Bubbled up worktop

[MM]

I plan to fit a new stainless steel kitchen sink in the new year. The current sink is an Astracast-type sink (composite) which is 90cm long. The new ss sink will probably be a Franke Ascona ASX 651 1.5 Kitchen Sink:

This sink is 100cm long. The extra length is on the drainer side.

The problem I have is that the laminate has lifted in an area close to the current sink. This video shows the extent:

It's not that the laminate is loose. Just bubbled up. As the video shows, at worst the bubble is approx 5mm high.

The area of this defect, caused by water ingress swelling the chipboard core, is approx 9cm x 15cm.

However, the new sink should cover over this section, because the new sink is approx 10cm longer

But I'd really like to get rid of the bubble, and therefore propose the following:

When the time comes to do the replacement,

1. Remove existing sink.

1. Undermine the defective section by drilling edge-on into the core. Drill enough smallish holes to weaken the material.

2. The laminate should now be amenable to the application of weight or cramps.

1. So what I would do is fill the holes just drilled with wood hardener, then cramp the worktop to compress down the laminate and leave it for a day or two.

2. I would expect this will flatten out the bubble, at least enough so that the new sink will easily fit snugly against the worktop.

Does anyone foresee problems with this approach?

Or has anyone got any better ideas? I don't want to have to replace the entire worktop, which runs around the kitchen on three sides. The remaining worktop is fine. It's just this one area next to the sink.

Thanks!

MM

[Andy Burns]

I'd expect worktops are formed in a press with many tonnes of pressure, you might get some glue in there and stop it getting any worse (varnish the edges round the sink cut-out to stop more water getting in).

But I doubt a clamp will provide enough force to re-flatten the 'bubble'.

[GB]

I'm slightly puzzled whether the newly enlarged hole for the sink won't cut out this section? In fact, I'd be sure to get a sink large enough to do that!

[harry]

It's either that or a new worktop. You need to seal the cut edges of the work surface under the sink to keewater out.p. The chipboard stuff they are made of is definitely non-waterproof.

[The Natural Philosopher]

ten tins over a hwhile worktop is nopt a huge perssure per little section area.

cramps can easily provide that. Yoiu can lift a 2 tonnne car on a bottle jack on an areae on half a square inch, and the same goes for most cast G cramps. They can exertr a tremendous force over a small area.

[MM]

Ah, well, I had thought of that, but I don't know (until I actually pucrhase the sink) whether the drainer section across the 10cm extra length (compared to the current sink) will need any further cut-out in the worktop. If it does, then problem solved.

All I'm doing right now is considering all the ramifications to avoid replacing the worktop at all costs. And since the current sink will be coming out, why not, I thought, take the opportunity to flatten that darned bubble.

By the way, do new sinks always/sometimes come with a paper template?

MM

[MM]

Indeed. It's a right pain. In my previous house I did have to replace the worktop because water got in. But at least that was a simple straight 3m run with no corners.

MM

[MM]

And let's not forget that I intend to weaken the core somewhat underneath where the laminate has bubbled, before applying pressure. It doesn't matter what it looks like at the end, because the longer sink will cover it up. But it does need to be as flat as possible.

MM

[harry]

Sometimes at least.

[Brian Gaff]

The problem is it needs to be made fully dry and also you need to stop ingress of water around the unprotected edges of the chipboard if you can. I guess it depends on how sure you are that no water can get under the new top. I had this issue in a bathroom basin surround and its started to expand again, one supposes due to steam in the edges inside the cupboard under the basin. Really these things should be made out of something less like glued together sawdust! Brian

[The Natural Philosopher]

This is the sort of situation where, if the substrate is actually dry, I would use not car body filler, but liquid polyester resin for better penetration to actually stabilise the thing under the cramp, and then fill up with body filler later to make the underside good.

Polyester resin (sold for use with glass reinforcement) is handy stuff, being syrupy in consistency, setting hard in a few minutes and utterly impervious to water.

Its just the thing to seal a chipboard top's cut edges.

[GB]

Ask Franke about theirs.

[MM]

Good to know. Thanks.

MM

[MM]

Well, separately I'm considering whether to use plumber's putty or a bead of silicon. The internet has dozens of recommendations for both.

Absolutely. If I ever replaced the entire kitchen I'd like a stainless steel work surface with combined/welded sink and upstand, but I expect such a thing would cost thousands. I don't like granite or solid wood.

The problem, I suppose, is that I prepare 98%of my meals from scratch and rarely use ready-made meals from the chiller cabinets. This means I'm always cutting, slicing, dicing, chopping etc, which in turn means I'm constantly washing up, so inevitably a few spots of water land on the work surface surrounding the sink. With the larger (longer) Franke sink I've got my eye on, this wetting risk might be reduced somewhat.

MM

[Huge]

Some of the mineral loaded polymer worktops don't have a wood core and don't need the edges sealing around sinks. They aren't cheap, though.

[F]

I gave the cut edges of our worktop a liberal coating of silicone and then ran a bead of transparent silicone around the edge of the installed sink. It worked well: no water got into the worktop for the 15 years it was installed.

[The Natural Philosopher]

[S Viemeister]

Perhaps not as bad as you think. An acquaintance used these people - this is her comment on them -

"We used RH Morton's in Glasgow, fantastic service. They couldn't have been more helpful.

"They made-to-measure our splashbacks and countertops, to J's exact design including matching the counter top front edge profiles to the one on our Franke SS sinks; and cut-outs for the SS power sockets. J collected the stuff from their factory, brought it to the island in the back of the car and installed it himself, no problem. Everything fitted perfectly. Still as new 15 years later."