Blown in insulation roughing tips

[frogneck77]

I am starting my second house where the GC is using blown in insulation thruout the house-Anyone not familiar with this product its similar to Great Stuff-only doesnt expand as much. Its extremely efficient-The GC is a mechanical engineer and the 5000 fsq ft house has only one air handler with 7 zones. This insulation is becoming more popular in my area as part of the whole "GREEN" movement. The first house I wired with it we ran into a couple problems.(1) Wires are nearly impossible to snake after the fact-In bathrooms we typically leave a large loop above the vanity location with no rough in box-This allows the HO to decide on # of sconces and fixture placement based on mirror size/decorations on the finish stage of the project. With this insulaton my method didnt work too well.(2) The LV rings for all cable/data/phone locations were full of this insulation making the jacks difficult to install without chipping out alot. Has anyone else dealt with this insulation, and if so any tips for rough wiring with it.
Thanks,
Bill

 

[stickboy1375]

I dont bury wires (EVER) , and i just use deep low voltage rings and just remove some of the insulation at trim out.


One problem I am somewhat concerned with is derating of the cables encased in this stuff.

 

[electricalperson]

its always good to leave the wires poking out of the wall when they use this stuff. its possible to fish in this stuff but it can be a pain. i was speaking to the guy that installed this stuff the other day at a job and he says it costs 3 times as much as normal fiberglass but you will save that much money in 2 years of using it. its nice stuff but it can be a problem for us

if the foam is soft enough you can reach in and pull chunks of it out easily.

 

[nizak]

I used the "buried wire" method up until this type of insulation came along. Now I insist that the GC make a decsion on where the fixture will be and place an outlet box accordingly. I know of few homes that didn't sell because the perspective buyers din't like the vanity light that was already in place.

 

[stickboy1375]

i was speaking to the guy that installed this stuff the other day at a job and he says it costs 3 times as much as normal fiberglass but you will save that much money in 2 years of using it.

I would tell you that also if I was in the market of selling insulation. I'm a firm believer a house needs to breathe by the way.

 

[electricalperson]

I would tell you that also if I was in the market of selling insulation. I'm a firm believer a house needs to breath by the way.

it looks like it does a better job of insulating then fiberglass does. if i built my own house i would use it

 

[stickboy1375]

it looks like it does a better job of insulating then fiberglass does. if i built my own house i would use it

What about a house being able to breathe?

 

[electricalperson]

What about a house being able to breathe?

if the house told me it had to breathe id move out in a second

 

[stickboy1375]

if the house told me it had to breathe id move out in a second

:grin: Yeah, I'm just curious as to what harms they find out later on how bad it is to have a house that tight.

 

[brandon2177k]

FYI, open cell polyurethane foam(the soft spongy type) is breathable and is permiable, and technically is not a listed vapor barrier. Closed cell polyurethane, however, is the opposite and is a listed vapor barrier. Check out this website for more info: http://www.envirofoaminsulation.com/versus.html

 

[electricalperson]

:grin: Yeah, I'm just curious as to what harms they find out later on how bad it is to have a house that tight.

what could be a problem?

 

[c2500]

When you use the closed cell stuff, you normally add a fresh air intake system to swap out air. The neat thing is when it is 100+ degrees outside, the attic assembly is slightly above the set a/c temp.

c2500

 

[electricalperson]

When you use the closed cell stuff, you normally add a fresh air intake system to swap out air. The neat thing is when it is 100+ degrees outside, the attic assembly is slightly above the set a/c temp.

c2500

the houses around here that install the foam put in nice heating/ac systems that do that. i love the cool attics

 

[brantmacga]

What about a house being able to breathe?

Yeh they need to be able to breathe. Some of these guys are sealing them up way too tight. The lack of ventilation can cause condensation problems, which leads to mold in the house. I've done a few of these lately myself. Fortunately I stopped by after they did the insulation so I could find all of my cabinet lighting wires completely buried in the stuff. Insulation guy said I should have stapled them and left them poking out at the height I wanted them; the staples were there, just buried inside the foam. They do not care!

More info on this stuff.

Icynene Website

I will say it does keep the temp. down. We did a house for a guy who owns an insulation company and he did all of his exterior walls and rafters w/ this stuff; also, EVERY wall in the house was insulated. We were trimming the house in July; I had to go put up some light fixtures in the attic (completely floored). It was probably a good humid 100 deg. outside, and in the attic was just above 85. Usually this time of year attic temps down here reach 110+, and I've been in a couple that were over 120 which is almost impossible to function in.

 

[infinity]

Is this stuff really called blown in insulation or is it spray foam insulation? I only ask because the two are vastly different. Blown in insulation is chopped up fiberglass that is usually used to add a layer of insulation to attics. Spray foam insulation is like the expanding foam that comes in a can.

 

[ultramegabob]

there is also blown in "high density cellulose" they blow in wet ground up newspaper material, its a good idea to make sure someone uses duct tape on all your boxes when they blow the stuff in, saves alot of mess when you go back to install your devices on the finish.

 

[cschmid]

the spray on foam insulation is becoming popular and more cost effective here..I do have some long term questions on the health issues though..by the time most home owners notice the air exchangers are not working they have mold issues..

the air exchangers are required to be serviced every 30 days..filters cleaned anyone here ever do that how about the home owner think they do that..nope..air exchangers are even buried in the attic how cost effective is that..so I believe the health risks out way the benefits for both serviceman and home owner..

I know how hard it is to keep up with the ones we take care of..they are also expensive to maintain..filters, motors and parts are all custom and manufacturer specific..motor only last about 4 to 5 years and are 350 bucks a pop..up here in the frigid north country you even need to have fresh air preheaters to keep from pumping in cool moist air..

 

[goldstar]

The real fun comes when you have to cut in a remodel hi hat. That "poodle hair" insulation will be falling out of the ceiling for about 20 minutes. Bring plenty of drop cloths.:grin:

 

[frogneck77]

Thanks for the tips-This house is the closed cell insulation and hardens up alot from what the GC told me. Interesting tidbit- I heard the GC yelling at the framer for putting in too much wood-he said"I specifically told you to use the absolute minimum required by code/structural engineer specs- your extra wood is gonna waste energy" This guy is fanatical about R value and has thouroghly researched all the pros and cons of this installation. He is even using heat exchanging exhaust fans in all baths-by Panasonic. Should be an interesting project

 

[TwinCitySparky]

I used the "buried wire" method up until this type of insulation came along. Now I insist that the GC make a decsion on where the fixture will be and place an outlet box accordingly. I know of few homes that didn't sell because the perspective buyers din't like the vanity light that was already in place.

Wise advice to have the GC decide where the questionable boxes will go before the rock and closed cell foam gets applied. The closed cell foam is so strong it actually acts as a structural component to the building. It is simply a major pain to dig out when adding a rework box after the fact. Another thing. It gets HOT while it cures to a solid. Smurf tube is your friend if you are installing the low voltage wiring. (Cheap insurance!!) I learned the hard way... I had to dig out some garage opener low volt wires and some alarm zone wiring not long ago with a house foamed in the stuff. It actually melted the wires together in several different places, shorting them out. The insulating company said they would switch to the "open cell foam" (lower curing temp.) because of this possibility when they sprayed around the low voltage stuff. (ya right! ) that didn't happen.... I too would like to see some thourough, comprehensive testing with regard to derating wire i.e. buring romex wiring in the stuff... John