Worktop sealing...again.

[DaveJ123]

When you guys talk about sealing a mason's mitre joint with silicone sealant, do you mean the same stuff that's used to seal the edge of a bath/sink? I'm imagining that stuff as having no real mechanical strength(?) But the joint is supposed to be, in effect, glued as well as bolted, is it not? (I'm assuming you just spread it on, push the joints together and tighten the bolts while the silicone's wet?) Also, Presumably, unless you screw the worktop down immediately, you need to clamp battens or something across the joint to stop the two pieces moving vertically with respect to each other?

Is there a recommended brand of silicone? The cheap stuff I got from Wilkinsons deteriorated pretty quick when I used it around a sink. How about water-proof wood adhesive? Any recommended products?

Shouldn't the routed bolt recesses be sealed too? My joint will be next to a washer/dryer?In fact, isn't there any extra protection needed for the whole underside area of the worktop that's immediately over a dryer?

DaveJ

 

[fitter]

Use a decent quality clear silicon, when you tighten the bolts it will squeeze out the top. Get the bolts fairly tight, then tap the tops level, I use a soft face mallet but a block and hammer will do. Once you are happy that they are level tighten the bolts.

Clean off the silicon from the top, you can screw to units at this point, have a further check for level, you can use the screws for a bit of leveling if required. You do not need silicon on the bolts.

You can get a kind of foil to put under the top to protect it from steam etc,
use contact adhesive and do it before you put the worktops in.

You could use waterproof wood glue instead of silicon, it's much easier to clean off, I've used both but seem to stick(no pun intended) with silicon
which when dry is very strong.

Be careful when taping not to do it too close to your new edge, as it can chip.

 

[breezer]

The cheap stuff

what did you expect

 

[DaveJ123]

Thanks for the run-through, fitter. I still don't understand why the routed recesses for the bolts don't have to be sealed when they're right next to the washer/dryer, though.

what did you expect

I assumed there'd be no practical difference in the formula, and that the more expensive stuff just smelled nicer.

DaveJ

 

[david and julie]

Hi Daveyj hope u r ok. generally speaking the better quality silicon smells worse!

You get what you pay for, is it worth saving a quid or so for poor longevity?(cr*p).

 

[DaveJ123]

Hi Dave. Fine thanks, hope all's well with you, too. I'm still accumulating tools, equipment, and know-how before my assault on: first the floor, then the kitchen units, and finally the plumbing.

So, what you're telling me, then, is that shampoo is no guide at all for silicone sealant! This DIY lark is more complicated than I thought.

DaveJ

 

[breezer]

I'm still accumulating tools, equipment, and know-how before my assault on: first the floor, then the kitchen units, and finally the plumbing.

DaveJ

hope you are joking about the order of things, you should do the plumbing first, that way if you do get a leak you will not damage anything new, and also if you have to remove anything to get to the pipes etc it wont matter how you get to it cos you are going to change it anyway

 

[fitter]

Dave, There is no hard and fast rules as to silicon, if you want to put it in the bolt grooves then do, if it gives you added piece of mind. It will be messy.
My own opinion is that if you are going to stick further protection under the top anyway, more silicon is overkill. I have never had a problem with heat and or steam causing trouble to the joints. I have been told but have never seen, that if an electric kettle is constantly used on the joint that it can cause blowing (laminate comes away from chipboard).

There is a very real difference in the quality of silicon, the cheap stuff takes a long time to cure and seems to stay slightly sticky for days.
My idea of a good silicon is that it is touch dry in about an hour or so and fully cured within 24 hours. In my expeirence the stronger the smell the better. Considering the difference in price is about 50p, I don't think it's worth messing with the cheaper stuff

 

[breezer]

Considering the difference in price is about 50p,

either your cheap stuff costs a lot or the expensive stuff is cheap.

difference down here is about £3/ tube

 

[fitter]

Cheap stuff £2-00, good stuff £2.50, expensive £4.50
I use Vallance general purpose sealant, I do buy dozen at a time so get discount but am sure full price is only £2.75 ish. I have seen cheap stuff for £1.25 but never used it.

Best I ever got was some french stuff at a car boot sale, bought a tube for 45p , it was great, went back for a few weeks to buy 100 tubes but could not find the bloke. Someone told me he had been nicked....hmmm
wounder why

 

[DaveJ123]

hope you are joking about the order of things, you should do the plumbing first, that way if you do get a leak you will not damage anything new, and also if you have to remove anything to get to the pipes etc it wont matter how you get to it cos you are going to change it anyway

I take your point Breezer, but there's not much plumbing (in theory), and a lot more of the other stuff. My aim is to cause as little disruption for my elderly mother as possible. I don't want to cut off the kitchen water right at the beginning and leave it off while I fix the floor joist(s), install the units, worktop, and deal with any unforeseens. In fact, I'm intending to leave the old, bib taps (in the wall above the sink) in place until after I've installed the new sink complete with mixer. I'll then make as much of the pipe work as I can to get from the old tap positions to underneath, and then, hopefully, whip out the old taps and connect up to the new. I'm also considering a cunning plan(?) of supporting the kitchen sink on some wall brackets (two of which would be bolted to the drainer) so I can remove the sink base unit, and repair the floor underneath (wet rot) with less time pressure; it will be obvious to you I've not done these things before - "it's so crazy, it just might work" - as they say in the old films. I am quite worried something will go wrong in the middle and leave me in a mess. But we've paid other people to mess things up before, so I thought I'd do it myself this time!

Thanks again, fitter.

Btw, the silicone I used was more expensive than I'd thought - £3.75 (Wilco). I've just searched B&Q, and their prices were: £5.98 (B&Q) £6.98 (Unibond). The Wilco actually still looks intact in the bathroom. It may have just been greasy in the kitchen - where it's degraded and failed to adhere in places. But Unibond, I think now

Thanks all

DaveJ

 

[fitter]

Nearly £7-00 for a tube of silicon, at that price I'd expect someone to come round and apply it.

 

[david and julie]

Davej... its about time you found a local builders/plumbers/timber etc merchant. Builder Centers/Travis Perkins usually do the lot. They are cheaper, stock better quality gear and will also give you advice too. Don't be put off by not knowing all the trade terms. If you go in the daytime rather than early morning they are quieter and will give you more time.

 

[DaveJ123]

Ok, I'll have to look into that. Thanks.

DaveJ

 

[darren7]

why not just splash out and use colour fill, a sealer that is a good match.

Darren