Styrofoam insulation

Neargale

Active member
Jul 4, 2013
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Would putting sheets of styrofoam on the inside of a house work as insulation against the heat?
If so, is it available at a regular ferreteria/costruction material place?

Many years ago I saw a DIY decorator project that covered the styrofoam with fabric (glue or staples) and then covered the wall. Obviously the styrofoam was cut first to fit and cover the wall.

Would that work covering 1 wall in the bedroom to reduce the heat? It is a west facing wall. Would it be worth it?The south facing wall is shaded by plants. 

Would the styrofoam hold up to the humidity?

Yes the walls are cement blocks.

Many thanks
 

Cdn_Gringo

Gold
Apr 29, 2014
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I would think that for your proposed project to be reasonably effective, you would need a vented air gap between the concrete wall and sheets of insulation. Concrete is pretty good at distributing heat via conduction. As you know, once heated, it takes a long time for concrete to release that heat. The most effective preventative measure would be a way to reduce the heating of the concrete in the first place. Somehow shading the outside exposures if possible or installing your insulation on the exterior surfaces. You shouldn't need to do anything to the interior walls but I would think that all exterior walls that are hit by direct sun would need some form of remediation.

If practical, you can plant some big leafy trees, install awnings/sun sails, a lighter coat of paint etc.

My current casa is a single floor structure with a high ceiling. There is no insulation between the concrete roof tiles and the wood interior ceiling. My laser thermometer shows interior air temps in the high 90's when the sun is out (which is always). I've installed sprinklers with a timer on the roof to wet it down every hour in an attempt to limit the temperature rise inside the house. The exterior of the roof is so hot that when water is applied it turns to steam for the first minute or so. My neighbors originally thought the house was on fire when I first installed this system.
 

cobraboy

Pro-Bono Demolition Hobbyist
Jul 24, 2004
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I would think that for your proposed project to be reasonably effective, you would need a vented air gap between the concrete wall and sheets of insulation. Concrete is pretty good at distributing heat via conduction. As you know, once heated, it takes a long time for concrete to release that heat. The most effective preventative measure would be a way to reduce the heating of the concrete in the first place. Somehow shading the outside exposures if possible or installing your insulation on the exterior surfaces. You shouldn't need to do anything to the interior walls but I would think that all exterior walls that are hit by direct sun would need some form of remediation.

If practical, you can plant some big leafy trees, install awnings/sun sails, a lighter coat of paint etc.

My current casa is a single floor structure with a high ceiling. There is no insulation between the concrete roof tiles and the wood interior ceiling. My laser thermometer shows interior air temps in the high 90's when the sun is out (which is always). I've installed sprinklers with a timer on the roof to wet it down every hour in an attempt to limit the temperature rise inside the house. The exterior of the roof is so hot that when water is applied it turns to steam for the first minute or so. My neighbors originally thought the house was on fire when I first installed this system.
In FL, we had a colored ceramic coating that looked like paint on the outside of the house that kept the concrete cooler and reduced a/c costs.

Spendy, but effective.
 

21yearsinDR

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May 29, 2013
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Your problem is apparently that the sun heats up the concrete wall. I have seen people installing a roller blind outside as we normally use for windows and big balconies. It was installed with a distance of approx 1 foot from the wall. The material is a kind of vinyl - slightly transparent and you can wash it down when dirty. The roller system is expensive, so you could let somebody make a square of that same fabric and attach it in the 4 corners with hooks. Eventually you can remove this during cooler seasons. The fabric is white and works very well blocking the sun. If you have a huge 3 level house it might be too complicated, however installed at a smaller wall it does not look bad.
 

jimbobo

Member
Feb 9, 2014
170
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Would putting sheets of styrofoam on the inside of a house work as insulation against the heat?
If so, is it available at a regular ferreteria/costruction material place?

Many years ago I saw a DIY decorator project that covered the styrofoam with fabric (glue or staples) and then covered the wall. Obviously the styrofoam was cut first to fit and cover the wall.

