katya said:
.......Within a year the area round the tap was badly stained, as was the back where it meets the splashback, and the draining board side where the drying rack stands was also developing black mould in places......
Well black mould means that you have a damp problem. Is your kitchen cold? Does your hob extractor vent to the outside or is it a recirculator? How well is your kitchen ventilated? Do you vent out the kitchen after steaming or frying food by opening a window? Is there a condenser dryer in there which isn't working as well as it should? You need to ascertain if there is a possibility of your kitchen retaining moisture in the air which then condenses on cold surfaces overnight - a common cause of black mould in centrally-heated houses fitted with double glazing but where ventilation is inadequate (i.e. lots of them these days). Another query - are there any obvious damp or cold patches on the walls indicating a bridged cavity or rising damp? Also are the walls heavily tiled? If you don't have an extractor it might be that you need one.
Well, the house is very old - 1830s, and the kitchen is in the basement, and yes, it is cold. There is a fireplace we don't use any more, though we used to, and the chimney breast is showing signs of damp. Apart from that and the cooker - a range with an extractor hood - there isn't any heating, though the rest of the house is centrally heated. The extractor fan in the hood ls a recirculator, but we only use it if we're flashfrying. There is a round ventilator inset into one of the window panes, but the window is quite a long way from the cooker and sink. The kitchen is 4x5 sq.ms. The whole basement is dry-lined following severe flooding about 30 years ago after which a sea wall was built, and our garden runs right up to it. At high tide the basement is beow sea level. the whole basement including the kitchen is tiled, and the wall behind the sink and cooker has a tiled splashback with handmade tiles, which are a lot thicker than standard wall tiles. The tumble dryer isn't in the kitchen.
katya said:
The other side, the plain work surface, is OK. I have rubbed, sanded, re-oiled, all to no avail. Lately I've been trying to get people (husband, children, friends) to use it as little as possible in the hope that it can be kept dry and I've rubbed it down lightly with scourers. I have also used bleach to remove the black.
Well it's true that you will need to dry out the work surfaces, but I reckon you may need to dry out the kitchen firstl because black mould will form on top of any surface if moist air is trapped in the kitchen after cooking, washing, etc.
katya said:
The next step is to try somehow to reseal it, and I'm tempted to use yacht varnish, as the oil will obviously take months, and doesn't seem to soak in where it's stained.
Don't! True yacht spar varnish is specifically formulated to remain soft forever - it never fully sets. In fact if you think about it for a yacht mast that's ideal as it means it always remains plastic and resists crazing (cracking), something varnishes are notorious for. Not an ideal material for kitchen worktops, however
I think I was using the term yacht varnish generically. What I have in my cellar is Ronseal floor varnish.
katya said:
Short of taking it off and starting again, which isn't really a goer, what are my options? Katya
I think that's the only goer to be honest. I'd suggest finding out whether or not your kitchen is damp and sorting that out first before even tackling the worktop. Then get the worktop dry - if needs be avoid using it for a week and don't steam or fry in that time.
I meant removing the whole wooden worktop, rather than the sealant. I understood that linseed oil and alternatives like duck oil penetrate the wood so that in fact they can't be removed, but the edges of the patches I've rubbed back under the drying rack look as they would if the surface had been varnished, not oiled.
Thereafter you can tackle the top, but there is no way you'll successfully refinish the top unless you strip back the old coating. The tap needs to be removed for this process and the timber sanded back with something like a belt sander in the direction of the grain - P120 grit should do - and hand sand with a sanding block with the direction of the grain to finish into the corners and where the joints, etc are. The way to tackle the mould staining is bleach, although I'd suggest getting some oxalic acid crystals (try a chemist or apiary suppliers - as beekeepers use it as well) and diluting that to get rid of the mould. Once the stains have been treated, sand again, this time to P150/P180 grit, wipe off with a clean cotton rag wetted with thinners/white spirits (to lift any remaining dust) and then seal the top with a clear acrylic or polyurethane floor lacquer, minimum 3 coats. Try to do the undersides and exposed edges as well - the more cfoats you get on the edges the better. Refinishing this way will not work unless you get rid of the old coating and kill the fungus. It' not all that easy, but anything worth doing well rarely is
Well, as I said above, I didn't think oil was a coating, but that it saturated the wood and thus waterproofed it. What you're saying is that I can sand the whole thing back, kill the mould with bleach, and varnish. So we forget about oil altogether? I should have mentioned also that the draining board has grooves - tricky for sanding down. We can probably resolve the damp issue by lighting the fire systematically.I can't think of any other cure. what do you think?
Scrit
)
