Recommended Roofing & Insulation Contractor Bangkok?

[lopburi3]

16 minutes ago, Yellowtail said:

It's like paying for insulation and getting a new roof free!

That might be the ideal (although a very high priced insulation here) - in practice you would have to remove house to afford that kind of access to evenly/fully cover - that just is not done.  I am a believer when applied to the roofing in factory conditions - and even for open roof factory or storage building - but not so much so for homes.  As said any decay of wood or termite hole will provide pooling areas.

[sometimewoodworker]

3 hours ago, bankruatsteve said:

Yes it does.  Especially important for reflective barrier under the roof tiles.

You are confusing a radiant barrier requirements with a reflective barrier. And the placement of them.

 

Radiant barrier needs no air gap on the hot side

Reflective barrier needs no air gap on the cool side

 

A Radiant barrier can be hot but it doesn’t radiate that heat well.

 

A Reflective barrier reflects the heat hitting it so will be cooler than other similar places surfaces 

 

 

You can have a double sided silver film which can act as both a Radiant and a Reflective Barrier in that case you need an air gap on both sides for barriers to work.

 

a piece of hardboard/plywood with a silver coating on 1 side can be either a Radiant or Reflective Barrier (never both) depending in its placement 

[sometimewoodworker]

2 hours ago, Yellowtail said:

Why will the spray on PU foam not work with wood?

First you would need to get the moisture content to well under 20% to avoid dry rot problems, then you are creating a perfect environment for termites. Neither of these are easy to achieve/avoid.

 

2 hours ago, Yellowtail said:

But would it not also hasten the corrosion corrosion of steel as well? 

As the steel is encased it’s unlikely that there would be enough water and O2 for that

[GlennSN20U5]

3 hours ago, lopburi3 said:

For one it would not fully enclose the wood so in effect keep water from leaks in contact with the wood making it rot out even faster?  We are talking wood beams with tile attached to it (not a good or flat seal).  And tile like that shown is very heavy so any rotting could be a major issue.  And if termites have had a bite even easier for water to rot it.  

Why would it not fully enclose the wood? Properly spray PU, it will act as insulation, sealant & even strengthen the object.

Correct me if I'm wrong. IMO, I see this as win-win situation.
Spray underside of the roof tile - Insulation & act as sealant. ( Leaking & Insulation solve.)
Spray the wooden roof structure - Insulation & strengthen/harden the structure. Possible of any existing rot issue. 

[Yellowtail]

1 hour ago, sometimewoodworker said:

As the steel is encased it’s unlikely that there would be enough water and O2 for that

How is the steel encased with foam between the rafters and the tiles?

 

You claim it will be encased, but also claim it will drain into the gutters. The water leaking through the roof will fill up all the voids.  Tubing would be worse than c-cannel, but the foam would effectively turn the c-channel into tubing. 

 

It would be a mess. I doubt very much you could even get a reputable contractor to do it on a leaky roof, much less warranty it.  

[Yellowtail]

17 minutes ago, GlennSN20U5 said:

Why would it not fully enclose the wood? Properly spray PU, it will act as insulation, sealant & even strengthen the object.

Correct me if I'm wrong. IMO, I see this as win-win situation.
Spray underside of the roof tile - Insulation & act as sealant. ( Leaking & Insulation solve.)
Spray the wooden roof structure - Insulation & strengthen/harden the structure. Possible of any existing rot issue. 

The foam would effectively seal in all the water leaking through the roof.

 

How do they get the underside of an old roof clean enough to get such a great bond?

[bankruatsteve]

2 hours ago, sometimewoodworker said:

You are confusing a radiant barrier requirements with a reflective barrier. And the placement of them.

I am not confused.  A reflective material can be/is a radiant heat barrier.  A reflective bat on the attic floor needs an air gap else it will conduct.  A reflective radiant heat barrier under the tiles needs a gap between the tiles and the barrier else there is nothing radiant to reflect. 

[GlennSN20U5]

40 minutes ago, Yellowtail said:

The foam would effectively seal in all the water leaking through the roof.

 

How do they get the underside of an old roof clean enough to get such a great bond?