Would that work covering 1 wall in the bedroom to reduce the heat? It is a west facing wall. Would it be worth it?The south facing wall is shaded by plants. 

Would the styrofoam hold up to the humidity?

Yes the walls are cement blocks.

Many thanks

Ochoa in Santiago sells styrofoam sheets 4 feet by 8 feet; they have them in 1 inch thick, 2 inch thick and 4 inch thick. A sheet of 2 inch thick costs 325 pesos....
 

ctrob

Silver
Nov 9, 2006
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It would work on the interior but it's the worst place to put it.

1 - fumes in the event of a fire. Very bad stuff to be breathing while sleeping.

2 - You always want to stop the heat before it gets into the house - thru the walls. Once that wall heats up that large mass of heat will be constantly trying to push into the house. Placing them on the exterior of the wall keeps that large mass of masonry cool. Plus the added benefit of the mass of your masonry/concrete walls will act as a thermal sink to capture any cool air you produce inside with your ac. And that cool mass will last longer.


Fasten them to the exterior surface, cover with mesh and slap on some stucco mixture. You'll be much happier with the results.
 

Derfish

Gold
Jan 7, 2016
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Ochoa in Santiago sells styrofoam sheets 4 feet by 8 feet; they have them in 1 inch thick, 2 inch thick and 4 inch thick. A sheet of 2 inch thick costs 325 pesos....

ANd has an R value of less than half of what standard Fiberglas insulation has. I don't remember the amounts at present, but did research it at one point.
Der Fish
 

Planter

New member
Aug 29, 2017
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Nice to see some advice on hear insulation here, maybe somebody can share their opinion on noise insulation on the walls too?
 

ExDR

Member
Jul 31, 2014
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Yes, it will work and very well. However, do not place it in the interior of the house. Have it installed to the exterior of the house and have stucco placed over it to protect from the elements. Another cheaper and quicker solution is to paint the house with white paint, preferably semi to glossy. It will reflect the sun's rays and keep the walls 5-10 degrees cooler. Your roof should also be painted white.
 

Neargale

Active member
Jul 4, 2013
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Thank you all for the answers!

Will paint the exterior white.... overdue as it is.. semi gloss...
 

william webster

Platinum
Jan 16, 2009
30,247
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I have seen some new construction and some refurbishing of buildings with Styrofoam sheets, but I believe they were on the outside walls. Then I think a stucco was applied over them.

Anything that adds insulation can help. R-5 for one inch panels. A cement block wall is about R-2.

http://homeguides.sfgate.com/increase-rvalue-concrete-block-wall-54431.html

That is a new building technique...
Styro panels filled in between with cement....fast and energy efficient.

Exterior needs to be covered after
 

oriole100

Bronze
Oct 9, 2005
807
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Put Styro. on the outside works but it damages easily. Even with stucco. Paint the wall white and if you can stand the color, the roof Alum. It will reduce the heat 15-20 degree's. Good luck.
 

cobraboy

Pro-Bono Demolition Hobbyist
Jul 24, 2004
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I'd add some ceramic micro-spheres to the white paint to reflect a great % of the west-facing sun rays from the house.

There are several prodicts available, one being manufactured by Hy-Tech. It works for walls exposed to direct sunlight, especially on west walls, not so much for walls in the shade.

And plant some shade trees.
 

Dolores1

DR1
May 3, 2000
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Filled in the large windows of a room that I wanted to turn into a closet and not allow the heat in. The styrofoam worked wonderfully. This indeed is a good solution. It does seem to capture the heat. No one can tell that it is styrofoam from a first glance. On the outside the windows have storm protectors, but the heat still steamed in, but no more with the styrofoam.

Purchased the sheets from Grupo Isotex north of Santo Domingo off the Autopista Duarte. They sell to the local construction industry but will sell an individual panel but you have to order ahead. Look them up online. You may need a large vehicle to transport the panel.

Also, when we had to add some rooms to our terrace, these were done with styrofoam blocks filled with cement inside. These rooms are very pleasant as the styrofoam does not hold in the heat as cement blocks do.
 
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