Reducing The Heat In The House

[JaseTheBass]

only if the by-laws of your homeowners' association allows them.

Do they have them in Thailand?

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[Grubster]

4 hours ago, Naam said:

 

everything makes perfect sense Grubster except... the "open chest freezers"

What don't you understand about that? Its a common feature in stores. I will say that the much less efficient stand up freezers are much more popular now as you can view all the products better, but have you noticed how fast the cold air pours out the bottom of the door when you open one. very inefficient.

 

4 hours ago, Strange said:

 

I'm on mobile so can't get detailed but again I'm from FL and climate is the same. We got metal, tile, and shingle roofs, central heat and air, every combo you can think of with ventilation, roof design, etc... 

 

We still insulate above the cieling, not only that but nowadays it's all spray foam all over. Top of cieling, bottom of roof, etc. everywhere. 

 

This is in Florida climate so it's not there to retain heat like Chicago. 

 

It is to lower the cooling requiremt for a home and make it more efficient and less costly to keep cool even though it's 105 outside. 

 

Thoughts?

The last time I was in Florida Three years ago I wasn't seeing many of these metal roofs with the reflective finish, but I bet they are starting to use some now. Florida has a very bad standard of construction, at least have of the homes there have less than a 4/12 pitch roof. Are the roofs your speaking of even insulated at all, Ok if there not but then as I said you will need to insulate the ceiling as it will get near 200 degrees in your attic. I think you should find someone who has one of these insulated metal roofs with the reflective finish on it, and ask them if you can go up in their attic and see/feel for yourself.

                 My walls here are double wall super block with 2" air space between "very good", I have all single glazed windows that will admittedly cost me a lot in cooling, but my attic is only a few degrees hotter than the outside air, not 90 degrees hotter like it would be with a low pitch shingle or stone uninsulated roof. The pay back for my insulation on the ceiling would be much longer than the rest of my life I think. The windows are another thing, I just couldn't find any good ones here and gave up as the only ones I could find on the net from Bangkok and Phuket were way overpriced.

[Grubster]

4 hours ago, Naam said:

forgot to exclude from perfect sense "no ceiling insulation"

Sorry I tried

[Grubster]

5 hours ago, JaseTheBass said:

Shallower pitched roof with large overhangs, don't use storage heaters (concrete tiles) on your roof - insulated metal roofs are so much better.

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The steeper the roof the better, for looks, performance, and longevity. Costs more though.

[JaseTheBass]

The steeper the roof the better, for looks, performance, and longevity. Costs more though.

Have to disagree from actual experience.

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[Grubster]

10 minutes ago, JaseTheBass said:

 

Have to disagree from actual experience.

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I had to work in attics for years and there's no doubt in my mind. Easy to look up to find why.

[JaseTheBass]

I had to work in attics for years and there's no doubt in my mind. Easy to look up to find why.

The way I build houses doesn't let any heat enter the house from above and shades the walls. Works better than any 'normal' houses I've been in.

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[Grubster]

2 minutes ago, JaseTheBass said:

 

The way I build houses doesn't let any heat enter the house from above and shades the walls. Works better than any 'normal' houses I've been in.

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I would have to question your building ability if you think a shallow pitched roof is good for any reason other than cheaper and easier to install.

[Naam]

5 hours ago, JaseTheBass said:

Do they have them in Thailand?

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they do!

[Naam]

3 hours ago, Grubster said:

I would have to question your building ability if you think a shallow pitched roof is good for any reason other than cheaper and easier to install.

Quote

3 hours ago, JaseTheBass said:

The way I build houses doesn't let any heat enter the house from above and shades the walls. Works better than any 'normal' houses I've been in.

Jase is building low pitch to achieve a deep roof overhang.

[skippybangkok]

may the force be with you!
i gave up working 26 years, 11 months and 12 days ago

Who's counting :)

We are jelous


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[Naam]

10 hours ago, Strange said:

 

I'm on mobile so can't get detailed but again I'm from FL and climate is the same. We got metal, tile, and shingle roofs, central heat and air, every combo you can think of with ventilation, roof design, etc... 

 

We still insulate above the cieling, not only that but nowadays it's all spray foam all over. Top of cieling, bottom of roof, etc. everywhere. 

 

This is in Florida climate so it's not there to retain heat like Chicago. 

 

It is to lower the cooling requiremt for a home and make it more efficient and less costly to keep cool even though it's 105 outside. 

 

Thoughts?

 

we lived 15 years in Florida. built three homes, one for us two for two friends. experience: nothing more efficient than central airconditioning with double ducts, ceilings properly insulated and forced attic ventilation (7 attic fans triggered by thermostat and manually controllable).