Good point. Cheers. 
Contractor be like: let me add extra pre-cleaning services to the quotation too.

[sometimewoodworker]

1 hour ago, bankruatsteve said:

I am not confused.  A reflective material can be/is a radiant heat barrier.  A reflective bat on the attic floor needs an air gap else it will conduct.  A reflective radiant heat barrier under the tiles needs a gap between the tiles and the barrier else there is nothing radiant to reflect. 

You may understand the physics but you are making a very poor job of explaining it in a way that shows you understand it.

Quote

A reflective bat on the attic floor needs an air gap else it will conduct.

If it’s a reflective barrier then there is no significant conduction to bother with. If it gets significantly hot then it isn’t reflecting well, so if you need an air gap it’s not working well
 

Quote

A reflective material can be/is a radiant heat barrier.

Yes but That depends on how/where it’s installed 

 

Quote

A reflective radiant heat barrier under the tiles needs a gap between the tiles and the barrier else there is nothing radiant to reflect. 

That is where you are either confusing the purpose, or are confused about the purpose, of Radiant barrier foil under the roof. It is used as a Radiant barrier it does not radiate much heat. In that location it is not functioning to any significant degree as a reflective barrier. Just look at the cheapest version that is silver on one side and brown paper on the other.

off the RADIANT barrier.

off the roof

NB only installed with air gap as I wasn’t going to take the roofing sheets off.

 

3 hours ago, sometimewoodworker said:

 

Radiant barrier needs no air gap on the hot side

Reflective barrier needs no air gap on the cool side

 

A Radiant barrier can be hot but it doesn’t radiate that heat well.

 

A Reflective barrier reflects the heat hitting it so will be cooler than other similar places surfaces 

or this foil coated board.

Or this a typical new roof insulation 

 

the difficulty for most people is that they understand that whilst there are 3 forms of heat transmission conduction, convection and radiation, there are more than 3 ways for protection.

 

There is 1 for conduction, provide a thermal break

There are 2 for convection, prevent airflow, direct the air to flow to a place you want.

There are 2 for radiation, stop the radiation, reflect the heat away.

 

those 5 ways may be used together but they are not the same they are 5 distinctly different ways to reduce heat.

 

Quote

Understanding how installing aluminum foil facing downward in your attic impacts heat transfer into your home’s living space isn’t intuitive for most.

 

Quote

The inclusion of a radiant barrier system significantly disrupts the heat transfer process From the hot roofing materials. The highly reflective aluminum surface has very low emissivity, typically .05 or less. Installed on the bottom side of the roof sheathing it helps to limit the heat energy in the sheathing panel from radiating into your attic (hence, radiant barrier), lowering attic temperatures by up to 30 degrees Fahrenheit during the heat of the day.

 

Edited September 12, 2020 by sometimewoodworker

[Bluedipper]

@sometimewoodworker @Yellowtail @lopburi3 @bankruatsteve @GlennSN20U5 

 

Thank you. Lots of interesting points to consider. Not keen on foam spray idea for all the reasons listed above. Foil seems the way to go but will need a bit more time to digest technicalities of reflective/radiant ???? (I may be in touch about that). 

Went to SCG today and they only offer thick fibreglass insulation StayCool rolls which would be fine except the sales person said rats love it - and we have some big ones around here. So that’s out. 
 

In the meantime, while I’m waiting on current quotations to come in, here’s some photos of the roof set up if that helps. Dusty and leaky. Looks like a couple random areas have old insulation layers there already. One contractor said the exposed concrete area also had hairline cracks which was letting water in, the other old guy said the concrete was fine and it was just the roof letting the water in ????????‍♀️ Remains to be seen. 
 

 

[lopburi3]

23 minutes ago, Bluedipper said:

Went to SCG today and they only offer thick fibreglass insulation StayCool rolls which would be fine except the sales person said rats love it - and we have some big ones around here. So that’s out. 

I would not pay too much attention to sales persons - fiberglass batts have been used for the last century in USA not only for ceilings but all walls and have never heard they attract rats.  In any case stray cats love rats and would be happy to take up residence in most homes at little or no cost.

 

I would be concerned with that flat cement roof having enough drainage for heavy rain and being properly sealed.

