said:

1. Installing a modern version of what I have was exactly my original thought, but then several posters suggested that it couldn't be done without major structural work because it would be too heavy for the existing battens (?purlins?).

 

I now have some data:

 

Battens (?purlins) are 1 meter distance apart and measure 3 x 2 inches.

 

Old tiles weigh 4.5 kg, are 120 cm x 50cm and about 4 mm thick

 

The newer tiles I had in mind were same diemnsions except 1 mm thicker due to paint layer. I don't know the weight but workers whi handled them (I already did this replacement on a small garden shed) state it is the same or lighter. I will try to get spoecific though.

 

Question:  from the above, does it sound like installing a newer fiber cement tile would be an issue?

 

2. What is an R rating and what would be a high one? Can you give me a name or brand? (I think you are referring to radiant foil not insulation, or am I wrong?)

 

Thanks!

 

1. Not necessarily true,  weight of old panel verse new as your outbuilding.

2. Quote...Battens (?purlin) are 1 meter distance apart and measure 3 x 2 inches. Unquote.  What material  ?

3.. Quote...   (I already did this replacement on a small garden shed) state it is the same or lighter. I will try to get specific though.  Unquote. 

The l would say they are probably right but still check to see what is the difference if any.

4.  Your Question:  from the above, does it sound like installing a newer fiber cement tile would be an issue? ......l would say no problem providing existing purlins if steel, battens if wood are OK.

5. ( R rating ) An insulating material's resistance to conductive heat flow is measured or rated in terms of its thermal resistance or R-value -- the higher the R-value, the greater the insulating effectiveness. The R-value depends on the type of insulation, its thickness, and its density.

[Kwasaki]

17 minutes ago, Sheryl said:

I have found specs for a metal roof sheet that comes with EPE foam insulation  that has "embossed aluminum foil with bubbles" under it, is that the sort of thing you mean? (made by SKC).

Very similar idea and a cheaper Thai construction method but looks good.