Countertop support options

Discussion in 'Remodel Forum & Blog' started by newowner, Feb 24, 2008.

  1. newowner

    newowner New Member

    Messages:
    32
    Location:
    Central Maryland
    We are remodeling our kitchen and creating a breakfast bar adjacent to a peninsula. The back side of the peninsula will butt up next to a 80" long, 4 1/2" wide, around 42" high knee wall. A 18 " wide 84" long silestone countertop will be put on the knee wall, with 2" of it overhanging the peninsula, 4 1/2" of it supported by the knee wall, and 11 1/2" hanging out as the breakfast bar. What are our support options for the 11 1/2" that hangs out? If we use brackets, how many and what size do we need? A box store kitchen designer said I could use Rubbermaid steel 8" shelf brackets sold in their shelving section as countertop supports, but I am a little wary of that. The Rubbermaid box says 2 of their brackets support a max of 80 lbs if installed 16" apart in studs.

    I am definitely concerned with having great support as I anticipate the counter being leaned on by adults and children, but I hope to have something that doesn't interfere with seating or look clunky. Our cabinets will be Thomasville and Thomasville sells a "snack bar support" that is like a corbel without scrolls that is 11 1/4" by 11 1/4" and 3" wide. From the small Black and White catalog photo it looks like it might get in the way since it will extend out to within 1/4" of the edge of the counter but hey, I am only guessing. We were planning on keeping the knee wall painted as opposed to covering with wood. Do you have any ideas on a support method that is strong but not that noticable or that at least doesn't get in the way?
    Last edited: Feb 24, 2008
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,153
    Location:
    New England
    On granite, they sometimes rout out grooves and insert steel bars for support. These need to go back into the counter behind the edge at least as far as they project. Then, they're epoxied in. If you can talk to the fabricator, see what they suggest and will warrantee. A corbel or two can do it, but it will be a kneebanger and restrict your available space.

    Another possibilty is have a steel flat support fabricated. There are shelf brackets that you can buy that will hold far more than that 80#; I've got some on my wall in the garage that are rated for close to 1/2T.

    What you don't want is to leave it unsupported, as it is highly likely some kid or adult will decide it is a good place to sit some day and snap it off.
  3. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    I agree with Jad....you definitely need to assume that Mighty Joe Young will someday sit on this thing, and construct accordingly. And if you remember Mighty Joe Young, you are too old to be tackling this project now anyway!!!!
  4. newowner

    newowner New Member

    Messages:
    32
    Location:
    Central Maryland
    Please explain how a steel flat support works and where can one be purchased?
  5. frenchie

    frenchie Jack of all trades

    You get flat steel from a local metalwork shop.

    Hold on - 11-1/2" hanging off of 4-1/2"? Flat steel won't work, there's not enough to attach it to. You need actual brackets. And you're right, those wimpy 8" rubbermaids won't do.

    I've used these:

    http://www.supportbrackets.com/metal-brackets.asp

    these:

    http://store.rakks.com/product_info.php?cPath=24&products_id=145

    and these:

    http://www.kitchensource.com/table-bases/ha-5-103.htm


    ...If you want it practically invisible, rakks also makes these:

    http://store.rakks.com/product_info.php?cPath=24&products_id=150


    How are you going to detail that knee wall so it'll support the side-force from the overhang?

    Might be a lot easier to give it legs.
  6. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,153
    Location:
    New England
    I was thinking something like flat plate steel - sort of like a huge piece of angle iron. It might be the least obtrusive, but would be heavy any require a good support structure inside of the cabinet, or just be a flat sheet that extended under the slab into the cabinet area a ways.

    Best thing is to talk to the fabricator. You'll want them on board to warrantee the install, and they have lots of experience in this and probably guidelines from the manufacturer. You could contact Silestone and see what they say, since they know the actual strength of their product.
  7. frenchie

    frenchie Jack of all trades

    I agree the flat steel supports is the usual thing, if the non-overhanging part of the counter was on a cabinet.

    But read the OP again - there's no cabinet under this thing. It's on a knee wall, higher than the kitchen counter... only 2 inches overhanging the kitchen side, plus 4-1/2 inches over the wall... 11-1/2 inches hanging in the air. How would you secure the plate steel with that config?
  8. MG

    MG New Member

    Messages:
    160
    Location:
    Illinois - Near St. Louis
    We have a Silestone countertop. From what I recall, you have to have one of their recommended installers put it in or they won't warranty it at all.

    Personally - I'm not all that enamored with it. I keep finding pinholes that need to be filled (part of the manufacturing process), and you have to be careful around the edges of it or it can chip. I have one that needs to be repaired.
  9. Bob NH

    Bob NH In the Trades

    Messages:
    3,317
    Location:
    New Hampshire
    I would have some brackets made as follows.

    Think of a T with the top of the T just shorter than the width of the Silestone, maybe 15", and beveled or tapered on the bottom so there are no sharp corners. If the top of the T is made from a solid piece you can taper it all the way from the stem and have it painted or chrome plated.

    The stem of the T is located so it goes into the cavity of the knee-wall and attaches to a stud of the knee-wall. One T per stud.

    The welded joint between stem and the bar is reinforced as necessary to develop the strength of the tube or bar. The joint is concealed in the knee-wall.

    Install the Ts so the tops are in a level plane.
  10. newowner

    newowner New Member

    Messages:
    32
    Location:
    Central Maryland
    Frenchie-you asked how we are going to detail the knee wall so it will support the side force from the overhang. Well, since the wall will be 80" long we thought it was o.k that the 4" on the left side hung off. :confused:

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  11. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

    Messages:
    2,718
    Location:
    Central Florida
    I've seen several kneewalls in new construction high-end homes, and I've always wondered why they don't collapse. I can't think of any way offhand of supporting an asymmetric countertop load on a conventionally-framed kneewall -- the twisting moment will destroy it.

    I think I'd plan on a supporting leg at the outside end of the countertop; you could make it purty somehow. Run a steel angle back from that leg to the wall, and several similar angles between the long angle and the kneewall -- sort of like a ladder on its side. Rest the Silestone on that ladder assembly and Mighty Joe Young could dance on it.

    Alternatively, build a new kneewall on a steel frame concealed in the finished wall, solidly embedded in the floor structure somehow, robust enough to support the offset load without twisting. I think we're talking serious steel here.
  12. BikerDave

    BikerDave New Member

    Messages:
    2
    Use Metal Plate to support breakfast bar overhang

    I had this same dilemma when I installed my breakfast bar with a granite countertop. I didn't want to use corbels or other supports because I didn't want folks banging their knees and I don't like the look. I like that "free float" look also. So, I actually purchase a custom cut metal plate, screwed it to top of the breakfast bar supporting wall, and then just layed the granite right on top. Make sure that your wall I had to go to a specialty machinist shop to get the metal sheet (roughly 10 gauge), and they laser drilled holes and countersunk the holes so that I could screw flush into the metal. I had screw holes countersunk and offset every 8 inches along the sheet metal. Also make sure that your top 2x4 is securely mounted. If you can add a 2x4 between each stud (directly under the top board, side nailed into the studs). Then, you can screw through the metal sheet securely onto not just the top 2x4, but also the 2x4 directly underneath it, giving you a very sturdy base to lay the granite on. You don't want the weight of the granite to rip the top 2x4 off.

    You can see the whole project at:

    http://www.thegoodrumfamily.com/ayrlee.kitchen

    Look at the pictures under the Saturday section and you can see the metal sheet, and see a small section how the top 2x4 is reenforced with another 2x4 underneath.
  13. PEW

    PEW DIY Senior Member

    Messages:
    487
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