As the chart indicated solid surface countertops may only overhang 6 inches without additional support.
Quartz countertop overhang without support.
Because not every bracket is the same certain support brackets may be too weak to hold stone like marble granite or quartz.
Amount of overhang you have is the most important factor to consider in deciding whether you need support brackets.
However the cantilevered portion cannot be more than 1 3 the total width of the countertop.
However once you gather your information and find out from the installation guide for your material you will then be better prepared for selecting countertop support brackets that are designed for your purpose.
That depends on many factors regarding the project material and the thickness of the surface.
3 cm quartz engineered stone can handle a 14 inch countertop overhang without additional support 3 cm granite overhangs should not exceed a 10 inch overhang without additional support bearing in mind the 70 rule.
However you may need to install supports such as corbels or legs.
Countertop overhang will depend on various other measurements such as the countertop itself and cabinetry.
Alternatively a weak bracket may not support the weight of the countertop overhang.
Even leaving your brackets weakly fastened leads to inadequate countertop support.
The allowable overhang with no additional support is no more than 1 3 of the depth of the countertop and not to exceed 15 total.
In conclusion the answer to the question how far can quartz overhang without support is.
That said there are standard dimensions that can help guide you as you plan out your kitchen remodel.
Yes you can extend the overhang on a kitchen island countertop.
According to the marble institute of america you can safely overhang granite that is 1 1 4 thick up to 10 without supports.
Overhangs greater than 15 require the installation of corbels.
Without any additional support solid surface countertop overhangs cannot exceed 6 engineered stone cannot exceed 14 and granite overhangs shouldn t be more than 10 without additional supports.
So we are ok on the first criteria but we exceed the 1 3 criteria by four inches.