marble tops on rads

steamychick

I have a question on putting a piece of marble on top of my radiators. In books I've seen things about proper radiator enclosures, but the marble radiates heat well, as opposed to wood. I've also saw where thay actually used to manufacture metal rad tops to accept a piece of marble, but I'm not entirely sure if it was meant to sit directly on top or with a gap. So, my question is, would it hinder anything to sit a piece of marble right on top?

Charlie from wmass

It will slow convection

of heat. That said if the radiators are over sized it would not be that bad of a thing. I would have a gap and make sure it is anchored. I think a marble shelf on the wall just above the radiator would be nice for proofing dough or drying mittens.

steamychick

shelf

Thanks! I don't want to slow down the convection, so a shelf sounds good. I bought an old ogee edge piece of marble at an antique shop I was rooting around in for really cheap and it's the perfect size for top of rad. Sounds like heavy-duty brackets and care with the horsehair plaster are in order. Don't know how much dough proofing will be going on, but fancy mitten dryer sounds good.

Maine Vent

Marble Tops

I have 2 rads that have marble tops. I get great heat off these 2. The tops get hot and stay hot giving off nice heat. My cats love them, and it also make a great food warmer.

steamychick

rads

I think your rads are exactly the ones that I saw in the old original catalog picture! They sure are beautiful. (love your cats also, but don't they block convection?) lol

Sil

TULIKIVI Finnish soapstone

Ya know, I once ate in a restuarant in Columbus Ohio when I was there on a business trip.  Their signature dish was called "The Rock" Filet.  They basically heat up a TULIKIVI Finnish soapstone to 450 degrees and give u a totally raw filet mignon. TULIKIVI translates into "fire stone" in English.



The stone stays hot for long enough to cook your filet to your exact desires.  made for a great dining experience.



I went to check how much genuine TULIKIVI Finnish soapstone costs... http://www.finnishsoapstone.com/soapstoneslabs.html  Wow... expensive!



Maybe should get a slab for the radiators!  Cheaper than a Nest...

Sil

that rad....

is HOT!

Hap_Hazzard

Cats

Cats are excellent heat transport mechanisms. After soaking up heat for six or seven hours, they jump in your lap or crawl under the covers with you and gradually re-radiate the heat they've absorbed.

steamychick

cats vs. boiler

So what you're saying is, forget a new boiler and fill my house with cats. Possibly could be cheaper, and they tend to balance without my help

Hap_Hazzard

All things in moderation

I think we've all known of people who didn't know where to draw the line when it comes to cats.

steamychick

crazy...or brilliant?

Maybe, all this time, that "crazy cat lady" in the neighborhood was just being energy efficient with all those heat exchangers running around...

steamychick

cats on rads

found this in an earlier post on the main wall (knotgrumpy's thread). starting to see a pattern here. maybe title to thread should have been 'cats on marble tops on rads'.

Maine Vent

Hot Topic

I know it's been a long cold wintha here in southern ME. If I could climb on top of these marble tops to take a nap, I would. Instead, I put my jammies on our bedroom Rad, which warms them up nice. Turn on the electric mattress pad, to warm up the bed. Put my towel on the best towel warmer in New England and settle in for a long winter. Steam Heat Priceless. Got my Dec/Jan Gas bill, $159.00.

steamychick

jealous

too late to climb on, your cat obviously has no intention of sharing! I do the same with heating of jammies & towels. couldn't do that with forced hot air! no doubt about it, steam wins. I am extremely jealous of your dec./jan. gas bill, especially in ME! What's the avg. dec./jan. temps up there?

Maine Vent

Average temps

Dec 19 degrees

Jan 11 degrees



Last year same time period, just less days, i.e. billing cycle difference, 189 therms, this year 109 therms. Reason way under fired last year, this year right size orifice in burner to match load. Copious main venting, clean water, slow radiator venting ( cats like it slow) great advise from all the pros and really smart homeowners.



These books of Dan's are worth every penny.



Also Dan I picked up a copy The Ideal Fitter. really cool little book.



