PU Sealer instead of caulk and silicone?

[rcx132]

The silicone around my sink lasted 3 years.... I've used PU sealer this time. Any reason not to?

The house was redecorated 3 and a half years ago, and the decorators used cault everywhere, along the skirting boards, around the door frames. It's shrunk and cracked and looks terrible. Seeing as PU is strong and over-paintable, would that be a better idea next time? Seeing as it's quite cheap these days, I'm wondering if cost wasn't the reason it wasn't used before.

 

[grim_d]

I'm sure it'd be fine but even the cheapest PU sealant is 4 times the cost of caulk so cost is probably a factor for decorators.

Decent caulk lasts fine and doesn't shrink but it will crack if there's too much movement.

I find Matt emulsion always looks a bit satin over a caulked corner too, I wonder how it would look over PU?

 

[slimjim]

I think it would be more difficult to get a smooth finish,

With caulking, I always end up re doing it after a period of time, once everything settles in,

If you use PU, and it turns out to be stronger than the wood, or wall, then any movement will just break elsewhere, therefore no benefit gain for the extra cost.

 

[Dcal]

Only problem with PU around sinks and the like is it's over-paintable, so will pick up dirt and get grubby a lot easier than silicone.

As an alternative to caulk it will be fine but a lot harder to put on and the clean up could be a pain.
Also it's difficult to put on in thin layers.

 

[mart]

The silicone around my sink lasted 3 years.... I've used PU sealer this time. Any reason not to?
.

If the PU sealer works better for you around the sink, then you have improved something. Try the same thing in the areas where the caulk failed but maybe in slighly obscured places first to see how it performs there.

 

[Olderisbetter]

I use the stuff from Toolstaion called puraflex40 rather than silicone for many uses, It costs way more than cheap caulking but about the same as a decent silicone, I think i have used white grey and black cost is £5.23
https://www.toolstation.com/puraflex-40-high-modulus-pu-sealant-adhesive-300ml/p67949

 

[Shedendman]

Caulk isn't designed to be waterproof as its mostly acrylic which can shrink and crack
Silicone sealant is the one to use for baths sinks etc,which brand is debatable
Yes you can use a PU sealant ideal one is PU18 which isn't that good for painting over
PU40 just as good but takes an age to go off but can take a lick of paint

 

[eLuSiVeMiTe]

Caulk will always shrink especially in deep fills. Usually caulk early and give it another hit at the end of a job.

What kind of sink. Ceramic? I'd stick with a decent brand of silicone. Clean out the old and clean well with upvc cleaner or similar and reseal it. Silicone applicators are cheap and work very well and a squinty bottle of diluted washing up liquid to polish.

 

[Turbo]

If you paint over caulk with water based paint it normally cracks. The solution - paint with an oil paint first - a bit of white undercoat is perfect then put your emulsion on top.