 

 

 

Edited October 15, 2016 by Naam

[JaseTheBass]

Jase is building low pitch to achieve a deep roof overhang.

But sadly, my builds which work extremely in the tropics don't give Grubster a loft to crawl around in.

[Naam]

6 hours ago, Naam said:

 

we lived 15 years in Florida. built three homes, one for us two for two friends. experience: nothing more efficient than central airconditioning with double ducts, ceilings properly insulated and forced attic ventilation (7 attic fans triggered by thermostat and manually controllable).

 

 

 

 

 

that was an "Alzheimer's" posting! 4 of the fans are to ventilate the semi-indoor pool area.

 

[Strange]

7 hours ago, Naam said:

Jase is building low pitch to achieve a deep roof overhang.

 

Exactly what I like to do as well, but not so much a low pitch. More like a modern variation on "Florida Cracker" homes from back in the day. Deep overhang either all the way around the home or where the sun rises and falls, with a gable pitch over the living areas for ventilation. Of course implementing modern cooling tech as well. 

[Naam]

7 hours ago, JaseTheBass said:

But sadly, my builds which work extremely in the tropics don't give Grubster a loft to crawl around in.

what depth of roof overhang are we talking about?

[Strange]

12 hours ago, Grubster said:

The last time I was in Florida Three years ago I wasn't seeing many of these metal roofs with the reflective finish, but I bet they are starting to use some now. Florida has a very bad standard of construction, at least have of the homes there have less than a 4/12 pitch roof. Are the roofs your speaking of even insulated at all, Ok if there not but then as I said you will need to insulate the ceiling as it will get near 200 degrees in your attic. I think you should find someone who has one of these insulated metal roofs with the reflective finish on it, and ask them if you can go up in their attic and see/feel for yourself.

                 My walls here are double wall super block with 2" air space between "very good", I have all single glazed windows that will admittedly cost me a lot in cooling, but my attic is only a few degrees hotter than the outside air, not 90 degrees hotter like it would be with a low pitch shingle or stone uninsulated roof. The pay back for my insulation on the ceiling would be much longer than the rest of my life I think. The windows are another thing, I just couldn't find any good ones here and gave up as the only ones I could find on the net from Bangkok and Phuket were way overpriced.

 

Florida is a big state with a lot of different...... "Cultural" areas. Not sure where you stayed, but I'm not talking about subdivision homes. Im talking about homes that people build for themselves in regards to using metal roofing. 

 

However I'm not sure where you get the "Very Bad" standard of construction from. Concrete slab, wood frame, insulated, forced ventilation, central air, high ceilings, open floor plan homes built to last and withstand hurricanes. You could easily transplant a home built in FL to most any other area in the US and it would be very much to code, probably even further. 

 

I haven't seen a home without insulation over the ceiling, regardless if the roof is insulated. You still need a barrier to separate a hot space from a climate controlled space. 

 

Quote

but my attic is only a few degrees hotter than the outside air

 

When its 40C outside and your attic is over 40C - this is hot. This is a lot of heat beating down on your gyprock/drywall ceiling with no barrier what so ever and you are going to be trying to cool the space beneath it to 24-25C. Also remember as it gets hotter, the effect multiplies. I mean this right here is the difference between a 9k BTU Aircon being more than enough and needing a 12K BTU unit that struggles. 

 

Im not Thai Bashing here but Thailand isn't pioneering anything in regards to roofing design and cooling effect. The metal roofing with the foam/air void stuck to it is probably good when added to a complete system, but its hardly enough alone. Being a HVAC guy I'm sure you know this but several systems of insulation are required to complete a well rounded design. 

[Naam]

38 minutes ago, Strange said:

 

Exactly what I like to do as well, but not so much a low pitch. More like a modern variation on "Florida Cracker" homes from back in the day. Deep overhang either all the way around the home or where the sun rises and falls, with a gable pitch over the living areas for ventilation. Of course implementing modern cooling tech as well. 

i don't like low pitch roofs. they look cheap and have to be very sturdy (it takes a lot of steel to compensate for the snow that doesn't slide off). taking into consideration the heavy snowfalls in Thailand (blizzards from november till february), building a low pitch roof is an unwise decision.

[Naam]

slightly off topic: "roof design". although i provided detailed sketches for our Florida home i did not interfere with the roof design, never even looked at the blueprints. was out of the country for two months and was horrified when i saw the roof structure with a zillion valleys and ridges. built a near identical home in Thailand (slightly bigger) without any architectural

roof farts, i.e. in Thailand hip roof all four sides and a small ridge because the home is not exactly square.

[Grubster]

10 hours ago, Naam said:

 

we lived 15 years in Florida. built three homes, one for us two for two friends. experience: nothing more efficient than central airconditioning with double ducts, ceilings properly insulated and forced attic ventilation (7 attic fans triggered by thermostat and manually controllable).

