Undermount sinktop - really just glued?

ThisIsWeird

A friend has had a SS undermount sink fitted to her stone worktops for over a year now. It recently became detached, and the fitter is sorting it - and is going to add some form of additional support.

Friend wondering why it came off, and is adamant that no excessive loads were placed on it. From what my friend says, the SS top was simply epoxied into place - is that usual? Ie no brackets or other supports fitted as standard?

Cheers.

DullGreyGuy

Ours is held on by clips that are screwed into the work surface, as it was stone it meant holes had to be drilled and filled with an anchor material

rob7475

Usually, the cabinet that the sink sits in would have a solid top if you are using an undermount sink. This allows you to cut out the shape of the sink into the top of the cabinet so it has something to sit on. If the cabinet didn't have a solid top, something would have to be made to support the sink. I wouldn't want to rely on glue holding a sink full of water to the worktop

vacheron

Epoxy is fine if done right, after all a huge amount of the wing bonding on commercial aircraft uses epoxies or other adhesives. It's only a problem if not done correctly, or using the wrong (or expired) adhesive. 

We also have an undermount SS which is bonded onto a quartz countertop. It has a couple of small clips underneath, but these only appear large enough to hold the sink in position while the adhesive cures.

The main issue with a large and deep sink is when it is filled with water. This could easily apply 40-50Kg (around 100lb) of additional weight. 

ThisIsWeird

Thanks everyone.

I just wondered what the 'norm' was. These units are Ikea, I believe, so are unlikely to have solid tops, but that's a neat idea, Rob.

I can see that drilling into the tops would be a chore, and a bit risky if only thin - I suspect this one is.

Yes, epoxy is powerful stuff, but I wouldn't be comfy with only that holding the sink in place! It would rely on a perfect installation, super-clean under-'top surface, a fresh and perfect epoxy mix, and no movement during the cure.

Scary.

The fitter is going to sort it, and also add under-sink bracing or brackets.

Cheers.

FFHillbilly

the undermount sinks I see are always supported from below, the base units tops are cut and routered so the sink fits in and it put in place or supported by battens before the template is done, the tops are then made and fitted ontop so the sink outer lip is sandwiched inbetween the base unit and the worktop.
old belfast sinks normally have a special base unit and theres a full shelf below to support it.
IMO glueing a sink in with epoxy is rough and I wouldn't want it in my house.