insulation question

[husky455rancher]

ok i have a small house by most standards. its a bit over 1200sqft. living space is on one floor. have a full basement and a full attic where i can walk around easily and have a full floor up ther also. now my basement walls arent studded or anything so it has no insulation on the walls. i did however put insulation on the ceiling in the basement or the floor of the living space. the attic roof has no isulation of any kind as of yet. the floor in the atic has that blown in crap. the house has aluminum siding and the widows are double hung double pane their about 5 yo.


thats the overview of my setup well i need to oput in a ridge vent in the roof to go with the soffet vents i did in the winter cuse the attic gets a bit moldy in the winter. now my question is their a value to insulation the attic roof?
im just not really sure if it would be as its freezing in there anyway the attic floor is insulated and the cellar ceiling is. would this increase the mold i come across in the winter?

on the mold issue a couple winters ago i went in the attic to see it everywhere much to my suprise. so we had a guy come and check it out. it turns out it wasnt harmful to us and he said it was because there wasnt enough ventillation. so i started cuttin soffet vents like mad. i think i cut 50 or more 3" holes and put vents over them. that made a big difference. once it gets a bit cooler im gonna do the ridge vent and that should totally take care of teh problem.

 

[huskystihl]

If you have blown in insulation as long as it's deep enough insulating the roof is overkill. Ridge cap is great on a re-roof but you would be better served just cutting in some good old fashioned roof vents, especially if you vented your soffits. As far as insulating the basement where is your furnace? if it's in the basement you don't need to insulate the ceiling but make sure the exposed part where your studs meet the foundation are insulated. Hope that helps.

 

[husky455rancher]

is there an advantage to the regular vents over a ridge vent? thanks for the response

 

[huskystihl]

is there an advantage to the regular vents over a ridge vent? thanks for the response

Ridge vent will grab a draft from both sides verus the roof vents but if you vented your overhangs you'll get plety of airflow.

 

[huskystihl]

is there an advantage to the regular vents over a ridge vent? thanks for the response

Also price! Ridge cap is quite expensive when a roof vents run around fifteen a piece. Just factor in about one vent for every 500 sq ft if your roof will support it or in your case 3 would be plenty and you could knock it out in about 2 hrs.

 

[ms310]

Builder since 89

Here are a few things to consider. First off the cans in the roof will work, however the ridge vent will give the whole roof room to breath. Don't use the cheap plastic crap you will have issues in the hot weather with it wanting to buckle up, use a rolled vent such as cobra. When you install it you will need to cut back the plywood or osb at the peak about 1/2'' on both sides, no more! This will allow the ridge vent to breath without letting blowing snow or rain in. Do Not insulate the roof! There is no need to do that, and if done incorrectly you will have a worse situation then you did before the soffit vents were put in. As far as the blown in crap on the ceiling of your 1st floor in Michigan we use at least 12'' this will help your home stay cooler in the summer warmer in the winter. Put more in if you don't have that, it is called cellulose, and you can usually rent the machine to blow it in at a local lumber yard such as hwi. Now in the basement when you put the insulation in the floor did you put a vapor barrier on it? This causes some issues either way. First if you are not running a dehumidifier (at least here in Michigan) the insulation will trap moisture between it and the floor causing the floor to rot out over time. If you put a vapor barrier on it now you per code need to cover it with a fireproof barrier! I build 90% of my homes on wood basements, they do not get the vapor, dampness, mold that you do with the masonry ones, and are allot easier to finish! One big thing that you should do if not done is put some r-19 in the bond plate. Make sure it has a vapor barrier on it; around here the building inspectors don't care whether that is facing in or out. While you are at it, take a look at your bond and see if it is sealed good, stick built homes hardly ever are sealed there. If it isn't take some expandable foam from the inside and run a bead long the bond and the sill plate. I hope this helps.