Thanks Dan

steamychick

wow! that's cold.

Tell me about it! Dan's books are the reason I've become mildly obsessed with steam systems. In short, he made it make sense. Still lots to learn, and this site seems a great place to do it! Just trying to navigate my way around and get a feel for who is who.

BTW, someone should tell Dan he could've charged twice as much

Hap_Hazzard

Great logo

I think a picture of a cat curled up sound asleep on a cushion in front of a radiator would make a great logo for a plumbing and heating company specializing in steam. Whenever I walk by and see one of my little friends parked next to a radiator I'm glad I put the time into keeping the heat on.

steamychick

logo

Good idea for a logo! Anyone with steam heat and a pet would be attracted. I feel bad for my cats right now, since I am trying to limp along with a cracked boiler. I keep finding them sitting by the cold rads looking at me expectantly. I keep depositing them to the warm ones, but apparently they have their favorites.

Dave in QCA

Here's another Marble Slab

Actually, I would say it's soapstone or slate.  It has been on top of the radiator since the house was completed in 1910.  This end of the living room was designed specifically for plants and this would have been a great place for them to set.  Note the tile floor.  The patch tiles are where piping came up for a fountain that also sat here.



I know that technically the slab reduced the amount of convection.  But, when I stand in front of the radiator, there is a LOT of convection going on.  More than anything, the slab seems to deflect the current into the room a bit instead for having the warm draft running straight up the front of the window.



Second and third shot are just to show the surrounding area.

steamychick

no pic

Hi Dave, for some reason I can't see any pctures on your post. I did take a look at the Best Mansion website, and am seriously considering packing my bags and moving to Iowa now! That mansion is just incredible!! A few years ago I went to Newport,RI to check out some of the mansions there. The woodwork was some of the best I've ever seen. I am definatley a large old house junkie, I just love to seem them and learn their histories. Now I can add the Best Mansion to my list!

steamychick

nevermind...

Now I can see the pics. My computer was just ,well, being a computer. Do you mind if I ask you some questions about your house?

Dave in QCA

Ask Away

Probably best to take the conversation off the wall.  Click on my name and send me an email.

MTC

Heating reduction from shelves

I'm a fan of things like marble tops, etc. I would do it if it makes you happy, but just keep in mind that a shelf over a radiator reduces the convection around that radiator by roughly 20%. If the room is plenty warm, this will probably not effect you much. If the system struggles to keep that room warm, and you don't have any ability to adjust the output of it higher, then you might want to rethink adding a shelf to it.

vaporvac

Same idea at 2nd best mansion!

I have similar marble slabs in my downstairs solarium; it must have been "the thing". Orchids love them, too! I also have a tile floor (herringbone multi-coloured green/rust mosaic), that has fill-ins where a fountain went. I always wonder what it looked like and why anyone removed it.

BTW, welcome Steamychick. Glad to have another chick as a regular visitor on the Forum.

My cat is definitely missing her heated rad this winter, but she's making due with a heating pad.

steamychick

Thanks vaporvac!

I sincerely appreciate the welcome! I'm fairly new to all of this, so I spent a lot of time reading the threads before finally working up the nerve to post. Then I thought -"what the heck"! So far most everyone has been nice, informative, and (for a newbie) most critical of all, patient. I don't always have important things to ask/say, and I'm certainly in no position to be giving advice (yet! :-), but it sure has been fun "meeting" new people from all over. It kinda feels like one big steam family! Glad to know I'm not the only steam chick out there!



As far as all of those missing fountains goes, I'm guessing they were probably removed when there was a plumbing problem. Most people end up taking the cheaper and easier route. Ugh! Breaks my heart that they are gone! Not only were they beautiful, but I'm sure they provided great humidity for the plants. On another note, I'm in the flooring business and I LOVE old mosaic floors! Most mosaics now are mesh-mounted sheets which still take some skill to install beautifully, but they are nothing compared to the skill it takes to install piece-by-piece! And patience...lots of patience...

steamychick

marble tops

On this particular rad in question, I had it sandblasted to remove umpteen layers of paint and haven't gotten it powder coated yet. And let me tell you, it kicks out the heat! So, I guess for now, it doesn't hurt to have the marble top on it. I am thinking that I will wait until I get around to having it painted to determine if a shelf above would work. Do you (or anyone else) know if I'm hurting anything by using the rad without it being painted? I didn't really think about it until now. Had it blasted, winter rolled around, so hooked it back up for now.