[Bluedipper]

20 minutes ago, lopburi3 said:

I would not pay too much attention to sales persons - fiberglass batts have been used for the last century in USA not only for ceilings but all walls and have never heard they attract rats.  In any case stray cats love rats and would be happy to take up residence in most homes at little or no cost.

 

I would be concerned with that flat cement roof having enough drainage for heavy rain and being properly sealed.

We have a dog, that eats the cats, that eat the rats. Lol. Regarding the flat cement roof, yes needs better drainage and good to know should it be sealed. The first guy said he could put layer of epoxy to seal and provide some reflective insulation? 

[Yellowtail]

8 minutes ago, Bluedipper said:

We have a dog, that eats the cats, that eat the rats. Lol. Regarding the flat cement roof, yes needs better drainage and good to know should it be sealed. The first guy said he could put layer of epoxy to seal and provide some reflective insulation? 

I would not use epoxy, I would use white or silver concrete roof sealer. It is easy to work and very forgiving. Rent a pressure washer and clean it good first.

 

I agree, the sales people are generally useless. 

 

In any event, I would focus on getting the roof sealed before you do anything. Looks like a nice build...

[sometimewoodworker]

2 hours ago, Bluedipper said:

In the meantime, while I’m waiting on current quotations to come in, here’s some photos of the roof set up if that helps. Dusty and leaky. Looks like a couple random areas have old insulation layers there already. One contractor said the exposed concrete area also had hairline cracks which was letting water in, the other old guy said the concrete was fine and it was just the roof letting the water in ????????‍♀️ Remains to be seen. 

If you have the money (possibly one of the cheaper options) wait until the rainy season is over. Strip the tiles off the roof (you will find out which ones are cracked) lay the film radiant barrier on the wood substructure (it looks to be in good condition) get the valleys done correctly with at least 50cm wide flashing under the tiles (what is there now is an abomination) while the tiles are off waterproof the concrete. Then replace the tiles. You will be able to salvage enough from the non show faces so the show sides don’t have any new tiles on them.

While the tiles are off and before putting on the foil film you have the chance to put down the glass fibre rolls on top of the ceilings.

 

That would give a roof that is like new with excellent insulation, waterproof and will last another 20 years or more.

 

It looks as if you can work in stages so you won’t need to tarp the whole roof.

 

If you go with patching you will be doing it every year and it may cost more in the long run.

Edited September 12, 2020 by sometimewoodworker

[bankruatsteve]

14 hours ago, sometimewoodworker said:

That is where you are either confusing the purpose, or are confused about the purpose, of Radiant barrier foil under the roof. It is used as a Radiant barrier it does not radiate much heat. In that location it is not functioning to any significant degree as a reflective barrier. Just look at the cheapest version that is silver on one side and brown paper on the other.

Again, I am not confused about heat transfer but you apparently are.  The purpose of radiant barrier foil is to reflect radiant heat.  If it is in contact with the roof, then it is not reflecting anything - it is conducting.  That is why it is necessary for a gap between the roof and the foil 

 

For Al bats on the ceiling, I will correct "air gap" to "insulated gap".  Again, if there is no insulation between the foil and a material that also conducts heat, conduction is what will occur.  Similar to electric wire: if there is no load there will be no conduction and no heat.  

[lopburi3]

10 hours ago, Bluedipper said:

We have a dog, that eats the cats, that eat the rats. Lol. Regarding the flat cement roof, yes needs better drainage and good to know should it be sealed. The first guy said he could put layer of epoxy to seal and provide some reflective insulation? 

Also have the dogs, who chase the cats, but only the cats can climb to second story.  Last time helped seal flat roof was 1974 at US Embassy Vientiane and believe that was epoxy and worked fine but had to avoid walking on as much as possible.  Expect there are better options these days.

[sometimewoodworker]

36 minutes ago, bankruatsteve said:

The purpose of radiant barrier foil is to reflect radiant heat. 

That is where you are completely wrong. 

 

The purpose of foil used as a radiant barrier is to NOT radiate heat
 

The purpose of foil used as a reflective barrier is to reflect heat

 

41 minutes ago, bankruatsteve said:

If it is in contact with the roof, then it is not reflecting anything - it is conducting.