 

[mga]

ok i have a small house by most standards. its a bit over 1200sqft. living space is on one floor. have a full basement and a full attic where i can walk around easily and have a full floor up ther also. now my basement walls arent studded or anything so it has no insulation on the walls. i did however put insulation on the ceiling in the basement or the floor of the living space. the attic roof has no isulation of any kind as of yet. the floor in the atic has that blown in crap. the house has aluminum siding and the widows are double hung double pane their about 5 yo.


thats the overview of my setup well i need to oput in a ridge vent in the roof to go with the soffet vents i did in the winter cuse the attic gets a bit moldy in the winter. now my question is their a value to insulation the attic roof?
im just not really sure if it would be as its freezing in there anyway the attic floor is insulated and the cellar ceiling is. would this increase the mold i come across in the winter?

on the mold issue a couple winters ago i went in the attic to see it everywhere much to my suprise. so we had a guy come and check it out. it turns out it wasnt harmful to us and he said it was because there wasnt enough ventillation. so i started cuttin soffet vents like mad. i think i cut 50 or more 3" holes and put vents over them. that made a big difference. once it gets a bit cooler im gonna do the ridge vent and that should totally take care of teh problem.

first of all, never put insulation against your roof. you're asking for major rot problems if you do that. you need at least 1" air clearance if you insulate your roof rafters. not a good idea unless you are making a living space in your attic.


use a ridge vent ONLY if you have soffit vents and no other vents near the roof. for example, if you have side wall vents in your attic, the ridge vents will be a waste of money and time. i suggest you block them off if installing a ridge vent. also, when installing a ridge vent, always end your opening about 2 feet from the ends. make sure your soffit vents are clear of any insulatuion or debris. as the hot air rises up thru the ridge vent, it draws coller air from the soffit vents.

however, your attic should be ventilated as much as possible. the other thing i would do is remove as much of the "floor" you have up there and just leave enough in the center for maintenance access to walk on. then, add an additional 12 to 16" of insulation. since you already have blown in stuff, you don't need a vapor barrier and can use unfaced fiberglass. or, use the blown in stuff. removing the "floor" will allow you to add insulation.

if you insulate your basement block walls, it's recommended now that you use foam panels, tightly locked together, from floor to the top of the blocks. then, you should glue another peice on the top of the blocks to fit tightly against the wall plate and the new wall foam. the reason for this is to prevent any air from reaching the cold blocks on the walls. this greatly reduces the humidity and 1" thick foam will insulate your basement walls like it's a new room. you can glue the panels to the blocks.

 

[husky455rancher]

310 and mga great stuff thank you for ther info rep for sure on those. i do have a very small vent on the very top on each side wall on the house. its almost non existant i dont think it really does anything but i can easily block it off if i need to.

my sisters boyfriend is a carpenter and he says the ridge vents are easy and hes described to to me exactly how you guys are.

my soffets are totally clear as i drilled them myself 2 winters ago. eventually i may rip up the floor but its all single pieces of board and nailed everywhere. i took some of it up to put in a exhaust fan in the bathroom and it was a pita let me tell you. i wish it was sheets of plywood that would be great! the blown in is pretty thick i forget how much exactly. ill have to go check as theres a spot i have to put the floor back together from a ceiling fan install i did with my dad.

i do run a dehumidifier in the cellar, the cellar never ever gets "wet" but the dehumidifier is a good thing to run in teh cellar ive been taught. theres a few spots that arent insulated yet on the cellar ceiling but most of it is r-19 i think i did the whole parimeter with it. oh and before i did that i sealed off any cracks i say with either caulking of that canned foam stuff. my foundation is cement and large pieces of stone its holding up very well. house was built in 1940.

 

[husky455rancher]

ms you said you were a builder

one thing i must to this summer is cement the small dirt flor in the cellar. well let me explain it i have sunroom its built off teh living room and i close it off in the winter as its not insulated and its prolly 60% all glass. underneith that room a small room with a dirt flooor. i put a tarp on the flor and i built a door to seal it off from the rest of the cellar as it gets so cold in there in the winter its crazy. i use it for odd storage, but id really like to put a cement floor in there and use it as a wood room i could store enough wood in there and in my cellar to last damn near all winter i think. if i was to guess the rooms prolly 10x12. my dad has a cement mixer does the type of cement i use matter? im not looking for anythign crazy just a floor thats better than dirt. any ideas oh whats the best way to go about doing this that wont cost me a ton?

