R-Value Of Cinder Block

mdshunk

I'm doing a heat loss calculation, and I'm at a stopping point. I need the R-value of an 8" cinder block (yes, old actual cinder type block) filled with vermiculite.

manhattan42

Commerical or Residential structure?

The R value of vermiculite will be determined by the manufacturer and type but will be from about R-2 to R-2.5 per inch. For a hollow core block you'll be lucky to get about 4" thick of insulation for an R factor of between about R-8 and R-10...Just barely enough to meet energy code minimum if at all.

Otherwise, you can assume zero insulation (since the existing R value isn't going to be much help anyhow) and design to the minimum required insulation of the thermal envelope wall. You also have to know whether this wall be considered an above grade wall or below grade wall because the required R values are different...and the energy compliance path you have chosen....

Once you establish the minimum insulation required by code, you can then design for energy gain/loss.

Jeff (socal)

I have a stupid question, just out of curiousity, by code are you required to calculate heatloss especially with CMU walls??

mdshunk

You are never required to calculate heat loss on existing construction, unless you're doing a major rehab. In my case, I simply need to in order to calculate the size for new central heating equipment. I have a fantastic manual J calculator, but it does not include the r-value for an 8" cinder block filled with vermiculite in the drop down menu for that purpose. Manhattan42's post confirms what I believe I've found on the net. An 8" block by itself has an r-value of about .2 and the vermiculite varies by manufacturer, with r-2 per inch being a conservative number. I intend to use R-8 for my heat loss calculation, as I suspect that will be close enough for my purpose.

K2

I found http://www.sizes.com/units/rvalue.htm for block walls which I'm sure you found also giving Block a 1.7 or a 1.1 depending on configuration. I would not consider much added for fill because there is already a dead/ non moving air space in the cells, which should be the best insulator, and the dead air was included in the original R value.

But besides that i lived in a block house with fill and can say "no ____way did it have an r-8" That sob was cold. brrrrrrrr!

Tscarborough

Cinder block have been out of production for about 50 years. Are you talking about a lightweight (<105 #pcf) or normal weight (>125 #pcf) CMU?

Lightweight is 2.8-3.03 alone, and normal weight is 2.01-2.06.

Using perlite (the form of vermiculite that is used to insulate CMU), you get:

LWT w/perlite: 9.07ish
HWT w/perlite: 4.40ish

Those numbers are useless in determining the efficiency of CMU, though. They make no allowance for thermal mass, though this is being studied for a new specification soon.

mdshunk

It is a bonafide cinder block building, from the ~30's, as evidenced by the rust streaks from all the iron cinders in the block. There's no way to tell the weight or density of such a block in an existing building, at least by me.

Tscarborough

Consider it to be a normal weight block, if it was made in the thirties, cinders or not. The factor that affects R value is heat transference, and the cinder block, while light, was also dense, edit-because it was wet poured.

manhattan42

MD Shunk said:

Oh yes you do.

Pennsylvania energy code requires if the space is going from unconditioned to conditioned, or if there is a change of occupancy that will result in the increase of fossil fuels or electrical energy consumption, then the structure must comply with the insulation and heat loss requirements of the Code.

For mass walls, like concrete block walls, this means they must provide an insulating factor of at least R-10 to R-13 if the walls are below grade and from R-13 to R-19 if the wall is considered an above grade wall.

And when mass walls have less than 50% of their exterior covered by insulation or less than 50% integral insulation, they need to be designed as above grade walls.

So be careful or you might find yourself failing your energy inspection....

mdshunk

Thanks for the head's up, but there is no energy inspection in this case, as central heating replacement is not required to be permitted.

What caused you to think that the building envelope consisted only of this 8" filled block anyhow? It is only a component of the exterior wall assembly that I do not know the R-value of. Simma down.

72chevy4x4

can someone explain the difference in a cinder block and other type of block? I live in a 1927ish block house-I've always called it 'ornamental concrete block'-the face is three dimensional like a stone face-is this cinderblock?

mdshunk

I dunnno what you call that stuff, but someone will. If it was modern, we'd likely call that "split face" or "slump block", depending.

Cinder block was made with actual coal cinders from power plants and the railroads in the block mix.

manhattan42

MDSHUNK said:

Uhhh. got that completely wrong for Pennsylvania, MD.

Replacing a central heating system DOES require a permit under Pennsylvania State Uniform Construction Code and DOES require inspection and energy compliance.

If it is for a commercial building it is required by state law to have an architect or engineer design the plans and energy conformance....

For residential work, the replacement of a central heating system most defintiely requires a permit and mechanical, electrical and energy inspections under State UCC Code since none of the these things are considered "non ordinary repairs"...

Check sections 403.61 through 403.62 of the "Permit and Inspection Process for Residential Buildings" on the PA DEpartment of Labor and Industry Website.

What you propose is illegal without permit in Pennsylvania and wherever the ICC Codes are enforced....

So no need to 'simmer down' here....

You need to 'get with the program'....

mdshunk

Manhattan.... this is a §403.1(b)(6) installation, thus exempted.



Consequently, why do you normally pick a different user name for each site your join? It's not hard to figure out that a users with the same IP are the same guy. We've ran into each other before, and you havn't been very helpful each time. There's a way to present your information without being confrontational. I understand that there are socially backwards people, so I recommend the book, "How to Win Friends and Influence People". You must understand that the confrontational way in which you come across will cause many folks, such as myself, to simply turn you off. If your posts were composed in a more palletable manner, they would be much more effective and educational. Put your ego in your pocket and teach us without being so hyper. I am generally excited when I run into guys of your caliber on forum sites, but I find I find your confrontational writing style (not the factual content) hard to stomach.

joasis

Yeah md, get with the program!

__________________

mdshunk

I need to know the r-value of an 8" filled block.

manhattan42

We already know you are a 'hack' by your disdain for Pennsylvania Uniform Construction Code, MDShunk and know you are trying to get away with something that is other than Code minimum.

That's why I called you on it.

Sorry.

But if the shoe fits, then wear it....

And pity you victim...err ahh "customer" yeah that's the ticket...customer....lol

mdshunk

Anyone know the r-value of an 8" cinderblock filled with vermiculite?

mighty anvil

I always thought these 2 were the same guy. Bummer!

mdshunk

No, but we're close. He's just down the road a piece.