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Anchor for undermount sink installation (3cm granite)

Posted by janeflaherty (My Page) on
Thu, Apr 25, 13 at 12:30

Picture 2 of anchoring to wood which is fastened to granite.

Any thoughts?


Follow-Up Postings:

RE: Anchor for undermount sink installation (3cm granite)

The granite guy I use cuts 'keyhole' type slots at the edges oft he sink cutout that hold the head of a 1/4-20 bolt.

A slot about every 6 to 8 inches or so, but at least as many as you would use to anchor the sink to a wood type substrate.

Regular sink clips are then used with a washer and locking nut (nylon ring type).

Slide the bolt heads in, slide the sink up into position, block it there temporarily, install clips, washers, nuts, tighten nuts.

The only other way i wold ever consider would be wood framing or angle iron supported by the cabinet.

A water filled sink is heavy.

Water is over 8 pounds a gallon, around 64 pounds a cubic foot.

Then add in the sink contents and maybe a GD.

The water usually dominates, then the GD.

RE: Anchor for undermount sink installation (3cm granite)

Our fabricator siliconed the sink to the underside of the countertop and installed shelving brackets mounted to the cabinet walls to support the sink bowl.
Here's how it looks.
Right side.
 photo RightSideBracketMedium.jpg
Left side.
 photo LeftSideBracketMedium.jpg
It's been 2+ years and it's still solid.

RE: Anchor for undermount sink installation (3cm granite)

willtv - is that the normal way to anchor a sink that is almost the width of the cabinet? My new sink will have maybe half an inch clearance on either side of the cab inside, and I've been wondering how it would be anchored.

RE: Anchor for undermount sink installation (3cm granite)

judibean, To my knowledge there is no "normal" way to mount a sink.
I've seen several diffferent schemes for supporting an undermount sink.
The method my fabricator used seems to be quite sturdy.
When I'm scrubbing difficult, burnt on food from my pots & pans, I lean on them pretty hard and in the 2+ years since the installation, I haven't detected any movement.
There is also a device called a sink setter which many folks on this forum have used and been very satisfied with.
I'm attaching a link.

Here is a link that might be useful: Sink Setter

RE: Anchor for undermount sink installation (3cm granite)

Thanks! That's pretty helpful!

RE: Anchor for undermount sink installation (3cm granite)

Don't know if this is right, but it's held for 10 months now (after sink fell after 11 months!) Kind of an after the fact sink setter:
 photo 100_3324_zps6d822758.jpg
 photo 100_3325_zps8b53f08c.jpg

RE: Anchor for undermount sink installation (3cm granite)

I am a fabricator.

there are many ways to mount a sink.

The "T" slot method described in the original post is called "T-31". It was originally designed for hanging slabs on the sides of building and is a very good mounting system. We have NEVER had a sink so mounted come loose.

other methods include framing the sink with wood strips attached to the cabinet. This is done sometimes when the sink is overlarge for the cabinet (happens a lot) and there is no access space for the T-31's.

Visit "Granquartz" or "BraxtonBragg" websites, both distributors of tooling and supplies for fabricators, and you'll see a variety of mounting methods.

IMNSHO (in my not so humble opinion) the T-31 system is best when it can be used.

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