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KrK
Heavy Artillery For The Little Guy
Premium
join:2000-01-17
Tulsa, OK
reply to ropeguru

Re: Insulating Behind Studs

Nice, that stuff is impressive.

Fireproof, water repellent, Energy efficient, and sound proofing.

Nice.


MaynardKrebs
Premium
join:2009-06-17
kudos:4

2 edits

1 recommendation

reply to QuaffAPint

Some observations.

OP is in PA. In that climate zone he needs a vapour barrier - a meaning just one and only one.

So, how does he get just one vapour barrier?
Either install a 6 mil poly barrier, sealed & taped, right under the drywall - or by utilizing 2lb. polyurethane spray foam.

But like most jobs , we want to get the most bang for the buck given the tradeoffs we have to make.
Since the wall is below grade and we have no real idea how well water proofed the exterior of the basement wall is, we have to assume that it isn't and that some moisture will permeate through the foundation.

So how do we best handle that, and insulate the wall so there is only one vapour barrier, and keep costs down?
Apply 2lb. polyurethane spray foam to the concrete in thin layers until it reaches the backside of the studs. This will resist the infiltration of water vapour through the concrete into the wall cavity. Then fill the stud cavity with batt insulation - your choice of fiberglass or mineral wool (Roxul). I'd choose Roxul for its fire suppressing and sound control properties vs. fiberglass.

Then apply the drywall directly over the studs WITHOUT a poly vapour barrier. Why? Because the wall has to dry to one side if, as, and when moisture gets trapped. Even painted drywall is still permeable to moisture, so if you have a polyurethane foam vapour barrier on the concrete then you MUST leave the opposite side of the wall cavity able to "breathe" in order to dry the wall assembly out when moisture gets in, hence only painted drywall is needed.

The sole plate will also absorb small amounts of moisture from the concrete floor if there is no foam gasket under the sole plate.

If you have one vapour barrier on each side of the wall assembly (ie. foam & poly) then you set the stage for mold growth inside the wall cavity.

Also use spray foam to insulate the band joist area between the joists above the foundation wall, minimum 2" thick, then add at least 4"-6" of Roxul on top of that (so the combination yields R24 or more). The band joist area is always a source of air leaks and heat loss which the foam & batts will solve.



Jack_in_VA
Premium
join:2007-11-26
North, VA
kudos:1

»Re: Insulating Behind Studs


MaynardKrebs
Premium
join:2009-06-17
kudos:4

Not all foam is created equal as far as vapour permenace is concerned.
EPS - expanded foam (the white grainy stuff) - is vapour permeable.
Extruded foam (like the blue Dow Styrofoam SM) is not vapour permeable.
Spray polyurethane foam is not vapour permeable if applied thick enough (ie. 1"-2" of 2lb. foam) or thinner if higher density foam. The "pound" rating is the weight of 1 cubic foot of properly expanded and cured spray foam.


alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1
reply to QuaffAPint

Guys, MaynardKrebs' recommendations on this matter (Insulation and all related matters) is as rock solid as Nunya's and Whizkid's with electrical issues.

He's basically been walking me through every details regarding my basement renovation project.



pike
Premium,MVM
join:2001-02-01
Washington, DC
kudos:3
reply to Badonkadonk

said by Badonkadonk:

Best suggestion. The air also feels better on the skin in the basement when it's spray foamed.

Can you elaborate? This statement makes absolutely no sense to me.


alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1

said by pike:

Can you elaborate? This statement makes absolutely no sense to me.

Of course it makes sense!
The basement air feels better to spray foamed skin.
It makes a killer winter suit as well.

Badonkadonk
Premium
join:2000-12-17
Naperville, IL
kudos:5
Reviews:
·Dish Network
reply to pike

When I'm in a typical basement where spray foam hasn't been used, there's an odd coolness that I feel. Even when the basement is heated, I still get a "basement feel". It's like the concrete is sucking moisture out of me or something and I can always smell that basement smell. It's hard to describe, but I hate basements and the feel I get.

Because of the above, I never wanted to finish the one in our own home. But about five years ago I let my wife talk me into getting our basement done. We talked to four different companies and actually walked around in people's basements to see the quality of work and to get an idea of design etc. Of those four company's basements, only a single one did spray-foam insulation. And I have to say, even my wife who thinks I'm weird about basements, agreed that the spray foam insulated basements felt different--like they weren't a basement. For a couple of years afterwards even my kids used to comment about basement smells in other people's houses and how they didn't like going into the basement of others.

Our basement is great and I have no problems going down there. It feels different than most and has no smell. We not only spray foam insulated the living space area but the entire basement including crawl space as well. That may have made a difference as well.

At any rate, it makes sense to us since we live there and can actually feel the difference when we compare our basement to others.
--
Biden--the bastard child of Otis the Drunk and a laughing hyena. No wonder the US is hurting. Vote Romney/Ryan 2012 and restore sanity.



alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1

said by Badonkadonk:

At any rate, it makes sense to us since we live there and can actually feel the difference when we compare our basement to others.

