hey- ive been in the trade for 27 years, and have gone and bought a cinderblock lakehouse ( deal ) . Its in central Georgia, so cooling is more important than heat. Would someone let me know if i am on the wrong page? Thanks. My thought is to apply 3/4 ” foil faced foam insulation direct to the interior walls with liquid nails. Drywall direct to that. On the exterior, same insulation application, paper,lath-(ram set ?) , stucco’ d- will the air pocket and porosity of the block allow this application?
Thanks
Replies
Foil faced is a vapor barrier. Double vapor barrier = no good.
In GA, predominately cooling, you need vapor barrier on the outside, though honestly either side would be fine and probably not even required at all on a block house. That block is going to trasmit some good moisture so I would be tempted to put the VB on the inside where you could more easily block that moisture transmission to the inside on cooling days and keep your block from sucking moisture on heating days.
And I'd go higher than 3/4" foam. I'd try for 2" foam (R-10). The outside I would put up no VB. Let the block breathe to the outside.
hey- thanks- you say you would put the VB on the interior- my thinking is there is so much thermal gain from the outside, with the block being so absorbant , is it more science than logic for vapor transmission? wouldnt "preventing" the heat buildup of the block from the outside reduce the thermal transmission and extra cooling to the interior air?
You are right a cooling climate requires the VB on the exterior.
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the foil won't do you any good in this case. And that type of foam degrades faster in certain environments. It can have a higher R-value, but it can absorb moisture also.
I would use XPS faom instead and apy very carefull attetion to detailing the flashings. i might do 2" on the exterior and 1" interior. leaving a 3/4" furring interior for wire runs and SR attachment.
Apply dryvit exterior.
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i have a thing about rats and roaches, which is what the firing runs are in this house- its a 3 storey block, no fill, painted outside, strapped, "inserted" with (very) loose (and useless) sheets of styrofoam, covered with sheetrock. I have stripped one room (3 ext walls) to the block- lookin at the amount of do-do from critters.
If i use a ridged core foil face towards the wall, glued, a router to clear wire runs, then drywall, wont i needsomething to help reduce solar gain from outside? I plan to stucco, and will paper and mesh - will a simple foil sheet be a strong enought to hold stucco, And B) do the job of heat retardent.
I spend alot of time there, would like it comfortable
Thanks guys
I'd be sorely tempted to make a "veneer" wall on both sides of the block (think an 1 1/2" basement style wall).
On the outside, you get to keep the heat off the thermal mass of the block, and also retain a way to get any moisture out of the block and out of the house.
On the inside, you get full control of interior finishes, and a really good excuse for re-doing all of the utilites (electric, speakers, what have you).
Do you need a full 1 1/2" wall both sides? Maybe not. It's just a nice, available size that came to mind first. That, and in Georgia's heat and humidity, you want to keep that heat and the humidity away from those blocks as long as possible (like until November or so)--so I'd insulate the outside.
If you add insulation to the oustide, you could probably use furring chanel to hang SR inside.
I built me a cinder block house in NW fla. I have 8 inch CMU filled solid with concrete. 2x4 wall on inside with r15 fiber, VB, drywall. outside traditional stucco directly on block. in the attic no VB and r80 of cellius(paper). light color metal roof All electric , electric water heater, heat pump. My highest electric bill in last two years $31. The house stays bewteen 68 and 72 all year round I have yet to turn ac on. Heat during couple them cold fronts
sounds great- this thing i bought is 3 storey, hollow block, stable ( held up under a flood), but it was always a fishing camp- I want to make it a villa type thing, plan to insulate the attics and power vent the roofs, and install a product called "steel tile" looks spanish, comes in 40 ' sheets- one time roof-so solar gain thru the roof should be way less, but the block walls wont heat in the winter, or cool in the summer- gotta get a handle on this before mom comes.
Thanks
rusty
thanks - i want to rid the interior of the rat run- roach hide gap- it doesnt have to be sheetrocked, if i dont insulate the interior, i will plaster it and pray for no mildue
Thanks
rusty
you can do as much or as little as you want... depends how much you'll use it (the house) really....
outside....has the block ever been painted? if not i'd go with real stuco on the outside... maybe add some detail with foam and use the nylon mesh and portland stuco over that...
inside... think i'd do the 1.5" of foam board with the foil vb... glued to the block wall... and drywall glued to the foam, seal everything up tight... and you'll still be better than anyone within 100 miles of you...
pony
thanks- plan to - have been using it 90%, but its still got a long way to go- the outsides been painted, could blast it, but its 3 stories :( , rather do 1" solid core insulation, paper and metal lath, then stucco. Dont wanna give termites, roaches n rats a good day
Thanks
Rusty
Rusty
I live in a cinder block house, year around, in these mountains of Virginia. The outside of the house is only panted. The east wall in the living room is bare because i put in a sliding glass door this last summer and haven't gotten around to replacing the sheet rock yet. During the summer that wall gets quit warm on the inside from what sun does shine on it. During this past winter i laid a hand on that wall on the outside and noticed that it was a bit warmer then the other walls that have sheet rock up, even though there is no insulation behind the sheet rock.
A couple of friends of mine, one of them is a master brick layer, told me that the best thing is to cover the outside of the house with insulation and some kind of siding or stocco. This keeps the sun from heating up the block and there for warming the inside of the house during the summer. They also said to take off the sheet rock and leave the inside part of the walls bare (if you can stand it, if not then pant them). During the summer, because the sun cann't heat up the block, the walls will stay cooler and there for so will the house. During the early part of winter the block will obsorb heat from your heating sorce, but then will return that heat later on reducing your heating bill.
Something that the brick layer told me is that if morter was laid across the block from one side to the other and the outside of the block is not protected from the weather mosture will seep thru to the other side. This is also true with brick veneer on a stick built houses.
I hope that i may have been some help to you
Dane
Thanks Dane- that is exactly what i was thinking- here in Georgia, its more about keeping the heat out- i will put foam core insulation up, then metal lath,and stucco. I intend as time and money allow to plaster the interior block for a Spanish look-
Would you ask your friend if he knows how to mottle or blotch stucco's finish coat, so it looks aged?
I thought about just tossing some on, while its wet, but am sure the pros have a better method
thanks again