Completely correct, in as far as yes it will get hot, but irrelevant.

 

42 minutes ago, bankruatsteve said:

That is why it is necessary for a gap between the roof and the foil 

Totally wrong when it is used as a radiant barrier, and clearly shows that you do not understand the way a radiant barrier functions

 

You seem not to understand the physics. The temperature of a polished aluminium surface is virtually irrelevant.

 

Take two pieces of metal one black one polished silver (aluminium oxidation is too fast so you would need to have some protection if using that)

Heat them to a similar temperature (say 400C) hold your hand near, but not over, each one.

Near the black, you will feel the heat radiating 

At the same distance from the silver one you will feel very much less. This is because a polished silver surface is a very poor radiator.
 

57 minutes ago, bankruatsteve said:

Again, if there is no insulation between the foil and a material that also conducts heat, conduction is what will occur. 

Again completely correct and irrelevant. 

[sometimewoodworker]

To convince yourself and demonstrate a radiant barrier.

 

Get a black frying pan, heat it to near the smoking point of oil (don’t use anything in it) hold your hand a near as you can.

 

Very carefully (using oven gloves) place aluminium foil (shiny side up) on the frying pan in contact with the pan, hold your hand a near as you can.

 

You will be able to bring your hand very very much closer. 
 

You will be able to calculate the reduction in radiation (don’t forget the inverse square law)

 

Don’t have a air gap between the foil an pan as then you are not testing a pure radiant barrier 

Edited September 13, 2020 by sometimewoodworker

[Lacessit]

From the OP's photos, it looks like there are no vents in the gables/soffits. That would help the heat problem significantly.

I regard PU foam in a fire as dangerous. Hydrogen cyanide is just one of the toxic decomposition products. Fibreglass insulation is a much safer alternative.

As other posters have said, SCG, HomePro, Thai Watsadu etc. can all find contractors for installation and/or rectification.

[bankruatsteve]

23 minutes ago, sometimewoodworker said:

Don’t have a air gap between the foil an pan as then you are not testing a pure radiant barrier 

Sorry to disturb your unusual perception of reality and science.  Al conducts heat.  It also reflects heat energy.  Quote from the Department of Energy:  "Radiant barriers are installed in homes -- usually in attics -- primarily to reduce summer heat gain and reduce cooling costs. The barriers consist of a highly reflective material that reflects radiant heat rather than absorbing it. They don't, however, reduce heat conduction like thermal insulation materials."

 

Furthermore, EVERYTHING in the universe from stars to the tiniest of atomic particles radiate heat energy.  To state that something stops radiation is simply ludicrous.

[bankruatsteve]

@sometimewoodworker your frying pan "experiments" do not illustrate what you are claiming.  Laying Al foil on hot oil will conduct heat very quickly.  It is not reflecting anything and therefore not a radiant barrier.

 

A better example is this:  Place a paper towel ("insulation") on the grate in your oven.  Place Al foil on top of that to completely cover the towel (dividing the oven in half).  The starting temp of the oven was 28C.  I put on 210C for 5 minutes with top element only.  Using surface temp gun, the top compartment was 190 or so.  The bottom compartment was 46 (obviously some convection taking place).  Neither the Al foil or the paper towel was hot, nor even very warm, to the touch.  That is example of reflecting radiant heat energy and not absorbing it.

 

I couldn't work out how to take photo and measure the temp at the same time, so just have to take my word for that.

 

[Yellowtail]

[maxpower]

I am no insulation expert but can see why some might be a little confused when the shiny side of barrier material faces into a attic space. 

A better understanding of the emissivity test using a hot plate with black and shiny side. The temp is set to 230 deg :-

 

 

 

 

The infrared reading is lower for the shiny side because of the lower emissivity and ability emit radiation. The smart guy would approach this plate on the shiny side.

[sometimewoodworker]

1 hour ago, bankruatsteve said:

Laying Al foil on hot oil will conduct heat very quickly.  It is not reflecting anything and therefore not a radiant barrier.

First point I specifically said do not use oil, but that is a total red herring and probably doesn’t effect the case.
 