You sure you didn't just visit basements that had POOR insulation and compared them to spray foamed insulated basements?

On a very productive day, I went from no insulation in my wall frames to full coverage of roxul batts (R22) and half my joist cavities sealed with R22 roxul + 2" XPS.

I could VERY much feel the difference. The humidity rose (I had a meter), the air was more "warm". The shock was more obvious after I went back to the basement after taking an hour break. Since my body temperature dropped from relaxing, I expected to walk back in there feeling a bit chilled (As it was always before). It was actually comfy.

As for the smell, well, I blame poor vapor barriers, carpets, and age of the renovation (You probably visited freshly renovated basements insulated with spray foam).

Badonkadonk
Premium
join:2000-12-17
Naperville, IL
kudos:5
Reviews:
·Dish Network

The initial visits were all upper end basement remodels done by well known building companies. One of the companies was the one who did a large remodel for us and who we really liked. But their basements again just didn't feel right to us. And the only difference we could come up with was the kind of insulation being used. The basements of homes that we go to nowadays, who knows. I wouldn't doubt that some are done by hacks.

But after our visits, we decided that spray foam was the way to go. So in the new non-basement remodeling that we're going to be doing soon, it's all going to be spray foam where insulation is needed. We're believers.
--
Biden--the bastard child of Otis the Drunk and a laughing hyena. No wonder the US is hurting. Vote Romney/Ryan 2012 and restore sanity.



alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1

said by Badonkadonk:

it's all going to be spray foam where insulation is needed. We're believers.

If I had the budget, I'd have went spray foam as well.
I can't say spray foam is inferior aside from a price perspective.

I already need to use a lot of it to fill certain nook and crannies.

Badonkadonk
Premium
join:2000-12-17
Naperville, IL
kudos:5
Reviews:
·Dish Network

Yeah, the price is high for sure.

I think at the end of the day spray foam isn't necessary and other methods, when done well, take you probably 90%+ of the way there.
--
Biden--the bastard child of Otis the Drunk and a laughing hyena. No wonder the US is hurting. Vote Romney/Ryan 2012 and restore sanity.


c4junk
Premium
join:2004-05-08
Orlando, FL
reply to QuaffAPint

Check around you may find that having a pro spray foam your walls may not be that far over do it yourself, my son-in-law had the attic of an addition done- he said it cost him about $400 more than fiberglass but was done in 2 hrs. It would have taken more than a day to staple up batts and then you have to deal with fiberglass every time you go into attic, he has also said he's really glad he did it.
He had 8in sprayed to plywood and rafters not attic side of drywall.



alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1

said by c4junk:

he said it cost him about $400 more than fiberglass but was done in 2 hrs.

400$ more is irrelevant if you don't compare it to what it is more from.

If it's 400$ more than 400$, that 100% more.
If it's 400$ more than 2000$, that's only 20%.


mattmag
Premium,ExMod 2000-03
join:2000-04-09
NW Illinois
kudos:3

said by alkizmo:

400$ more is irrelevant if you don't compare it to what it is more from.

If it's 400$ more than 400$, that 100% more.
If it's 400$ more than 2000$, that's only 20%.

I don't live by percentages, real numbers make much more sense. $400 more is $400 more, no matter how you slice it. Percentages are inherently inaccurate with smaller figures, and don't mean a thing.

It's like someone saying "our burglary rate has increased 100%!!!" when it went from one a year to two a year. Meaningless....


alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1

said by mattmag:

I don't live by percentages, real numbers make much more sense. $400 more is $400 more, no matter how you slice it. Percentages are inherently inaccurate with smaller figures, and don't mean a thing.

A cost increase in dollars doesn't make sense when comparing two differently sized project.

If someone tells me I gotta pay 400$ more for sprayfoam compared to 400$ in fiberglass, I'd react very differently than if I had to pay 400$ over 3000$ of fiberglass.


mattmag
Premium,ExMod 2000-03
join:2000-04-09
NW Illinois
kudos:3


This is the problem with percentages though (and we're probably drifting this thread,) however, we pay with dollars, not percentages. You don't deposit percentages in the bank, you deposit dollars. I want to know how many more *dollars* it is costing. That's my point.

The size of the compared projects *both* need to be large in order for percentages to have merit. When one is small and the other large, it becomes skewed before you even start to compare.


Badonkadonk
Premium
join:2000-12-17
Naperville, IL
kudos:5
Reviews:
·Dish Network

On the other hand, percentages help in making a relative value judgement. Spray foam that costs $2K on a $60K basement project is of much more value to me than spending $1K on foam for a $4K shed. The actual dollar amounts in that case don't matter much to me, but the percentage in terms of overall cost do.
--
Binders and Big Bird, because there's nothing else to worry about. Drop the stooges and vote Romney/Ryan in 2012.


