Building a house in the Philippines
and I would like advice. It is being made the way they build there. It is a 450 square meter, six bedroom, one story, hollow block wall with reinforced with rebar, steel roof house.
So far the best energy saving move we have made is the roof. We had ours painted white which few people there do and we found a company that put 50mm of PU foam under their zinc coated steel roof. Everyone is impressed how cool it is inside now.
Next I am looking to put in a whole house fan. I found a company in Australia called Breezepower that modifies Triangle Engineering fans with 220v, 3 speed with timer, and a 6 blade design instead of 4. We want the biggest they have which is 48 inch. Going to pair that with a Dayton shutter. I am hoping to buy that next week.
My major concern is the hollow block walls. Should I insulate from the interior or exterior? Would EIFS be ok there where it rains a lot? Or would it be better to use EPS on the interior walls? Or is there another way? As info my builder doesn’t think we need to bother with the walls at all due to roof and he is very familiar with EIFS.
Also with the PU roof do I still need a radiant barrier? I found an Australian run company there that blows cellulose into attics. Do I need that with a PU roof? Here again my Philippine builder thinks it is overkill.
Lastly if any knows any western building experts around Angeles City, Philippines please let me know. Things like insulation, building green, security etc.
Any other tips?
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Replies
Insulating the exterior will maximum the use of your thermal mass.
Barry,
Q. "Should I insulate from the interior or exterior?"
A. The preferred approach is to install the insulation on the exterior.
Q. "Would EIFS be OK there where it rains a lot?"
A. Yes. If the wall is made of concrete blocks, it will not be harmed by moisture.
Q. "Would it be better to use EPS on the interior walls?"
A. No.
Q. "Is there another way?"
A. I think that your two choices are interior insulation or exterior insulation. Either approach is better than no insulation.
Q. "With the PU roof do I still need a radiant barrier? I found an Australian run company there that blows cellulose into attics. Do I need that with a PU roof?"
A. You have 50 mm. of foam, which is a little less than 2 inches. That's about R-12. That is far less than the minimum insulation required in Florida (R-30 to R-38), so additional insulation wouldn't hurt. You can either add more spray foam, or you can add cellulose. (These would be better options than the radiant barrier.)
That helps a lot. I know where to do my research now. My builder knows how to do EIFS and it is affordable. I will still install the radiant barrier as they are so cheap and I have the labor. And I am going to put as much cellulose insulation as the weight of the ceiling will allow. I was quoted 10 inches 620 PHP per SQM installed ex VAT (r-value 36) which comes out to about 6000 dollars plus Value Added Tax.
One more question please, how thick would you go with the EIFS insulation? Are there problems going thicker? I read that one inch of EPS has about a 4.5 R value. I thought why not go six inches then. Is there a limit to the thickness?
Barry,
It would be hard to justify the installation of 6 inches of rigid foam on the walls of a home in a tropical climate. After about 2 inches of rigid foam, additional foam doesn't save enough on your energy bills to justify the cost to install the foam.
And two inches will be easier to do. I understand what path to take now. Thank you.
with all that foam and insulation, the home with be soaking with humidity...as it is in the Philippines -especially during wet season... mold will be a huge problem unless you install a good high volume dehumidifier or two. Set them at a percentage of humidity you want - say 40-50 percent and let them keep the home dryer and cooler. the construction methods and standards there is so poor it is a joke, so when a builder over there says its overkill, what they are saying is it's over my skill and intelligence, even in a million dollar home, you can see daylight under the doors and areas that should be sealed when closed.... I would order windows from outside the country as they have no clue about dual or triple pane windows.
sorry, i re-read your post and say that the builder says since you have a white insulated roof you don't need to worry about the walls...... tell him you would like to build a concrete block 6 by 6 building, tin roof painted white in the middle of a sunny field and have him lay down in it all day for 24 hours... you will pay him.... you see that concrete walls absorbs all that heat and sun all day long radiating it into your home /oven you have created and come sundown that heat will continue to radiate into your home all night making sure it is hotter inside than outside...
That builder is an idiot- I would fire him if you can