Where is the heat conducted to? Given that in my experiment that foil is about the same size as the pan. 

 

second point. You are talking about a different property of aluminium “conduction”

third point you (by your example) still don’t understand the difference between a radiant barrier IT DOES NOT RADIATE (very much) 

and a reflective barrier IT REFLECTS VERY WELL 

 

Thanks to @maxpower for that example as it may make understandable a concept that many people find incredibly difficult to comprehend. 

 

personally I understand the theory, though I was a little skeptical, I did put it into practice in the example shown in the pictures earlier in this thread and a 28^oC difference in surface temperature made a room that was very uncomfortable to be in into one that was perfectly useable.

 

2 hours ago, bankruatsteve said:

Place a paper towel ("insulation") on the grate in your oven.  Place Al foil on top of that to completely cover the towel (dividing the oven in half).  The starting temp of the oven was 28C.  I put on 210C for 5 minutes with top element only.  Using surface temp gun, the top compartment was 190 or so.  The bottom compartment was 46 (obviously some convection taking place).  Neither the Al foil or the paper towel was hot, nor even very warm, to the touch.  That is example of reflecting radiant heat energy and not absorbing it.

No question that, that Is an example of a reflective barrier.

 

It is not however in any way “A better example”. It is demonstrating a different property “a reflective barrier” 

 

 

[bankruatsteve]

5 minutes ago, sometimewoodworker said:

It is not however in any way “A better example”. It is demonstrating a different property “a reflective barrier”

Well, I give up.  By definition, a radiant barrier is a material that reflects radiant energy.  Google it.  What I have stated is backed by science.  I have no idea where you are coming from.

[sometimewoodworker]

38 minutes ago, maxpower said:

I am no insulation expert but can see why some might be a little confused when the shiny side of barrier material faces into a attic space. 

You probably would not be surprised to find that there are many who are confusing emissivity and reflectivity, how they work and how they should be used.
 

I think that that is why double sided film was made so that they cannot get it badly wrong.

 

There are also many web sites who don’t understand the difference or can’t explain it so helping along the confusion, and mixing of the concepts 

[bankruatsteve]

13 minutes ago, sometimewoodworker said:

First point I specifically said do not use oil, but that is a total red herring and probably doesn’t effect the case.
 

Where is the heat conducted to? Given that in my experiment that foil is about the same size as the pan. 

I don't know how to heat a pan to the point of smoking oil without oil.  But, whatever.  Placing foil in the pan will effectively become part of the pan, conducting the heat from the pan.  If nothing is in the pan (or on top of the foil) then it is not conducting heat further.  It is radiating heat.

Edited September 13, 2020 by bankruatsteve

[sometimewoodworker]

2 minutes ago, bankruatsteve said:

Well, I give up.  By definition, a radiant barrier is a material that reflects radiant energy.  Google it.  What I have stated is backed by science.  I have no idea where you are coming from.

You are completely wrong

 

By definition, a radiant barrier is a material that does NOT RADIATE radiant Energy.

 

By definition, a reflective  barrier is a material that reflects radiant energy.

[sometimewoodworker]

6 minutes ago, bankruatsteve said:

I don't know how to heat a pan to the point of smoking oil with oil.  But, whatever.  Placing foil in the pan will effectively become part of the pan, conducting the heat from the pan.  If nothing is in the pan (or on top of the foil) then it is not conducting heat further.  It is radiating heat.

“I don't know how to heat a pan to the point of smoking oil with oil“

a non contact thermometer helps

“Placing foil in the pan will effectively become part of the pan”

yes it will 

 

“conducting the heat from the pan“ 

to where?
 

“If nothing is in the pan (or on top of the foil) then it is not conducting heat further”
yes I agree 

 

“It is radiating heat”

very poorly at about 5% of the black pan

 

look at @maxpower post.

 

Edited September 13, 2020 by sometimewoodworker

[bankruatsteve]

2 minutes ago, sometimewoodworker said:

By definition, a radiant barrier is a material that does NOT RADIATE radiant Energy.

Please reference your source for that definition.  A material that reflects energy does not absorb it so of course it would not radiate energy that it doesn't have.