MaynardKrebs
Premium
join:2009-06-17
kudos:4

Percentages are for losers

In a down market your mutual fund may lose 20% vs. another fund that's down 30%. Are you a winnner?

No. You've still lost 20% of your equity


Badonkadonk
Premium
join:2000-12-17
Naperville, IL
kudos:5

1 recommendation

That has to be one of the worst analogies I've ever heard.



KrK
Heavy Artillery For The Little Guy
Premium
join:2000-01-17
Tulsa, OK

lol


H_T_R_N
Premium
join:2011-12-06
Valencia, PA
kudos:1
Reviews:
·voip.ms
reply to QuaffAPint

6" of 2 pound in walls and ceiling in my 900 sf office and 1.5" of foam-board over concrete under the finished floor. I pay less than $25 a month in the middle of winter in NW PA to heat it with a electrically heated fluid filed radiant floor system. There is nothing like spray foam. I will never do another job without it.



Draiman
Let me see those devil horns in the sky

join:2012-06-01
Kill Devil Hills, NC
Reviews:
·Verizon FiOS

said by H_T_R_N:

6" of 2 pound in walls and ceiling in my 900 sf office and 1.5" of foam-board over concrete under the finished floor. I pay less than $25 a month in the middle of winter in NW PA to heat it with a electrically heated fluid filed radiant floor system. There is nothing like spray foam. I will never do another job without it.

Compared to what? How much was it before?
--
IF YOU FIND ANY MISTAKES IN MY WORK...Please consider that they are there for a purpose. I try to please everyone and there is always someone looking for mistakes!

H_T_R_N
Premium
join:2011-12-06
Valencia, PA
kudos:1
Reviews:
·voip.ms

said by Draiman:

said by H_T_R_N:

6" of 2 pound in walls and ceiling in my 900 sf office and 1.5" of foam-board over concrete under the finished floor. I pay less than $25 a month in the middle of winter in NW PA to heat it with a electrically heated fluid filed radiant floor system. There is nothing like spray foam. I will never do another job without it.

Compared to what? How much was it before?

It matters to you why? If the OP is interested he can ask.


ropeguru
Premium
join:2001-01-25
Mechanicsville, VA

1 recommendation

said by H_T_R_N:

It matters to you why? If the OP is interested he can ask.

Because MAYBE some of us like to gain knowledge in case we might want to do something similar in the future?

Just cannot understand the crappy attitude towards such a simple question.


alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1

1 recommendation

said by ropeguru:

Just cannot understand the crappy attitude towards such a simple question.

Neither do I.
He gives us a very incomplete feedback on his experience with spray foam.

Just like Amazon reviews of people complaining/praising about the shipping time, his feedback is useless.

H_T_R_N:

What did his heating cost before the spray foam?
What was the insulation before the spray foam?
What does it cost to heat the rest of the house?

Am I being out of line asking these questions?
If so, why am I being out of line?
Were you being out of line by sharing your experience?
If not, why were you not being out of line by sharing your experience?

H_T_R_N
Premium
join:2011-12-06
Valencia, PA
kudos:1
Reviews:
·voip.ms
reply to ropeguru

said by ropeguru:

said by H_T_R_N:

It matters to you why? If the OP is interested he can ask.

Because MAYBE some of us like to gain knowledge in case we might want to do something similar in the future?

Just cannot understand the crappy attitude towards such a simple question.

Mind boggling, isn't it?


Draiman
Let me see those devil horns in the sky

join:2012-06-01
Kill Devil Hills, NC
Reviews:
·Verizon FiOS

said by H_T_R_N:

said by ropeguru:

said by H_T_R_N:

It matters to you why? If the OP is interested he can ask.

Because MAYBE some of us like to gain knowledge in case we might want to do something similar in the future?

Just cannot understand the crappy attitude towards such a simple question.

Mind boggling, isn't it?

Not really just completely discrediting to your original statement. Don't make claims you can't or won't back up next time. If people even give you the benefit of the doubt to have a 'next time'.
--
IF YOU FIND ANY MISTAKES IN MY WORK...Please consider that they are there for a purpose. I try to please everyone and there is always someone looking for mistakes!

H_T_R_N
Premium
join:2011-12-06
Valencia, PA
kudos:1
Reviews:
·voip.ms

1 recommendation

said by Draiman:

Not really just completely discrediting to your original statement. Don't make claims you can't or won't back up next time. If people even give you the benefit of the doubt to have a 'next time'.

Exactly why I didn't bother taking the time to answer the question.
You were not interested in the answer.

Not sure why you feel its OK to crap in someone thread, when you were so adamant about people not doing it in yours.

edit: I guess I should have added the sarcasm tag in my response to ropeguru, but I really didn't think it was necessary.


ropeguru
Premium
join:2001-01-25
Mechanicsville, VA

said by H_T_R_N:

edit: I guess I should have added the sarcasm tag in my response to ropeguru, but I really didn't think it was necessary.

Actually yes, given the past response we were discussing.