 

 

 

Yes double duct, Very hard to get that system here though or I would have done it. I checked prices in Bangkok for the air handlers for that and they were ridiculous, not to mention lack of a good sheet metal shop in my area for fabrication. The drains on the split system wall units here tend to plug up a lot but regular maintenance can avoid that. Looks like a great home,  I love to Bass fish there, got one 11 lbs a few years back.

[Grubster]

3 hours ago, Strange said:

 

Florida is a big state with a lot of different...... "Cultural" areas. Not sure where you stayed, but I'm not talking about subdivision homes. Im talking about homes that people build for themselves in regards to using metal roofing. 

 

However I'm not sure where you get the "Very Bad" standard of construction from. Concrete slab, wood frame, insulated, forced ventilation, central air, high ceilings, open floor plan homes built to last and withstand hurricanes. You could easily transplant a home built in FL to most any other area in the US and it would be very much to code, probably even further. 

 

I haven't seen a home without insulation over the ceiling, regardless if the roof is insulated. You still need a barrier to separate a hot space from a climate controlled space. 

 

 

When its 40C outside and your attic is over 40C - this is hot. This is a lot of heat beating down on your gyprock/drywall ceiling with no barrier what so ever and you are going to be trying to cool the space beneath it to 24-25C. Also remember as it gets hotter, the effect multiplies. I mean this right here is the difference between a 9k BTU Aircon being more than enough and needing a 12K BTU unit that struggles. 

 

Im not Thai Bashing here but Thailand isn't pioneering anything in regards to roofing design and cooling effect. The metal roofing with the foam/air void stuck to it is probably good when added to a complete system, but its hardly enough alone. Being a HVAC guy I'm sure you know this but several systems of insulation are required to complete a well rounded design. 

The heat gained from the ceiling will have a much smaller transfer effect than a wall, window, door, and most of all an uninsulated floor that is not a slab on the ground, This said of course insulation would decrease the transfer, but I feel that with only 40 degree air above as opposed to 70 degree air above the ceiling because of the insulated roof, my pay back on that would be a long time, that does not mean insulation wouldn't be better of course it would. The air in your attic is much hotter than 40, more like 70. Do you know what stratification is? The hot air will stratify less than 2' below the ceiling if you don't force it down. Some of that air will waft into your cooling air stream causing the unit to remove humidity from the room. Still it would be better to have insulation if properly installed. Good luck with the properly installed part if you don't do it yourself. I think my system will be fine and if not I will have insulation blown in. The metal roof I have is not foam, you are talking about the straight line insulated pre made cheap roof panels. My roof looks like a stone roof and only on close inspection could you see that it isn't. It has foil lined fiberglass glued to it durring the custom rolling process. The metal with relective finish is very expensive as I'm sure the chemical company that came up with this finish is making a killing. You can set a piece of this metal directly in the sun and it will be only warm to the touch, then touch your car and get burnt.

[Grubster]

3 hours ago, Naam said:

slightly off topic: "roof design". although i provided detailed sketches for our Florida home i did not interfere with the roof design, never even looked at the blueprints. was out of the country for two months and was horrified when i saw the roof structure with a zillion valleys and ridges. built a near identical home in Thailand (slightly bigger) without any architectural

roof farts, i.e. in Thailand hip roof all four sides and a small ridge because the home is not exactly square.

The more roof lines the better people think where Im from, I'm with you a simple hip roof design looks and works the best.

[Grubster]

4 hours ago, Strange said:

 

Exactly what I like to do as well, but not so much a low pitch. More like a modern variation on "Florida Cracker" homes from back in the day. Deep overhang either all the way around the home or where the sun rises and falls, with a gable pitch over the living areas for ventilation. Of course implementing modern cooling tech as well. 

I put 1.2 meter overhangs and would have done more but I wanted the 4' soffit panels to fit in one piece. I went fishing with a big guy in florida who had a big tattoo that said "The Big Cracker" , I said what does that mean, he said that is in reference to the florida cattle drivers that would crack their bullwhips to keep the herd in line, he said you could here that from miles away. Is that right.

[Grubster]

4 hours ago, Strange said:

 

Florida is a big state with a lot of different...... "Cultural" areas. Not sure where you stayed, but I'm not talking about subdivision homes. Im talking about homes that people build for themselves in regards to using metal roofing. 

 

However I'm not sure where you get the "Very Bad" standard of construction from. Concrete slab, wood frame, insulated, forced ventilation, central air, high ceilings, open floor plan homes built to last and withstand hurricanes. You could easily transplant a home built in FL to most any other area in the US and it would be very much to code, probably even further. 

