Sealant on wood worktops -

[Jaybee111]

I very recently (less than 2 months ago) had a walnut kitchen worktop fitted. I have been taking extra care to mop up spills immediately and oil the surface once a week. However, already, behind the taps some black mould seems to have appeared where the sealant joins to the tile.

I believe that the problem is that the fitter used a sealant which did not adhere properly to the worktop - its been peeling off in certain places. The result has been that water got trapped under the sealant and, because it was under the sealant, the wood never got a chance to dry out. Hence the appearance of the mould.

I have removed the sealant in the affected area and tried to clean it with bleach, which hopefully will work. (Any other recommendations for getting rid of the mould would be much appreciated). However, I am wondering whether I should try to reseal the wood and, if so, what kind of sealant to use that will prevent the problem from reoccurring.

Help really appreciated...

 

[squowse]

silicone may have trouble adhering to the worktop if it is too oily. maybe sand it lightly along the seal line.

 

[David P]

behind the taps some black mould seems to have appeared where the sealant joins to the tile.

I believe that the problem is that the fitter used a sealant which did not adhere properly to the worktop - its been peeling off in certain places. The result has been that water got trapped under the sealant and, because it was under the sealant, the wood never got a chance to dry out. Hence the appearance of the mould.

I have removed the sealant in the affected area and tried to clean it with bleach, which hopefully will work. (Any other recommendations for getting rid of the mould would be much appreciated). However, I am wondering whether I should try to reseal the wood and, if so, what kind of sealant to use that will prevent the problem from reoccurring.

Help really appreciated...

The real problem here is that a couple of incompatible processes have been used together. wood always has a moisture content, it never dries out completely, and this is not normally a problem until someone goes and slaps some impervious silicon onto it. The moisture trapped just below the silicon has found the perfect environment to grow mould.
If you had a completely unsealed wooden worktop, as I have, you would notice that mould only develops in places where the water never dries out fully - I have also got a wooden draining board, which only has four small dots of mould, where the feet of the draining rack sit and trap water.

Using oil is a good thing, it doesn't completely seal the wood, and discourages water to seep too far into the wood. I would suggest, rather than squowse's suggestion of trying to make a better silicone seal, find a more porous filler to grout the tiles up to the wood, clean off the bad silicone entirely and make a minimal seam (even consider a deep 'pointing' type of approach) - that way even if any mould should appear you can zap it with some bleach (neat toilet cleaner works well - but only apply for a minute and wash off well before the walnut feels the effect).

Seriously, I would avoid trying to seal the wood at all, with anything other than oil (danish oil is good) - as an experiment I have tried most things on my ash kitchen tops over the years, even melting beeswax into them with a heat gun, and it seems that anything that adds a film onto the surface ends up looking awful. Luckily I made my tops removable, so that if they get too ropey I can just resurface them. The best thing by far is oil, or next best leave them natural and minimise places where water gets trapped and can't dry out.
You implied it yourself - the wood isn't the problem, its the sealant.

 

[Jaybee111]

Many thanks for the responses. Much appreciated. Will go the no sealant route.