Pumpguy

Typically,

when cast iron is sandblasted, it begins to rust almost immediately, just from the moisture in the air.  If this hasn't happened already, you should be OK until it gets warm outside and the humidity inside goes up.

steamychick

thanks

It does have 2 very small (less than the diameter of a pencil eraser) rust spots, but that's it. I actually very much like the gray-silver color of the raw cast iron. Would it be possible to just put some kind of clear coat on it instead of an actual color?

MTC

Color you pick

can have an effect on heat output as well. I believe that powder coating has a fairly minimal effect, unless you get some kind of metallic coating, but not sure. The reason so many rads are painted gold or silver is b/c that reduced the radiant output by about 20%, when people stopped sleeping with the windows open in winter and now had oversized systems to deal with. Anyway, just something else to keep in mind, and I'm sure that the powder coaters will do some minor surface prep to take care of any surface rust, etc before coating it, I just wouldn't wait long after the heating season is over to get it done.



FWIW, though this may not be the aesthetic you're looking for, if you pull that shelf up off the top of the radiator about the distance from the wall to the front of the radiator, there will be almost no change in convection around the radiator. The closer you get, the more you'll restrict it. If I were to hang a shelf over a radiator and wanted it closer, w/o losing as much heat, I'd try to leave about 2 inches behind the shelf before it hits the wall, allowing the air to circulate both in front and behind the radiator.

steamychick

little important bits

I've read about the color affecting the output. I know that metallic would lessen it, and I don't really want to do that if I can help it. That's why I was curious about just a clear coat, because if I get it painted to mimic the raw cast iron, it would probably have some sort of metallic in it so as not to look like a flat gray color.



Good point about leaving a gap between the shelf and the wall. Makes sense. Sometimes I overthink things and end up missing the little important bits. I will have to look for some wall brackets that are configured that way if I decide to go with the wall shelf idea. I know they are out there, just have to find them. Thanks also for the shelf height recommendation. Another one of those little important bits!

SWEI

two inches

Just the right size for a paw or a tail to drape over the back of the shelf.

steamychick

LOL

Congrats SWEI, on being the first one here to make me bark out a laugh hard enough to have to clean a fine spray of coffee off of my keyboard.

Dave in QCA

It Depends on the design of the Radiator

The effect that a slab of marble has on a radiator depends a lot on the design of the radiator.  In the home that I live in, we have quite a few of those short 17" tall x 5 column "window" radiators.  The castings come very close together, in fact so close that you can't get anything through from the front face to clean the dust bunnies out.  If we were to put a slab of marble on these, it would pretty much close off all of the interior flue passages and would greatly restrict the radiator.



However, the one that I showed from over at the Best mansion, it is a simple 3 column radiator and there is ample spacing between the castings.  When the radiator is hot, you can feel a huge draft, the same as what you'd expect to feel, above the front edge of the shelf slab. It seems that what normally would flow out of the top of the radiator is flowing out of the front top area of the radiator.  Given that this little 52 sq ft radiator heats the room just fine, and its 17' x 30', I would say that the effect of a top shelf on this particular radiator is negligable.  



Physically, I know that it would still have some effect.  If the radiator was fully steamed and stayed that way continuously, and you measured the total heat output with the slab and without the slab, there would be some difference.  However, in the real world, the radiators in this system usually only partially steam.  The boiler cycles once per hour.  By the time the boiler starts to run its next cycle, this radiator has cooled about the same as all of the rest of the radiators in the house.  So... I would conclude the effect of the shelf on this radiator, given the way it operates in this house, has no impact at all.   And so in answer to the question, how much difference does it make?  It all depends.