 

I haven't seen a home without insulation over the ceiling, regardless if the roof is insulated. You still need a barrier to separate a hot space from a climate controlled space. 

 

 

When its 40C outside and your attic is over 40C - this is hot. This is a lot of heat beating down on your gyprock/drywall ceiling with no barrier what so ever and you are going to be trying to cool the space beneath it to 24-25C. Also remember as it gets hotter, the effect multiplies. I mean this right here is the difference between a 9k BTU Aircon being more than enough and needing a 12K BTU unit that struggles. 

 

Im not Thai Bashing here but Thailand isn't pioneering anything in regards to roofing design and cooling effect. The metal roofing with the foam/air void stuck to it is probably good when added to a complete system, but its hardly enough alone. Being a HVAC guy I'm sure you know this but several systems of insulation are required to complete a well rounded design. 

Yes it is a big state, From what I have seen most walls there are thin and poorly insulated, the ceilings are made on 24" centers, not enough electrical outlets, many electrical connections above the ceilings, low profile roofs unless in areas like Naam mentioned. AC/furnace crammed in a closet. Flexible duct throughout the attic, greatly reducing airflow and costing constantly in electrical and maintainence costs. I'm sure they use a lot of insulation above the ceilings as insulation is very cheap and of good quality in the US,  also using a vapor barrier in a ceiling like foil backed is a no no there, and here as it will cause mildew in your ceiling, shouldn't have to worry much here though as the gaps they leave everywhere will allow the moisture to mix into the hot air. All this said a nice layer of raw fiberglass insulation above the ceiling here would be optimum no doubt. I couldn't find any of that, but if I need I can have the blown in done later but I doubt it. 40 degrees is not hot for an attic.

[Grubster]

12 hours ago, JaseTheBass said:

But sadly, my builds which work extremely in the tropics don't give Grubster a loft to crawl around in.

What does the overhang have to do with the roof pitch other than the fact that a steeper roof would travel further down at an equal distance out increasing the amount of wall shaded from the sun.  Steeper roofs have less leaks, look better, last longer, the shingle manufacturers will not warranty their products if under a 4/12 pitch. Snow load is a factor in the north but not the biggest factor, the shingles on a low pitched roof will begin to cup in just a few years. The oven effect is also much greater in a lesser pitched roof.

[Naam]

4 hours ago, Grubster said:

Yes double duct, Very hard to get that system here though or I would have done it. I checked prices in Bangkok for the air handlers for that and they were ridiculous, not to mention lack of a good sheet metal shop in my area for fabrication. The drains on the split system wall units here tend to plug up a lot but regular maintenance can avoid that. Looks like a great home,  I love to Bass fish there, got one 11 lbs a few years back.

 

another problem in Thailand is that quite often one of the three phases have a brown-out or are completely off. 48k btu/h and higher rated compressor/condensers need a 3-phase connection. you either protect the units then you are without aircondition or the units are damaged.

[Naam]

2 hours ago, Grubster said:

What does the overhang have to do with the roof pitch other than the fact that a steeper roof would travel further down at an equal distance out increasing the amount of wall shaded from the sun.  Steeper roofs have less leaks, look better, last longer, the shingle manufacturers will not warranty their products if under a 4/12 pitch. Snow load is a factor in the north but not the biggest factor, the shingles on a low pitched roof will begin to cup in just a few years. The oven effect is also much greater in a lesser pitched roof.

envisage a steep roof with a big overhang Grubster. the end of the overhang will come down too low. that can be compensated by having higher outside walls or by a crooked roof which looks like...

[JaseTheBass]

What does the overhang have to do with the roof pitch other than the fact that a steeper roof would travel further down at an equal distance out increasing the amount of wall shaded from the sun.  Steeper roofs have less leaks, look better, last longer, the shingle manufacturers will not warranty their products if under a 4/12 pitch. Snow load is a factor in the north but not the biggest factor, the shingles on a low pitched roof will begin to cup in just a few years. The oven effect is also much greater in a lesser pitched roof.

Are you lost? This is a Thai forum, not Merkin. Snow... [emoji3]

[Linzz]

21 hours ago, Grubster said:

The steeper the roof the better, for looks, performance, and longevity. Costs more though.

 

Steep roof also deflects heat. The flatter the roof the more available to sun. Extended eaves provide shade, Roof vents provide expelling of heated air. Looks like the postings are shaping up to look more like the traditional Thai house with modern add ons. If contemporary Thais have forgotten their past that does not mean that 100's of years of accumulated history is nonsense as some seem to think.  

[Naam]

44 minutes ago, Linzz said:

Steep roof also deflects heat. The flatter the roof the more available to sun.

correct! and the less attic space, respectively distance from roof to ceiling, the more penetrating heat radiation.