 

[Wet1]

I don't know about the cement, but I don't think I'd want that firewood in the house...

 

[husky455rancher]

why? last winter i had prolly a cord and a half in the cellar.

 

[Geez]

You've been given good advice by some of the other guys here so I'll try not to be repetitious. As far as the ventilation, the formula is about 1 sq. inch ov ventilation per sq. foot of attic floor area, divided equally between the exhaust (upper) and intake (lower) vents. Such as, if your attic is 1000 sq ft., you need 500 sq inches of eave ventilation and 500 sq. inches of ridge vent or roof vent. Another option is a turbine vent. Because it is a mechanical vent, it breaks all these rules and has it's own rate. I believe a 14" turbine will handle about 900 sq, feet of attic. If your attic is, say 1200 sq.feet, you will have to install two of them, and so on. If they still make them, get a Lomanco brand aluminum turbine. They are guaranteed for life and don't freeze up like the crappy galvanized steel ones do.
As far as ridge vs. roof cans, the cans give uneven moisture removal on the underside of the roof deck. The only really efficient system is full ridge vent with full soffit ventilation.
During the energy crunch of the seventies, when everyone was going nuts with super insulation, solar, etc, they did some smoke tests in attics. That is, they filled attics with smoke and so were able to visually see how well different ventilation systems worked.
Some interesting results...
With only soffit vents, the air entered one side, flowed across the attic floor and out the other side with virtually no air circulation up above, leaving damaging moisture on the underside of the roof.
With only gable vents at either end of the attic, the air did not travel in one vent and out the other as expected. Instead, each vent acted as both intake and exhaust. The air entered half of each vent, went in about 3 feet, swirled around in a bulb shape and exited the same vent. Totally useless, except when used with a turbine vent. But then it went straight down the ridge and out the turbine and never ventilated the lower part near the insulation.
With full soffit vent and roof cans, each roof can covered a triangular area, with the upper point being the roof can and spreading out toward the soffit. This sawtooth shaped pattern left many voids near the ridge.
With full soffit and ridge vent, the air flow ventilated the entire attic floor and roof deck.
Hope this gives you a better idea about how attic ventilation works.

 

[husky455rancher]

very good post geez i understand it perfectly now nice explanation

 

[fastmopar1k]

I have the blown in stuff in my attic. Over time it has setteled to about half of what it was. On top of that they installed a "floor" in the attic. Would I have to remove the "floor" to add insulation or can i just get like the attic blanket stuff and roll it out? Also if I can roll out fresh stuff, do I need a vapor barrier? Thanks for the help. I was gonna start this thread myself.

 

[logbutcher]

What a place here !! Solid advice....and free.opcorn:
Just adding one big thing: in our cold temperate climate ( AlGore where are you ? ) you think about making your ROOF COLD. You don't want any heat getting from the house up to the roof. That's the primary function of vents in the winter; then exiting moisture in a humid summer. That's what these guys are telling you.
We have two types of cold roofs: 1. "Cathedral" ceiling with soffit and roof ridge vents, and , 2. a partial attic well insulated from the living space also with soffit and roof vents. Look over your neighborhood roofs under snow cover. In theory :censored: , the well done roofs will have NO melted areas. Insulation is cheap. Don't forget air infiltration: caulk and foam the s%#@& out of all spaces.

 

[Jkebxjunke]

one more thing.... make sure the insulation doe not cover up you eve vents if you are going to add any insulation make sure you dint cover them up... might want to get those Styrofoam thingys that they sell at the home centers that tack up to the sheathing that create an airway from the eve to above the insulation.