Lesgrandepotato

Fitting an undermount sink to granite

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I’m having a bit of fun fitting the sink. I have the same sink as the previous owner of the granite. You would imagine therefore (or at least i did !) that it would mount straight up. This does not seem to be the case. 

 

Now the sink has been fitted to the worktop previously with silicon that I have cleaned back. There are some holes underneath but these do not contain threads or go all the way round so I’m starting to wonder if they were jig holes for cutting it out. 

 

I have tried fitting the push in threaded studs from the kit (I assume that’s what they are) but they seem to be very very easy to crack the test stone with unless they are drilled over size. 

 

Is it possible it was simply just siliconed in from underneath?

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The guys who fitted my under mounted sink to my quartz worktop used stixall extreme. Hasn't budged in 3 years. 

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Just now, Declan52 said:

The guys who fitted my under mounted sink to my quartz worktop used stixall extreme. Hasn't budged in 3 years. 

 

Presumably glopped on and then just clamped up?

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1 minute ago, Declan52 said:

The guys who fitted my under mounted sink to my quartz worktop used stixall extreme. Hasn't budged in 3 years. 

Second that, used for our sink to quartz

and recommended by others. 

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They used a few bits of timber underneath to hold it in place wedged against the worktop. 

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8 minutes ago, Declan52 said:

They used a few bits of timber underneath to hold it in place wedged against the worktop. 

Ditto

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Our sink is fitted underneath the stone worktop.  The advice I was given was to rout out space for the sink flanges (it was a stainless 1 1/2 sink) in the edges of the underlying cabinets, so the top face of the flanges were dead flush with the upper surface of the cabinet edges at the top.  The sink was left with a bit of wiggle room, so it could be aligned with the cut out in the stone.

 

When fitting the stone, as well as using neutral silicone on all the cabinet upper edges where they were going to contact the stone, clear neutral silicone was also run around the sink flange.  The stone was then lifted into place, with the sink position adjusted very slightly to get it dead centre in the cut out.  The stone overhangs the sink by a few mm, so there is also a thin bead of sealant underneath the overhang.

 

The sink and the stone are only held in place by silicone, there are no mechanical fixings at all.

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There are 2 ways to fit a sink to stone.

 

1. Cradle it in the carcase or on a timber frame slightly rebated to ensure top face is flush with the top end of the units.  The worktop is then lowered  on and siliconed in.

 

2. Fit sink in place with clips. This only really works with worktop thicker than 20mm. Slits are cut in the worktops and pressure clips fitted into place and then silicone the sink in. Very few fabricators like to do this as there is very limited space available in front of and behind the sink to allow this to happen.

 

3. Fit screwed lugs. Again suitable only for 20mm+ worktops. Holes drilled in the worktop and plastic lugs fitted in with resin based adhesive. Clips are then screwed into these lugs that push the sink to the worktop. Again access issues means this is almost never done.

 

I think OP has the 3rd solution in place. The hole wont (cant) have threads so its not going to be an easy job to do. The solution would be to procure a set of clips and set about messing out at impossible angles inside the sink cabinet.

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Hi Peter

 

How're your G clips holding up?

 

I've been struggling to work out how to fix my Franke undermount sinks to the quartz worktops we're about to order and these clips just seem so simple.

 

Anyone else used them?

 

Cheers

 

Rob

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2 minutes ago, Rob99 said:

Hi Peter

 

How're your G clips holding up?

 

I've been struggling to work out how to fix my Franke undermount sinks to the quartz worktops we're about to order and these clips just seem so simple.

 

Anyone else used them?

 

Cheers

 

Rob

They've been in use for over a year now without any problems. Probably fatal saying that though.

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Thanks Peter that's good to hear.

 

I did wonder if I could fit them myself or whether I should ask the worktop supplier if their installation team could do it. The videos make it look really easy and I'm pretty handy with most stuff.

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1 minute ago, Rob99 said:

 

I did wonder if I could fit them myself or whether I should ask the worktop supplier if their installation team could do it. The videos make it look really easy and I'm pretty handy with most stuff.

 

Have to admit we wimped out and got the granite installer to fit the undermounted sink. My hubby did everything else in the kitchen himself but the granite and the sink were the 2 things he got someone else to do.

 

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Our under mount sink was fitted on top of the base unit by me, with rebates cut into the top of the units so its top face was level with the under side of the stone worktop.  The worktop people took templates from that, and when they fitted them they just used clear silicone to both bond the stone down and seal around the sink.  I have to say that they did a neater job than I could have done.

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Lots of how tos on YouTube:

 

 

I searched:

 

"fitting undermount sink to granite worktops"

 

Like the idea of fitting a bit of timber secured through the plug hole.

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1 hour ago, JSHarris said:

Our under mount sink was fitted on top of the base unit by me, with rebates cut into the top of the units so its top face was level with the under side of the stone worktop.  The worktop people took templates from that, and when they fitted them they just used clear silicone to both bond the stone down and seal around the sink.  I have to say that they did a neater job than I could have done.

 

This is exactly what I did to fit a pair of undermount stainless sinks into wooden work surfaces. Just rebated a thin slip and then used clear CT1 to bond them down. 

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15 hours ago, Rob99 said:

Thanks Peter that's good to hear.

 

I did wonder if I could fit them myself or whether I should ask the worktop supplier if their installation team could do it. The videos make it look really easy and I'm pretty handy with most stuff.

The granite worktop supplier/fitter just cut the slots in the underside of the granite and I fitted the sinks. It was straightforward.

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