Base cabinets were mentioned once. They would be good bracing! It seems the discussion went towards braces that you buy in a store. To attach base cabinets as bracing one will need angle iron, and a lot of fine tuning work in terms of the cabinet feet and height above the floor. Uh-oh. Sounds impractical now. So, the 90 degree braces at floor level now seem to be the best thing to do. mudworm, on lowes.com I entered two keywords: aluminum tube. I got positive results. Here are some of them. Item #: 215640 Item #: 216100. Go to wherever they have these in the store and you will see steel tube too. Or, web search for steel tube. I just figured that "aluminum tube" would be easier to search for. Buy aluminum tube if there is no steel. Once a metal is made into a tube it is very rigid. In home depot I have also seen steel and aluminum tube. So, tube IS available if you know where to get it. Tube is stronger than thin flat metal. If you add tube on top of the braces you will have both the benefits of what advertguy proposes and the benefits of the 90 degree bracing, and no deleterious secondary impact. advertguy in your latest post "Remove those braces from the bottom" is not clear. Hth

Thank you to all of you for your help and those photos. I think I see the light...but I still have questions. If I want a 12" overhang, 2cm granite, I need to have 6" of support under my overhang and 12" under the rest of my granite. If I want a15" overhang, 2cm granite, I need 9" of support and 18" under the rest of my granite. If I want 12" OH, 3cm granite, then it's 2" support and 4" under the rest and if it's 15" OH, 3cm granite, then it's 5" of support and 10" under the rest. If I did the rolled steel, would it make a big difference if I had a sink cutout on the other side? I plan for a 15" deep cabinet along the backside, so in the situation where I need 18" under the rest of my granite, could I eliminate the 3" under that section, or cheat and just cover the 15" cabinet? And do you just screw this into the cabinets along the top edges? And how often do you add a screw? One every 12"? Do you also add glue? How am I suppose to balance out the 1/4" difference from the front of the island to the back? And once balanced, do I still need a plywood underlay? Who normally supplies the underlay? Is it only for counters who are 2cm thick? Sorry for all the questions. This is my first reno and I'm not reno savvy. The most I've done is paint and build a few ikea shelves. Sum5463, it looks like your steel ends in the middle of the cabinet closest to us. How did you balance out the difference? Again, a big thanks to you and your photos. Jams

First I will show you the layout to show you the shape of the island. Note the end on the right side (no cabinet) will be radiused. This is what our installer approved for support. 3/4 inch plywood glued to 1/2 plywood out to within 3 inches of the edge. A steel support will be in the middle of the radiused end which supports 660 lbs which is way more than the granite weighs. For extra insurance this is what we are doing/did. 1/4 inch plywood (smooth finish) at the bottom, then 3/4 inch plywood on top of it. Note we did this to provide a smooth surface underneath the island and had these materials already on hand. Ok then 2 1/2 inch wide 1/4 inch thick flat steel bars laid about 5 inches apart. 1/4 plywood in between the bars and over the rest of the island. Note no bars over the cabinet. All these glued with locktite glue, lots of clamps and heavy weights were used for several days. We used alot more than what is shown in the pics. Here of some pics of it now. Our case is a little different as on top of all of this we are laying a floor heating pad to heat the granite. That is why we went to 3 inches of the edge. Our installer/granite yard showroom has a similiar island on display that we looked at. In that case the plywood only went to 12" of the edge. We plan to add wood trim under the granite to have a nice edge to cover all this plywood. Our installer said we could also angle the edge back if that makes sense. The only cabinet in at the end by the sink and is 36" wide and 24" deep. Will be building a box behind the cabinet not only for extra support but to run electrical lines in for the heating pad and for electrial outlets that will be in the box. Hope that all makes sense! Any other questions, just post here or email me directly.

I review the plans of everyone working on my house. [...] My general contractor and the granite fabricator/installer will warrant their work, and like everything else going into my house, I want to double check, and I want them to justify their plans if they differ from what I have learned from Professor Google. We don't have their plans though, if that sketch was given to you as their plan for support, then you are in trouble and need to hire another professional. To evaluate their plan we need to know what system they plan to use to limit flex. Make a wall beyond the cabinets, or close in the ends. for additional support. I am not a huge fan of walls that dissect long pieces of granite unless the people building the walls really understand what they are doing. I think the post is a much better idea that accomplishes substantially the same thing as a wall. ----------------------------------- When we talk about supporting granite we are talking about one thing. Limiting the tensile pressures. Granite, just like concrete, has great compressive strength and rotten tensile strength, when granite flexes you get compressive force on the concave side and tensile force on the convex side. Moving from theory to reality in granite we really have to do three things, (1) limit flex, (2) limit movement and (3) avoid isolation. Many inexperienced people will address movement and flex while ignoring isolation and when that happens you get the result that Joseph posted above. If we look at the brackets that are often used for granite islands we can see that their real purpose isn't to stop movement but to avoid creating a fulcrum so that the entire sheet of granite moves together. http://www.countertopbracket.com/countertop-island-support-brackets-hidden-p/ib.htm I guarantee you that something heavy placed on that overhang will cause the countertop to tip slightly in that direction, but the brackets ensure that the movement is carried past the edge of the cabinets so that the entire piece moves rather than creating a fulcrum at the back of the cabinets that isolates the overhang from the cabinets. Too much movement must be avoided because then you get the shock of the cabinets moving which can be bad so walls in long islands may be necessary but when they are you must avoid isolating them. In other words, in Joseph's example above had the brackets been extended and tied into the cabinets in such a way that the entire piece was tied together or tied to the cabinets sufficiently that everything moved together, the break is unlikely to have occurred. Technically the brackets in Joseph's post above did exactly what they were designed to do. They eliminated breakage at the fulcrum...They just created a new fulcrum because their designer didn't understand the problem. From a physics stand point, a post is nothing but a very short wall. You can get substantially the same results from a post that you can from a wall, by adding cost. Essentially the white arrows would be a wall while the red arrows will be a post. So long as the post doesn't flex more than a wall (which it will compress less than a wall), mechanically you can achieve the same thing. However, you create more isolation points, all of the red arrows need to either have very little movement at all, or be tied together in such a way that they move together (note the arrows actually form a circle). Achieving no movement is much harder than tying them together in such a way that the limited movement extends through the area. A 2" tubular frame under the entire granite surface would absolutely be preferred, as that is the best way to carry movement to the entire counter. My original advocacy for plate was in opposition of L brackets rather than a tubular frame, to avoid isolation. I think you can achieve much the same result with a steel plate (a 36" steel plate is roughly equivalent to about 20 brackets) but I am not opposed to a tubular frame, especially if you are going as deep as 2". Anyway, this is just my 2 cents. In the end, to evaluate the solution that your contractor is using we need to know that.