Hap_Hazzard

Clear Powdercoat

Clear powdercoat finishes are available. It's commonly used on aluminum wheels. Any shop that repairs wheels should be able to do it as long as the oven is big enough. It takes a bit longer for cast iron to get up to 500°, but they will probably know what they need to do.

MTC

It does depend on lots of things,

i agree.



And it should be noted that the statistic is that an enclosure similar to a shelf over the top of a radiator (with 3" gap, if i remember correctly) will reduce the CONVECTION output by about 20%, but not the radiation. Heat output from radiators is roughly 60% convection and 40% radiation, so the actual decrease of the shelf in overall heating capacity is closer to 10%. In fact, the marble would probably increase the radiation in non-firing conditions slightly. And since the "comfort index," if you can call it that, of radiant heat is much higher than convection, then you could assume that the comfort level of the room would likely not change to any substantial degree.



Overall, as long as your room isn't having trouble heating now, I doubt you'd have much trouble. If its kind of iffy, I'd forego the shelf or do some of the suggestions mentioned above as far as clearances etc to keep up airflow.



But you can always try it and find out... the proof is in the pudding, not the theory

bob_46

Tops and enclosures

Kind of the last word .

SWEI

no shelves above radiators here

but we have lived with cats for a long time.  They LOVE to drape...

Dave in QCA

Thanks Bob

I knew that enclosures and shelves caused a reduction in the thermal efficiency of a radiator, but I do find this report VERY interesting.  I am cutting and pasting the section of the conclusions that deal directly with the radiator and shield or enclosure.  Surprisingly, the overall economy is actually improved by a properly designed sheilf or enclosure because of its effect in lowering the temperature at the ceiling and raising the temperature at or below the breathing level.  That is to say, less steam condensed and less heat produced, but more heat and improved temperatures where they matter for the occupant's comfort.  I am surprised!  

Attaching a couple photos of an original heat shield at the Best Mansion.



XI. CONCLUSIONS35.

Conclusions.-As a result of the investigation the following conclusions may be drawn:

(1) A reduction in steam condensing capacity of an enclosed radiator represents a sensible gain in steam economy if the reduction is accompanied by equally or more satisfactory air temperature conditions within the room.

(2) A reduction in steam condensing capacity of an enclosed radiator represents a sensible loss in steam economy if the reduction is accompanied by less satisfactory air temperature conditions within the room.

(3) More satisfactory air temperature conditions in the room are represented in general by higher temperatures of the air near the floor, higher mean temperatures of the air in the living zone, or below the breathing level, and lower temperatures of the air near the ceiling.

(4) The use of a properly designed radiator enclosure, or shield, results in a gain in steam economy, and equally or more satisfactory air temperature conditions in the room as compared with those obtained by the use of an unenclosed radiator.

(5) The use of an improperly designed radiator enclosure, or shield, results in unsatisfactory air temperature conditions in the room unless an amount of radiation in excess of that required for an unenclosed radiator is installed.

(6) A properly designed enclosure or shield should offer a minimum of resistance to the flow of air over the radiator under gravity head, and should protect the wall back of the radiator against the effect of direct radiation from the radiator. It should have the topof the opening in the face of the enclosure as high as possible, and permit free access of air over the lower half of the radiator, especially near the floor.

jumper

generally

Generally radiation is over sized because better windows have been installed, gaps have been sealed, attics have been insulated, etcetra. So enclosures make sense for balance and control. It doesn't take that much ingenuity to put in adjustable shutters or dampers to control the convection. A high mass top also improves performance by continuing to radiate heat after radiator cools.



A high mass top over a finned coil convector would be an even better improvement. Those terminals heat up and cool off too soon.

bonniekay

Cast Iron Radiators and marble slab placed directly on top

I have had two radiators rupture in the last 48 hours spewing black oily water, steaming hot over the entire floors.   They ruptured right down the middle.

Would a marble slap sitting directly on the top of it, and yes we would sometimes sit on it as it was so nice and warm have contributed to this.

SWEI

In short, no

but you might want to start a new thread as you clearly have some issues with your system.