d_Isigny

To make a very long and painful story short...I'll just offer the high level details.

We have a 1440 SQ/FT Spanish style house in Phoenix Arizona. Our plan is to live in this home for 10-12 more years. The exterior is block and the builder added stucco to the front (only).

We were saving up to replace our ~20 year old air conditioner, however the October hail storm required our insurance company to do this for us (sometimes...it's better to be lucky than good). A higher efficiency unit will help our energy bills, but we'd like to go a little further.

First project will be adding 10-12" of cellulose insulation. The current fiberglass insulation is at or just above the rafters.

Second project being considered is wrapping the house with Styrofoam outsulation and a fresh coat of stucco. We are bored with the exterior of the house and need/want a new change. Further - our east wall gets baked in the Az sun. This wall will have a thicker barrier and hopefully reduce the heat that builds up.

I truly believe we will gain a financial benefit by adding insulation to the attic. My concern and request for feedback is about adding the outsulatoin and stucco. Would sure appreciate some sharing their experiences.

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[FONT="Arial Black"][COLOR="Blue"]Take good care of you and yours, K[/COLOR][/FONT]

oldognewtrick

When you say outsulation do you mean Dryvit? I would suggest doing a goggle search of Dryvit related problems if this is what you are referring to.

Oh... and welcome to House Repair Talk.

joecaption

Adding it on the outside will throw off every window and door opening and the trim will have to be all redone.
Is there a ridge vent on the roof now. Is there soffit vents and are they clear of insulation? When adding blown in insulation your going to also need to add foam baffles in every bay in the eaves.
Recommended Levels of Insulation : ENERGY STAR

Perry525

You need to understand that a lot of that heat in the home arrives by conduction.
Sun on roof, heats rafters, timber frame, joists, ceiling that passes heat into home.

Your proposal, adding Styrofoam to the outside is spot on, the Styrofoam will disconnect the frame from the siding or whatever, providing you are careful how you fix the polystyrene sheets. (you do not want to bridge the polystyrene insulation and provide an express route for that heat into your home)
A better solution, easier to handle is SIPS, using this system you can have conduction proof walls.

Instead of adding cellulose, you should think of using a SIPS system on the roof, this will give you maximum separation, stop the heat from reaching the rafters and frame, take care with how you join the roof to the walls, using polyurethane foam as a sealant. (If you work indoors read the Health and Safety)

d_Isigny

First...thank you for the warm replies and very helpful information.

We've not finalized things - yet. We are grateful for experienced input to helps us 'open our eyes' and make the best decision. THANK YOU!!

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[FONT="Arial Black"][COLOR="Blue"]Take good care of you and yours, K[/COLOR][/FONT]

Scott_W

cellulose insulation is a very smart choice. I think it will definitely help you to protect your house from conduction of heat. Want to make a 'green house', huh?

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Perry525

Cellulose is a bad choice.
Cellulose is an open cell insulation made of old newspapers.
All of the best insulators are comprised of 98/99% air.
Polystyrene is 98% air and 2% plastic.
The way a good effective insulator works, is by trapping thousands of very small bubbles of air inside thousands of tiny plastic bubbles.
Still air is one of the best insulators available.
The cellulose fabric itself conducts heat.
The open cell nature of cellulose enables the movement of warm air through the newspaper, thereby passing the heat from the warm air through the insulation and onto the fabric of the building.

sway

Sorry to barge in on thread, but I am a bit confused. It sounded like the OP was planing on putting 10-12" insulation in the joists in his attic. Isn't the SIPS system put on the outside of the roof? Are you suggesting this over the alternative? Or are you thinking a SIPS system for the outside of the house? I am getting ready to buy a house to rehab that is very old, so these suggestions really help.

Perry525

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Chicago can be cold and windy!

The typical American light weight home is not suited to Chicago weather as originally built.

What you need is a modern air tight insulated home, to avoid the effects of the wind.

Luckily the original home can be modified to meet modern Passive House standards.

An original new SIP's building will be made in a factory, where each side of the home will be made in one piece, a piece that is self supporting has all the window and door openings in place and is just stood up on site and joined together. Minimum joins equal minimum heat loss due to wind suction. No frame.

You are proposing to convert an existing frame building, placing the SIP's structure on the outside creates problems.

You will have problems sealing the sides to the roof and base. You also have the problem that you will be heating the frame and the spaces inside the frame, when you are intending to save the maximum amount of heat and heating/cooling cost.

By placing the SIP's structure or similar, on the inside of the rooms, you end up with rectangular boxes, that are easy to join together easy to seal and you only heat the comfort zone that you live in, no heating of frame or spaces between the frame.

You also maintain the exterior appearance of your home.

If you are buying in a high Radon gas zone, you really need a home that is sealed against rising Radon gas.